An inclusive perspective on the recent development of tungsten-based catalysts for overall water-splitting: A review

The problems of energy shortages, environmental pollution and the ever-increasing global population are creating serious concerns for mankind. For a sustainable future, it is essential to explore clean and renewable alternate energy sources. The green energy consumption model aims towards a future with a competent and sustainable hydrogen economy to fulfill the global energy demands. Water-splitting is a promising method for clean hydrogen production. A highly active noble metal-free catalyst is the main pre-requisite, to make the process energy-efficient and economical. An optimum catalyst lowers the energy required for the disassociation of water by driving down the overpotential of the process. Tungsten-based materials are an considered effective catalyst for water-splitting due to natural availability, environmental friendliness, high photostability, high electron mobility, large hole diffusion length and high catalytic activities. In recent years, a diverse range of tungsten-based materials has been developed as photo/electro catalysts for water-splitting. This review aims to present a comprehensive understanding and timely reference for the progress of tungsten-based catalysts in this field. This study begins with the fundamental principle of water splitting and the properties of tungsten and its hybrids then moves on to different techniques for producing binary/ternary nanocomposites for overall water splitting. A comprehensive overview of the recent developments in tungsten-based photo/electro catalysts for overall water splitting is then presented with the techniques to enhance the catalyst activity, such as morphological control, surface modification, heteroatom doping, and heterojunction construction. Finally, recommendations for the future are proposed.