Cocatalyst designing: a binary noble-metal-free cocatalyst system consisting of ZnIn2S4 and In(OH)3 for efficient visible-light photocatalytic water splitting

Abstract

A binary noble-metal-free cocatalyst consisting of ZnIn₂S₄ and In(OH)₃ was developed via a facile one-step hydrothermal method. The ZnIn₂S₄/In(OH)₃ modified ZnWO₄ nanocomposite exhibited enhanced photocatalytic H₂ evolution activity compared to all the related pure samples and binary composite photocatalysts under visible light irradiation. The enhanced photocatalytic hydrogen production activities can be attributed to the synergistic effects of the favorable light trapping ability and efficient spatial charge separation. The photocatalytic hydrogen evolution activity over other semiconductors, such as Zn₂SnO₄ and TiO₂, can also be significantly increased by loading ZnIn₂S₄/In(OH)₃ as a cocatalyst. The results clearly demonstrated that ZnIn₂S₄/In(OH)₃ is discovered as a new class of earth-abundant cocatalyst for water-splitting under visible light irradiation. It is expected that our work could provide a new strategy to improve the visible light response of semiconductors and facilitate their application in water splitting.