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Current Opinion in Electrochemistry
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  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Online) 2451-9103
Published by Elsevier Homepage  [3155 journals]
  • Enzyme based amperometric biosensors
    • Abstract: Publication date: Available online 5 July 2018Source: Current Opinion in ElectrochemistryAuthor(s): Paolo Bollella, Lo GortonCurrent research on enzyme based electrochemical biosensors deals essentially with the same target analytes as was at focus in the early days of biosensor research, that is those within the clinical/medical, food/agriculture, and environmental fields 1.•, 2., 3., 4., 5., 6., 7., 8., 9.•, 10., 11., 12., 13.. However, there has been substantial progress through the years and progress continues, as resumed in Figure 1A. One of the major differences is that (bio)electrochemists finally seem to start to understand what kind of molecules they deal with, that is with biological molecules and vice versa, biochemists, (micro)biologists start to become interested in (bio)electrochemistry. This is clearly shown for example in the recent very intense research on biofuel cells 14., 15., 16., 17.•, 18., 19., 20., 21., 22., 23., 24., 25., 26. and lately also on biosupercapacitors [27] that has absolutely had a great influence on current research on enzyme based biosensors and bioelectrochemistry as a whole.Graphical abstractImage, graphical abstract
       
  • Editorial Overview: Tuning chemistry for better electrocatalysis
    • Abstract: Publication date: Available online 4 July 2018Source: Current Opinion in ElectrochemistryAuthor(s):
       
  • Editorial Overview: Surface electrochemistry
    • Abstract: Publication date: Available online 3 July 2018Source: Current Opinion in ElectrochemistryAuthor(s):
       
  • Editorial Overview: Materials and characterization tools for
           electrochemical energy storage in batteries and electrochemical capacitors
           
    • Abstract: Publication date: Available online 3 July 2018Source: Current Opinion in ElectrochemistryAuthor(s):
       
  • ELECTROCHEMICAL DETECTION AND REMOVAL OF PHARMACEUTICALS IN WASTE WATERS
    • Abstract: Publication date: Available online 3 July 2018Source: Current Opinion in ElectrochemistryAuthor(s): Bogdan Feier, Anca Florea, Cecilia Cristea, Robert Sandulescu The main classes of pharmaceuticals found in environmental samples, wastewaters included, contain various compounds such as antibiotics, antipyretics, analgesics, anti-inflammatories, antimicrobials and hormones. These compounds and their bioactive metabolites are continuously introduced into the aquatic systems at ng L−1 or pg L−1 levels by several routes including emission from production sites, direct disposal of drugs in households and hospitals, excretion after drug administration to humans and animals and water treatments in fish farms. Due to their toxicity and accumulation into living organism, their presence constitutes a serious environmental problem even at trace concentrations and, unfortunately, they are resistant to biological degradation processes, escaping almost intact from conventional wastewater treatments. Various detection methods using unmodified and modified electrodes with enzymes, antibodies and aptamers are presented, while the main part of this review is focusing on the removal of drugs from wastewaters by electrochemical methods. The main challenges as well as future trends regarding the electrochemical detection and removal methods are also pointed out.Graphical abstractImage, graphical abstract
       
  • A perspective on non-enzymatic electrochemical nanosensors for direct
           detection of pesticides
    • Abstract: Publication date: Available online 3 July 2018Source: Current Opinion in ElectrochemistryAuthor(s): Amina Rhouati, Marjan Majdinasab, Akhtar HayatThis paper provides an insight on the recent advances towards development of nanomaterials based non-enzymatic electrochemical sensors for the detection of pesticides. The non-enzymatic nanosensors have been emerged as an effective tool to replace the conventional analytical methodologies towards detection of pesticides. The nanosensors offer advantages such as low cost per assay, ease in manipulation, large scale production and stability over an extended period of time. The integration of naomaterials including carbon nanotubes, metal oxide nanoparticles and quantum dots has greatly enhanced the performance of pesticides electrochemical sensors. With the advent of nanotechnology, advancement has been made towards synthesis of analyte specific nanomaterials for subsequent integration in the construct of highly specific, selective and cost effective electrochemical sensors, to replace the need of bioreceptor elements. Keeping in view the importance of this novel construct, the present review is focused to provide a precise description of recent progress in the field of non-enzymatic electrochemical nanosensors, with a particular focus for the analysis of pesticides.Graphical Image, graphical abstract
       
  • Editorial Overview: Driving innovation into multiple dimensions
    • Abstract: Publication date: Available online 30 June 2018Source: Current Opinion in ElectrochemistryAuthor(s):
       
  • Water oxidation: From mechanisms to limitations
    • Abstract: Publication date: Available online 30 June 2018Source: Current Opinion in ElectrochemistryAuthor(s): Michael Busch Water oxidation is a central reaction for energy conversion and storage. On the basis of the detailed analysis of different reaction mechanisms the limitations associated with the O2 evolution reaction is analysed. We find that overpotentials lower than the 0.4 eV, which have been observed for a mono-nuclear mechanism, are possible if the problematic *-OOH intermediate is avoided. This is the case for the bi-nuclear and bi-functional reaction paths. 3-dimensional volcano plots are constructed and used to explore the performance of these reaction mechanisms. Our results suggest, that in contrast to previous analysis of the mono-nuclear mechanism, the true top of the water oxidation volcano is placed at slightly lower *=O binding energies of only 2.46 eV if combined with a suitable co-catalyst. On the basis of this new analysis, design criteria for improved catalysts are developed.Graphical Image, graphical abstract
       
  • Beyond the hype surrounding biofuel cells: What's the future of enzymatic
           fuel cells'
    • Abstract: Publication date: Available online 28 June 2018Source: Current Opinion in ElectrochemistryAuthor(s): Serge Cosnier, Andrew J. Gross, Fabien Giroud, Michael Holzinger After a short comparison of biofuel cells based on enzymes and microorganisms, several important developments and applications of enzymatic fuel cells (EFCs) are discussed. This discussion emphasizes how to evaluate the performance of EFCs, and highlights the influence of temperature and how it must be carefully considered for practical use of EFCs as power sources. Some of the latest and most important innovations in EFC design using buckypapers and redox nanoparticles are briefly reviewed.
       
  • Micro- and nano-robots based sensing and biosensing
    • Abstract: Publication date: Available online 28 June 2018Source: Current Opinion in ElectrochemistryAuthor(s): Lei Kong, Jianguo Guan, Martin PumeraSynthetic micro- and nano-robots have attracted considerable attentions for their potential applications in environment, biomedicine and microengineering. In this review, we summarize the recent works on micro/nanorobots based sensing and biosensing according to different mechanisms: motion based sensing, electrochemical sensing with micro/nanorobots and fluorescent, electrochemiluminescent, colorimetric sensing with micro/nanorobots. Micro/nanorobots offer a convenient and active detection for nucleic acid, protein, glucose, heavy metal ions, and so on. in solution and surrounding atmosphere. Furthermore, the detection sensitivity and efficiency has been significantly improved due to the stirring in solution by the motion of micro/nanorobots.
       
  • Interfacial supramolecular electrochemistry
    • Abstract: Publication date: Available online 27 June 2018Source: Current Opinion in ElectrochemistryAuthor(s): Kang Cui, Iris Dorner, Stijn F.L. MertensSupramolecular chemistry at solid–liquid interfaces is guided by the interactions between the molecular building blocks, the solid substrate and the liquid phase. At an electrochemical interface (i.e., at the interface between an electronic and ionic conductor), the substrate potential allows modulating many of these interactions, resulting in a high level of control over the supramolecular structures that are formed and their reactivity. In this paper, we review key principles and recent work in this area, and discuss how a standard scanning tunneling microscope setup allows to scale down interfacial supramolecular electrochemistry to the few-molecule level.
       
  • Long-term implantable glucose biosensors
    • Abstract: Publication date: Available online 19 June 2018Source: Current Opinion in ElectrochemistryAuthor(s): Tim Bobrowski, Wolfgang SchuhmannSummaryLong-term implantable glucose sensors with a demonstrated lifetime of at least two weeks play a key role in continuous glucose monitoring (CGM) and the development of closed-loop artificial pancreas systems for the emerging number of diabetes patients. This short review summarises the current state of the art of CGM systems and points out specific limitations of amperometric glucose biosensors regarding their inherent sensor long-term and signal stability that are mainly caused by the inevitable foreign body response after sensor implantation.
       
  • Editorial overview: A glimpse into the multicolored facets of organic and
           molecular electrochemistry
    • Abstract: Publication date: Available online 19 June 2018Source: Current Opinion in ElectrochemistryAuthor(s):
       
  • Recent advances in bimetallic electrocatalysts for oxygen reduction:
           design principles, structure-function relations and active phase
           elucidation
    • Abstract: Publication date: Available online 18 June 2018Source: Current Opinion in ElectrochemistryAuthor(s): María Escudero-Escribano, Kim D. Jensen, Anders W. JensenThe electrocatalytic oxygen reduction reaction (ORR) is of fundamental importance for sustainable energy conversion. Model studies are essential to elucidate the design principles as well as the structure-activity-stability relations. Knowledge from extended surfaces combined with fine control of the nanoscale structure has enabled the development of highly efficient nanoparticulate catalysts. This review discusses recent advances in bimetallic electrocatalysts for enhanced ORR, from model surfaces to nanoparticles. A special focus has been placed on novel strategies involving morphology-controlled Pt-based nanomaterials with enhanced mass activity and high electrochemically active surface area. We conclude by highlighting the importance of in situ characterisation methods in order to both elucidate the active phase and understand the catalyst degradation mechanisms.Graphical abstractImage, graphical abstract
       
  • Bio(inspired) strategies for the electro-sensing of β-lactam
           antibiotics
    • Abstract: Publication date: Available online 14 June 2018Source: Current Opinion in ElectrochemistryAuthor(s): F. Bottari, R. Blust, K. De WaelSummaryThe dire previsions of the WHO on the so-called “post-antibiotic era” and the continuous and global rise of anti-microbial resistance, spurs our research community to find better ways to fight these threats. In light of this severe threat to human health many attempts have been made to develop efficient methods to detect antibiotic residues in different streams. The use of electrochemistry seems an inviting approach for on-site and fast monitoring. In this critical review, recent developments in the field of (bio) electro-sensing of β-lactam antibiotics will be presented, with a focus on aptamers and molecularly imprinted polymers, the two main promises of a new generation of biosensors, yet to be fulfilled.
       
