Mechanistic Understanding of CO₂ Electroreduction on Cu₂O

Cu₂O demonstrates the unique selectivity and efficiency to methanol in CO₂ electroreduction, which is a potential strategy to convert CO₂ to important fuels and chemicals; however, its reaction mechanism is still controversial. To address this issue, we have built a model of partially reduced Cu₂O­(100) with the consideration of solid–liquid interface by using density functional theory methods. These allow us to uncover inherent mechanism of CO₂ electroreduction to methanol on Cu₂O­(100) and find the key intermediate CH₃OH*–OH*, which can explain the experimental results well. Our results reveal that the synergy of surface morphology and solvation is essential to the selectivity and efficiency of Cu₂O­(100) in reducing CO₂ to methanol. More importantly, we find that the variation trend of charge distribution on catalyst surface accounts for the minimum-energy pathway of CO₂ electroreduction, which could act as a descriptor for understanding the mechanism of CO₂ electroreduction and designing advanced catalysts