First Principles Study of Photocatalytic Reduction of CO2 to CH4 on WS2-Supported Pt Clusters

CO2 conversion into valuable chemicals and fuels is a sustainable route to the concurrent mitigation of the energy crisis and the greenhouse effect. Herein, first principles calculations were employed to study the photocatalytic CO2 reduction over pristine WS2, S-vacancy WS2, and Pt cluster loaded WS2. Our results indicate that the introducing of S-vacancy and loading of Pt clusters can improve the optical absorption in the visible-light region. Furthermore, S-vacancy can lower the barrier (by about 0.17 eV) for *COOH intermediate formation. For Pt/WS2, the strong metal–support interaction is confirmed by high adsorption energy and charge transfer. Importantly, the electron-rich Pt cluster promotes *CO intermediates to facilitate the formation of *CHO intermediates and to further protonate to CH4. This study provides some useful insights into designing the catalysts for the reduction of CO2 and further widens the applications of WS2-based catalytic materials.