Non-Noble Metal Incorporated Transition Metal Dichalcogenide Monolayers for Electrochemical CO₂ Reduction: A First-Principles Study

Using non-noble metal atoms as catalysts is attractive for decreasing the cost of the CO₂ reduction reaction (CO₂RR). By screening first-row transition metals and noble metals through extensive first-principles calculations, non-noble Sc and Ti single atoms binding on vacancy-defected transition metal dichalcogenide (TMD) monolayers exhibit better catalytic performance and selectivity for electrochemical CO₂RR than noble metal single atoms. The overpotentials of Sc and Ti atoms for the CO₂RR can be reduced lower than 0.09 V after applying suitable biaxial tensile strains on vacancy-defected TMDs, which are approximately 1 order of magnitude lower than that of most reported metal atom catalysts. The vacancy defects of TMDs and charge transfer to metal atoms induced by tensile strain play a key role in improving the catalytic activity of non-noble metal single atoms. These results highlight a possible way to design new single atom catalysts for electrochemical CO₂RR by utilizing the combination of non-noble metal atoms, defected TMDs, and strain engineering.