The mainstream electrocatalysts for direct ethanol fuel cells (DEFCs) are Pt- or Pd-based nanomaterials, which are severely hampered by CO intermediate poisoning and the relatively low selectivity of the C1 pathway in anodic ethanol oxidation reaction (EOR), thereby impeding the efficiency enhancement and practical application of DEFCs. Herein, we report a Pt-decorated amorphous PdS nanowire [denoted as a-Pd(S)NWs/Pt] catalyst with abundant crystalline/amorphous heterogeneous interfacial active sites for alkaline EOR. The a-Pd(S)NWs/Pt was demonstrated a superior EOR mass activity of 6.16 Amg(Pd+Pt)(-1), which is 22.81 times over that of commercial Pt/C (0.27 Amg(Pt)(-1)) and 34.22 times over that of commercial Pd/C (0.18 Amg(Pd)(-1)). Additionally, the a-Pd(S)NWs/Pt exhibited considerable stability, significantly enhanced resistance to CO poisoning and enhanced selectivity for the EOR C1 pathway. Density functional theory calculations and experimental results further revealed that the optimized COads and OHads binding energies due to the decoration of Pt nanoclusters can be responsible for the enhanced CO resistance and C1 selectivity of a-Pd(S)NWs/Pt. Furthermore, benefiting from its optimized electronic configuration at the interfacial active sites and the appropriate intermediate adsorption capacity, the a-Pd(S)NWs/Pt electrocatalyst was successfully extended to the electrocatalytic methanol and ethylene glycol oxidation reaction systems.

As a novel electrochemical energy conversion device, direct ethanol fuel cells are currently encountering two significant challenges: CO poisoning and the difficulty of C-C bond cleavage in ethanol. In this work, an amorphous PdS nanowires/ultrafine IrMnOx bimetallic oxides (denoted as a-PdS/IrMnOx NWs) catalyst with abundant oxide/metal (crystalline/amorphous) inverse heterogeneous interfaces was synthesized via a hydrothermal process succeeded by a nonthermal air-plasma treatment. This unique interfacial electronic structure along with the incorporation of oxyphilic metal has resulted in a significant enhancement in the electrocatalytic performance of a-PdS/IrMnOx NWs toward the ethanol oxidation reaction, achieving current densities of 12.45 mAcm(-2) and 3.68 Amg(Pd)(-1). Moreover, the C1 pathway selectivity for ethanol oxidation has been elevated to 47%, exceeding that of other as-prepared Pd-based counterparts and commercial Pd/C catalysts. Density functional theory calculations have validated the findings that the decoration of IrMn species onto the amorphous PdS surface has induced a charge redistribution in the interface region. The redistribution of surface charges on the a-PdS/IrMnOx NWs catalyst results in a significant decrease in the activation energy required for C-C bond cleavage and a notable weakening of the CO binding strength at the Pd active sites. Consequently, it enhanced both the EOR C1 pathway selectivity and CO poisoning resistance to the a-PdS/IrMnOx NWs catalyst.

The electrocatalytic oxidation of urea combined with wastewater splitting is considered a promising approach for sustainable hydrogen production, characterized by minimal energy consumption. However, its evolution is greatly hindered by the shortage of efficient and easily accessible electrocatalytic materials. Here, a facile electrochemical activation strategy was conceived and proposed to construct a Cu-doped NiOOH nanolayer encapsulated on Cu2O nanodendrites on Cu mesh substrate (Cu-NiOOH/Cu2O/CM) from the electrodeposited Ni/Cu2O/CM heterostructured precatalyst. It was verified that the incorporation of Cu not only facilitates the rapid formation of Ni(III) species but also contributes to the formation of Cu-Ni(III) bifunctional electrocatalytic active sites. Benefiting from the accessible Cu-Ni(III) dual active sites, high active surface area, good hydrophilic and aerophobic surface properties and superior electrical conductivity of the Cu mesh substrate, the as-prepared Cu-NiOOH/Cu2O/CM exhibits enhanced bifunctional electrocatalytic abilities for electrocatalytic urea oxidation reaction (UOR) and hydrogen evolution reaction (HER). Particularly, for the Cu-NiOOH/Cu2O/CM||Cu-NiOOH/Cu2O/CM configuration toward the UOR||HER coupled system, a significantly reduced cell voltage of 1.43 V vs. RHE @ 10 mA·cm−2 was obtained. The observed cell voltage for the conventional overall water splitting is approximately 190 mV higher than that observed for overall urea splitting. This study proposes a viable approach to achieve and optimize the bifunctional UOR/HER performance of NiOOH active species, which holds significant importance for efficient and stable hydrogen generation from urea-contaminated substandard water.

