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Similar Journals
 Nano ResearchJournal Prestige (SJR): 3.064 Citation Impact (citeScore): 8Number of Followers: 4      Hybrid journal (It can contain Open Access articles) ISSN (Print) 1998-0000 - ISSN (Online) 1998-0124 Published by Springer-Verlag  [2658 journals]
• Exposing Cu-Rich {110} Active Facets in PtCu Nanostars for Boosting

Abstract: In catalysis, tuning the structural composition of the metal alloy is known as an efficient way to optimize the catalytic activity. This work presents the synthesis of compositional segregated six-armed PtCu nanostars via a facile solvothermal method and their distinct composition-structure-dependent performances in electrooxidation processes. The alloy is shown to have a unique six arms with a Cu-rich dodecahedral core, mainly composed of {110} facets and exhibit superior catalytic activity toward alcohols electrooxidation compared to the hollow counterpart where Cu was selectively etched. Density functional theory (DFT) calculations suggest that the formation of hydroxyl intermediate (OH*) is crucial to detoxify CO poisoning during the electrooxidation processes. The addition of Cu is found to effectively adjust the d band location of the alloy catalyst and thus enhance the formation of *OH intermediate from water splitting, which decreases the coverage of *CO intermediate. Our work demonstrates that the unique compositional anisotropy in alloy catalyst may boost their applications in electrocatalysis and provides a methodology for the design of this type catalyst.
PubDate: 2019-03-21
DOI: 10.1007/s12274-019-2367-y

• Aqueous organic redox flow batteries

Abstract: Redox flow batteries (RFBs) are promising candidates to establish a grid-scale energy storage system for intermittent energy sources. While the current technology of vanadium RFBs has been widely exploited across the world, the rise in the price of vanadium and its limited volumetric energy density have necessitated the development of new kinds of redox active molecules. Organic molecules can be used as new and economical redox couples in RFBs to address these issues. In addition, the redox organic species also provide ample advantages to increase the voltage and solubility, provide multiple numbers of electron transfer, and ensure electrochemical/chemical stability by molecular engineering through simple synthetic methods. This review focuses on the recent developments in aqueous organic RFBs, including the molecular design and the corresponding cycling performance as these organic redox molecules are employed as either the negolyte or posolyte. Various strategies for tuning the electrochemical/chemical characteristics of organic molecules have improved their solubility, redox potential, cycling stability, and crossover issue across a separating membrane. We also put forward new strategies using nanotechnology and our perspective for the future development of this rapidly growing field.
PubDate: 2019-03-21
DOI: 10.1007/s12274-019-2355-2

• Stress-induced CsPbBr 3 nanocrystallization on glass surface: Unexpected
mechanoluminescence and applications

Abstract: In this work, we discovered an unexpected mechanoluminescence (ML) phenomena occurring when transforming amorphous into crystalline, due to the stress-induced precipitation of CsPbBr3 perovskite nanocrystals on glass surface. It is revealed that, unlike the conventional thermal-induced phase transformation mechanism, the breakage of bonding of glass network provides the energy for nucleation and growth, and the shear stress avoids the long-range migration of structural units for crystallization. Such unique ML phenomenon enables the visualization of dynamical force that is inaccessible by common strategy, and so, opens up some novel applications, such as the pressuresensitive “glassy pencil” to learn people’s writing habits, and the Pb2+-detection with good sensitivity and selectivity. These findings not only demonstrate an effective route for the preparation of perovskite materials in a green, time-saving, low cost, and scalable way, enrich the knowledge of glass crystallization mechanism, but also exploit a useful avenue to quantitatively visualize the dynamical force.
PubDate: 2019-03-15
DOI: 10.1007/s12274-019-2338-3

• Polypyrrole-based hybrid nanostructures grown on textile for wearable
supercapacitors

