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

Copper oxide‐based materials effectively electrocatalyze carbon dioxide reduction (CO 2 RR). To comprehend their role and achieve high CO 2 RR activity, Cu + in copper oxides must be stabilized. As an electrocatalyst, Cu 2 O nanoparticles were decorated with hexagonal boron nitride (h‐BN) nanosheets to stabilize Cu + . The C 2 H 4 /CO ratio increased 1.62‐fold in the CO 2 RR with Cu 2 O−BN compared to that with Cu 2 O. Experimental and theoretical studies confirmed strong electronic interactions between the two components in Cu 2 O−BN, which strengthens the Cu−O bonds. Electrophilic h‐BN receives partial electron density from Cu 2 O, protecting the Cu−O bonds from electron attack during the CO 2 RR and stabilizing the Cu + species during long‐term electrolysis. The well‐retained Cu + species enhanced the C 2 product selectivity and improved the stability of Cu 2 O−BN. This work offers new insight into the metal‐valence‐state‐dependent selectivity of catalysts, enabling the design of advanced catalysts.