Exploring CO2 electrochemical reduction mechanism on two-dimensional metal 2,3,6,7,10,11-triphenylenehexathiolate frameworks using density functional theory

The reduction of CO2 into valuable chemicals through electrocatalytic techniques provides a potential strategy to alleviate energy crises and environmental pollution. In this study, 2D M3(THT)2 (M = Fe, Co, Ni, Ru, Rh, Pd, THT = 2,3,6,7,10,11-triphenylenehexathiolate) framework as CO2 reduction reaction (CO2RR) electrocatalysts was investigated by using the density functional method. The results showed that the studied catalysts are stable both thermodynamically and electrochemically. Rh3(THT)2 exhibits the best catalytic performance to produce CH4 with the overpotential of 0.61 V in the gas phase and 0.63 V in solution. The inactive hydrogen evolution reaction in Rh3(THT)2 would favour CO2RR. For Fe3(THT)2 and Ru3(THT)2, the main product is CO. However, the strong CO adsorption on the catalyst surface can lead to catalyst to be poisoned, which makes Fe3(THT)2 and Ru3(THT)2 to be poor CO2RR catalysts. We anticipate that this work may provide a new avenue for the development of high-performance 2D metal-organic framework-based electrocatalysts.