Discovering a Single-Atom Catalyst for CO2 Electroreduction to C-1 Hydrocarbons: Thermodynamics and Kinetics on Aluminum-Doped Copper

The 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 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 CO2 electroreduction to C-1 hydrocarbons.

Automated summary

The addition of aluminum to the surface of copper can lower the energy required for carbon dioxide reduction to methane. Aluminum doping can also weaken the adsorption of carbon monoxide and hydrogen on the aluminum-copper surface, increasing the production of C-1 hydrocarbons and inhibiting hydrogen evolution. Therefore, aluminum-copper alloys have potential catalytic activity in the electroreduction of CO2 to hydrocarbons.