  • Calendar aging of commercial Li-ion cells of different chemistries –
           A review
    • Abstract: Publication date: Available online 12 June 2018Source: Current Opinion in ElectrochemistryAuthor(s): Matthieu Dubarry, Nan Qin, Paul BrookerSummaryIn the past twenty years, intensive experimental and modeling efforts have been carried out to access and predict the life expectancy of lithium-ion (Li-ion) batteries under calendar aging conditions. Aging studies are time intensive and usually only focus on one or two chemistries and a few aging conditions. They are therefore not providing a complete understanding of the entire range of temperatures and state of charges. This review is constructed from a comprehensive survey on the Li-ion calendar aging research from the past twenty years. It is the first effort at this scale that provides quantitative and comparative analyses on the aging behaviors of commercially available Li-ion batteries with different cathode and anode chemistries. The results presented in this review can be used to guide future aging studies to fill current knowledge gaps, and can also be used to make an informed selection on Li-ion chemistries for intended applications.
       
  • Recent developments in electrocatalyst design thrifting noble metals in
           fuel cells
    • Abstract: Publication date: Available online 6 June 2018Source: Current Opinion in ElectrochemistryAuthor(s): Giorgio Ercolano, Sara Cavaliere, Jacques Rozière, Deborah J. JonesSummaryProton exchange membrane fuel cells are uniquely placed as the key technology for the successful conversion of hydrogen-containing fuels to electricity and heat. Critically, they currently use platinum group metal (PGM) catalysts to meet performance targets in amounts too high for large scale market introduction cost targets. Here, the status, concepts and challenges of recent developments in engineered catalysts aimed at reducing the total PGM content in fuel cells are reviewed and the latest advances in the catalyst layer architecture design are discussed.
       
  • Recent advances of immunosensors for detecting food allergens
    • Abstract: Publication date: Available online 4 June 2018Source: Current Opinion in ElectrochemistryAuthor(s): Oana Hosu, Giulia Selvolini, Giovanna MarrazzaSensitive detection of allergens in a large variety of food samples has become increasingly important considering the emergence of functional foods and new food manufacturing technologies. Safety and quality are key issues of today's food industry. In this review, we highlight the success achieved in the design of electrochemical immunosensors towards detection of protein allergens. Different methodologies employed for immobilization of bioreceptors on transducer surface and strategies for signal amplification will be discussed.
       
  • Gold nanoparticles in bioelectrocatalysis – The role of nanoparticle
           size
    • Abstract: Publication date: Available online 1 June 2018Source: Current Opinion in ElectrochemistryAuthor(s): Michal Kizling, Maciej Dzwonek, Agnieszka Wieckowska, Renata BilewiczIn recent decades, considerable attention has been paid to the application of gold nanostructures and nanoparticles in various fields of chemistry. Gold nanoparticles (AuNPs) are also employed to improve the performance of enzymatic electrodes in fuel cells and biosensor applications. This paper reviews the recent reports discussing the effect of AuNPs on the kinetics, and thermodynamics of bioelectrocatalytic reactions. The focus of this review is on the size of AuNPs and on the behavior of smallest gold nanoparticles – clusters, with diameters ranging from 2 nm to subnanometer size, since they are shown to influence the enzymatic reactions at electrodes – improving the performance or in some cases even changing the mechanism of the bioelectrocatalytic process.
       
  • Electrode-supported biomimetic membranes: An electrochemical and surface
           science approach for characterizing biological cell membranes
    • Abstract: Publication date: Available online 1 June 2018Source: Current Opinion in ElectrochemistryAuthor(s): ZhangFei Su, J. Jay Leitch, Jacek LipkowskiSummaryPlanar solid-supported lipid bilayers have been developed as simplified biological membranes to model the physical properties of cell membrane processes. Lipid bilayer membranes supported at conductive metal substrates provide a unique opportunity to investigate the effect of the static electric field on the membrane structure and function. The insights gained from this research can be used to develop novel biosensors and biomedical devices. This review summarizes the recent developments in metal-supported biomimetic membrane systems. It provides an overview of the various models, such as metal-supported monolayers and bilayers, hybrid bilayers, tethered bilayers, and floating bilayers, used to study membrane processes at electrode surfaces, such as metal-supported monolayers and bilayers, hybrid, tethered, and floating bilayers. The paper discusses the recent advancements in these biomimetic models and describes the fundamental knowledge about membrane processes that has been extracted from these different platforms. The potential for the design and improvement of biomedical devices using metal-supported bilayers is also discussed. Metal-supported bilayers allow for the application of a plethora of spectroscopic and surface imaging techniques to obtain information about the voltage-dependent properties of biomolecules at the molecular level. The underlying methodology of these analytical techniques and the structural, chemical and kinetic information extracted are reviewed.
       
  • Concurrent measurements of neurochemical and electrophysiological activity
           with microelectrode arrays: New perspectives for constant potential
           amperometry
    • Abstract: Publication date: Available online 29 May 2018Source: Current Opinion in ElectrochemistryAuthor(s): Ana Ledo, Cátia F. Lourenço, João Laranjinha, Greg A. Gerhardt, Rui M. BarbosaOur current understanding of neurotransmission and neuromodulation stands to gain from concurrent electrochemical and electrophysiological measurements, which have been attempted since the introduction of in vivo electrochemical techniques. Dual in vivo recordings have evolved from parallel approaches using two distinct microelectrodes towards serial strategies encompassing “time-sharing” between two independent recording systems while using a single microelectrode. More recently, fast sampling amperometry has been demonstrated to allow concurrent measurement of rapid neurochemical and electrophysiological events using a single sensor and recording system. This is supported by the fact that the high-frequency component of an amperometric recording (>1 Hz) resembles the local field potential while the low frequency component (
       
  • Building switchable peptide-architectures on gold/composite surfaces: New
           perspectives in electrochemical bioassays
    • Abstract: Publication date: Available online 26 May 2018Source: Current Opinion in ElectrochemistryAuthor(s): Mihaela Puiu, Camelia BalaPeptide elements have emerged as building blocks for bio-inspired nanohybrids due to their stability and ability to fold in highly organized supramolecular aggregates. Nanomaterials decorated with peptide motifs are suitable for interfacing the electrode surface because they are able to combine the high-specificity of biomolecular interactions with the excellent conducting properties of metallic or carbon nanostructures. Herein, we present the latest achievements in electrochemical peptide-based bioassays, overviewing their multiple functionalities from ligand sensing, receptor detection to signal amplification.Graphical abstractImage, graphical abstract
       
  • Deep eutectic solvents and applications in electrochemical sensing
    • Abstract: Publication date: Available online 24 May 2018Source: Current Opinion in ElectrochemistryAuthor(s): Christopher M.A. BrettSummaryThis review focusses on deep eutectic solvents (DES) and their applications in the construction of electrochemical sensing platforms. The preparation and properties of DES are first described, with a brief survey of their applications, focusing on recent advances concerning materials and coatings prepared in DES as solvent. Their importance in the preparation of electrochemical sensors is then addressed in more detail, particularly regarding electroactive conjugated polymer and redox polymer modified electrodes. Future perspectives in the electrochemical sensing and biosensing fields are discussed.
       
  • Wearable electrochemical alcohol biosensors
    • Abstract: Publication date: Available online 23 May 2018Source: Current Opinion in ElectrochemistryAuthor(s): Alan S. Campbell, Jayoung Kim, Joseph WangSummaryThe rapid development of wearable sensing platforms in recent years has led to an array of viable monitoring applications for various target analytes. As a significant biomarker with high impact in diverse areas, the reliable on-body detection and continuous monitoring of alcohol has become a focus of many such systems. Currently, several commercial sensing platforms are available that are capable of transdermal monitoring of alcohol consumption using insensible sweat. Drawbacks of existing alcohol sensing platforms that apply this sensing strategy have led to efforts in developing wearable biosensors capable of real-time alcohol detection in sampled biofluids such as sensible sweat and skin interstitial fluid. This review discusses the current trends in wearable electrochemical alcohol biosensing and highlights recent advances in such systems toward continuous, real-time monitoring of alcohol consumption. Our perspective on this important field is given with an outlook on the future of wearable electrochemical alcohol biosensors.
       
  • New insights on hydrogen evolution at Au single crystal electrodes
    • Abstract: Publication date: Available online 21 May 2018Source: Current Opinion in ElectrochemistryAuthor(s): Ludwig A. Kibler, Johannes M. Hermann, Areeg Abdelrahman, Ahmed A. El-Aziz, Timo JacobSummaryThe understanding of fundamental relationships between the structure of an electrode and its activity for a given reaction is crucial for catalyst development in electrocatalysis. The hydrogen evolution reaction (HER) on Au single crystal electrodes belongs to the class of structure-sensitive processes. HER can be used to study dynamic processes of the electrode surface. It is shown that kinetics of surface reconstruction is significantly dependent on the electrode potential. The role of Au in binary electrocatalysts for HER is discussed.Graphical abstractImage, graphical abstract
       
  • Novel graphene materials for the oxygen reduction reaction
    • Abstract: Publication date: Available online 19 May 2018Source: Current Opinion in ElectrochemistryAuthor(s): Luis Miguel Rivera, Gonzalo García, Elena PastorSummaryHerein, the general concepts of low temperature fuel cells (LT-FCs) are discussed, with special attention to the oxygen reduction reaction (ORR) on novel graphene materials. With the aim to solve the principal catalytic and economic problems at the cathode of LT-FCs, a fundamental understanding of the principal parameters that modify the ORR activity as well as the new advances in graphene-based catalysts are reviewed and discussed. Thus, the present manuscript may help to improve the fabrication of novel cathodes in order to decrease the cost and to enhance the performance of LT-FCs.Graphical Image, graphical abstract
       
  • Self-powered bioelectrochemical devices
    • Abstract: Publication date: Available online 19 May 2018Source: Current Opinion in ElectrochemistryAuthor(s): Felipe Conzuelo, Adrian Ruff, Wolfgang SchuhmannSummaryAutonomous bioelectrochemical devices have been described since the beginning of the 21st century. The properties and broad potential applications of such devices encouraged the development of a plethora of examples. Self-powered biodevices have been mainly used for sensing applications with different strategies reported for the detection of various important analytes. Moreover, these devices had also inspired the design and fabrication of logic- and biocomputing-based systems with further applications in logic-activated drug release for the development of sense-act-treat systems. In addition, their use as self-sustained systems for energy supply has been recently reported. This review summarizes the development and progress of self-powered biodevices with particular attention to latest advances and novel applications.
       
