W18O49-based photocatalyst: Enhanced strategies for photocatalysis employment

Due to its unique localized surface plasmon resonance (LSPR) effect, oxygen-deficient tungsten oxide (WO3-x) obtains almost full-spectrum response ability, which has great potential in solving energy and environmental problems. In WO3-x, W18O49 owns the highest degree of reduction, which is an ideal material for the preparation of full-spectrum responsive photocatalysts. However, inherent drawbacks still severely inhibit the photocatalytic activity of W18O49. Recently, great attention has been focused on enhancing the catalytic activity and comprehending the LSPR effect. In this review, the crystal and energy band structure of W18O49 have been introduced, and then the strategies to improve the relative photocatalysis performance have been discussed in detail, including morphology optimization, elemental doping, and fabricated composites. The mechanism of improving photocatalytic performance is summarized, such as enhancing light absorption, optimizing electron and band structure, and improving charge transfer mode. In addition, the development of W18O49 for applications, including degradation of organic pollutants, hydrogen evolution, nitrogen fixation, and carbon dioxide reduction, was comprehensively reviewed. Finally, prospects for the development of W18O49 photocatalysts as well as challenges are also discussed.