Subjects -> METALLURGY (Total: 58 journals)
 Showing 1 - 10 of 10 Journals sorted alphabetically Acta Metallurgica Slovaca       (Followers: 2) Advanced Device Materials       (Followers: 6) American Journal of Fluid Dynamics       (Followers: 44) Archives of Metallurgy and Materials       (Followers: 9) Asian Journal of Materials Science       (Followers: 4) Canadian Metallurgical Quarterly       (Followers: 21) Complex Metals       (Followers: 2) Energy Materials : Materials Science and Engineering for Energy Systems       (Followers: 24) Graphene and 2D Materials       (Followers: 6) Handbook of Ferromagnetic Materials       (Followers: 1) Handbook of Magnetic Materials       (Followers: 2) High Temperature Materials and Processes       (Followers: 6) Indian Journal of Engineering and Materials Sciences (IJEMS)       (Followers: 11) International Journal of Metallurgy and Alloys       (Followers: 1) International Journal of Metals       (Followers: 7) International Journal of Minerals, Metallurgy, and Materials       (Followers: 11) International Journal of Mining and Geo-Engineering       (Followers: 4) Ironmaking & Steelmaking       (Followers: 5) ISIJ International - Iron and Steel Institute of Japan       (Followers: 26) Izvestiya Vuzov. Poroshkovaya Metallurgiya i Funktsional’nye Pokrytiya (Proceedings of Higher Schools. Powder Metallurgy аnd Functional Coatings)       (Followers: 2) JOM Journal of the Minerals, Metals and Materials Society       (Followers: 35) Journal of Central South University       (Followers: 1) Journal of Cluster Science Journal of Heavy Metal Toxicity and Diseases Journal of Iron and Steel Research International       (Followers: 11) Journal of Materials & Metallurgical Engineering       (Followers: 2) Journal of Materials Processing Technology       (Followers: 21) Journal of Metallurgical Engineering       (Followers: 4) Journal of Sustainable Metallurgy       (Followers: 3) Materials Science and Metallurgy Engineering       (Followers: 6) Metal Finishing       (Followers: 20) Metallurgical and Materials Engineering       (Followers: 7) Metallurgical and Materials Transactions A       (Followers: 41) Metallurgical and Materials Transactions B       (Followers: 32) Metallurgical and Materials Transactions E       (Followers: 2) Metallurgical Research and Technology       (Followers: 8) Metallurgy and Foundry Engineering       (Followers: 2) Mining, Metallurgy & Exploration Powder Diffraction       (Followers: 1) Powder Metallurgy       (Followers: 36) Powder Metallurgy and Metal Ceramics       (Followers: 8) Powder Metallurgy Progress       (Followers: 5) Practical Metallography       (Followers: 6) Rare Metals       (Followers: 3) Revista de Metalurgia Revista del Instituto de Investigación de la Facultad de Ingeniería Geológica, Minera, Metalurgica y Geográfica Revista Remetallica       (Followers: 1) Revue de Métallurgie Russian Metallurgy (Metally)       (Followers: 4) Science and Technology of Welding and Joining       (Followers: 7) Steel Times lnternational       (Followers: 19) Transactions of the IMF       (Followers: 14) Transactions of the Indian Institute of Metals       (Followers: 5) Tungsten Universal Journal of Materials Science       (Followers: 3) Welding in the World       (Followers: 7) Welding International       (Followers: 11) Вісник Приазовського Державного Технічного Університету. Серія: Технічні науки
Similar Journals
 Rare MetalsJournal Prestige (SJR): 0.454 Citation Impact (citeScore): 1Number of Followers: 3      Hybrid journal (It can contain Open Access articles) ISSN (Print) 1001-0521 - ISSN (Online) 1867-7185 Published by Springer-Verlag  [2626 journals]
• Editorial for advanced energy storage and conversion materials and
technologies
• PubDate: 2021-01-12