Abstract: In the development of wearable energy devices, polypyrrole (PPy) is considered as a promising electrode material owing to its high capacitance and good mechanical flexibility. Herein, we report a PPy-based hybrid structure consisting of vertical PPy nanotube arrays and carbon nano-onions (CNOs) grown on textile for wearable supercapacitors. In this hybrid nanostructure, the vertical PPy nanotubes provide straight and superhighways for electron and ion transport, boosting the energy storage; while the CNOs mainly act as a conductivity retainer for the underlayered PPy film during stretching. A facile template-degrading method is developed for the large-area growth of the PPy-based hybrid nanostructures on the textile through one-step polymerization process. The fabricated stretchable supercapacitor exhibits superior energy storage capacitance with the specific capacitance of 64 F·g−1. Also, it presents the high capacitance retention of 99% at a strain of 50% after 500 stretching cycles. Furthermore, we demonstrate that the textile-based stretchable supercapacitor device can provide a stable energy storage performance in different wearable situations for practical applications. The use of the PPy-based hybrid nanostructures as the supercapacitor electrode offers a novel structure design and a promising opportunity for wearable power supply in real applications.
PubDate: 2019-03-14
DOI: 10.1007/s12274-019-2360-5

• The fabrication and application of Ni-DNA nanowire-based nanoelectronic
devices

Abstract: DNA is a self-assembled, double stranded natural molecule that can chelate and align nickel ions between its base pairs. The fabrication of a DNA-guided nickel ion chain (Ni-DNA) device was successful, as indicated by the conducting currents exhibiting a Ni ion redox reaction-driven negative differential resistance effect, a property unique to mem-elements (1). The redox state of nickel ions in the Ni-DNA device is programmable by applying an external bias with different polarities and writing times (2). The multiple states of Ni-DNA-based memristive and memcapacitive systems were characterized (3). As such, the development of Ni-DNA nanowire device-based circuits in the near future is proposed.
PubDate: 2019-03-14
DOI: 10.1007/s12274-019-2363-2

• Illumining phase transformation dynamics of vanadium oxide cathode by
multimodal techniques under operando conditions

Abstract: Subtle structural changes during electrochemical processes often relate to the degradation of electrode materials. Characterizing the minute-variations in complementary aspects such as crystal structure, chemical bonds, and electron/ion conductivity will give an in-depth understanding on the reaction mechanism of electrode materials, as well as revealing pathways for optimization. Here, vanadium pentoxide (V2O5), a typical cathode material suffering from severe capacity decay during cycling, is characterized by in-situ X-ray diffraction (XRD) and in-situ Raman spectroscopy combined with electrochemical tests. The phase transitions of V2O5 within the 0–1 Li/V ratio are characterized in detail. The V–O and V–V distances became more extended and shrank compared to the original ones after charge/discharge process, respectively. Combined with electrochemical tests, these variations are vital to the crystal structure cracking, which is linked with capacity fading. This work demonstrates that chemical bond changes between the transition metal and oxygen upon cycling serve as the origin of the capacity fading.
PubDate: 2019-03-12
DOI: 10.1007/s12274-019-2321-z

• Analysis of structural distortion in Eshelby twisted InP nanowires by
scanning precession electron diffraction

Abstract: Transmission electron microscopes (TEM) are widely used in nanotechnology research. However, it is still challenging to characterize nanoscale objects; their small size coupled with dynamical diffraction makes interpreting real- or reciprocal-space data difficult. Scanning precession electron diffraction ((S)PED) represents an invaluable contribution, reducing the dynamical contributions to the diffraction pattern at high spatial resolution. Here a detailed analysis of wurtzite InP nanowires (30–40 nm in diameter) containing a screw dislocation and an associated wire lattice torsion is presented. It has been possible to characterize the dislocation with great detail (Burgers and line vector, handedness). Through careful measurement of the strain field and comparison with dynamical electron diffraction simulations, this was found to be compatible with a Burgers vector modulus equal to one hexagonal lattice cell parameter despite the observed crystal rotation rate being larger (ca. 20%) than that predicted by classical elastic theory for the nominal wire diameter. These findings corroborate the importance of the (S)PED technique for characterizing nanoscale materials.
PubDate: 2019-03-12
DOI: 10.1007/s12274-019-2328-5

• Multiscale carbon foam confining single iron atoms for efficient
electrocatalytic CO 2 reduction to CO

