Boosting CO2 electroreduction to ethylene via CoII-porphyrin regulated Cu2O/Cu nanocomposite

CO₂ electroreduction (CO₂ER) into high value-added chemicals or fuels is of great significance to solve the current energy shortage and realize the carbon cycle. Although there are reports that Cu-based CO₂ER catalysts can achieve multicarbon products, the influence of the microenvironment of Cu-based catalysts on their valence states, interface and CO₂ER performance still deserve further investigation. Herein, a Co^II-porphyrin derivative (m-CoTPyP) is used to decorate on Cu₂O/Cu nanoparticles with Cu⁺/Cu⁰ mixed valence states and Cu₂O/Cu interface for constructing a novel CoTPyP-Cu₂O/Cu composite, where m-CoTPyP as ultrathin layer on Cu₂O/Cu nanoparticles can not only efficiently promote the adsorption/activation of CO₂ and the formation of *CO on the active sites by regulating the microenvironment via H-bonding, but also improve the stability of Cu valence states. Moreover, the Cu⁺/Cu⁰ mixed valence states and abundant Cu₂O/Cu interfaces of the Cu₂O/Cu nanoparticles significantly enhance the electron transfer rate and CC coupling kinetics. Specifically, the CoTPyP-Cu₂O/Cu(1:15) delivers an ethylene (C₂H₄) Faraday efficiency up to 71 % and excellent stability (>50 h). This work provides a new perspective on the structural design of CO₂ER catalyst with synergistic active sites, high Faraday efficiency and selectivity of C₂H₄ by regulating the microenvironment.