• Sensing mechanism of Ag/α-MoO 3 nanobelts for H 2 S gas sensor
• Abstract: Abstract Sensing mechanism is still a big problem in the field of gas sensor. In-depth study of the sensing mechanism can provide better ideas for the design of sensing materials, and it is also more conducive to the improvement in gas-sensing performance. In this work, Ag/α-MoO3 material was obtained by loading Ag in α-MoO3 nanobelts prepared by hydrothermal method. The material was characterized by field electron scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Comparing the gas sensing properties of α-MoO3 and Ag/α-MoO3, it is found that Ag effectively improves the selectivity of the material to H2S at 133 °C. The response of the 5 wt% Ag/α-MoO3 sensor to 100 × 10−6 hydrogen sulfide (H2S) is 225 and the detection limit is 100 × 10−9. The sensing mechanism was verified by gas chromatography and mass spectrometer (GC–MS), XPS and Fourier transform infrared spectroscopy (FTIR).
PubDate: 2021-01-12

• Multi-core–shell-structured LiFePO 4 @Na 3 V 2 (PO 4 ) 3 @C composite
for enhanced low-temperature performance of lithium-ion batteries
• Abstract: In this work, a multi-core–shell-structured LiFePO4@Na3V2(PO4)3@C (LFP@NVP@C) composite was successfully designed and prepared to address inferior low-temperature performance of LiFePO4 cathode for lithium-ion batteries. Transmission electron microscopy (TEM) confirms the inner NVP and outer carbon layers co-existed on the surface of LFP particle. When evaluated at low-temperature operation, LFP@NVP@C composite exhibits an evidently enhanced electrochemical performance in term of higher capacity and lower polarization, compared with LFP@C. Even at − 10 °C with 0.5C, LFP@NVP@C delivers a discharge capacity of ca. 96.9 mAh·g−1 and discharge voltage of ca. 3.3 V, which is attributed to the beneficial contribution of NVP coating. NASICON-structured NVP with an open framework for readily insertion/desertion of Li+ will effectively reduce the polarization for the electrochemical reactions of the designed LFP@NVP@C composite. Graphic abstract
PubDate: 2021-01-12

• Phase-field simulation of re-dissolution of γ′ phase in Ni–Al alloy
by continuous and second-order aging treatment
• Abstract: The morphology and kinetics evolution of the γ′(Ni3Al) phase during re-dissolution are studied in Ni-15 at% Al alloy, the changes of volume fraction and average particle radius of the γ′ phase were clarified with phase-field simulation. During isothermal aging, the interdistance of the neighboring γ′ phase affects the interface concentration gradient of Al, which dominates the growth or re-dissolution of the γ′ phase particle. After isothermal aging at 700 K, the alloy is continuously heated to 900 K with different heating rates, the re-dissolution lag happens, meaning the coalescence coarsening of adjacent γ′ phase particles still proceeds at the initial heating stage. The pre-dissolution of γ′ phase with cubic shape is re-dissolved firstly at the edges and corners, in continuous heating to 900 K or by second-order aging from 700 to 900 K. Different from continuous heating, in the second-order aging process, the connected particles with band shape are broken initially by re-dissolving. At different heating rates, the similar dynamic relationships are abstracted for the volume fraction and the heating rates, and the average particle radius and the heating rates. Graphic abstract
PubDate: 2021-01-12