The corrosion interface characteristics and corrosion behavior of Cu-C alloys in liquid Ga at 100-180 degrees C were studied in this paper. The corrosion mechanism of Cu-C alloys was microscopically studied via the first-principles calculation based on the density functional theory (DFT). The results, the diffusion of Ga atoms leads to the phase transition of Cu in the Cu-C alloy and the generation of the corrosion product CuGa2. The corrosion rate of the Cu-C alloy is related to the dissolution rate, and growth rate and exfoliation rate of corrosion product layer. C led to much better corrosion resistance of Cu-C alloys.

This study aims to explore a preparation method based on a combination of melting and ultrasound to produce a Ga2O3/ZnO (GZ) spherical composite with a snake raspberry structure for the degradation of methyl orange at room temperature in dark. The catalyst exists in the form of a (GZ) composite and an anhydrous ethanol mixture after the ultrasonic treatment of premelted GaZn liquid metal alloy in anhydrous ethanol. The degradation activity of the catalyst was evaluated according to the amount of catalyst, alloy extraction temperature, acid–base environment, and inorganic salt ions. A transmission electron microscope (TEM) was used to confirm that the material was Ga2O3 coated with ZnO, with a structure similar to that of snakeberry. The electron paramagnetic resonance (EPR) and a series of free radical inhibition experiments demonstrated that ·O2− is produced during the ultrasonic preparation of the catalyst and plays an important role in the degradation process after adding MO. The removal rate of MO reached 99.75% at 3 min. Three possible degradation pathways were proposed based on the intermediates produced during the degradation process, which were identified by liquid chromatography–mass spectrometry (LC–MS). The results of this study may provide a new choice for the degradation of organic pollutants.

Constructing heteronanostructures is an essential approach for integrating multiple functionalities into one single entity. Here, PtCo/Co9S8 composites with bridging heterointerfaces are synthesized using an ultrafast hightemperature shock strategy. The oxygen electrocatalysis of PtCo/Co9S8 is remarkably enhanced by constructing the well-coupled Pt-Co-S interfaces in the composites, in which the Co acts as the bridging linkage. PtCo/Co9S8 composites show efficient bifunctional activities toward oxygen evolution and reduction reactions (OERs and ORRs). The OER overpotential (10 mA cm(-2)) and ORR half-wave potential reach 284 and 832 mV, respectively. The rechargeable aqueous zinc-air battery (ZAB) using PtCo/Co9S8 composites as air cathodes achieves high power density (262.5 mW cm-2) and long-term cycling life (more than 1000 cycles). Moreover, the assembled flexible solid-state ZAB can power electronic devices well. The theoretical results suggest that the catalytic sites of Co and Pt in the bridging interfaces could impressively optimize the adsorption/desorption/transformation of O* to OH*, thus lowering the ?G and facilitating the ORR process. This work provides an extremely promising strategy to develop bridging heterointerfaces for their application in energy storage and conversion systems.

