A Theoretical Study of the Electrochemical CO2 Reduction Over Single Atom Catalysts Using Grand-Canonical DFT

Abstract

Electrochemical CO2 reduction (CO2ER) is a rational method to mitigate climate change effects. The first step of this process is CO formation, which can be selectively achieved over gold or silver metals. However, their high overpotentials, high costs, and/or low atomic efficiencies limit their usage industrially. Metal/nitrogen-doped graphene (MNC) electrocatalysts, which are atomically efficient, have been found to electroreduce CO2 to CO selectively. Herein, we test CO2ER to CO over 3d pyridinic MN4Cs using grand-canonical DFT to elucidate the applied potential effects on reaction energetics and electronic structures as well as to predict promising CO-producing sites. Our results capture the applied potential effects and display nonlinear energy changes with the applied potential. We conclude that TiN4C is a promising CO-producing site based on a pure thermodynamic analysis. However, further kinetic investigations are required to assess CO2ER activity. At the end of this paper, we discuss study limitations and future outlook.