Cu4@C2N for effective electrochemical CO2 reduction and intermediates dependent adsorption behaviours: A computational study

Abstract

Electrochemical CO2 reduction (eCO2R) to valuable products is an effective solution for carbon emission and energy related issues but limited by the lack of high performance catalysts. Herein, Cu4 supported by C2N for CO2 reduction to various products was systematically investigated using first principles calculations. Our results indicate that Cu4@C2N is a promising catalyst for eCO2R with limiting potential of −0.46 and −0.81 V for HCOOH and C2 products, respectively. Cu on top site with higher d-band center is the major active site for eCO2R. Besides, due to the heterogeneity of the active sites of Cu and abundant intermediate, the complexity of the calculation increased significantly. Thus, possible intermediates dependent adsorption behaviours were proposed to determine the interaction types for searching the lowest energy adsorption configuration. More importantly, we found that electron donating ability of the active sites, the electronegativity difference between the adatom and active sites, and the coordinative unsaturation of the contact sites in the intermediates are the major physical origin governing the adsorption geometry. Our work not only provides guidance for developing high-performance small cluster electrocatalyst for CO2 reduction, but brings inspiration for the theoretical study of complex reaction systems to find the optimal adsorption model.