Junction of ZnmIn2S3+m and bismuth vanadate as Z-scheme photocatalyst for enhanced hydrogen evolution activity: The role of interfacial interactions

A series of Zn m In 2 S 3+m photocatalysts were synthesized to show tunable band gap energy with the variation of Zn/S atomic ratio. The junction of Zn m In 2 S 3+m and BiVO 4 led to intimate interfacial contacts. Both experimental and theoretical results implied that electrons flowed from Zn m In 2 S 3+m to BiVO 4 at the Zn m In 2 S 3+m /BiVO 4 interface to form built-in electric field due to the variation of Fermi level, which promised Z scheme charge transfer feature for improving separation of charge carriers for enhanced photocatalytic performance. A higher degree of charge transfer process occurred for Zn 2 In 2 S 5 /BiVO 4 heterostructure promised stronger built-in electric field, higher charge separation efficiency and improved photocatalytic activity in comparison to ZnIn 2 S 4 /BiVO 4 and Zn 3 In 2 S 6 /BiVO 4 heterojunctions . The optimal hydrogen production rate of Zn 2 In 2 S 5 /BiVO 4 photocatalyst is 8.42 mmol•g −1 •h −1 with apparent quantum yield of 22.32 % at 435 nm, which is about 2.2 and 1.5 times higher than that of ZnIn 2 S 4 /BiVO 4 and Zn 3 In 2 S 6 /BiVO 4 , respectively.