The interface characteristics and corrosion behavior of Cu/C composites subjected to static corrosion in liquid gallium (Ga) were investigated. The results revealed that the wettability of Cu/C composites and liquid Ga was weakened by C phase, and the progress of corrosion was effectively hindered by C phase. At 720 h following corrosion, the corrosion thickness loss of Cu/C composites was only 33.37% of that of Cu. The corrosion products of Cu/C composites and Cu in liquid Ga were CuGa2. The CuGa2 and the residual C phase generated by the corroded Cu/C composites formed a mixed corrosion product layer, effectively preventing the composites from being corroded by liquid Ga. The diffusion of atoms can be blocked by C phase during the corrosion process, and thus the corrosion of the Cu/C composites and the growth of CuGa2 are inhibited.

As potential electrode materials with a high specific capacity, vanadium-based amorphous materials have attracted a great deal of attention in lithium-ion batteries (LIBs). Herein, different valence states of manganese, MnO2 and Mn2O3 are utilized to replace V in V2O5. The results reveal that the MnO2-substituted glass exhibits a high initial capacity of 1029.8 mAh g- 1 and preserves a capacity of 210.3 mAh g- 1 after 50 cycles at the current density of 10 mA g- 1 . After Mn substitution, the content of V4+ increases from 15.6% to 57.3% and 60.9%. Moreover, it is demonstrated that the increase in average valence state of Mn effectively suppresses the JahnTeller effect in the local structure. For instance, both VO and Li3MnO4 nano-crystals are identified after 50 charge/discharge cycles, whose synergistic effect with the amorphous matrix ameliorates the conductivity of the electrode and enhances the reaction kinetics. Furthermore, density functional theory calculations reveal that the substitution of Mn moves the Fermi level close to the conduction band to reduce the bond gap, corresponding to an increase in conductivity, and facilitates the charges transfer from Li to O contrarily, improving the cyclic stability of the anode material. The order-disorder transition mechanism presents a novel perspective for the selection of materials for LIBs

Amorphous vanadates are of increasing interest for use as electrode materials in lithium ion batteries. A series of (100-x)(40 V2O5-60TeO(2))-xCoO (x = 0, 5, 10, 15, 20, 25) glasses were obtained by traditional melt quenching method. The initial discharge capacity of the 40 V2O5-60TeO(2) glass was 416.0 mAh g(-1), while the initial discharge capacity of the 34 V2O5-51TeO(2)-15CoO (x = 15) glass reached 726.4 mAh g(-1). Among all glass samples, 34V2O5-51TeO2-15CoO glass had the highest V4+ content (52.26%) and showed the best electrical conductivity. The addition of CoO increases the content of V4+, realizing a multi-electron reaction of Co2+/Co-0, which enhances the electronic conductivity and capacity. It also increases the content of NBO as well as the number of VO5 units decreases with a corresponding increase in the number of VO4 units, leading to an inferior connection between structural units of glasses and loosening the glass structure. Consequently, the space for Li+ transmission increases, thereby providing more sites for Li+ insertion-extraction. This work provides a novel multi-electron reaction ternary glass anode material for the preparation of lithium-ion battery.

Highly active and durable electrocatalytic materials towards small molecules electro-oxidation reaction are critical to the large-scale commercial applications of direct liquid fuel cells.Unfortunately,current nanocrystalline electrocatalysts normally suffer from low catalytic efficiency,severe CO poisoning and rapid activity decay.Herein,we report a novel amorphous PdNiCuP catalyst synthesized with laser liquid ablation as a potential settlement to this issue.The as-obtained amorphous PdNiCuP catalyst exhibits enhanced electrocatalytic performance with the mass activity of 1.61 A mg-1 and 737.8 mA mg-1 towards methanol oxidation reaction(MOR)and formic acid oxidation reaction(FAOR),respectively.Moreover,amorphous PdNiCuP displays excellent operation stability and CO-poisoning resistance in both alkaline and acidic medium.P was proposed to play the decisive role for forming the amorphous structure and maintaining the catalytic stability in MOR and FAOR processes.This work provided insights for the ration design of active and durable amorphous electrocatalysts applied in direct liquid fuel cells.

