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

Cu 2 O is promising to catalytically convert CO 2 into C 2 products by overcoming the instability and slow multi-electron transfer. Regulating catalytic construction and interface microenvironment is challenging to stabilize Cu 2 O and selectively convert CO 2 to C 2+ hydrocarbons. A photocatalyst (Cu 2 O@Cu-CN) of oxygen vacancy–rich Cu 2 O@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 Cu 2 O redox reaction. The hydrophobic interface can make the catalyst favorable for trapping CO 2 . The asymmetric interface with oxygen vacancy can enhance the adsorption and activation of CO 2 and *CO, thus reducing the energy barrier for the formation of *OCCO intermediates and promoting the coupling conversion of *OCCO to C 2 H 4 . The C 2 H 4 evolution rate reaches 46.27 μmol C2H4 g cat -1 h −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 C 2 H 4 evolution rate is 2.10 μmol C2H4 g cat -1 h −1 in water without TEOA. Moreover, the productive rate of C 2 H 4 still maintains 95.37 % after lasting 20 h, showing a robust long − term stability.