  • Recent trends on the application of PGM-free catalysts at the cathode of
           anion exchange membrane fuel cells
    • Abstract: Publication date: Available online 19 May 2018Source: Current Opinion in ElectrochemistryAuthor(s): Luigi Osmieri, Lorenzo Pezzolato, Stefania SpecchiaAnion exchange membrane fuel cells (AEMFCs) are becoming more and more attractive due to their alkaline environment, being less aggressive and favorable to the use of low-cost materials. Furthermore, the alkaline medium displays enhanced alcohol oxidation reaction kinetics, which favors the use of fuels different from hydrogen, ranging from alcohols to polyols, and enhanced oxygen reduction reaction (ORR) kinetics. This allows the use of non-noble transition metals to synthesize cathodic catalysts, avoiding the costly platinum-group metals (PGM). In particular, the most active catalysts developed so far are mostly synthesized by sacrificial support method, which allows the fine tuning of the morphology, favoring oxygen transport, water removal, density of Fe–Nx active sites, and thus an enhanced electrochemical ORR activity. This mini-review analyzes the best AEMFCs cell performance achieved so far in recent years when PGM-free catalysts based on Me–N–C (Me = Fe, Co) are used for ORR at the cathode side, for AEMFCs fed with hydrogen, methanol, and ethanol.Graphical abstractImage, graphical abstract
       
  • Elucidation of role of graphene in catalytic designs for electroreduction
           of oxygen
    • Abstract: Publication date: Available online 19 May 2018Source: Current Opinion in ElectrochemistryAuthor(s): Pawel J. Kulesza, Jerzy K. Zak, Iwona A. Rutkowska, Beata Dembinska, Sylwia Zoladek, Krzysztof Miecznikowski, Enrico Negro, Vito Di Noto, Piotr ZelenayGraphene is, in principle, a promising material for consideration as component (support, active site) of electrocatalytic materials, particularly with respect to the reduction of oxygen, an electrode reaction of importance to low-temperature fuel cell technology. Different concepts of utilization, including nanostructuring, doping, admixing, preconditioning, modification or functionalization of various graphene-based systems for catalytic electroreduction of oxygen are elucidated, as well as important strategies to enhance the systems’ overall activity and stability are discussed.
       
  • Photoelectrochemical bioanalysis of protein biomarkers
    • Abstract: Publication date: Available online 18 May 2018Source: Current Opinion in ElectrochemistryAuthor(s): Yuan-Cheng Zhu, Ling Zhang, Nan Zhang, Wei-Wei Zhao, Yan-Yu Liang, Jing-Juan Xu, Hong-Yuan ChenPhotoelectrochemical (PEC) bioanalysis represents a unique and dynamically developing methodology that offers an elegant route for sensitive biomolecular detection. Protein biomarkers, generally refers to biomolecules whose presence or level of expression are indicative of the occurrence or severity of some diseases. With the development of PEC bioanalytical technique and ever-increasing demands for sensitive disease diagnosis, there is an increasing impetus for innovative PEC bioanalysis towards various protein biomarkers, especially those of cancer and heart diseases. Using illustrative examples, this brief review will highlight the current advances in this topic, and the future prospects are also discussed.
       
  • Fuel cell-based breath-alcohol sensors: Innovation-hungry old
           electrochemistry
    • Abstract: Publication date: Available online 17 May 2018Source: Current Opinion in ElectrochemistryAuthor(s): Kenneth I. Ozoemena, Suhail Musa, Refiloe Modise, Adewale K. Ipadeola, Lesego Gaolatlhe, Siwaphiwe Peteni, Guy KabongoFuel cell-based breath-alcohol sensor (FCBrAS) remains the most widespread and reliable electrochemical device, for the detection of alcohol due to its inherent advantages such as portability, rapid detection, acceptable accuracy, sensitivity and selectivity. However, despite the advances in nanotechnology, FCBrAS still suffers from several technical challenges including the use of extremely high platinum loadings. In this short review, we opine that this old electrochemistry requires urgent innovative research interventions to be able to serve its purpose in the years ahead.
       
  • Redox active electrolytes in carbon/carbon electrochemical capacitors
    • Abstract: Publication date: Available online 17 May 2018Source: Current Opinion in ElectrochemistryAuthor(s): Barbara Gorska, Elzbieta Frackowiak, Francois BeguinSummaryThe application of redox-active electrolytes to realize carbon/carbon electrochemical capacitors has created a great opportunity to enhance the mediocre energy of these devices. Taking advantage of the faradic current from the redox transformation of electrolyte species, which generates a large capacity at one electrode, the resulting hybrid cells can store twice more energy than typical electrical double-layer capacitors based on the same carbon electrode material. However, among a relatively large number of tested redox active electrolytes, only few are acknowledged to provide ideally performing hybrid capacitors. This review critically discusses the literature data and provides clues for realizing optimized systems.Graphical abstractImage, graphical abstract
       
  • Polycationic oxides as potential electrode materials for aqueous-based
           electrochemical capacitors
    • Abstract: Publication date: Available online 16 May 2018Source: Current Opinion in ElectrochemistryAuthor(s): Olivier Crosnier, Nicolas Goubard-Bretesché, Gaëtan Buvat, Laurence Athouël, Camille Douard, Pierre Lannelongue, Frédéric Favier, Thierry BrousseSummarySince the early use of RuO2-based electrodes in electrochemical capacitors, so called supercapacitors, metal oxides have always attracted much attention as pseudocapacitive electrode materials for such energy storage devices. Although the literature is well documented about electrode materials based on single metal oxides, polycationic oxides have also drawn some attention upon the last five years. It is however still quite difficult to build a pertinent strategy to design polycationic architectures that can provide at the same time pseudocapacitive behavior, high capacitance and long term cycling efficiency. This review aims at providing more insight into these polycationic oxide materials as potential electrode materials for supercapacitors.Graphical abstractImage, graphical abstract
       
  • Recent advances in spectroscopic investigations on ionic liquid/electrode
           interfaces
    • Abstract: Publication date: Available online 14 May 2018Source: Current Opinion in ElectrochemistryAuthor(s): Kenta Motobayashi, Masatoshi OsawaSummaryPotential applications of room temperature ionic liquids (RTILs) for electrochemical energy devices motivate a better fundamental understanding of electrochemical interfaces of RTILs. Potential-dependent structural changes of RTILs/electrode interfaces and elementary processes of electrode kinetics must be elucidated. Interface-sensitive spectroscopic techniques, powerful probes for analyzing structures and dynamics of interfaces, have revealed hysteretic adsorption/desorption of ions on electrodes, interplay between the interfacial structures and reactions, and dynamics of intermediate species. Here, we briefly review selected publications reported over the past 3 years related to molecular-scale investigations on electrochemical interfaces of RTILs with the use of spectroscopic techniques.
       
  • Future trends in the market for electrochemical biosensing
    • Abstract: Publication date: Available online 11 May 2018Source: Current Opinion in ElectrochemistryAuthor(s): Marta Maria Pereira da Silva Neves, María Begoña González-García, David Hernández-Santos, Pablo Fanjul-BoladoSummaryIn the past years, research into electrochemical sensors and biosensors has been continuously growing and has especially focused on new materials and strategies to improve miniaturization and portability as an answer to new analytical paradigms. Moreover, important breakthrough achievements in terms of wearable and wireless technology with friendly operating systems and applications are also being accomplished, improving tremendously the user's experience. In this review, we summarize the current outline of electrochemical biosensors market and discuss some of the most recent advances, as well as the remaining challenges and future prospects, for electrochemical biosensing development that could make an impact on the future global market.Graphical abstractSchematic representation of the path that electrochemical biosensing is following in terms of future market trends.Image, graphical abstract
       
  • Advances in signal amplification strategies for electrochemical biosensing
    • Abstract: Publication date: Available online 9 May 2018Source: Current Opinion in ElectrochemistryAuthor(s): Yujie Liu, Yixin Liu, Liang Qiao, Yun Liu, Baohong LiuSummarySignal amplified electrochemical (EC) biosensing has broad significance and practical values in the study of clinical medicine and genetic project. Using a variety of signal amplification strategies based on functional nanomaterials, enzyme catalysis, biological reactions, etc., one could effectively enhance biosensing response and reduce noise signals to detect trace number of analytes. To date, signal amplified EC biosensing has been widely used in the study of life science, biomedical research, food and environmental analysis, chemical analysis, etc. This review focuses on the advances during the last decade in the development and application of signal amplified EC , photoelectrochemical and electrochemiluminescence biosensing, using functional nanomaterials, enzyme catalysis and biological reactions. Perspectives of signal amplification strategies for EC biosensing are also addressed.Graphical abstractImage, graphical abstract
       
  • Fourier transformed alternating current voltammetry in electromaterials
           research: Direct visualisation of important underlying electron transfer
           processes
    • Abstract: Publication date: Available online 8 May 2018Source: Current Opinion in ElectrochemistryAuthor(s): Ying Zhang, Alexandr N. Simonov, Jie Zhang, Alan M. BondRecent advances in materials science have significantly broadened the range of electrodes available for use in dynamic forms of electrochemistry. In the modern era of dc voltammetry when the kinetic-based model of electron transfer with coupled chemical reactions was introduced, initial emphasis in theory-experiment comparison was placed on use of the ideal homogenous liquid mercury electrode with significant attention also given to polycrystalline and faceted metal electrodes. Nowadays, there are a plethora of carbon-based electrodes such as glassy carbon, edge and basal plane graphite, boron doped diamond, graphene and carbon nanotubes that may be extremely heterogeneous. These are supplemented by chemical modifications designed for example to improve the efficiency of electrocatalysis. In this review, it is shown that analysis of the higher harmonics available in large amplitude Fourier transformed alternating current voltammetry (FTacV) allows key processes to be detected, that are masked under commonly used dc voltammetric conditions. In particular it is shown how underlying fast electron processes that facilitate carbon dioxide reduction at tin electrodes and oxygen evolution at cobalt modified carbon-based electrodes can be directly detected and analysed for the first time. FTacV also experimentally reveals that structural defects or ad atoms can give rise to well-defined higher order ac harmonics suggesting that a fast electron transfer process is associated with the active sites during electrocatalytic oxidation or reduction. Importantly, electron transfer processes often can be evaluated by FTacV in the presence and absence of the electrocatalysts, unlike dc voltammetric methods. The ability to analyse third and higher order ac harmonics that are essentially devoid of background charging current and which allow the electron transfer and catalytic steps to be resolved presents new opportunities for fundamental advances in understanding complex electrochemical reaction mechanisms taking place at heterogeneous electrodes. Related advantages in studying electron transfer of surface confined metallo-enzymes or proteins in the presence and absence of their catalytically oxidised or reduced biologically relevant substrate partners are also surveyed. Finally, prospects for providing quantitative accounts of complex reactions at highly heterogeneous electrodes by FTacV are considered.
       