As nickel-based alloys are more and more widely used in engineering fields for bearing cyclic loadings, it is necessary to study their very-high-cycle fatigue (VHCF) properties. In this paper, the fatigue properties of nickel-based alloy 625 were investigated using an ultrasonic fatigue test apparatus. The fracture microscopy shows that around the crack initiation site there are two characteristic zones, a rough area (RA) and a fine granular area (FGA). Inclusions caused the interior fatigue crack initiation, and the coalescence of neighboring micro cracks was strongly influenced by the local microstructure, resulting in the RA morphology. Subsequently, the contact and compressing of the crack surfaces contributed to the formation of the FGA. Finally, the stress intensity factors of the RA and FGA were quantitatively evaluated for further discussion of the crack initiation and propagation processes.

We have developed an efficient strategy to synthesize an active and durable electrocatalyst of Pd hydride nanocubes (NCs). Instead of the traditional chemical method, the PdH 0.43 NCs are firstly prepared via a hydrogen diffusion procedure, followed by hydrothermal synthesis of an amorphous CuO layer encapsulating the PdH 0.43 NCs to prevent the hydrogen atoms from escaping. Obvious lattice expansion is demonstrated playing a pivotal role in the enhancement of their oxygen reduction reaction (ORR) activity and durability. The obtained PdH 0.43 @CuO NCs catalysts exhibit an ORR mass activity of 0.18 A mg -1 at 0.90 V versus reversible hydrogen electrode in an alkaline medium, which is about five times higher than that of commercial Pt/C. Accelerated durability tests show that there is only a 32 mV decay in halfwave potential even after 10,0 0 0 potential cycles, indicating the excellent stability of PdH 0.43 @CuO NCs. Density functional theory (DFT) calculations also indicate that, compared to Pd, PdH 0.43 has a lower limiting barrier to form OH - during the ORR process. The present study illustrates the importance of lattice expansion caused by hydrogen and offers an available strategy to design highly efficient and durable Pdbased electrocatalysts for alkaline fuel cells. (c) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Developing robust and highly active non-precious electrocatalysts for the hydrogen/oxygen evolution reaction (HER/OER) is crucial for the industrialization of hydrogen energy. In this study, a highly active and durable single-atom W-doped NiS0.5 Se0.5 nanosheet @ NiS0.5 Se0.5 nanorod heterostructure (W-NiS0.5 Se0.5 ) electrocatalyst is prepared. W-NiS0.5 Se0.5 exhibits excellent catalytic activity for the HER and OER with ultralow overpotentials (39 and 106 mV for the HER and 171 and 239 mV for the OER at 10 and 100 mA cm-2 , respectively) and excellent long-term durability (500 h), outperforming commercial precious-metal catalysts and many other previously reported transition-metal-based compounds (TMCs). The introduction of single-atom W delocalizes the spin state of Ni, which results in an increase in the Ni d-electron density. This causes the optimization of the adsorption/desorption process of H and a significant reduction in the adsorption free energy of the rate-determining step (O* → OOH*), thus accelerating the thermodynamics and kinetics of the HER and OER. This work provides a rational feasible strategy to design single-atom catalysts for water splitting and to develop advanced TMC electrocatalysts by regulating delocalized spin states.

Transparent glass-ceramics based on ZnO–Al2O3–SiO2 (ZAS) glass system exhibit excellent optical and mechanical properties that are dependent on crystal grains. Gahnite (ZnAl2O4) was the main phase that crystallized in ZAS glass-ceramics via thermoelectric coupling treatment. The morphology and size of ZnAl2O4 crystal were controlled by the electric field strength. Introduction of thermoelectric coupling field led to the refinement and dispersion of large and agglomerated ZnAl2O4 crystal grains, which improved the transmission and Vickers' hardness of the ZAS-based glass-ceramics. Theoretical calculations revealed that crystal phase is the area of low electric field strength, which resulted in the migration of Zn ions (Zn2+) from glass phase to the ZnAl2O4 crystal regions under the effect of thermoelectric coupling field. The decrease in the amount of Zn2+ in glass phase further limited its grain growth, and refinement of ZnAl2O4 grains was achieved. This research shows an efficient and rapid approach to refine grains in ZAS glass-ceramics by application of thermoelectric coupling treatment.