Abstract: Electrocatalytic CO2 reduction to CO is a sustainable process for energy conversion. However, this process is still hindered by the diffusion-limited mass transfer, low electrical conductivity and catalytic activity. Therefore, new strategies for catalyst design should be adopted to solve these problems and improve the electrocatalytic performance for CO production. Herein, we report a multiscale carbon foam confining single iron atoms prepared with the assistant of SiO2 template. The pore-enriched environment at the macro-scale facilitates the diffusion of reactants and products. The graphene nanosheets at the nano-scale promote the charge transfer during the reaction. The single iron atoms confined in carbon matrix at the atomic-scale provide the active sites for electrocatalytic CO2 reduction to CO. The optimized catalyst achieves a CO Faradaic efficiency of 94.9% at a moderate potential of −0.5 V vs. RHE. Furthermore, the performance can be maintained over 60 hours due to the stable single iron atoms coordinated with four nitrogen atoms in the carbon matrix. This work provides a promising strategy to improve both the activity and stability of single atom catalysts for electrocatalytic CO2 reduction to CO.
PubDate: 2019-03-12
DOI: 10.1007/s12274-019-2316-9

• Mn 3 O 4 nanoparticles@reduced graphene oxide composite: An efficient

Abstract: Currently, industrial-scale NH3 production almost relies on energy-intensive Haber-Bosch process from atmospheric N2 with large amount of CO2 emission, while low-cost and high-efficient catalysts are demanded for the N2 reduction reaction (NRR). In this study, Mn3O4 nanoparticles@reduced graphene oxide (Mn3O4@rGO) composite is reported as an efficient NRR electrocatalyst with excellent selectivity for NH3 formation. In 0.1 M Na2SO4 solution, such catalyst obtains a NH3 yield of 17.4 μg·h−1·mg−1cat. and a Faradaic efficiency of 3.52% at −0.85 V vs. reversible hydrogen electrode. Notably, it also shows high electrochemical stability during electrolysis process. Density functional theory (DFT) calculations also demonstrate that the (112) planes of Mn3O4 possess superior NRR activity.
PubDate: 2019-03-12
DOI: 10.1007/s12274-019-2352-5

• A novel near-infrared light responsive 4D printed nanoarchitecture with
dynamically and remotely controllable transformation

Abstract: Four-dimensional (4D) printing is an emerging and highly innovative additive manufacturing process by which to fabricate pre-designed, self-assembly structures with the ability to transform over time. However, one of the critical challenges of 4D printing is the lack of advanced 4D printing systems that not only meet all the essential requirements of shape change but also possess smart, dynamic capabilities to spatiotemporally and instantly control the shape-transformation process. Here, we present a facile 4D printing platform which incorporates nanomaterials into the conventional stimuli-responsive polymer, allowing the 4D printed object to achieve a dynamic and remote controlled, on-time and position shape transformation. A proof-of-concept 4D printed brain model was created using near-infrared light (NIR) responsive nanocomposite to evaluate the capacity for controllable 4D transformation, and the feasibility of photothermal stimulation for modulating neural stem cell behaviors. This novel 4D printing strategy can not only be used to create dynamic 3D patterned biological structures that can spatiotemporally control their shapes or behaviors of transformation under a human benign stimulus (NIR), but can also provide a potential method for building complex self-morphing objects for widespread applications.
PubDate: 2019-03-12
DOI: 10.1007/s12274-019-2340-9

• Dependence of interface energetics and kinetics on catalyst loading in a
photoelectrochemical system

Abstract: Solar hydrogen production by the photoelectrochemical method promises a means to store solar energy. While it is generally understood that the process is highly sensitive to the nature of the interface between the semiconductor and the electrolyte, a detailed understanding of this interface is still missing. For instance, few prior studies have established a clear relationship between the interface energetics and the catalyst loading amount. Here we aim to study this relationship on a prototypical Si-based photoelectrochemical system. Two types of interfaces were examined, one with GaN nanowires as a protection layer and one without. It was found that when GaN was present, higher Pt loading (> 0.1 μg/cm2) led to not only better water reduction (and, hence, hydrogen evolution) kinetics but also more favorable interface energetics for greater photovoltages. In the absence of the protection layer, by stark contrast, increased Pt loading exhibited no measurable influence on the interface energetics, and the main difference was observed only in the hydrogen evolution kinetics. The study sheds new light on the importance of interface engineering for further improvement of photoelectrochemical systems, especially concerning the role of catalysts and protection layers.
PubDate: 2019-03-11
DOI: 10.1007/s12274-019-2346-3