  • Recent advances in electrochemical analysis of biomacromolecules.
           Catalytic hydrogen evolution and modification of glycoproteins and glycans
           by Os(VI) complexes
    • Abstract: Publication date: Available online 7 May 2018Source: Current Opinion in ElectrochemistryAuthor(s): Emil Paleček, Hana ČernockáGraphical abstractImage, graphical abstract
       
  • Electrochemical detection of nitric oxide and S-nitrosothiols in
           biological systems: Past, present & future
    • Abstract: Publication date: Available online 4 May 2018Source: Current Opinion in ElectrochemistryAuthor(s): Fethi Bedioui, Abdulghani Ismail, Sophie GriveauSummaryElectrochemical detection of nitric oxide (NO) using different electrode materials and strategies exploded after the discovery of NO as important biological messenger. S-nitrosothiols (RSNOs), which result from interaction of NO with peptides and proteins, were shown to be important pools of NO that interfere in different physiological and pathological conditions. This led to the development of several decomposition methods to detect RSNOs electrochemically. This mini-review summarizes the beginning and the current investigations in electrochemical methods to detect NO and RSNOs. Indeed, it describes the latest trends using microfluidic technologies coupled to electrochemistry and discuss the future of NO and RSNOs detection.
       
  • Current trends and challenges in bioelectrochemistry for non-invasive and
           early diagnosis
    • Abstract: Publication date: Available online 4 May 2018Source: Current Opinion in ElectrochemistryAuthor(s): Susana Campuzano, Paloma Yáñez-Sedeño, José Manuel PingarrónThis short article reviews critically the latest advances, current trends, potentiality and existing challenges in electrochemical sensing of circulating biomarkers for early and minimally invasive diagnosis. The extensive literature in this field clearly demonstrates that electrochemical biosensors provide very interesting features and substantial advantages over more complex conventional strategies to perform, in a simple and rapid way, single or multiplexed determination of target biomarkers at low concentrations in minimally treated liquid biopsies, meeting also the requirements of point-of-care devices and applicability at different settings. Despite the numerous challenging issues to overcome before achieving the translation of these biosensing strategies into the clinic, the potentiality demonstrated so far for the accurate electrochemical determination of biomarkers at different molecular levels for early and non-invasive diagnosis permits to foresee they will take a privileged place together with the traditional methods in the clinical routine.
       
  • Electrochemistry of membrane proteins and protein–lipid assemblies
    • Abstract: Publication date: Available online 3 May 2018Source: Current Opinion in ElectrochemistryAuthor(s): Jan Vacek, Martina Zatloukalova, David NovakSummaryThe electrochemistry of membrane proteins allows us to examine the association of proteins with membranes and low-molecular ligands, such as drugs, toxins and others. In addition, electrochemical methods are applicable for the quantification of transport phenomena, for monitoring the change in the structure of the protein, and determining its catalytic activity if the protein is an enzyme. In addition to approaches based on the concept of protein film voltammetry, methods based on the direct redox transformations or electrocatalytic reactions of the amino acid residues in the protein structure could be used. The above areas of interest fall under basic research, which is the main subject of this paper. However, the utilization of new immobilization strategies for proteins and the application of redox active polymers is an important part of the development of new biosensors and the construction of devices employing the principles of bioelectrocatalysis.Graphical abstractImage, graphical abstract
       
  • Durability challenges and perspective in the development of PGM-free
           electrocatalysts for the oxygen reduction reaction
    • Abstract: Publication date: Available online 26 April 2018Source: Current Opinion in ElectrochemistryAuthor(s): Ulises Martinez, Siddharth Komini Babu, Edward F. Holby, Piotr ZelenaySummarySignificant advancement in the development of highly active platinum group metal-free (PGM-free) electrocatalysts is giving rise to the possibility of a low-cost replacement for Pt electrocatalysts in polymer electrolyte fuel cells. However, before the successful implementation of PGM-free electrocatalysts, the challenge of long-term stability under fuel cell operating conditions needs to be addressed. In this opinion, the current status of PGM-free electrocatalyst performance and durability is reviewed. A perspective on the route for the study of degradation mechanisms in PGM-free electrocatalysts in both half-cell and membrane electrode assembly environments is presented. The analysis of proposed degradation mechanisms suggests classification into two relevant length scales: atomic scale and macro/mesoscale. Lastly, an overview of different characterization techniques (both experimental and theoretical) for studying different possible degradation mechanisms is outlined. Directly addressing the underlying mechanisms leading to loss of activity in PGM-free electrocatalysts will provide valuable insight necessary for the development of next-generation materials with improved durability capable of competing with Pt-based counterparts.
       
  • Innovative methods in electrochemistry based on polymers of intrinsic
           microporosity
    • Abstract: Publication date: Available online 26 April 2018Source: Current Opinion in ElectrochemistryAuthor(s): Elena Madrid, Neil B. McKeownPolymers of intrinsic microporosity (PIMs) are a new class of material that offer excellent processability and ion (semi-)permeability with great potential for applications in electrochemical technologies. The intrinsic microporosity is generated from inefficient packing of the rigid polymer backbone. Solutions of PIMs are used to form porous polymer matrices with embedded nano-particles and molecular catalysts for modified electrodes. Because of the hydrophobicity of PIMs, trapped liquid electrolyte and gas can coexist for “triphasic” electrochemistry and for electrocatalysis. Deposition of PIMs onto laser-drilled microholes in PET films enables ion conductivity studies that have revealed “ionic diode” effect. These ionic diodes have been proposed for applications in desalination and in sensing. Finally, mild carbonization of PIMs yield carbons without disrupting microporosity. This provides a new methodology for the development of functionalised conductive porous materials.Graphical Image, graphical abstract
       
  • Insight of electrolyte-free voltammetry at microelectrodes
    • Abstract: Publication date: Available online 26 April 2018Source: Current Opinion in ElectrochemistryAuthor(s): Koichi Jeremiah Aoki, Jingyuan ChenElectrode reactions without deliberately adding supporting electrolyte are complicated with electric migrations associated with redox reactions, formation of double layers and ion–ion interactions relevant to electrode reactions. The complications can be realized quantitatively through voltammetry at various sized microelectrodes, partly because of negligibly small solution resistance effects and partly because of steady-state voltammograms, which can be analyzed theoretically without capacitive time-dependent current. The present review deals with (i) techniques of fabrication of many sized microelectrodes, (ii) conditions of keeping low electrolyte concentrations, (iii) ionic contribution of forming double layers, (iv) participation in counter ions for electrode reactions and (v) change in ionic environment by redox reactions.Graphical abstractDistance (w)-changeable Pt wire electrodes and the resistivity of water when voltage over 1 V was applied to the two electrodes. Image, graphical abstract
       
  • Computer simulation studies of nanoporous carbon-based electrochemical
           capacitors
    • Abstract: Publication date: Available online 26 April 2018Source: Current Opinion in ElectrochemistryAuthor(s): Zhujie Li, Trinidad Mendez-Morales, Mathieu SalanneSummaryAmong the various techniques that are used for understanding the operation of electrochemical energy storage devices, computer simulations are now playing a key role. In the case of electrochemical capacitors, the main driving force is the adsorption of ions at the surface of a nanoporous electrode, so that the most widespread simulation technique is molecular dynamics, which gives access to a microscopic picture. Here, we review the most recent advances in the elucidation of charging mechanisms for a wide range of electrode geometries, ranging from slit to amorphous nanopores. We also discuss the impact of surface functionalization, doping and oxidation on the performance of electrochemical devices as predicted using such computer simulation techniques. Finally, we provide a few perspectives on the difficulties that still need to be overcome for fully understanding the complex systems, which are used in electrochemical devices.
       
  • Searching for new truths of nature and creating people-serving products
           through bio-electrochemistry: The brain interface
    • Abstract: Publication date: Available online 21 April 2018Source: Current Opinion in ElectrochemistryAuthor(s): Adam Heller
       
  • Is a major breakthrough in the oxygen electrocatalysis possible'
    • Abstract: Publication date: Available online 18 April 2018Source: Current Opinion in ElectrochemistryAuthor(s): Aleksandar R. ZeradjaninSummaryAs we are witnessing the renaissance of electrochemistry, particularly noticeable is emerging interest in the electrochemical energy conversion and storage. Today, general tendencies are intensive research activities in the material's science, what has been useful in the process of electrode design. However, papers offering in-depth conceptual understanding of electroctalytic processes are rare. One of the perpetual challenges in electrocatalysis is irreversibility of oxygen electrode. As complexity of oxygen electrochemistry requires comprehensive understanding of interfacial phenomena, within this critical review the boundaries of existing knowledge about the oxygen reduction and oxygen evolution are re-visited. Intention is to give diagnostics about the key challenges in oxygen electrocatalysis. Key conceptual contributions relevant to the electrochemistry of oxygen are reconsidered, as well as the core of the current theory of electrocatalysis. Finally, key questions are formulated and perspectives for future comprehensive analysis are given.Graphical abstractImage, graphical abstract
       
  • All-solid-state potentiometric sensors: A new wave for in situ
           aquatic research
    • Abstract: Publication date: Available online 16 April 2018Source: Current Opinion in ElectrochemistryAuthor(s): María Cuartero, Gastón A. CrespoSummaryOver the last few years, all-solid-state potentiometric ion-selective sensors have demonstrated a huge potential for environmental water analysis. Beyond the excellent analytical performances exhibited in benchtop conditions for the detection of important targets (e.g. pH, species relevant to the carbon and nitrogen cycles, trace metals), the challenge now lies in bringing those sensors to in situ format and obtaining valuable chemical information directly in the field while minimizing or avoiding the need for sampling. Technically speaking, the instrumentation for potentiometric assessment is extremely simple, low cost and requires minimal space. In addition, the all-solid-state configuration seems ideal to fabricate miniaturized sensors with sufficient analytical performance to detect certain ions in water resources. Herein, we highlight the power of all-solid-state potentiometric sensors applied to environmental water analysis providing a threefold overview: (i) the recent materials used in the fabrication of all-solid-state polymeric membrane electrodes, both the solid contact and ion-selective membrane; (ii) a collection of the main targets explored during the last 5 years; and (iii) examples of the most recent and relevant in situ applications employing submersible equipment. Throughout the review, issues such as ‘What are the real implications of all-solid-state membrane electrodes in the environmental field?’ and ‘To what extent has the effort in developing new sensors over time been well-exploited?’ are addressed. Convincingly, all-solid-state potentiometric sensors are positioning as a unique in situ interface providing real-time data that allow for an understanding of ongoing biogeochemical processes and possible anthropogenic activities implications.Graphical abstractImage, graphical abstract
       
