Cu doping induced synergistic effect of S-vacancies and S-scheme Cu: Mn0.5Cd0.5S@CuS heterojunction for enhanced H2 evolution from photocatalytic seawater splitting

S-scheme heterojunction preserves strong redox capacity by the unique spatial separation of charge carriers, which will greatly boost the photocatalytic activity. In this study, Cu ions doped in Mn0.5Cd0.5S (MCS) nanorods (NRs) resulted in rich S vacancies in MCS. S vacancies can regulate the energy band structure of MCS and enable the transform of type-I MCS@CuS heterojunction into S-scheme Cu:MCS@CuS heterojunction. S-scheme Cu:MCS@CuS exhibited high light harvesting capability and the apparent quantum efficiency (AQE) under visible light, charge carriers separation and transfer ability and enhanced H2 production efficiency and stability from seawater. The H2 production rate of Cu: MCS @ CuS NRs in seawater under visible light reached up to 40.6 mmol g−1 h−1, and it could still remain above 80 % after six cycles. This study provides a new idea for the design and synthesis of high-efficiency catalysts for hydrogen production from seawater under visible light.