Vanadium-based amorphous materials are an emerging category of lithium ion battery cathodes with high specific capacity and high voltage performance. In this study, we investigated the effect of fluorination on the performance of an amorphous vanadium-phosphorus-lithium (VPLi) cathode for lithium ion battery applications. Results show that the fluorinated product consists Li3VF6 and VF4 nanocrystals embedded in an amorphous phase when the V4+ content was in the range of 16.3% to 23.8%. VPFLi has an optimal specific capacity of 344.3 mAh g(-1) in the first cycle and 269.7 mAh g(-1) after 200 cycles at a current of 50 mA g(-1) within the voltage range of 1.5-4.2 V. VPLi has an amorphous structure, and the reversible V4+/V5+ lithiation process corresponds to the conversion between V2O5 and Li2V2O5 during the charge-discharge cycle. Compared to VPLi, VF4 and Li3VF6 crystals were found to convert into LiVP2O7 in VPFLi, which led to the increased specific capacity. Simulation based on density functional theory show that fluorine for oxygen has led to the movement of Fermi level moves towards the edge of the conduction band. Charge mostly transferred from Li to O which contributed to the improved cathode stability. This study provides a new perspective towards selecting novel cathode for lithium-ion batteries.

Sluggish water dissociation kinetics severely limits the rate of alkaline electrocatalytic hydrogen evolution reaction (HER). Therefore, finding highly active electrocatalysts and clarifying the mechanism of water dissociation are challenging but important. In this study, we report an integrated nanoporous nickel (np-Ni) catalyst with high alkaline HER performance and the origin of the corresponding enhanced catalytic activity. In 1 mol L−1 KOH solution, this np-Ni electrode shows an HER overpotential of 20 mV at 10 mA cm−2, along with fast water dissociation kinetics. The excellent performance is not only attributed to the large surface area provided by the three-dimensional interconnected conductive network but also from the enhanced intrinsic activity induced by the unique surface properties. Further studies reveal that the types of oxygen species that naturally form on the Ni surface play a key role in water dissociation. Remarkably, when the lattice oxygen almost disappears, the Ni surface terminates with adsorbed oxygen (Oads), exhibiting the fastest water dissociation kinetics. Density functional theory calculation suggests that when Oads acts as the surface termination of Ni metal, the orientation and configuration of polar water molecules are strongly affected by Oads. Finally, the H—OH bond of interfacial water molecules is effectively activated in a manner similar to hydrogen bonding. This work not only identifies a high-performance and low-cost electrocatalyst but also provides new insights into the chemical processes underlying water dissociation, thus benefiting the rational design of electrocatalysts.

V2O5-TeO2 (VT) is one of the promising vanadium-based materials for electrodes in Li-ion batteries, but its application is impeded by its low conductivity and poor capacity retention. The initial cyclic efficiency of V2O5-TeO2-Li2O(VTL) is enhanced by the addition of Li2O, implying that the pre-intercalation of Li-ions significantly improves the performance. The thermal treatment of VTL leads to the formation of V(2)O(5)and Li1.2V9O22 crystals in the polycrystalline state (VTL-X). The VT, VTL and VTL-X exhibited specific capacitie of 821.9, 842.1, and 867.2 mAh g(-1), respectively for the 1st cycle with respective retention rates of 19.6%, 19.5% and 27.5% after 1000 cycles. To elucidate the reaction mechanism, a structural simulation diagram of VTL during the heat treatment is modeled for the first time. The conversion of [VO5] to [VO4] transformed the structure of [TeO4] into [TeO3]. The DFT model reveals that the highest diffusion barriers for VTL and VTL-X are 0.49 eV and 0.16 eV, respectively. After crystallization, the conductivity and specific capacity of the resulting electrode material are significantly improved. LiV3O8 precipitated after 200 cycles promotes the reaction kinetics and specific ca-pacity. The synergistic effect of precipitating crystals impacts the glass structure, electrochemical reversibility, and reaction kinetics enormously, revealing the pivotal function of nanocrystal in regulating the battery cycling stability. The formation mechanism of nanocrystals during cycling is entirely different from thermal induced crystallization. The crystallization of glass electrodes during battery cycles helps to unfold the properties of glassy materials.

