Discovering a Single‐Atom Catalyst for CO<sub>2</sub> Electroreduction to C<sub>1</sub> Hydrocarbons: Thermodynamics and Kinetics on Aluminum‐Doped Copper
Anwin John, Anand Mohan Verma, M. Shaneeth, Ananth Govind Rajan
Abstract
Abstract The electrochemical reduction of carbon dioxide (CO 2 ) to hydrocarbons is a potential option to achieve carbon neutrality. Although copper (Cu) shows the highest activity for the CO 2 reduction reaction (CO 2 RR) to hydrocarbons among metals, high reaction overpotentials and significant H 2 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 C 1 hydrocarbons and inhibition of H 2 evolution. Finally, activation barrier calculations for the PDS on Al−Cu(111) involving an explicitly hydrated proton indicated better intrinsic activity for C 1 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 CO 2 electroreduction to C 1 hydrocarbons.