• Improving phase transition temperature of VO 2 via Ge doping: a combined
experimental and theoretical study
• Abstract: Enhancing the semiconductor–metal phase transition temperature (TSMT) of VO2 is of great consequence for further exploring the potential applications of VO2 at elevated temperatures. In this study, Ge4+-doped VO2 (GexV1−xO2) samples were prepared by the hydrothermal and annealing approach. X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), differential scanning calorimetry (DSC) and resistivity–temperature (R-T) analyses were used to investigate the influence of Ge doping on the lattice structures and phase transition properties of GexV1–xO2 samples. We found that the lattice parameter of GexV1−xO2 decreased with the Ge concentration increasing from 2 at% to 18 at%, which was further supported by density functional theory (DFT)-based first-principle simulations. TSMT firstly increased from 64.5 to 73.0 °C at 8 at% Ge and then decreased to 71.5 °C at higher Ge concentration. Furthermore, DFT analysis revealed that the impact of lattice distortion induced by Ge doping rather than the changes in electronic structure is more pronounced on modulating TSMT of GexV1−xO2. The present work has pointed out the direction that the TSMT could be enhanced and illustrated the physical reason behind the regulation of TSMT in ions-doped VO2 systems. Graphic The d (logρ)/dT vs T curves are plotted for GexV1−xO2 (0≤x≤0.18) samples (a) un-doped VO2 ; (b) 2%; (c) 8%; (d) 18%, the transition temperatures upon heating, Th, and cooling, Tc. The difference between Th and Tc gives the hysteresis width, ΔTt, while the FWHM determines the sharpness of the semiconductor-to-metal transition
PubDate: 2021-01-12

• Thermal stability of bimodal grain structure in a cobalt-based superalloy
subjected to high-temperature exposure
• Abstract: The present work investigates the thermal stability and mechanical properties of a Co–20Cr–15W–10Ni (wt%) alloy with a bimodal grain (BG) structure. The BG structure consisting of fine grains (FGs) and coarse grains (CGs) is thermally stable under high-temperature exposure treatments of 760 °C for 100 h and 870 °C for 100–1000 h. The size of both FGs and CGs remains no significant changes after thermal exposure treatments. The microstructural stability is associated with the slow kinetics of grain growth and the pinning of carbides. The thermal stability enables to maintain the BG structures, leading to the same mechanical properties as the sample without thermal exposure treatment. In particular, the BG alloy samples after thermal exposure treatment exhibit superior mechanical properties of both high strength and high ductility compared to the unimodal grain (UG) structured ones. The BG structure of the alloy samples after thermal exposure is capable of avoiding severe loss of ductility and retaining high strength. More specifically, the ductility of the BG alloy samples after thermal exposure treatments of 870 °C for 500–1000 h is ten times higher (44.6% vs. 3.5% and 52.6% vs. 5.0%) than that of the UG ones. The finding in the present work may give new insights into high-temperature applications of the Co–20Cr–15W–10Ni alloy and other metallic materials with a BG structure. Graphical abstract
PubDate: 2021-01-12

• Fluorescent graphene oxide derived from carbonized citric acid for
copper(II) ions detection
• Abstract: Abstract Fluorescent graphene oxide (GO) nanoparticles were obtained from the thermal carbonization of citrate acid. Depending on the synthesizing temperature, the size of GO varied from several to several hundred nanometers. Owing to the confinement from the size, green and blue emissions at around 504 and 450 nm were observed from the GO suspension. These emissions could be dynamically quenched by titrating against copper (II) (Cu2+) ions, and the emission intensity was reduced exponentially as a function of Cu2+ concentration. The quenching mechanism was ascribed to the bridging of the surface –COOH and –OH groups by Cu2+, which restricted the vibration of edge atoms or clusters and reduced the number of luminophores of GO nanosheets. As a result, the concentration of Cu2+ was detectable with the fluorescent intensity of GO.
PubDate: 2021-01-10

• In situ deformation behavior of TC21 titanium alloy with different α
morphologies (equiaxed/lamellar)
• Abstract: To study the effect of α phase morphology (equiaxed α (αE)/lamellar α (αL)) on the in situ tensile behavior of TC21 alloy, the slip band, dislocation, crack initiation, and propagation were analyzed by scanning electron microscopy (SEM) with in situ tensile stage and transmission electron microscopy (TEM). The results show that the slip bands first concentrate in the αE phases and easily truncate at the α/β phase boundaries, whereas the slip bands move across the α lamellae in the αL phase. Microcracks are easily generated in αE or α/β phase boundaries with large plastic deformation. When the quantity of αL is more than αE, the crack tip is more easily deflected at α phases or α clusters with different orientations, making the main crack propagation path more zigzag. When the volume fraction ratio of αE to αL is ~ 3:4, i.e., the volume fraction of αE is close to that of αL, TC21 alloy exhibits better strength and slower crack propagation rate. Graphic abstract
PubDate: 2021-01-09

