Support cooperative single atoms on Ti3−xC2Oy for efficient electrochemical CO2 reduction: a DFT study

Abstract

The electrochemical CO₂ reduction reaction (CO₂RR) is an effective way to convert carbon dioxide into high value-added chemicals. However, the activity and selectivity of CO₂RR catalysts are often limited by the linear scaling relationships of reaction intermediates. Herein, we designed a series of titanium-defected Ti_3−xC₂O_y single-atom catalysts to overcome this limitation. Our results show that the synergistic structure of the single-atom active center and oxygen defect enhances the adsorption energy of CHO species. Based on density functional theory (DFT) calculations, Au@Ti_3−xC₂O_y, Cu@Ti_3−xC₂O_y, Ag@Ti_3−xC₂O_y, and Fe@Ti_3−xC₂O_y are found to be excellent catalysts for CH₄ production with a low limiting potential of −0.16, −0.23, −0.32, and −0.42 V, respectively. The difference between the adsorption energy of CHO and CO for catalysts can be used as an activity descriptor. These findings shed light on the significance of supports in single-atom catalysts and offer guidance for creating extremely active CO₂RR catalysts.