  • Progress in all-organic rechargeable batteries using cationic and anionic
           configurations: Toward low-cost and greener storage solutions'
    • Abstract: Publication date: Available online 14 April 2018Source: Current Opinion in ElectrochemistryAuthor(s): Philippe Poizot, Franck Dolhem, Joël GaubicherSummaryOur entry into the Fourth industrial revolution since the turn of the century is set to revolutionize our daily life notably with the booming of digital technologies such as communications, artificial intelligence, the Internet of Things (loT), 3-D printing or nano/biotechnologies. It is however hoped this new paradigm shift will integrate sustainable development goals and actions to address the critical damage caused by the previous industrial revolutions especially the threat of global warming. We have to be particularly aware there remains the urgent need for cleaner energy technologies which calls for a radical change in the energy mix to favor renewable energy and environmentally responsible energy storage solutions. Organic materials should provide opportunities to further improve existing energy storage technologies while offering sustainable, versatile and potentially low-cost energy storage devices. This review seeks to provide an update on all-organic battery assemblies reported to date as well as some perspectives we can expect in the future notably for stationary applications.Graphical abstractImage, graphical abstract
       
  • Metal organic frameworks as catalysts for oxygen reduction
    • Abstract: Publication date: Available online 12 April 2018Source: Current Opinion in ElectrochemistryAuthor(s): Shmuel Gonen, Lior ElbazNon-precious metal catalysts for polymer electrolyte membrane fuel cells cathode are well studied for years in order to obtain commercial and durable fuel cell. First row transition metal complexes offer the most promising oxygen reduction reaction of this class. The attempts to increase the number of catalytic sites and surface area of catalysts lead to materials based on metal organic frameworks (MOFs). These highly organized inorganic materials show impressive catalysis when comparing other non-precious metal catalysts and platinum as well, especially in the case of zeolitic imidazolate frameworks derived materials. Currently, MOFs-based materials have very good opportunity to replace platinum and bring fuel cells technology to commercialization.
       
  • New electrode materials and devices for thermoelectrochemical studies and
           applications
    • Abstract: Publication date: Available online 9 April 2018Source: Current Opinion in ElectrochemistryAuthor(s): Gerd-Uwe FlechsigSummaryHeated electrodes have been introduced a few decades ago to perform thermoelectrochemical investigations in a very flexible manner. This review considers unusual materials and devices that have been introduced recently to create new heated and also actively cooled electrodes: carbon paste with ionic liquids as binder, carbon nanotubes, iridium, Hg films, Bi films, Bi–Au alloys, gold nanostructures, and indium-doped tin oxide. Scanning electrochemical microscopy (SECM) based on thermocouple tips, as well as SECM of heated electrode arrays, and hot-tip-SECM have been proposed to study surfaces. Thermo-responsive layers allow for rapid switching of heated electrode surfaces. Recent years have seen a broad variety of thermoelectrochemical studies enabled by actively heated and cooled electrodes based on new materials. Very quick temperature changes and very high energy efficiency are two very distinct advantages of directly heated electrodes over both isothermal electrochemical cells and indirectly heated electrodes that suffer from high heat capacity.
       
  • Electrocatalytic oxygen reduction on transition metal macrocyclic
           complexes for anion exchange membrane fuel cell application
    • Abstract: Publication date: Available online 9 April 2018Source: Current Opinion in ElectrochemistryAuthor(s): Kaido Tammeveski, José H. ZagalSummaryThis review discusses the electrocatalytic activity of MN4 macrocyclic complexes for the O2 reduction reaction. The main reactivity descriptors for these complexes, essentially the M(III)/(II) redox potential and the MO2 binding energies are considered. MNx pyrolysed catalysts are only discussed briefly as this will be covered in other articles of this issue. The performance of these catalysts in anion exchange membrane fuel cell (AEMFC) is thoroughly reviewed.Graphical abstractImage, graphical abstract
       
  • Pore-forming confined space for the innovative electrochemical methods
    • Abstract: Publication date: Available online 6 April 2018Source: Current Opinion in ElectrochemistryAuthor(s): Kaipei Qiu, Xue-Yuan Wu, Jie Yang, Yi-Lun Ying, Yi-Tao LongPore-forming confined space, especially at nanoscale, creates a unique environment that is able to controllably and precisely influence the interaction between pores and analytes. Hence, nanopore-based methods offer the possibility to in-situ and operando characterize single particle or molecule at ultra-high temporal and spatial resolutions. This review is to highlight the latest research progress of a typical biological nanopore (aerolysin) as an example to demonstrate the capability of this technique, covering the direct use of wild-type aerolysin nanopores to detect and discriminate nucleotides of difference lengths or with various nucleobases, and the rational mutation of aerolysin nanopores to further enhance the sensitivity and selectivity. These progresses clearly demonstrate the great potential of nanopore or confined space approach in novel electrochemical sensing.
       
  • Non-aqueous electrolytes for electrochemical capacitors
    • Abstract: Publication date: Available online 4 April 2018Source: Current Opinion in ElectrochemistryAuthor(s): J. Krummacher, C. Schütter, L.H. Hess, A. BalducciSummaryThis review supplies an overview about the most recent work which has been carried out toward the realization of innovative non-aqueous electrolytes for high energy electrochemical capacitors (EDLCs). The solvents, conducting salts and ionic liquids proposed in the past years are discussed, and their impact on the EDLC performance is critically analyzed. Furthermore, the actual status of the research dedicated to the identification, characterization and application of novel electrolytes is analyzed. The aim of this latter section is to supply indications about the most important aspects, which still need to be investigated in order to realize a novel generation of electrolytes suitable for the realization of high energy EDLCs.
       
  • Approaching the self-consistency challenge of electrocatalysis with theory
           and computation
    • Abstract: Publication date: Available online 4 April 2018Source: Current Opinion in ElectrochemistryAuthor(s): Mohammad Javad Eslamibidgoli, Michael H. Eikerling This opinion piece centers around challenges involved in developing first-principles electrochemical methods. In recent years, theory and computation have become indispensable tools to navigate the parameter space that controls the activity and stability of electrocatalytic materials and electrochemical devices. Viable methods process as input details on materials structure, composition and reaction conditions. Their output includes metrics for stability and activity, phase diagrams, as well as mechanistic insights on reaction mechanisms and pathways. The core challenge, connecting input to output, is a self-consistency problem that couples the electrode potential to variables for the electronic structure of the solid electrode, solvent properties and ion distributions in the electrolyte as well as specific properties of a boundary region in-between. We will discuss a theoretical framework and computational approaches that strive to accomplish this feat.
       
  • Structure and activity of metal-centered coordination sites in pyrolyzed
           metal–nitrogen–carbon catalysts for the electrochemical reduction of
           O2
    • Abstract: Publication date: Available online 4 April 2018Source: Current Opinion in ElectrochemistryAuthor(s): Jingkun Li, Frédéric JaouenSummaryPyrolyzed metal–nitrogen–carbon (M–N–C) materials have become a mainstream research as inexpensive and sustainable catalysts for the oxygen reduction reaction (ORR) in both acid and alkaline media for low and intermediate temperature fuel cells. Tremendous advancements in the initial activity and power performance of M–N–C catalysts and cathodes have been achieved, as driven by their possible application in e.g. automotive fuel cell stacks. Based on a selected number of recent studies, this review critically discusses the advancements, but also highlights the remaining scientific questions and technical issues important in this field. The nature of the active site(s) as well as their intrinsic activity toward ORR have been clarified in particular through the preparation of model catalysts comprising only MNxCy moieties. Recently developed methods hold promise to reliably enumerate the number of electrochemically accessible active sites in such materials, which would allow deconvoluting the activity into site density and turnover frequency.
       
  • Stability and dissolution of electrocatalysts: Building the bridge between
           model and “real world” systems
    • Abstract: Publication date: Available online 3 April 2018Source: Current Opinion in ElectrochemistryAuthor(s): Serhiy CherevkoSummaryThis review gives a snapshot of the current state of the electrocatalyst stability research. The accent is put on the dissolution of the state-of-the-art oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) Pt- and Ir- or Ru-based catalysts, respectively. Two important aspects at the cutting edge of the ORR and OER catalyst stability research, viz. stability of the catalyst layers containing very small loadings of Pt and Ir/Ru and the question of the conformity of the model dissolution studies with degradation of the “real world” catalyst layers are highlighted. It is shown that in both systems catalyst degradation accelerates with decrease in catalyst loading. Situation is more complex though, when model and real systems are contrasted. Thus, while dissolution of Pt is comparable, no convincing comparison for Ir/Ru can be provided yet. The potential near future research directions are emphasized throughout the text.
       
  • Is the Li–S battery an everlasting challenge for operando
           techniques'
    • Abstract: Publication date: Available online 30 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): J. Conder, C. VillevieilleSummaryThe promise of high-energy density and the predicted role of the Li–S batteries in electrochemical energy storage applications are largely based on sulfur's high theoretical specific charge. Unfortunately, to date the commercialization of Li–S battery is still hindered due to the complexity of the reaction mechanism involving a sequence of dynamically changing liquid and solid equilibria. Operando techniques have been widely employed to study these performance-limiting phase transformations; however, they often fall short in tracking and resolving simultaneously the solid and liquid phases. Here, we present a review summarizing the last efforts in the field.
       
