Energy-Band-Controlling Strategy to Construct Novel CdxIn1-xS Solid Solution for Durable Visible Light Photocatalytic Hydrogen Sulfide Splitting

Photocatalytic waste hydrogen sulfide (H2S) conversion into clean energy (H-2) has an alluring prospect. Herein, a series of novel CdxIn1-xS solid solutions are constructed by a mild hydrothermal method for visible light photocatalytic H2S splitting. The CdxIn1-xS solid solutions with an orderly tuned visible-light response range from 550 to 600 nm present a more positive valence band (VB) position and remarkable separation ability of charge carriers. As a result, the optimized cubic CdxIn1-xS solid solution casts the extraordinary photocatalytic H-2 evolution rate (16.35 mmol g(-1) h(-1)) from H2S, which is 5- and 23-fold higher than that over bare CdS (3.40 mmol g(-1) h(-1)) and beta-In2S3 (0.72 mmol g(-1) h(-1)), respectively, exceeding previous CdS-based photocatalysts in the absence of co-catalysts. The corresponding quantum efficiency (QE) at 420 nm is 26.7%. The combination of experiment and density functional theory (DFT) calculation confirms that the formation of CdxIn1-xS solid solution has three functions for H2S splitting: i) improving anti-photocorrosion properties of CdS-based catalytsts; ii) promoting the further oxidation of sulfur (S) adsorbed on the catalyst surface; and iii) enhancing the charge-separation efficiency. This work reports a novel CdxIn1-xS solid solution for highly efficient photocatalytic H-2 generation from H2S under visible light irradiation.