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

Copper oxide‐based materials effectively electrocatalyze carbon dioxide reduction (CO2RR). To comprehend their role and achieve high CO2RR activity, Cu+ in copper oxides must be stabilized. As an electrocatalyst, Cu2O nanoparticles were decorated with hexagonal boron nitride (h‐BN) nanosheets to stabilize Cu+. The C2H4/CO ratio increased 1.62‐fold in the CO2RR with Cu2O−BN compared to that with Cu2O. Experimental and theoretical studies confirmed strong electronic interactions between the two components in Cu2O−BN, which strengthens the Cu−O bonds. Electrophilic h‐BN receives partial electron density from Cu2O, protecting the Cu−O bonds from electron attack during the CO2RR and stabilizing the Cu+ species during long‐term electrolysis. The well‐retained Cu+ species enhanced the C2 product selectivity and improved the stability of Cu2O−BN. This work offers new insight into the metal‐valence‐state‐dependent selectivity of catalysts, enabling the design of advanced catalysts. Strong electronic interactions between hexagonal boron nitride (h‐BN) and Cu2O protect the Cu−O bonds against electron attack through the transfer of accumulated electrons from Cu2O to h‐BN. This effect stabilizes the active Cu+ species during CO2 electroreduction.