• An integrated cathode with bi-functional catalytic effect for
excellent-performance lithium-sulfur batteries

Abstract: The high energy density of lithium-sulfur batteries (LSBs) is mainly based on the complex redox reactions and phase conversions. The sluggish redox kinetics and the large accumulation of soluble polysulfides in the electrolyte leads to low sulfur utilization and serious shuttle effect. Herein, an integrated sulfur cathode is constructed through a facile and large-scale method. It is composed of sulfur-N, S doped bamboo like CNTs@Co3S4 (CNTs@Co3S4) composites on polypropylene separator. The immobilized polysulfides on the CNTs@Co3S4 surface are further reduced/oxidized during the discharge/charge process via the efficient bi-functional catalytic effect of CNTs@Co3S4, resulting in the rapid conversion of LiPSs. Consequently, the integrated sulfur cathode delivers a high initial reversible capacity of 1,473.6 mAh·g−1 at 0.2 C and a high specific capacity of 979 mAh·g−1 at 1 C after 500 cycles as well as excellent cycling stability for 1,000 cycles with a high specific capacity of 362.5 mAh·g−1 at 5 C, which are superior to reported similar host materials.
PubDate: 2019-03-11
DOI: 10.1007/s12274-019-2334-7

• Nitrogen-doped graphene quantum dots: Optical properties modification and
photovoltaic applications

Abstract: In this work, we utilize a bottom-up approach to synthesize nitrogen self-doped graphene quantum dots (NGQDs) from a single glucosamine precursor via an eco-friendly microwave-assisted hydrothermal method. Structural and optical properties of as-produced NGQDs are further modified using controlled ozone treatment. Ozone-treated NGQDs (Oz-NGQDs) are reduced in size to 5.5 nm with clear changes in the lattice structure and ID/IG Raman ratios due to the introduction/alteration of oxygen-containing functional groups detected by Fourier-transform infrared (FTIR) spectrometer and further verified by energy dispersive X-ray spectroscopy (EDX) showing increased atomic/weight percentage of oxygen atoms. Along with structural modifications, GQDs experience decrease in ultraviolet–visible (UV–vis) absorption coupled with progressive enhancement of visible (up to 16 min treatment) and near-infrared (NIR) (up to 45 min treatment) fluorescence. This allows fine-tuning optical properties of NGQDs for solar cell applications yielding controlled emission increase, while controlled emission quenching was achieved by either blue laser or thermal treatment. Optimized Oz-NGQDs were further used to form a photoactive layer of solar cells with a maximum efficiency of 2.64% providing a 6-fold enhancement over untreated NGQD devices and a 3-fold increase in fill factor/current density. This study suggests simple routes to alter and optimize optical properties of scalably produced NGQDs to boost the photovoltaic performance of solar cells.
PubDate: 2019-03-11
DOI: 10.1007/s12274-019-2337-4

• Vacuum-tuned-atmosphere induced assembly of Au@Ag core/shell nanocubes
into multi-dimensional superstructures and the ultrasensitive IAPP
proteins SERS detection

Abstract: Utilizing vacuum-tuned-atmosphere induced dip coating method, we achieve the cross-dimensional macroscopic diverse self-assemblies by using one building block with one chemical functionality. Coordinated modulating the vacuum degree, colloid concentration and evaporation atmosphere, Au@Ag core/shell NCs can controllably assemble into diverse multi-dimensional superstructures. Under 0.08 MPa, we obtained the two-dimensional (2D) stepped superstructures with continuously tunable step width. In addition, we generated a series of tailorable nanoscale-roughened 2D Au@Ag NCs superstructures at 0.04 MPa, which exhibited the label-free ultrasensitive SERS detection for the different mutants of IAPP8-37 proteins. Under 0.01 MPa, we obtained the cross-dimensional tailorable Au@Ag NCs assemblies from random to macroscale 2D and three-dimensional (3D) densest superstructures by adjusting the capping ligand-environmental molecule interactions. This is a flexible method to generate as-prepared Au@Ag core/shell NCs into well-defined macroscopic diverse superstructures and to promote the exploitation into biological applications.
PubDate: 2019-03-11
DOI: 10.1007/s12274-019-2325-8