Transition metal chalcogenides (TMCs) have been identified as pre‐electrocatalysts for the oxygen evolution reaction (OER) and the high valent TMs in the in situ generated oxyhydroxides are considered to be the real OER catalytic center. However, the role of chalcogens for OER process has been ignored and not fully elucidated. Herein, it is discovered that about 2.8–3.5% of chalcogens remain in as oxidized derivatives at a steady state, which plays a vital role for enhancing the catalytic activity. A facile and spontaneous sulfurizing method is developed to synthesize sulfur‐doped NiCo‐(oxy)hydroxysulfides (NCOSH) nanosheets, in which the sulfur can directly bond with high‐valence TMs and keep them stable for OER catalysis. Theoretical and experimental results suggest that the S‐coordination in NCOSH can cause bond length strengthening and electronic modulation between TM‐S and TM‐O, thus enhancing the oxidation activity and stability of high‐valence TMs in NCOSH. Consequently, the as‐obtained NCOSH exhibits superior bifunctional activities and durability for oxygen electrocatalytic reactions, and also serves as a superb air cathode in rechargeable solid state Zn‐air batteries. This work sheds light on the rational design of (oxy)hydroxysulfides as efficient electrocatalysts and gains deeper fundamental insights on the enhancing mechanism of S in oxyhydroxysulfides for diverse electrochemical applications.

The excessive consumption of fossil energy caused an energy crisis and a series of environmental issues. Therefore, it is necessary to develop sustainable and clean energy sources. Electrocatalysts play an important role in the development of various new energy devices; in particular, high-efficiency and low-cost catalysts are essential for the large-scale application of these new devices. Among the many electrocatalysts, metal chalcogenides (sulfides, selenides, and tellurides) as emerging materials own abundant active sites and good electrical conductivity and are widely studied for their excellent electrocatalytic performances. This Perspective reviews the recent applications of metal chalcogenide materials in electrocatalysis, including hydrogen evolution reaction, oxygen evolution reaction, and electrolyzing water and specifically summarizes different optimization strategies and catalytic reaction mechanisms. The several regulation strategies include heteroatom doping, phase engineering, heterostructures, and hybrid materials, which are capable of improving conductivity, increasing active site exposure, and reducing the energy barrier of catalytic reactions to enhanced electrocatalytic performances. In Sec. IV, the existing problems and future challenges are proposed for the improvement of catalytic performance of metal chalcogenide materials, which provide an insight into and valuable guidelines for the future development of high-efficiency and low-cost electrocatalysts for new energy devices.

Abstract Developing robust nonprecious electrocatalysts towards hydrogen/oxygen evolution reaction (HER/OER) is crucial for the spread of hydrogen energy industrialization. Here, we prepared a highly active and durable electrocatalyst of W single-atoms doped NiS0.5Se0.5 nanosheets@NiS0.5Se0.5 nanorods heterostructure (W-NiS0.5Se0.5). The W-NiS0.5Se0.5 exhibits superior catalytic activity for HER and OER with an ultralow overpotential (39, 106 mV for HER and 171, 239 mV for OER) and excellent long-term durability (500 h) at 10 and 100 mA cm− 2, outperforming commercial precious-metal catalysts and many other reported transition-metal-based compounds. The spin state of Ni was delocalized by introducing low spin-state of W single-atom, thus increasing the electron density of Ni 2p orbital, optimizing the adsorption/desorption process of H, significantly reducing the energy barrier of the rate-determining step (O* → OOH*), finally accelerating thermodynamics and kinetics of HER/OER. This work provides a rational feasible strategy to design single-atom catalysts for water splitting and develop advanced transition metal-based electrocatalysts via regulating delocalized spin states.