Oxygen vacancy–rich Cu2O@Cu with a hydrophobic microenvironment for highly selective C C coupling to generate C2H4

Cu2O is promising to catalytically convert CO2 into C2 products by overcoming the instability and slow multi-electron transfer. Regulating catalytic construction and interface microenvironment is challenging to stabilize Cu2O and selectively convert CO2 to C2+ hydrocarbons. A photocatalyst (Cu2O@Cu-CN) of oxygen vacancy–rich Cu2O@Cu symbiont embedded in N-doped carbon skeleton is achieved by ligand competition strategy. The Schottky junction and the hydrophobic microenvironment in the catalyst together stabilize the active site against the Cu2O redox reaction. The hydrophobic interface can make the catalyst favorable for trapping CO2. The asymmetric interface with oxygen vacancy can enhance the adsorption and activation of CO2 and *CO, thus reducing the energy barrier for the formation of *OCCO intermediates and promoting the coupling conversion of *OCCO to C2H4. The C2H4 evolution rate reaches 46.27 μmolC2H4 gcat-1h−1 with a high selectivity of 40.3 % using triethanolamine (TEOA) as a sacrificial agent, and the apparent quantum yield (AQY) is as high as 14.41 % (λ = 420 nm). The C2H4 evolution rate is 2.10 μmolC2H4 gcat-1h−1 in water without TEOA. Moreover, the productive rate of C2H4 still maintains 95.37 % after lasting 20 h, showing a robust long − term stability.