• Inverse opal manganese dioxide constructed by few-layered ultrathin
nanosheets as high-performance cathodes for aqueous zinc-ion batteries

Abstract: Considering the high safety, low-cost and high capacity, aqueous zinc ion batteries have been a potential candidate for energy storage ensuring smooth electricity supply. Herein, we have synthesized inverse opal manganese dioxide constructed by few-layered ultrathin nanosheets by a solution template method at mild temperature. The ultrathin nanosheets with the thickness as small as 1 nm are well separated without obvious aggregation. Used as cathode material for aqueous zinc ion batteries, the few-layered ultrathin nanosheets combined with the inverse opal structure guarantee excellent performance. A high specific discharge capacity of 262.9 mAh·g−1 is retained for the 100th cycle at a current density of 300 mA·g−1 with a high capacity retention of 95.6%. A high specific discharge capacity of 121 mAh·g−1 at a high current density of 2,000 mA·g−1 is achieved even after 5,000 long-term cycles. The ex-situ X-ray diffraction (XRD) patterns, selected-area electron diffraction (SAED) patterns and high-resolution transmission electron microscopy (HRTEM) results demonstrate that the discharge/charge processes involve the reversible formation of zinc sulfate hydroxide hydrate on the cathode while in-plane crystal structure of the layered birnessite MnO2 could be maintained. This unique structured MnO2 is a promising candidate as cathode material for high capacity, high rate capability and long-term aqueous zinc-ion batteries.
PubDate: 2019-03-11
DOI: 10.1007/s12274-019-2303-1

• Nanoscale monitoring of mitochondria and lysosome interactions for drug
screening and discovery

Abstract: Technology advances in genomics, proteomics, and metabolomics largely expanded the pool of potential therapeutic targets. Compared with the in vitro setting, cell-based screening assays have been playing a key role in the processes of drug discovery and development. Besides the commonly used strategies based on colorimetric and cell viability, we reason that methods that capture the dynamic cellular events will facilitate optimal hit identification with high sensitivity and specificity. Herein, we propose a live-cell screening strategy using structured illumination microscopy (SIM) combined with an automated cell colocalization analysis software, Cellprofiler™, to screen and discover drugs for mitochondria and lysosomes interaction at a nanoscale resolution in living cells. This strategy quantitatively benchmarks the mitochondria-lysosome interactions such as mitochondria and lysosomes contact (MLC) and mitophagy. The automatic quantitative analysis also resolves fine changes of the mitochondria-lysosome interaction in response to genetic and pharmacological interventions. Super-resolution live-cell imaging on the basis of quantitative analysis opens up new avenues for drug screening and development by targeting dynamic organelle interactions at the nanoscale resolution, which could facilitate optimal hit identification and potentially shorten the cycle of drug discovery.
PubDate: 2019-03-11
DOI: 10.1007/s12274-019-2331-x

• Insight of the stability and activity of platinum single atoms on ceria

Abstract: Single-atom catalysts (SACs) have recently attracted broad attention in the catalysis field due to their maximized atom efficiency and unique catalytic properties. An atomic-level understanding of the interaction between the metal atoms and support is vital for developing stable and high-performance SACs. In this work, Pt1 single atoms with loadings up to 4 wt.% were fabricated on ceria nanorods using the atomic layer deposition technique. To understand the Pt–O–Ce bond interfacial interactions, the stability of Pt1 single atoms in the hydrogen reducing environment was extensively investigated by using in situ diffuse reflectance infrared Fourier transform spectroscopy CO chemisorption measurements. It was found that ceria defect sites, metal loadings and high-temperature calcination are effective ways to tune the stability of Pt1 single atoms in the hydrogen environment. X-ray photoemission spectroscopy further showed that Pt1 single atoms on ceria are dominantly at a +2 valence state at the defect and step edge sites, while those on terrace sites are at a +4 state. The above tailored stability and electronic properties of Pt1 single atoms are found to be strongly correlated with the catalytic activity in the dry and water-mediated CO oxidation reactions.
PubDate: 2019-03-11
DOI: 10.1007/s12274-019-2351-6

