Composition-dependent activity of ZnxCd1-xSe solid solution coupled with Ni2P nanosheets for visible-light-driven photocatalytic H2 generation

Metal selenide semiconductors have been rarely used for photocatalytic water splitting because of their poor stability and severe photocorrosion properties. Hence, designing stable metal selenides with suitable bandgap energies has considerable practical significance in photocatalytic H 2 evolution. In this work, a novel series of Zn x Cd 1-x Se (x = 0 ∼ 1) with tunable band structure were fabricated through a simple solvothermal method. Impressively, the ZnSe exhibited a maximum H 2 production rate of 1056 µmol g −1 h −1 , which was higher than that of CdSe and Zn x Cd 1-x Se solid solutions. Such visible-light photoactivity for water reduction to H 2 was attained even after 6 cycling photocatalytic experiments. Moreover, the two-dimensional (2D) Ni 2 P nanosheets act as a high-efficiency cocatalyst integrated with Zn x Cd 1-x Se semiconductor to boost photocatalytic H 2 generation performance. The optimal 8% Ni 2 P/ZnSe composites displayed excellent cycling stability and superior photocatalytic H 2 evolution performance (4336 µmol g −1 h −1 ), which was about 4.1 times that of pure ZnSe under visible light irradiation. Photoelectrochemical (PEC), photoluminescence (PL), and time-resolved photoluminescence (TRPL) measurements reveal that the improved photoactivity Ni 2 P/ZnSe photocatalysts were ascribed to the effective separation and migration of photoinduced carriers. The present work paves a pathway to explore the fabrication of Zn x Cd 1-x Se solid solutions and the hybridization of 2D transition metal phosphides nanosheets toward photocatalytic applications.