• Dielectric relaxation and conduction behaviors of Aurivillius Na 0.5 Bi
4.5 Ti 4 O 15 ceramics with Na doping
• Abstract: Abstract Aurivillius Na0.5Bi4.5Ti4O15 and Bi4Ti3O12 compounds were synthesized via solid-state reaction technique. X-ray powder diffraction study confirmed monophasic four-layered Na0.5Bi4.5Ti4O15 and three-layered Bi4Ti3O12 ceramics. Dielectric relaxation and conduction behaviors of Na-contained Na0.5Bi4.5Ti4O15 ceramics were thoroughly investigated in a large scale of temperature of 30–650 °C and frequency of 40 Hz–1 MHz. In addition, comparative studies of both the compounds were discussed. Impedance and modulus analyses revealed a single relaxation behavior in Na0.5Bi4.5Ti4O15 compound which was originated from the grain’s interior with grain resistance of 2.189 × 105 Ω and capacitance of 4.268 × 10−10 F at 570 °C. While in Bi4Ti3O12 ceramic the relaxation was due to the contributions of grain and grain boundaries. Alternating current (AC) conductivity analysis revealed the presence of two different conduction regions in both the compounds. Activation energies for the two different conduction mechanisms, i.e., in low-temperature region and in high-temperature region were calculated to be ~ 0.23 and ~ 1.27 eV at 1 kHz for Na0.5Bi4.5Ti4O15 compound and ~ 0.43 eV and ~ 0.97 eV at 1 kHz for Bi4Ti3O12 compound, respectively. The present study of dielectric relaxation and conduction behaviors would be helpful for further investigations of Na0.5Bi4.5Ti4O15-related Aurivillius compounds.
PubDate: 2021-01-09

• Electrolytes speed up development of zinc batteries
• PubDate: 2021-01-07

• Fabrication and characterization of nanoporous Ag–Pt alloy
• Abstract: Abstract Nanoporous Ag–Pt bi-metallic alloy was fabricated by free dealloying of amorphous Ag-based precursor with the nominal composition of Ag38.25Pt0.5Cu38.75Si22.5. The noble Ag and Pt were left after the less noble Cu and Si dissolved in a certain acid solution. Bi-continuous nanoporous microstructure was formed with asymmetric ligaments and pores with typically 30–200 nm in width. The trace addition of Pt has refined the grains of the ligaments to the average size of less than 20 nm in the substrate and induced the formation of rods with nanopores. The morphologies of the rods were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) both in the form of clusters and as scattered individuals with characteristic length of several micrometers and diameter of tens of nanometers. The grains sizes in the rods were finer than those in the ligaments. The good mechanical integrity might be due to the combination of continuous ligaments and clusters of rods.
PubDate: 2021-01-07