  • Toward high lithium conduction in solid polymer and polymer–ceramic
           batteries
    • Abstract: Publication date: Available online 30 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Basile Commarieu, Andrea Paolella, Jean-Christophe Daigle, Karim ZaghibSummaryHigh-energy-density batteries use lithium electrodes because they provide the highest theoretical capacity and widest electrochemical potential window of all the possible anodes for rechargeable lithium batteries. However, adoption of metallic lithium leads to safety problems and low cycling performance due to the reactivity of lithium with standard liquid electrolytes (LEs). Solid electrolytes (SEs) are a promising solution to replace LEs due to their high thermal and chemical stability. They also possess numerous other advantages such as light-weight, flexibility, low-cost and a high operating window voltage. The aim of this review is to present a summary of recent advances in polymer and inorganic SEs for all-solid lithium metal batteries (LMBs). We will discuss the replacement of polyethylene oxide (PEO) and the crucial parameters for achieving a suitable combination of polymer matrix with inorganic ceramic fillers to obtain viable SE composites for high-voltage and high-capacity cell.
       
  • Solvation-controlled ester-based concentrated electrolyte solutions for
           high-voltage lithium-ion batteries
    • Abstract: Publication date: Available online 30 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Takayuki Doi, Michihiro Hashinokuchi, Minoru InabaHighly concentrated electrolyte solutions exhibit high stability against oxidation, and hence have a high potential for the high voltage operation of lithium-ion batteries (LIBs). However, they are highly viscous and very costly due to an extensive use of lithium salts. These problems were solved by diluting the highly concentrated electrolyte solutions with a diluent that has a low donor number, a high miscibility, and a high stability against oxidation. The resultant electrolyte solutions suppressed the degradation of 5 V-class LiNi0.5Mn1.5O4 positive-electrodes upon repeated charge/discharge cycling, and extended the reversible capacity of LiNi0.5Co0.2Mn0.3O2 electrodes to ca. 200 mAh g−1 by charging to a high voltage of 4.6 V.
       
  • Non-aqueous potassium-ion batteries: a review
    • Abstract: Publication date: Available online 30 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Christoph Vaalma, Daniel Buchholz, Stefano PasseriniSummaryPotassium-ion batteries using non-aqueous electrolyte currently face fast growing interest since they hold the promise of combining the advantageous properties of lithium- and sodium-ion batteries without having the individual drawbacks. In this review, recent studies are analyzed and the main material classes as well as novel research strategies are discussed.Graphical abstractImage, graphical abstract
       
  • Engineering exoelectrogens by synthetic biology strategies
    • Abstract: Publication date: Available online 30 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Feng Li, Lei Wang, Chenguang Liu, Deguang Wu, Hao SongSummaryHighly efficient extracellular electron transfer (EET) of electroactive bacteria is essential for economically viability of a diverse array of bioelectrochemical systems (BES) in environmental and energy fields. However, the EET efficiency of exoelectrogens remained a primary bottleneck. Synthetic biology is a research field that combines the investigative nature of biology with the constructive nature of engineering, which offers great prospects in rationally engineering to facilitate highly efficient EET of electroactive cells. In this review, we firstly summarized the recent advances in synthetic biology strategies to enhance the EET efficiency of exoelectrogens, which included broadening feedstock spectrum, strengthening intracellular electron generation, optimizing conductive cytochromes systems, promoting biosynthesis and secretion of electron shuttles, and constructing conductive biofilms. Genetic technologies in engineering exoelectrogens, in particular the genomic editing tools, were then reviewed. Lastly, a number of fundamental questions to be addressed in this field were proposed as a perspective for further boosting the EET efficiency and practical applications of BES systems.
       
  • Electronic structure calculations on electrolyte–electrode interfaces:
           Successes and limitations
    • Abstract: Publication date: Available online 29 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Ryosuke Jinnouchi, Kensaku Kodama, Yu MorimotoSummaryDensity functional theory calculations on electrolyte–electrode interfaces are briefly reviewed in this article. The calculation methods are roughly categorized into two types: calculations on electrically neutral surfaces and electrified surfaces. The former methods have been successfully applied to reproduce observed trends in catalytic activities and to design new materials. The methods, however, cannot evaluate any electrochemical properties originated from surface electrifications. By this reason, several theoretical methods on electrified interfaces have been proposed. The methods can provide properties originated from charge transfers, such as electrosorption valency values, symmetry factors and potential-dependent spectroscopies, within self-consistent manners. Many limitations, however, still exist, and further studies are necessary particularly on effects of dynamical atomic motions on free energies.
       
  • Graphene-based bioelectrochemistry and bioelectronics: A concept for the
           future'
    • Abstract: Publication date: Available online 29 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Sabine Szunerits, Rabah BoukherroubSummarySituated at the interface of materials science, chemistry and the life sciences, graphene- based electronics and electrochemistry offer a broad palette of opportunities for researchers and clinicians for targeted theranostics as outlined in this article.
       
  • Does the breaking of adsorption-energy scaling relations guarantee
           enhanced electrocatalysis'
    • Abstract: Publication date: Available online 27 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Nitish Govindarajan, Juan M. García-Lastra, Evert Jan Meijer, Federico Calle-VallejoThe adsorption energies of numerous species on homogeneous and heterogeneous catalysts scale linearly with each other. Such linear dependence lowers the degrees of freedom in multistep reactions, greatly simplifying computational electrocatalysis models. The downside of scaling relations is that they limit the efficiency of electrocatalytic reactions. For instance, the scaling relation between *OOH vs *OH supposedly limits the oxygen evolution and reduction reactions (OER, ORR): while the energetic separation of these intermediates should ideally be 2.46 eV, on most catalysts it is ∼3.20 eV. Thus, it is currently assumed that breaking such scaling relation might lead to significant enhancement of OER/ORR electrocatalysis. In this review, we evaluate this hypothesis using literature data. The analysis suggests that breaking the *OOH vs *OH scaling relation is a necessary yet insufficient condition to optimize OER/ORR electrocatalysts. Alternatively, we define a new descriptor: the electrochemical-step symmetry index (ESSI), the optimization of which effectively corresponds to low calculated overpotentials.Graphical abstractImage, graphical abstract
       
  • Unfolding the versatile potential of EC-TERS for electrocatalysis
    • Abstract: Publication date: Available online 27 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Jonas H.K. Pfisterer, Katrin F. DomkeThe rational design of electrocatalysts demands the in situ experimental identification of specific surface sites that are most active toward certain electrochemical reactions. Therefore, surface-sensitive techniques with high chemical specificity and the ability to resolve nanoscale features are required. Even more challenging is the requirement to operate in aqueous electrolytes under potential control. Electrochemical tip-enhanced Raman spectroscopy (EC-TERS) smartly comprises these prerequisites. To date, EC-TERS has been used to study the potential-dependent protonation/deprotonation, reorientation and redox reactions of self-assembled monolayers in contact with aqueous electrolytes. This review article highlights the pioneering work of EC-TERS and discusses the enormous potential that this spectro-electrochemical tool entails for the field of electrocatalysis.
       
  • Electrochemistry of surface-confined enzymes: Inspiration, insight and
           opportunity for sustainable biotechnology
    • Abstract: Publication date: Available online 27 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Leon P. Jenner, Julea N. ButtRedox enzymes can generate electricity from sunlight and produce valuable chemicals, including fuels, from low-value materials. When an electrode takes the role of an enzyme's natural redox partner, these properties inspire creative approaches to generate renewable resources. Enzymatic fuel cells produce electricity, enzyme electrosynthesis drives chemical transformations and biophotovoltaics harness solar energy. Underpinning rational development of these applications, time-dependent currents resolved by dynamic electrochemistry provide quantitative insight into the determinants of enzyme activity. This article reviews popular and emerging routes to sequester, study and exploit redox enzymes on two- and three-dimensional electrode materials. Studies are highlighted that draw on synergies of these different aspects of enzyme electrochemistry.Graphical abstractImage, graphical abstract
       
  • Prospects for single-site interrogation using in situ multimodal
           electrochemical scanning probe techniques
    • Abstract: Publication date: Available online 27 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Noah B. Schorr, Zachary T. Gossage, Joaquín Rodríguez-LópezSummaryNew multimodal methodologies are required to ascertain detailed information that correlates spatially resolved electrochemical reactivity with composition and structural motifs. This strategy will allow a comprehensive understanding of single reacting sites and single entities within bulk electrodes. Electrochemical scanning probe microscopies (EC-SPM), with the inherent ability to resolve site-specific electrochemical heterogeneities, are the perfect platform to couple with techniques capable of resolving composition and structural information. Here we highlight the advantages of multimodal experiments, recent progress, and prospects toward pairing EC-SPMs simultaneously with vibrational spectroscopies, mass spectrometry and X-ray methods.Graphical abstractImage, graphical abstract
       
  • Graphene-based nanomaterials in innovative electrochemistry
    • Abstract: Publication date: Available online 26 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Sabine Szunerits, Rabah Boukherroub
       
  • Water – A key parameter in the stability of anion exchange membrane
           fuel cells
    • Abstract: Publication date: Available online 26 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Charles E. Diesendruck, Dario R. DekelAnion exchange membrane fuel cells can potentially revolutionize energy storage and delivery; however, their commercial development is hampered by the chemical decomposition of the anion exchange membranes during operation. The hydroxide anions, while transported from the cathode to the anode, attack the positively charged functional groups in the polymer membrane, neutralizing it and suppressing its anion-conducting capability. In recent years, several new quaternary ammonium salts have been proposed to address this challenge, but while they perform well in ex-situ chemical studies, their performance is very limited in real fuel cell studies. While cation chemistry dictates the intrinsic chemical stability of the anion conducting ionomeric materials, it was recently shown that chemical degradation is significantly influenced by the hydration level at which the fuel cell operates. Understanding the principles governing the chemical degradation under fuel cell operation, and its critical relationship with the hydration levels in the operating fuel cell electrodes will facilitate the path to overcome the challenge and finally develop and demonstrate highly stable AEMFC devices.Graphical abstractImage, graphical abstract
       
  • Nanoparticle impacts in innovative electrochemistry
    • Abstract: Publication date: Available online 26 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Laura K. Allerston, Neil V. ReesRecent developments in the use of nanoimpacts as an investigative electrochemical technique are discussed. Highlights include literature on the imaging of nanoimpacts themselves and developments in the application of nanoimpacts such as, surface analysis of single particles including surface coverage and sizing. Also included are factors to consider which may affect the outcome of nanoimpact experiments.
       
