Stabilization of Cu⁺ via Strong Electronic Interaction for Selective and Stable CO₂ Electroreduction

Copper oxide-based materials effectively electrocatalyze carbon dioxide reduction (CO₂ RR). To comprehend their role and achieve high CO₂ RR activity, Cu⁺ in copper oxides must be stabilized. As an electrocatalyst, Cu₂ O nanoparticles were decorated with hexagonal boron nitride (h-BN) nanosheets to stabilize Cu⁺ . The C₂ H₄ /CO ratio increased 1.62-fold in the CO₂ RR with Cu₂ O-BN compared to that with Cu₂ O. Experimental and theoretical studies confirmed strong electronic interactions between the two components in Cu₂ O-BN, which strengthens the Cu-O bonds. Electrophilic h-BN receives partial electron density from Cu₂ O, protecting the Cu-O bonds from electron attack during the CO₂ RR and stabilizing the Cu⁺ species during long-term electrolysis. The well-retained Cu⁺ species enhanced the C₂ product selectivity and improved the stability of Cu₂ O-BN. This work offers new insight into the metal-valence-state-dependent selectivity of catalysts, enabling the design of advanced catalysts.