• Stacking fault, dislocation dissociation, and twinning in Pt 3 Hf
compounds: a DFT study
• Abstract: The Pt3Hf compound plays a decisive role in strengthening Pt–Hf alloy systems. Evaluating the stacking fault, dislocation dissociation, and twinning mechanisms in Pt3Hf is the first step in understanding its plastic behavior. In this work, the generalized stacking fault energies (GSFE), including the complex stacking fault (CSF), the superlattice intrinsic stacking fault (SISF), and the antiphase boundary (APB) energies, are calculated using first-principles calculations. The dislocation dissociation, deformation twinning, and yield behavior of Pt3Hf are discussed based on GSFE after their incorporation into the Peierls-Nabarro model. We found that the unstable stacking fault energy (γus) of (111)APB is lower than that of SISF and (010) APB, implying that the energy barrier and critical stress required for (111)APB generation are lower than those required for (010)APB formation. This result indicates that the $$a\left\langle {1\bar{1}0} \right\rangle$$ superdislocation will dissociate into two collinear $${a \mathord{\left/ {\vphantom {a 2}} \right. \kern-0pt} 2}\left\langle {1\bar{1}0} \right\rangle$$ superpartial dislocations. The $${a \mathord{\left/ {\vphantom {a 2}} \right. \kern-0pt} 2}\left\langle {1\bar{1}0} \right\rangle$$ dislocation could further dissociate into a $${a \mathord{\left/ {\vphantom {a 6}} \right. \kern-0pt} 6}\left\langle {\bar{1}\bar{1}2} \right\rangle$$ Shockley dislocation and a $${a \mathord{\left/ {\vphantom {a 3}} \right. \kern-0pt} 3}\left\langle {2\bar{1}\bar{1}} \right\rangle$$ super-Shockley dislocation connected by a SISF, which results in an APB → SISF transformation. The study also discovered that Pt3Hf exhibits normal yield behavior, although the cross-slip of a $${a \mathord{\left/ {\vphantom {a 2}} \right. \kern-0pt} 2}\left\langle {1\bar{1}0} \right\rangle$$ dislocation is not forbidden, and the anomalous yield criterion is satisfied. Moreover, it is observed that the energy barrier and critical stress for APB formation increases with increasing pressure and decreases as the temperature is elevated. When the temperature rises above 1400 K, the $${a \mathord{\left/ {\vphantom {a 2}} \right. \kern-0pt} 2}\left\langle {1\bar{1}0} \right\rangle$$ dislocation slipping may change from the {111} planes to the {100} planes. Graphical abstract
PubDate: 2021-01-07

• High-pseudocapacitance of porous and square NiO@NC nanosheets for
high-performance lithium-ion batteries
• Abstract: Layered nickel oxides have been focused with intense research interests as high-performance lithium-ion batterie (LIB) anode. However, it is hard to obtain few layered nickel oxides material directly as it easily forms bulk material with the strong interaction between the interlayer. In this work, two-dimensional (2D) nickel-based coordination polymers were successfully prepared according to aqueous phase copolymerization approach. And then uniform carbon-doped NiO nanosheets were successfully obtained from facile solution assembly and post-thermal treatment. The detailed electrochemical testing shows that the uniform NiO nanocrystals encapsulated into porous N-doped carbon (NiO@NC) nanosheets present much higher rate capability with the discharge specific capacity of 782.7 mAh·g−1 at high current density of 2.0 A·g−1 than pure NiO (690 mAh·g−1). It also shows long-term cycling performance with 91% retention after 50 cycles at 1.0 A·g−1. The high rate capability, cycling stability and the easy synthesis make NiO@NC nanosheets as a promising candidate for LIB anode and build up new way for the fabrication of metal oxides anode materials. Graphical abstract
PubDate: 2021-01-07

• Photocatalytic and photochemical processes of AgCl/TiO 2 studied with a
fully integrated X-ray photoelectron spectrometer
• Abstract: A fully integrated X-ray photoelectron spectrometer (XPS) was employed for the investigation of the separation processes and recombination behaviors of photogenerated electrons and holes on the surface of AgCl and ultra-small nano-titanium oxide cluster composite photocatalyst (AgCl/TiO2). A facile route, by direct colloidal synthesis, for preparing AgCl/TiO2 with high stability and enhanced visible light (Vis) driven catalytic activity was reported. The photocatalytic activity of AgCl/TiO2, which revealed that the photo-degradation rate of the as-prepared AgCl/TiO2 was nearly 10.5 times higher than that of bare AgCl, was evaluated by applying it to the photo-degradation of methyl orange (MO) in water solution. Moreover, AgCl/TiO2 exhibited an outstanding long-term stability during ten cycles of photo-degradation. The band gap of AgCl decreased from 3.25 to 2.85 eV because of the ultra-small nano-TiO2 clusters that were pinned to its surface. The results indicate that the band gap narrowing and surface plasmon resonance (SPR) of Ag (0) were two major contributors to the enhancement of the photocatalytic activity of AgCl/TiO2 by improving the utilization of Vis. In situ XPS analysis was, therefore, certified as a beneficial method to explore the catalytic mechanism of photocatalysts. Graphic abstract
PubDate: 2021-01-07

