Efficient electroreduction of CO2 to C2+ products on CeO2 modified CuO.

Electrocatalytic reduction of CO2 into multicarbon (C2+) products powered by renewable electricity offers one promising method for CO2 utilization and promotes the storage of renewable energy under an ambient environment. However, there is still a dilemma in the manufacture of valuable C2+ products between balancing selectivity and activity. In this work, cerium oxides were combined with CuO (CeO2/CuO) and showed an outstanding catalytic performance for C2+ products. The faradaic efficiency of the C2+ products could reach 75.2% with a current density of 1.21 A cm-2. In situ experiments and density functional theory (DFT) calculations demonstrated that the interface between CeO2 and Cu and the subsurface Cu2O coexisted in CeO2/CuO during CO2RR and two competing pathways for C-C coupling were promoted separately, of which hydrogenation of *CO to *CHO is energetically favoured. In addition, the introduction of CeO2 also enhanced water activation, which could accelerate the formation rate of *CHO. Thus, the selectivity and activity for C2+ products over CeO2/CuO can be improved simultaneously.