Unraveling the surface self-reconstruction of Fe-doped Ni-thiophosphate for efficient oxygen evolution reaction.

Surface self-reconstruction of oxygen evolution reaction (OER) electrocatalysts generally occurs during the electrochemical activation process. Herein, we study the surface self-reconstruction of a 2D layered Fe-doped Ni-thiophosphate (NixFe1-xPS3) nanosheet. The role of Fe in the surface self-reconstruction of NiPS3 during the OER is investigated by using an in situ Raman analysis. Formation of amorphous metal/non-metal oxide layers on the surface of NixFe1-xPS3 can efficiently act as the ultimate catalytic center for the OER.

Recent advances in the biomolecules mediated synthesis of nanoclusters for food safety analysis.

The development of nanoclusters based on incorporating biomolecules like proteins, lipids, enzymes, DNA, surfactants, and chemical stabilizers creates a stable and high fluorescence bio-sensors promising future due to their high sensitivity, high level of detection and better selectivity. This review addresses a comprehensive and systematic overview of the recent development in synthesizing metal nanocluster by various strategized synthesis techniques. Significantly, the application of nanometal clusters for the detection of various food contaminants such as microorganisms, antibodies, drugs, pesticides, metal contaminants, amino acids, and other food flavors have been discussed briefly concerning the detection techniques, sensitivity, selectivity, and lower limit of detection. The review further gives a brief account on the future prospects in the synthesis of novel metal nanocluster-based biosensors, and their advantages, shortcomings, and potential perspectives toward their application in the field of food safety analysis.

Internal Thermal Stress-Driven Phase Transformation in Van der Waals Layered Materials.

High pressure or strain is an effective strategy for generating phase transformations in van der Waals (vdW) layered materials without introducing defects, but this approach remains difficult to perform consistently. We present a scalable and facile method for achieving phase transformation in vdW materials, wherein solid vdW materials are subject to internal thermal stress within a molten metal mantle as it undergoes cooling. This internal thermal stress is principally the product of differential thermal expansion between mantle and core and can be tuned by the mantle material and temperature conditions. We validated this approach by achieving phase transformation of red phosphorus to black phosphorus, and metallic 1T'- to semiconducting 2H-MoTe2 crystals. We further demonstrate quantum electronic phase transformation of suppressed charge density wave in TiSe2 by means of electron-phonon coupling using the same system.

Atomic and structural modifications of two-dimensional transition metal dichalcogenides for various advanced applications.

Two-dimensional (2D) transition metal dichalcogenides (TMDs) and their heterostructures have attracted significant interest in both academia and industry because of their unusual physical and chemical properties. They offer numerous applications, such as electronic, optoelectronic, and spintronic devices, in addition to energy storage and conversion. Atomic and structural modifications of van der Waals layered materials are required to achieve unique and versatile properties for advanced applications. This review presents a discussion on the atomic-scale and structural modifications of 2D TMDs and their heterostructures via post-treatment. Atomic-scale modifications such as vacancy generation, substitutional doping, functionalization and repair of 2D TMDs and structural modifications including phase transitions and construction of heterostructures are discussed. Such modifications on the physical and chemical properties of 2D TMDs enable the development of various advanced applications including electronic and optoelectronic devices, sensing, catalysis, nanogenerators, and memory and neuromorphic devices. Finally, the challenges and prospects of various post-treatment techniques and related future advanced applications are addressed.

Substitutional Vanadium Sulfide Nanodispersed in MoS2 Film for Pt-Scalable Catalyst.

Among transition metal dichalcogenides (TMdCs) as alternatives for Pt-based catalysts, metallic-TMdCs catalysts have highly reactive basal-plane but are unstable. Meanwhile, chemically stable semiconducting-TMdCs show limiting catalytic activity due to their inactive basal-plane. Here, metallic vanadium sulfide (VSn ) nanodispersed in a semiconducting MoS2 film (V-MoS2 ) is proposed as an efficient catalyst. During synthesis, vanadium atoms are substituted into hexagonal monolayer MoS2 to form randomly distributed VSn units. The V-MoS2 film on a Cu electrode exhibits Pt-scalable catalytic performance; current density of 1000 mA cm-2 at 0.6 V and overpotential of -0.08 V at a current density of 10 mA cm-2 with excellent cycle stability for hydrogen-evolution-reaction (HER). The high intrinsic HER performance of V-MoS2 is explained by the efficient electron transfer from the Cu electrode to chalcogen vacancies near vanadium sites with optimal Gibbs free energy (-0.02 eV). This study provides insight into ways to engineer TMdCs at the atomic-level to boost intrinsic catalytic activity for hydrogen evolution.

Morphology restrained growth of V2O5 by the oxidation of V-MXenes as a fast diffusion controlled cathode material for aqueous zinc ion batteries.

Herein, we report morphology controlled growth of layered V2O5 on V2C by the oxidation of V-MXenes at different temperatures and used it as a cathode material for Zn-ion batteries (ZIBs). Hence, the V2O5 nanoparticles are uniformly grown on the V2C nanosheets with interlinked disordered carbon which provide fast diffusion and high rate performance in aqueous zinc-ion batteries.

In situ grown nickel selenide on graphene nanohybrid electrodes for high energy density asymmetric supercapacitors.

Nickel selenide (NiSe) nanoparticles uniformly supported on graphene nanosheets (G) to form NiSe-G nanohybrids were prepared by an in situ hydrothermal process. The uniform distribution of NiSe on graphene bestowed the NiSe-G nanohybrid with faster charge transport and diffusion along with abundant accessible electrochemical active sites. The synergistic effect between NiSe nanoparticles and graphene nanosheets for supercapacitor applications was systematically investigated for the first time. The freestanding NiSe-G nanohybrid electrode exhibited better electrochemical performance with a high specific capacitance of 1280 F g-1 at a current density of 1 A g-1 and a capacitance retention of 98% after 2500 cycles relative to that of NiSe nanoparticles. Furthermore, an asymmetric supercapacitor device assembled using the NiSe-G nanohybrid as the positive electrode, activated carbon as the negative electrode and an electrospun PVdF membrane containing 6 M KOH as both the separator and the electrolyte delivered a high energy density of 50.1 W h kg-1 and a power density of 816 W kg-1 at an extended operating voltage of 1.6 V. Thus, the NiSe-G nanohybrid can be used as a potential electrode material for high-performance supercapacitors.