Highly Selective CO2 Electroreduction to C2H4 Using a Dual-Sites Cu(II) Porphyrin Framework Coupled with Cu2O Nanoparticles via a Synergetic-Tandem Strategy.

Low *CO coverage on the active sites is a major hurdle in the tandem electrocatalysis, resulting in unsatisfied C2H4 production efficiencies. In this work, we developed a synergetic-tandem strategy to construct a copper-based composite catalyst for the electroreduction of CO2 to C2H4, which was constructed via the template-directed polymerization of ultrathin Cu(II) porphyrin organic framework incorporating atomically isolated Cu(II) porphyrin and Cu(II) bipyridine sites on a carbon nanotube (CNT) scaffold, and then Cu2O nanoparticles were uniformly dispersed on the CNT scaffold. The presence of dual active sites within the Cu(II) porphyrin organic framework create a synergetic effect, leading to an increase in local *CO availability to enhance the C-C coupling step implemented on the adjacent Cu2O nanoparticles for further C2H4 production. Accordingly, the resultant catalyst affords an exceptional CO2-to-C2H4 Faradaic efficiency (FEC2H4) of 71.0 % at -1.1 V vs reversible hydrogen electrode (RHE), making it one of the most effective copper-based tandem catalysts reported to date. The superior performance of the catalyst is further confirmed through operando infrared spectroscopy and theoretic calculations.