Surface modification of Cu2O with stabilized Cu+ for highly efficient and stable CO2 electroreduction to C2+ chemicals

Copper (Cu)-based materials are known as the most attractive catalysts for electrochemical carbon dioxide reduction reaction (CO2RR), especially the Cu+ species (e.g., Cu2O), which show excellent capability for catalyzing CO2 to C2+ chemicals because of their unique electronic structure. However, the active Cu+ species are prone to be reduced to metallic Cu under an electroreduction environment, thus resulting in fast deactivation and poor selectivity. Here, we developed an advanced surface modification strategy to maintain the active Cu+ species via assembling a protective layer of metal–organic framework (copper benzenetricarboxylate, CuBTC) on the surface of Cu2O octahedron (Cu2O@CuBTC). It's encouraging to see that the Cu2O@CuBTC heterostructure outperforms the bare Cu2O octahedron in catalyzing CO2 to C2+ chemicals and dramatically enhances the ratio of C2H4/CH4 products. A systematic study reveals that the introduced CuBTC shell plays a critical role in maintaining the active Cu+ species in Cu2O@CuBTC heterostructure under reductive conditions. This work offers a practical strategy for improving the catalytic performance of CO2RR over copper oxides and also establishes a route to maintain the state of valence-sensitive catalysts.