  • Silica-based electrochemical sensors and biosensors: Recent trends
    • Abstract: Publication date: Available online 23 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Alain WalcariusSummaryNotwithstanding their insulating properties, silica-based materials have become ubiquitous in electrochemistry. Thanks to the versatility of the sol–gel process to manufacture materials with controlled composition, structure and morphology, their use as electrode modifier has offered new avenues in electrochemical sensing and biosensing. This review highlights some of the most recent developments in the field, focusing especially on devices based on engineered nanoparticles and ordered mesoporous silica thin films, and discussing their interest in designing sensors and biosensors for improved electrochemical detection.Graphical abstractImage, graphical abstract
       
  • Oxygen reduction at platinum electrodes: The interplay between surface and
           surroundings properties
    • Abstract: Publication date: Available online 23 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Ana M. Gómez-Marín, Juan M. FeliuSummaryIn this work, recent progress in the understanding of the mechanism of the oxygen reduction reaction at Pt surfaces is shortly reviewed. Specifically, the presence of a soluble and short-lived intermediate different to H2O2 in the ORR reaction path and the interrelated effect between the surface arrangement, adsorption of oxygen-containing species and water structure in the ORR reactivity in acid environments are discussed. Besides, the influence of the proton concentration on the ORR product distribution, the existence of a chemical step and the possible role of the soluble intermediate as a bifurcation point in the mechanism are also analyzed.
       
  • Frontiers in first principles modelling of electrochemical simulations
    • Abstract: Publication date: Available online 20 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Alberto RoldanComputer simulations are a useful tool to describe physical and chemical processes. However, the state-of-the-art techniques lack practicality to simulate the dynamical movement of species while accounting for the electron exchange. This is the case of electrochemical processes, i.e. species in solution interact with the surface of the electrode and the solvent molecules arrange at the interface according to the field created by the electrode potential. Here we present the latest innovative methods and frontiers for the treatment of electrochemical simulations including microsolvation protocols implemented in the density functional theory framework. We also suggest alternative electronic structure mixed-force calculations to pioneer a more realistic simulation framework of reactive processes.Graphical abstractImage, graphical abstract
       
  • Controllable synthesis of nanostructured metal oxide and oxyhydroxide
           materials via electrochemical methods
    • Abstract: Publication date: Available online 20 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Matthew J. Lawrence, Adam Kolodziej, Paramaconi RodriguezSummaryThe synthesis of metal oxide and metal oxyhydroxide nanomaterials is a very active area of research that has an enormous impact on the development and progress of new technologies. This review summarizes the most relevant and recent work on the electrochemical synthesis of metal oxides and oxyhydroxide nanostructures. It also provides the personal, critical view of the authors regarding the advantages and challenges of the methods upon potential commercialization.
       
  • Design strategies for non-precious metal oxide electrocatalysts for oxygen
           evolution reactions
    • Abstract: Publication date: Available online 20 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Qingxiang Wang, Kamran Dastafkan, Chuan ZhaoDeveloping highly active electrocatalysts for oxygen evolution reaction (OER) is key to improve the water splitting efficiency for production of clean hydrogen energy. Non-precious transition metal oxides (TMOs) are attractive electrocatalysts for OER but usually suffer from relatively low intrinsic activity, poor electrical conductivity and inferior stability. In this current opinion article, recent design strategies for enhancing TMO-based OER electrocatalysts have been outlined including (i) nanostructuring for enhancing surface area and number of active sites, (ii) tuning catalyst composition and electronic structure for enhancing intrinsic activity of each site, (iii) hybridizing with catalyst support for enhancing conductivity, and stability, and (iv) hierarchical porous electrode architecture for enhancing OER efficiency.
       
  • A brief review of the computational modeling of CO2
           electroreduction on Cu electrodes
    • Abstract: Publication date: Available online 19 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Alejandra Rendón-Calle, Santiago Builes, Federico Calle-VallejoSummaryElectrochemical reduction of CO2 (CO2RR) to hydrocarbons and alcohols is a promising yet intricate catalytic process with large associated overpotentials. On Cu, the most active metal, factors such as pH, solvation, anions and cations in solution, in addition to the catalysts’ structure, modify the reaction mechanism and play an important role on the catalytic activity and selectivity. Such an extraordinary complexity calls for an in-depth understanding of CO2RR that eventually leads to its optimization. In this brief review, we illustrate how computational methods have aided in recent years to gain insight on CO2RR. We show the achievements and limitations of well-established methods based on Gibbs energy diagrams, calculations in vacuum, the computational hydrogen electrode and scaling-relation-based volcano plots. Besides, we review advances on kinetics of electrochemical steps, structure-sensitive screening, ion effects, and machine learning.Graphical abstractImage, graphical abstract
       
  • Photocatalysis an enhancer of electrocatalytic process
    • Abstract: Publication date: Available online 13 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Nicolas Alonso-VanteSummaryThe phenomenon to restrain electrocatalytic particle agglomeration, while boosting the activity of multi-electron charge transfer reactions, known as strong-metal support-interaction, is reviewed. The main insights of this phenomenon are outlined. In this respect, the connection of a photo-induced process, to anchor metal centers, contributes to the electrocatalytic activity enhancement. Selected examples are given.
       
  • A reviewed vision of the oxygen reduction reaction mechanism on Pt-based
           catalysts
    • Abstract: Publication date: Available online 13 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Ana M. Gómez–Marín, Edson A. TicianelliSummaryIn this work, a short revised analysis regarding the ORR mechanism at Pt-based surfaces has been performed and some common kinetic criteria have been reexamined in light of recent experimental results. In this sense, the production of H2O2 under high mass transport conditions and the lack of reduction currents at potentials higher than the experimental reaction onset, EonsetORR, have been analyzed, considering the existence of a soluble intermediate species and an outer sphere reaction inside the ORR mechanism, besides the possible occurrence of a zero current cycle at EonsetORR. Finally, the implications of these findings in the stability and durability of Pt-based catalysts have been also discussed.
       
  • Ammonia electro-oxidation reaction: Recent development in mechanistic
           understanding and electrocatalyst design
    • Abstract: Publication date: Available online 13 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Kumar Siddharth, Yattung Chan, Lu Wang, Minhua ShaoSummaryAmmonia electro-oxidation reaction is one of the most prominent electrochemical reactions having great potentials to solve severe energy and environmental problems. It is the anodic reaction in direct ammonia fuel cells, ammonia electrolysis, wastewater remediation and electrochemical sensors. However, slow reaction kinetics require use of electrocatalysts and the most active one, i.e. platinum, is expensive. Understanding the mechanism and reaction intermediates during the reaction is important for the development of active and stable electrocatalysts. In this review, recent progress in interpretation of mechanisms through use of different on-line techniques is discussed. Advances in development of efficient electrocatalysts are also overviewed.
       
  • Understanding PGM-free catalysts by linking density functional theory
           calculations and structural analysis: Perspectives and challenges
    • Abstract: Publication date: Available online 13 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Ivana Matanovic, Kateryna Artyushkova, Plamen AtanassovSummaryWe discuss perspectives and challenges in applying density functional theory for the calculation of spectroscopic properties of platinum group metal (PGM)-free electrocatalysts for oxygen reduction. More specifically, we discuss recent advances in the density functional theory calculations of core-level shifts in binding energies of N 1s electrons as measured by X-ray photoelectron spectroscopy. The link between the density functional theory calculations, the electrocatalytic performance of the catalysts, and structural analysis using modern spectroscopic techniques is expected to significantly increase our understanding of PGM-free catalysts at the molecular level.
       
  • Understanding formic acid oxidation mechanism on platinum single crystal
           electrodes
    • Abstract: Publication date: Available online 13 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Enrique Herrero, Juan M. FeliuSummaryRecent results on the formic acid oxidation reaction on platinum electrodes, especially those obtained for platinum single crystal electrodes are reviewed. With all the available data, a detailed mechanism for both reaction paths of the mechanism is proposed. For the CO formation path, oxidation and reduction steps are involved sequentially. On the other hand, the active species is a monodentate adsorbed formate. This adsorption mode is favored in the presence of additional adsorbed species in the neighborhood. The proposed mechanism agrees with all the experimental results obtained for the reaction.
       
  • Adatom decorated shape-controlled metal nanoparticles: Advanced
           electrocatalysts for energy conversion
    • Abstract: Publication date: Available online 13 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Matheus B.C. de Souza, Pablo S. Fernández, J. Solla-GullónSummaryThe use of adatom decorated shape-controlled metal nanoparticles in electrocatalysis, and particularly for energy conversion reactions, has made important contributions to the development of better electrocatalysts. In this short review, we highlight some of the most relevant findings and discuss about future challenges.
       
  • Ionic liquids in electrochemical energy storage
    • Abstract: Publication date: Available online 12 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Vitor L. Martins, Roberto M. TorresiSummaryIonic liquids are liquids containing solely ions having melting points lower than 100 °C. Their potential applications in electrochemical energy storage and conversion were generated mainly by their negligible vapor pressure, in most cases, and by their thermal stability. An overview of these novel materials and their limitations is provided from their fundamental properties to the recent essential advances in the field.
       
  • Advanced analytical techniques to characterize materials for
           electrochemical capacitors
    • Abstract: Publication date: Available online 8 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): Zifeng Lin, Pierre-Louis Taberna, Patrice SimonThis review covers recent developments in advanced analytical techniques to characterize materials for electrochemical capacitors. For double layer capacitors, examples of the use of in situ X-ray photoelectron spectroscopy (XPS), pulsed electrochemical mass spectrometry (PEMS) technique, temperature-programmed desorption coupled with mass spectroscopy (TPD-MS) technique, in situ NMR spectroscopy, and in situ dilatometry measurement are presented, for studying carbon/electrolyte interface with a focus onto electrolyte ions confinement in nanopores and changes during ageing. For the pseudocapacitive system, in situ X-ray (neutron) diffraction or scattering, in situ dilatometry technique, cavity micro-electrode, in situ Raman spectroscopy, TPD-MS technique, and electrochemical quartz crystal microbalance (EQCM) technique have been employed for studying materials structure, electrochemical kinetic, interface interaction, and ions adsorption/desorption. These advanced analytical techniques probe insight into charge storage mechanisms, and guiding the fast development of supercapacitors.
       
  • Si-alloy negative electrodes for Li-ion batteries
    • Abstract: Publication date: Available online 5 March 2018Source: Current Opinion in ElectrochemistryAuthor(s): M.N. ObrovacThe use of Si-alloys as negative electrode materials in Li-ion cells can increase their energy density by as much as 20%, compared to conventional graphite electrodes. However, several technical challenges related with the massive volume expansion associated with Si-alloy lithiation have impeded their implementation. A number of advances in recent years have occurred in the understanding of these challenges and in means of overcoming them through new materials, electrolyte additives, binders and electrode formulations. Here, the current understanding of these challenges and the latest advances in the field are reviewed.
       
