Noble-Metal-Free Janus-like Structures by Cation Exchange for Z-Scheme Photocatalytic Water Splitting under Broadband Light Irradiation.

Z-scheme water splitting is a promising approach based on high-performance photocatalysis by harvesting broadband solar energy. Its efficiency depends on the well-defined interfaces between two semiconductors for the charge kinetics and their exposed surfaces for chemical reactions. Herein, we report a facile cation-exchange approach to obtain compounds with both properties without the need for noble metals by forming Janus-like structures consisting of γ-MnS and Cu7 S4 with high-quality interfaces. The Janus-like γ-MnS/Cu7 S4 structures displayed dramatically enhanced photocatalytic hydrogen production rates of up to 718 μmol g-1  h-1 under full-spectrum irradiation. Upon further integration with an MnOx oxygen-evolution cocatalyst, overall water splitting was accomplished with the Janus structures. This work provides insight into the surface and interface design of hybrid photocatalysts, and offers a noble-metal-free approach to broadband photocatalytic hydrogen production.