Insights into the mechanisms of H2S adsorption and dissociation on CdS surfaces by DFT-D3 calculations

The adsorption and dissociation of H2S on CdS surfaces is investigated using dispersion-corrected density functional theory (DFT-D3) to provide quantum-level insights into their (photo)catalytic performance for H2S splitting. Calculations of structural parameters, electronic properties and energies of intermediates adsorption on perfect CdS surfaces indicate that the (110) facet is the most stable surface, while the most active surface (100) is quickly covered by sulfur formed during the reaction, unfavorable for catalyst stability and reuse. Calculations of CdS (110) surfaces with an S vacancy demonstrate that the vacancy serves as an electron donor center and atomic S∗ capture center, favoring the adsorption of dissociative species, and significantly reducing the energy barriers and reaction energies for the hydrogen evolution process, hence increasing the CdS surface catalytic performance. These theoretical results complement and reinforce available experimental studies, guiding the rational design of efficient photocatalysts for hydrogen production from H2S splitting.