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Electrocatalytic water splitting, as a sustainable, pollution-free and convenient method of hydrogen production, has attracted the attention of researchers. However, due to the high reaction barrier and slow four-electron transfer process, it is necessary to develop and design efficient electrocatalysts to promote electron transfer and improve reaction kinetics. Tungsten oxide-based nanomaterials have received extensive attention due to their great potential in energy-related and environmental catalysis. To maximize the catalytic efficiency of catalysts in practical applications, it is essential to further understand the structure–property relationship of tungsten oxide-based nanomaterials by controlling the surface/interface structure. In this review, recent methods to enhance the catalytic activities of tungsten oxide-based nanomaterials are reviewed, which are classified into four strategies: morphology regulation, phase control, defect engineering, and heterostructure construction. The structure–property relationship of tungsten oxide-based nanomaterials affected by various strategies is discussed with examples. Finally, the development prospects and challenges in tungsten oxide-based nanomaterials are discussed in the conclusion. We believe that this review provides guidance for researchers to develop more promising electrocatalysts for water splitting. [ABSTRACT FROM AUTHOR]

Constructing a heterogeneous interface using different components is one of the effective measures to achieve the bifunctionality of nanocatalysts, while synergistic interactions between multiple interfaces can further optimize the performance of single-interface nanocatalysts. The non-precious metal nanocatalysts MoS2/NiSe2/reduced graphene oxide (rGO) bilayer sandwich-like nanostructure with multiple well-defined interfaces is prepared by a simple hydrothermal method. MoS2 and rGO are layered nanostructures with clear boundaries, and the NiSe2 nanoparticles with uniform size are sandwiched between both layered nanostructures. This multiple-interfaced sandwich-like nanostructure is prominent in catalytic water splitting with low overpotential for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) and almost no degradation in performance after a 20 h long-term reaction. In order to simulate the actual overall water splitting process, the prepared nanostructures are assembled into MoS2/NiSe2/rGO||MoS2/NiSe2/rGO modified two-electrode system, whose overpotential is only 1.52 mV, even exceeded that of noble metal nanocatalyst (Pt/C||RuO2~1.63 mV). This work provides a feasible idea for constructing multi-interface bifunctional electrocatalysts using nanoparticle-doped bilayer-like nanostructures. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS 2), as a classic two-dimensional material, is limited in applications with its relatively poor conductivity and chemical instability due to its single morphology/phase structure in electrocatalytic activity and specific capacitance. Moreover, up to date, it is still an open area in establishing cost-effective approaches to fabricate exotic MoS 2 nanostructures with desired morphology and phase component for exhibiting excellent performance in energy conversion and storage. Herein, only using extremely ordinary sources of molybdenum and sulfur and a simple one-pot hydrothermal method, we efficiently and economically synthesized two types of stable MoS 2 nanostructures with a certain percentage of the metastable metallic (1T) phase, i.e., spherical nanoflowers (SNF) and random nanosheets (RNS). Both SNF–MoS 2 and RNS-MoS 2 exhibited excellent electrocatalytic activity for hydrogen evolution reaction with ultra-high stability and high specific capacitance. These remarkable properties are due to the dramatically increased number of active sites in these unique nanostructures and their enhanced electric conductivities due to the metallic 1T phase. Furthermore, when these two types of nanostructures are physical decorated with carbon black, their electrocatalysis is further enhanced. Our findings offer an economical approach to fabricate stable MoS 2 -based nanomaterials for practical applications with highly efficient energy conversion and energy storage. Image 1 • Spherical nanoflower and random nanosheet MoS 2 are mixed with 1T phase. • The preparation method is extremely simple and cost effective. • SNF- and RNS-MoS 2 possess significant HER and supercapacitors performance. • HER performance is enhanced upon the physical mixing of carbon black. • Excellent stability is surveyed for HER. [ABSTRACT FROM AUTHOR]