• Rare earth element-doped porous In 2 O 3 nanosheets for enhanced
gas-sensing performance
• Abstract: Rare earth (La, Pr, Sm, Ce and Yb)-doped porous In2O3 nanosheets are prepared by a solvothermal method. The effect of rare earth elements on the structure, morphologies and gas-sensing performance of In2O3 nanosheets is systematically investigated. The mixed phase composed of c-In2O3 and rh-In2O3 can be transformed into rh-In2O3 by doping with rare earth elements. After doping with rare earth elements, the morphology can be changed from compact nanosheets to porous sheets. Compared with pure In2O3 and La, Pr, Sm, Ce-doped porous In2O3 nanosheets, Yb-doped In2O3 nanosheets present the best gas-sensing performance. Among 3%–10% Yb-doped samples, 6% Yb-doped In2O3 porous nanosheets exhibit the optimal gas-sensing performance to 5 × 10−6–750 × 10−6 acetone, giving a high response of 15.3 toward 50 × 10−6 acetone and fast response/recovery time at the operating temperature of 220 °C. Moreover, 6% Yb-doped porous In2O3 nanosheet sensor also exhibits excellent selectivity and stability, indicating its potential in the next-generation gas sensor. Graphic abstract
PubDate: 2021-01-07

• Electrochemical dissolution behavior of gold and its main coexistent
sulfide minerals in acid thiocyanate solutions
• Abstract: Electrochemical tests were developed to investigate the electrochemical dissolution behavior of gold and its main coexistent sulfide minerals in acid thiocyanate solutions. The optimal leaching conditions for gold in acidic thiocyanate system were pH 2, 0.15 mol·L−1 thiocyanate and 0.2 g·L−1 Fe3+. Fe3+ addition to the acidic thiocyanate system promoted gold dissolution significantly, arsenopyrite dissolution was inhibited, chalcopyrite dissolution was increased, and the dissolution behavior of other associated minerals remained mostly unchanged. Thiocyanate made gold and associated mineral leaching easier. The galvanic corrosion effect of gold and its main coexistent sulfide minerals in an acidic thiocyanate-free system was that the chalcocite, arsenopyrite and pyrite acted as a cathode to reduce anodic gold dissolution; galena as an anode undergoes oxidation to inhibit anodic gold dissolution. There was almost no galvanic corrosion behavior between stibnite, yellow sphalerite and black sphalerite and gold. Thiocyanate addition changed the galvanic corrosion behavior of stibnite and yellow sphalerite in the thiocyanate system, which inhibited anodic gold dissolution. In the acidic thiocyanate system in the presence of ferric iron, the arsenopyrite promoted anodic gold dissolution, the chalcocite and gold were mostly free of galvanic corrosion, and the remaining minerals inhibited anodic gold dissolution.
PubDate: 2021-01-07

• Chemical synthesis and characterization of SmCo 5 /Co magnetic
nanocomposite particles
• Abstract: Magnetic nanocomposite material has been widely focused for the potential to become the next generation of magnetic material. In this paper, two kinds of chemical coating methods were used to prepare SmCo5/Co nanocomposite particles which were further characterized and compared. The two methods were carried out by using different materials and at different temperatures. In Method I, oleylamine (OAm), oleic acid and Ca(acac)2 were used and the reaction was carried out at the temperature of 300 °C. In Method II, anhydrous isopropanol, polyvinylpyrrolidone (PVP), N2H4·H2O and CoCl2·6H2O were used and the reaction temperature was ~ 55 °C. It was found that by using the two methods, the growth and the crystal structure of the Co nanoparticles (NPs) are different. In Method I, epitaxial growth on the surface of SmCo5 NPs was observed and the Co NPs were in a face-centered close packing crystal structure. While in Method II, the coated Co NPs were self-nucleated with a crystal structure of hexagonal close packing. Using Method II with the addition of surfactant, anisotropic nanocomposite particles were achieved with an enhanced saturated magnetization of 84.2 A·m2·kg−1. And the coercivity change of the NPs illustrates that a nonmagnetic interlayer between the hard and soft magnetic phase is beneficial to maintain the coercivity. Graphic abstract
PubDate: 2021-01-07

