Design of AgxAu1-x alloy/ZnIn2S4 system with tunable spectral response and Schottky barrier height for visible-light-driven hydrogen evolution

A 3-dimensional AgxAu1-x alloy/ZnIn2S4 system (AgxAu1-x/ZIS) has been designed and constructed for high-efficiency H-2 production ability under visible light. In this system, the AgxAu1-x alloyed nanoparticles (NPs) are deposited on ZIS microsphere self-assembled by ZIS sheets, and have an intimate contact with ZIS. The elaborate construction of AgxAu1-x/ZIS makes it own remarkable advantages in driving and controlling light-related reaction. Firstly, the maximizing of optical adsorption properties can be achieved via coupling of ZIS with plasmonic AgxAu1-x NPs in one system, and the absorption band can be tuned by plasmon hybridization through regulating the proportion of Ag and Au in AgxAu1-x NPs. Secondly, the Schottky barrier height formed at AgxAu1-x NPs and ZIS interface could be adjusted by adapting the Ag-Au metal alloy composition, and the optimal height of Schottky barrier (Ag0.6Au0.4/ZIS) plays a key role in prolonging electron-hole pair lifetimes and making them capable of facilitating chemical reactions. All of these lead to the significant improvement of H-2 production ability. The H-2 production ability of Ag0.6Au0.4/ZIS is 7.1 times higher than that of ZIS under the same condition after 10 h irradiation. The Apparent quantum yield (AQY) of Ag0.6Au0.4/ZIS is about 8.06%. Based on the results, a mechanism is proposed for Ag0.6Au0.4/ZIS.