Discovering a Single‐Atom Catalyst for CO2 Electroreduction to C1 Hydrocarbons: Thermodynamics and Kinetics on Aluminum‐Doped Copper

Abstract

AbstractThe electrochemical reduction of carbon dioxide (CO2) to hydrocarbons is a potential option to achieve carbon neutrality. Although copper (Cu) shows the highest activity for the CO2 reduction reaction (CO2RR) to hydrocarbons among metals, high reaction overpotentials and significant H2 production limit its use. We investigate single‐atom alloys (SAAs) of ten metals (Ag, Au, Fe, Ir, Ni, Pd, Pt, Rh, Ru, Al) on Cu(111), which is the most‐favored facet on Cu for methane production, using density functional theory. We examined the dopants’ ability to lower the free energy of the elementary reaction, *CO to *CHO, which is the potential‐determining step (PDS). Out of the SAAs studied, only Al‐doped Cu demonstrated a lowering of the PDS free energy. Additionally, weaker adsorption energies of *CO and *H on Al−Cu(111) suggest a preference for C1 hydrocarbons and inhibition of H2 evolution. Finally, activation barrier calculations for the PDS on Al−Cu(111) involving an explicitly hydrated proton indicated better intrinsic activity for C1 hydrocarbons compared to pure Cu(111). We also confirmed the stability of Al−Cu SAA compared to small Al clusters. Through a comprehensive study of both thermodynamics and kinetics, our study presents Al−Cu SAA as a promising catalyst for CO2 electroreduction to C1 hydrocarbons.