• When thermoelectric materials come across with magnetism
• Abstract: Nowadays, thermoelectric materials have attracted a lot of attention as they can directly convert heat into electricity and vice versa. However, while strenuous efforts have been made, those conventional strategies are still inevitably going to meet their performance optimization limits. For this reason, brand new strategies are badly needed to achieve further enhancement. Here, the roles played by magnetism in recent advances of thermoelectric optimization are concluded. Firstly, magnetic thermoelectric materials can just be treated like other normal materials because the use of universal optimization strategies can still get good results. So, it is not a situation which is all or nothing and the tactics of using magnetism for thermoelectric optimization can coexist with other strategies. Besides, through magnetic doping, we can introduce and adjust magnetism in materials for further optimization. Magnetism provides more possibilities in thermoelectric optimization as it can directly influence the spin states in materials. Furthermore, in the form of magnetic second-phase nanoclusters, magnetism can be introduced to thermoelectric materials to conquer the dilemma that the solid solubility of many magnetic ions in thermoelectric materials is too low to have any significant effect on thermoelectric properties. Finally, when exposed to an external magnetic field, topological materials can rely on its unique band structures to optimize. Graphic
PubDate: 2021-01-07

• Cobalt monosulfide nanofibers: ethanol sensing and magnetic properties
• Abstract: Metal sulfide nanomaterials have attracted great interest because of their excellent properties and promising applications in sensing, energy harvesting, magnetic and optoelectronic devices, especially their well-aligned crystalline nanostructures are highly desirable for the enhanced performance and novel applications. In this study, the cobalt monosulfide (CoS) nanofibers with uniform shape and good crystallinity were firstly obtained via electrospinning and atmospheric calcination routes under controllable conditions. It was found that the CoS nanofibers exhibited ethanol sensing properties at the optimum working temperature of 200 °C, the response was 11.6 toward 100 × 10−6 ethanol gas, and the CoS nanofibers-based sensor exhibits a short response time and recovery time of 5 and 6 s at the optimum temperature, respectively, the result also shows that the sensor has good stability after 50 days, which would be a favorable characteristic as a promising sensor. In addition, the Pauli paramagnetic property of CoS nanofibers was also investigated at room temperature. Graphic abstract
PubDate: 2021-01-07

• Enhanced formaldehyde sensitivity of two-dimensional mesoporous SnO 2 by
nitrogen-doped graphene quantum dots
• Abstract: Formaldehyde (HCHO) is widely known as an indoor air pollutant, and the monitoring of the gas has significant importance. However, most HCHO sensing materials do not have low detection limits and operate at high temperatures. Herein, two-dimensional (2D) mesoporous ultrathin SnO2 modified with nitrogen-doped graphene quantum dots (N-GQDs) was synthesized. The N-GQDs/SnO2 nanocomposite demonstrated high efficiency for HCHO detection. With the addition of 1.00 wt% N-GQDs, the response (Ra/Rg) of SnO2 gas sensor increased from 120 to 361 at 60 °C for the detection of 10 × 10−6 HCHO. In addition, the corresponding detection limit was as low as 10 × 10−9. Moreover, the sensor exhibited excellent selectivity and stability for the detection of HCHO. The enhanced sensing performance was attributed to both the large specific surface area of SnO2 and electron regulation of N-GQDs. Therefore, this study presents a novel HCHO sensor, and it expands the research and application potential of GQDs nanocomposites. Graphical abstract
PubDate: 2021-01-07

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