Novel MnS/(InxCu1-x)2S3 composite for robust solar hydrogen sulphide splitting via the synergy of solid solution and heterojunction

Large photocatalytic hydrogen (H-2) production from copious waste hydrogen sulphide (H2S) can meet the increasing demand for H-2 in a sustainable manor which is beneficial from both environmental and energy standpoints. In this work, we reported a robust MnS/(InxCu1-x)(2)S-3 composite photocatalyst. Both experimental results and density functional theory (DFT) calculations proved that Cu does not act as a cocatalyst but forms a solid solution ((InxCu1-x)(2)S-3) in the composites, which plays dual roles in improving the photocatalytic performance of H2S splitting: (i) enhancing solar light absorption, and (ii) promoting the desorption of sulfur (S) adsorbed on the catalyst surface. Moreover, the formation of a heterojunction between gamma-MnS and (InxCu1-x)(2)S-3 can significantly improve charge separation and migration in the composites. As a result, the MnS/(InxCu1-x)(2)S-3 exhibits greatly extended visible light absorption up to 599 nm and extraordinarily high photocatalytic H-2 production under visible light from H2S with a maximum rate of 29,252 mu mol h(-1) g(-1). The corresponding apparent quantum efficiencies (AQE) at 420 and 450 nm are as high as 65.2% and 6/6%, respectively. They are the highest so far for the visible light photocatalytic splitting of H2S in the absence of noble-metal co-catalysts.