Controllable preparation of Cu2O/Cu-CuTCPP MOF heterojunction for enhanced electrocatalytic CO2 reduction to C2H4

Copper-based metal-organic framework (Cu-MOF) materials with multiple active sites have attracted increasing attention to the electrocatalytic CO 2 reduction reaction (ECR), however, face the huge challenge owing to the poor stability and low C 2 selectivity. Here, the Cu 2 O/Cu-CuTCPP heterojunction (Cu 2 O/CPFs) with three Cu active sites are firstly constructed through in-situ electrodeposition method. The effect of CuSO 4 concentration and electrodeposition conditions on ECR is systematically investigated. The optimized Cu 2 O/CPFs composite achieves the ethylene Faraday efficiency (FE C2H4 ) of 61.8 % at –1.3 V vs. RHE, which is 1.9 and 3.42 times higher than those of CPFs and Cu 2 O, respectively. Meanwhile, the C 2 H 4 partial current density ( j C2H4 ) of –7.96 mA·cm −2 is 2.91 and 4.68 times higher than those of CPFs and Cu 2 O. Further experiments reveals that the formation of Cu 2+ –O–Cu + –O bond between Cu 2 O and Cu–O 4 sites in Cu 2 O/CPF heterojunction is crucial. Consequently, the hydrogen (H 2 ), formic acid (HCOOH) and methane (CH 4 ) evolution reactions are restricted, the C–C coupling reaction of *CHO and *CO intermediates is significantly enhanced, and the Cu–O 4 sites in CPFs are protected. This work provides an effective strategy to stabilize MOF structure and obtain high value-added C 2+ products.