• Atomistic insight into ordered defect superstructures at novel grain
boundaries in CuO nanosheets: From structures to electronic properties

Abstract: Determining atomistic structures of grain boundaries (GBs) is essential to understand structure–property interplay in oxides. Here, different GB superstructures in CuO nanosheets, including $$(11\bar1)$$ and (114) twinning boundaries (TBs) and (002)/(223) GB, are investigated. Unlike the lower-energy stoichiometric $$(11\bar1)$$ TB, both experimental and first-principles investigations reveal a severe segregation of Cu and O vacancies and a nonstoichiometric property at (114) TB, which may facilitate ionic transportation and provide space for elemental segregation. More importantly, the calculated electronic structures have shown the increased conductivity as well as the unanticipated magnetism in both (114) TB and (002)/(223) GB. These findings could contribute to the race towards the property-directing structural design by GB engineering.
PubDate: 2019-03-11
DOI: 10.1007/s12274-019-2354-3

• Sustained co-delivery of gemcitabine and cis-platinum via biodegradable
thermo-sensitive hydrogel for synergistic combination therapy of
pancreatic cancer

Abstract: Pancreatic cancer is one of the most devastating cancers with poor prognosis and no significant change in the survival rate over the past decades. Localized targeted drug delivery through interventional endoscopic ultrasonography-guided fine-needle injection (EUS-FNI) is an attractive and minimally invasive strategy for inoperable pancreatic cancer. An injectable in-situ formed long-lasting drug delivery system is a promising alternative for the localized treatment of pancreatic cancer via EUS-FNI. Here, a biodegradable thermo-sensitive copolymer hydrogel for the co-delivery of anticancer agents gemcitabine (GEM) and cis-platinum (DDP) was developed. This hydrogel is a free flowable liquid at room temperature that changes into a semi-solid hydrogel following injection in response to the physiological temperature. Both in vitro and in vivo drug release behaviors indicate sustained drug release of this delivery system. Synergistic cellular proliferation inhibition and desirable apoptosis promotion have been found when pancreatic cancer Bxpc-3 cells were co-cultured with this GEM-DDP/hydrogel system. After a single intratumoral injection, the dual-drug loaded hydrogel formulation exhibited superior anti-tumor efficacy and minimized systemic side effect on pancreatic cancer xenograft mouse model in comparison to the intravenously injected free GEM and DDP combination. In addition, a strong synergistic therapeutic effect of the GEM-DDP/hydrogel system against pancreatic cancer has been found in vitro and in vivo compared to the single-drug loaded hydrogel composites. The obtained findings suggest this developed thermo-sensitive copolymer hydrogel system as a potential universal carrier for the localized targeted delivery of multi-drugs, for use in a variety of inoperable solid tumors.
PubDate: 2019-03-11
DOI: 10.1007/s12274-019-2342-7

• Metal organic frameworks derived single atom catalysts for
electrocatalytic energy conversion

Abstract: The development of efficient and cost-effective catalysts to catalyze a wide variety of electrochemical reactions is key to realize the large-scale application of renewable and clean energy technologies. Owing to the maximum atom-utilization efficiency and unique electronic and geometric structures, single atom catalysts (SACs) have exhibited superior performance in various catalytic systems. Recently, assembled from the functionalized organic linkers and metal nodes, metal-organic frameworks (MOFs) with ultrafine porosity have received tremendous attention as precursors or self-sacrificing templates for preparing porous SACs. Here, the recent advances toward the synthesis strategies for using MOF precursors/templates to construct SACs are systematically summarized with special emphasis on the types of central metal sites. The electrochemical applications of these recently emerged MOF-derived SACs for various energy-conversion processes, such as oxygen reduction/evolution reaction (ORR/OER), hydrogen evolution reaction (HER), and CO2 reduction reaction (CO2RR), are also discussed and reviewed. Finally, the current challenges and prospects regarding the development of MOF-derived SACs are proposed.
PubDate: 2019-03-11
DOI: 10.1007/s12274-019-2345-4

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