  • Electrochemical triggering and control of atom transfer radical
           polymerization
    • Abstract: Publication date: March 2018Source: Current Opinion in Electrochemistry, Volume 8Author(s): Francesca Lorandi, Marco Fantin, Abdirisak Ahmed Isse, Armando GennaroSummaryElectrochemically mediated atom transfer radical polymerization (eATRP) is an advanced method to produce well-defined polymers. In eATRP, an electric current is used to trigger the polymerization, (re)generate the active catalyst, and strictly control the process. This review describes the fundamentals of eATRP and its applications to prepare homopolymers, block copolymers, star polymers, and surface-grafted polymer brushes.Graphical abstractImage, graphical abstract
       
  • Stereoelectrochemistry of calixarenes – Molecules with multiple
           redox centers
    • Abstract: Publication date: March 2018Source: Current Opinion in Electrochemistry, Volume 8Author(s): Alan Liška, Jiří LudvíkElectrochemical experiments are generally source of thermodynamic and kinetic data, analytical results or mechanistic considerations. The present contribution shows that using redox probes and the way of interpretation typical for molecules with multiple redox centers, electrochemistry can offer also information about the actual shape, geometry and rigidity of the studied molecules in the solution, and, consequently, about the electron distribution and delocalization. This “stereoelectrochemical” approach has been demonstrated on the large series of differently substituted oligonitro calix[4]arenes and thia calixarenes and represents an additional tool for better understanding of the relationship between structure and general properties of new compounds including supramolecules.Graphical abstractImage, graphical abstract
       
  • Enantioselective selectors for chiral electrochemistry and
           electroanalysis: Stereogenic elements and enantioselection performance
    • Abstract: Publication date: March 2018Source: Current Opinion in Electrochemistry, Volume 8Author(s): Serena Arnaboldi, Mirko Magni, Patrizia Romana MussiniSummaryThe ability to select among different electroactive molecules, or among different redox centers on a single molecule, in both analytical and synthetic applications, is a typical asset of electrochemistry, based on fine control of the electrode potential, possibly enhanced by the choice of appropriate electrode surfaces and media. An attractive step further, of great fundamental and applicative interest, is represented by enantioselective electrochemistry, implying the ability to discriminate the enantiomers of chiral molecules (in electroanalysis), or to selectively activate or achieve a given enantiomer of a chiral molecule controlling the electrode potential (in electrosynthesis). Since the enantiomers of a chiral molecule have identical scalar physico-chemical properties and therefore the same electrochemical behavior except when interacting with some other chiral entity, enantioselective electrochemistry necessarily implies the electron transfer process to take place in asymmetric conditions. This can be achieved by the use of a chiral electrode surface or a chiral medium. Artificial selectors are particularly interesting on account of the virtually unlimited range of tailored structures possible as well as the possibility to have both enantiomers of a given selector equally available. Among the many approaches so far proposed for this ambitious target along either of the two above ways, outstanding results have been recently obtained, based on the use of "inherently chiral molecular materials" (either as electrode surfaces or as media) in which the same structural element endows the molecule with both its key functional property and with chirality.Graphical abstractImage, graphical abstract
       
  • Molecular electrochemistry of multi-redox functionalized 5-membered
           heterocycles
    • Abstract: Publication date: March 2018Source: Current Opinion in Electrochemistry, Volume 8Author(s): Dominique Miesel, Alexander Hildebrandt, Heinrich LangSummaryRecent developments in the electron transfer behavior of multi-redox functionalized 5-membered heterocycles are discussed on the basis of (spectro)electrochemistry. Where appropriate, potential applications are presented.Graphical abstractImage, graphical abstract
       
  • Electrogenerated chemiluminescence: A molecular electrochemistry point of
           view
    • Abstract: Publication date: March 2018Source: Current Opinion in Electrochemistry, Volume 8Author(s): A. Fiorani, G. Valenti, M. Iurlo, M. Marcaccio, F. PaolucciThe history of light emission triggered by electrochemical reactions, the so-called electrogenerated chemiluminescence (ECL), spans over 50 years and the relevance of the molecular approach to the development of the field can hardly be overlooked. Molecular electrochemists’ contribution has mainly focused on unraveling fundamental aspects associated to the mechanisms of ECL as well as on singling out new luminophores/coreactants systems to achieve higher efficiency and stability, with important consequences in the analytical exploitation of this technique. The latest and most important investigations on electrogenerated chemiluminescence which concern, in particular, inorganic and organic luminophores and the relevant mechanistic models and simulations are briefly reviewed.Graphical abstractImage, graphical abstract
       
  • Electrochemistry and catalytic properties of vitamin B12
           derivatives in nonaqueous media
    • Abstract: Publication date: March 2018Source: Current Opinion in Electrochemistry, Volume 8Author(s): Hisashi Shimakoshi, Yoshio HisaedaSummaryElectroorganic synthesis mediated by vitamin B12 derivatives has been developed in nonaqueous media. Especially, amphiphilic heptamethyl cobyrinate with a high solubility in various organic solvents was used in various kinds of electroorganic syntheses based on enzymatic function. Electrolysis of an organic halide catalyzed by the B12 model complex provided dechlorinated products under anaerobic conditions, while the electrolysis under aerobic conditions afforded oxidized products such as an ester and amide with dechlorination. Electrochemical reductions of an alkene and alkyne were also catalyzed by the B12 model complex at less negative applied potentials than those of the alkene and alkyne reductions. A bioinspired intermediate, expected as a cobalt–hydrogen complex, should be formed and catalyze the reaction.Graphical abstractImage, graphical abstract
       
  • The molecular electrochemistry of metal–organic metallamacrocycles
    • Abstract: Publication date: March 2018Source: Current Opinion in Electrochemistry, Volume 8Author(s): Rainer F. Winter Considering that most metallamacrocycles possess redox-active metal nodes as well as redox-active linker ligands, the number of studies aimed at investigating that inherent property is astoundingly small. This microreview summarizes the most relevant, recent work on the electrochemistry of organometallic macrocycles. We hope that this article encourages further incentives to not only explore, but also exploit the inherent redox-activity of metal–organic macrocycles.Graphical abstractImage, graphical abstract
       
  • Combinatorial electrochemistry for organic synthesis
    • Abstract: Publication date: March 2018Source: Current Opinion in Electrochemistry, Volume 8Author(s): Koichi Mitsudo, Yuji Kurimoto, Kazuki Yoshioka, Seiji SugaSummaryIn this study, recent advances in electro-organic chemistry based on combinatorial approaches are reviewed. As examples of combinatorial organic electrosynthesis, some batch and flow electrolysis systems for the screening and optimization of electro-organic reactions are described along with the construction of chemical libraries of organic compounds.
       
  • On the road toward calcium-based batteries
    • Abstract: Publication date: Available online 28 February 2018Source: Current Opinion in ElectrochemistryAuthor(s): A. Ponrouch, M.R. PalacinSummaryThis article reviews the progress in the development of a possible battery technology based on calcium, which is an abundant element and has an interesting standard reduction potential. The main bottleneck has been to find electrolytes enabling reversible plating and stripping of calcium, which has been overcome recently. Ongoing efforts focus in optimizing them to enable effective operation of calcium anodes at room temperature and within a large redox potential operation window, despite the formation of a passivation layer at the electrolyte/anode interface. In parallel, researchers are looking for suitable cathode materials enabling reasonably fast insertion and de-insertion of Ca2+ ions, which need to be probed using diverse complementary characterization techniques to avoid biased interpretation of results derived from possible side reactions.Graphical abstractImage, graphical abstract
       
  • Chiral self-assembled monolayers in electrochemistry
    • Abstract: Publication date: January 2018Source: Current Opinion in Electrochemistry, Volume 7Author(s): Daniel MandlerSummaryThe activity of chiral self-assembled monolayers (SAMs) in electrochemistry is reviewed. Chiral SAMs have been used as a means of introducing stereoselectivity in electron transfer at the electrode/electrolyte interface. In most cases, a cysteine-based SAM was used on gold electrodes. Different attempts have involved the application of chiral thiolated molecules, e.g., cyclodextrin, imprinting of chiral objects and competitive complexation. More recently, spintronics in which magnetic fields applied next to chiral SAM induced chiral effects, were also reported. Yet, there is much room for additional and innovative ideas in this field of electrochemistry.
       
  • Computational modelling of water oxidation catalysts
    • Abstract: Publication date: January 2018Source: Current Opinion in Electrochemistry, Volume 7Author(s): Joaquín Soriano-López, Wolfgang Schmitt, Max García-MelchorSummaryIn this opinion, we review the state-of-the-art in modelling of the water oxidation reaction catalysed by homogeneous and heterogeneous systems. We start by introducing the potential and current limitations in the development of energy conversion technologies based on this process, followed by a brief description of the two main proposed reaction mechanisms. We next present an overview of the different theoretical approaches adopted to describe this reaction, and summarise the most recent computational works devoted specifically to the investigation of the O–O bond formation step. The latter part also includes a review of the advances in the modelling of electrochemical energy barriers. The chemical descriptors proposed to rationalise the OER activity and the theoretical methods developed to account for solvent effects, are also reviewed. Finally, we present a selection of theoretical studies reported over the last two years to illustrate the descriptive and predictive power of computational methods.
       
  • Electrochemical water oxidation: The next five years
    • Abstract: Publication date: January 2018Source: Current Opinion in Electrochemistry, Volume 7Author(s): Ian Godwin, Aurelie Rovetta, Michael Lyons, Jonathan ColemanSummaryRecent developments in the literature of oxygen evolution catalysis are discussed. Issues in experimental testing for catalyst comparison are detailed with particular focus on the use of porous foam supports. Ideas for optimization of the system are given such as increasing electrolyte concentration and film thickness.
       
  • Redox cycling in nanogap electrochemical cells
    • Abstract: Publication date: January 2018Source: Current Opinion in Electrochemistry, Volume 7Author(s): Henry S. White, Kim McKelveySummaryThe repeated oxidation and reduction of a redox species (redox cycling) in a gap between two working electrodes has primarily been used to study the kinetics of electrochemical reactions. New fabrication methods have allowed the gap between the two working electrodes to be reduced to 10′s of nanometers in size. This reduced nanogap width has allowed recent innovations such as single molecule electrochemistry and probing the effect of electrical double layer on molecular transport at electrode/electrolyte interfaces.Graphical abstractImage, graphical abstract
       
 
 
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