Structural design of TiO₂-based photocatalyst for H₂ production and degradation applications

TiO₂-based photocatalysts, being inexpensive and abundant, in conjunction with having high photostability and environmentally friendly characteristics, are the most extensively studied photocatalytic material for hydrogen production and pollutant degradation. However, its existing issues, such as wide bandgap, high overpotential and rapid recombination of photogenerated carriers limit its photocatalytic properties. The opportunities for structural development of a TiO₂ nanomaterial towards highly efficient and pragmatic photocatalysis applications are evidently plentiful. Hence, in this review, we will look into critical structural engineering strategies that give favorable physicochemical properties such as improved light absorption, photostability, charge-carrier dynamics, increase surface area etc. that benefit photocatalysis functionalities. Amongst the various structural engineering options, we will be covering the most prevalent and elegant core-shell and hierarchical structural designs, which rationally combine the advantages of structural manipulation and multi-material composition engineering. This review aims to provide a comprehensive and contemporary overview, as well as a guide of the development of new generation TiO₂ based photocatalysts via structural design for improved solar energy conversion technologies.