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

Abstract

Large photocatalytic hydrogen (H2) production from copious waste hydrogen sulphide (H2S) can meet the increasing demand for H2 in a sustainable manor which is beneficial from both environmental and energy standpoints. In this work, we reported a robust MnS/(InxCu1-x)2S3 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)2S3) 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 γ-MnS and (InxCu1-x)2S3 can significantly improve charge separation and migration in the composites. As a result, the MnS/(InxCu1-x)2S3 exhibits greatly extended visible light absorption up to 599 nm and extraordinarily high photocatalytic H2 production under visible light from H2S with a maximum rate of 29,252 μmol h−1 g−1. The corresponding apparent quantum efficiencies (AQE) at 420 and 450 nm are as high as 65.2% and 62.6%, respectively. They are the highest so far for the visible light photocatalytic splitting of H2S in the absence of noble-metal co-catalysts.