Stable and robust single transition metal atom catalyst for CO2 reduction supported on defective WS2

Under mild conditions, carbon dioxide reduction reactions (CO2RRs) retain a tremendous complexity in effective CO2 activation on metal based catalysts. Single-atom catalysts are only effective if all the isolated metal centers on the support interact in the same way. However, the support often has different topologies and defects, which can lead to a lack of homogeneity. In this study, we anchored Co, Cu, Ni, Pt, and Pd on a WS2 nanosheet as a single-atom catalyst support for the activation and reduction of CO2. The results showed that S-vacancies in WS2 nanosheets are good sites for depositing single metal atoms and that WS2 nanosheets with a well-distributed distribution of S-vacancies are good substrates for anchoring single metal atoms. The addition of S-vacancies and single metal atoms to WS2 changes its electronic structure and reduces the band gap value from 1.98 eV to 1.17, 1.19, 1.45 and 1.42 eV respectively. Additionally, the Cu- and Co/S-vacancy WS2 system showed good activity for the reduction of CO2 to formic acid and CO, making it effective single-atom catalyst with low energy consumption and high stability for the activation and reduction of CO2 to valuable products.