Solid-state Z-scheme assisted hydrated tungsten trioxide/ZnIn_(2)S_(4) photocatalyst for efficient photocatalytic H_(2) production

Efficient water splitting for H_(2) evolution over semiconductor photocatalysts is highly attractive in the field of clean energy.It is of great significance to construct heterojunctions,among which the direct Z-scheme nanocomposite photocatalyst provides effective separation of photo-generated carriers to boost the photocatalytic performance.Herein,Z-scheme hydrated tungsten trioxide/ZnIn_(2)S_(4) is fabricated via an in-situ hydrothermal method where ZnIn_(2)S_(4) nanosheets are grown on WO_(3)·xH_(2)O.The close contact between WO_(3)·0.5H_(2)O and WO_(3)·0.33H_(2)O as well as ZnIn_(2)S_(4) improve the charge carrier separation and migration in the photocatalyst,where the strong reducing electrons in the conduction band of ZnIn_(2)S_(4) and the strong oxidizing holes in the valence band of WO_(3)·0.33H_(2)O are retained,leading to enhanced photocatalytic hydrogen production.The obtained WO_(3)·xH_(2)O/ZnIn_(2)S_(4) shows an excellent H_(2) production rate of 7200μmol g^(−1) h^(−1),which is 11 times higher than pure ZnIn_(2)S_(4).To the best of our knowledge,this value is higher than most of the WO_(3)-based noble metal-free semiconductor photocatalysts.The improved stability and activity are attributed to the formation of the Z-scheme heterojunction,which can markedly accelerate the interfacial charge separation for surface reaction.This work offers a promising strategy towards the design of an efficient Z-scheme photocatalyst to suppress electron–hole recombination and optimize redox potential.