Regulating ethane and ethylene synthesis by proton corridor microenvironment for CO2 electrolysis

Abstract

Electrocatalytic reduction of carbon dioxide is one of the most effective strategies to achieve carbon neutrality and energy sustainability. Although high-value multi-carbon products have been widely studied, limited electrocatalysts have been reported for the selective conversion of ethane. More importantly, the factors tuning the selectivity between ethane and ethylene have not been clarified. Here, Zn@Cu nanowire arrays (Zn@Cu-NWAs) catalyst is proposed to stimulate the maintenance of efficient CO2-to-C2H6 conversion at high current densities. Meanwhile, in order to investigate the factors affecting the interconversion between ethane and ethylene, the counterpart catalyst that facilitates C–C coupling to ethylene was also synthesized. Time-of-flight secondary-ion mass spectroscopy (TOF-SIMS), in-situ Raman spectroscopy, and simulation results show that Zn@Cu-NWAs can provide a localized proton corridor environment for the formation of ethane, accelerating the further proton-coupled CO2 reduction reaction (CO2RR) kinetics. Hence, this catalyst delivered an ethane Faraday efficiency of over 65% at −1.14 V vs. RHE with a total current density of 142.3 mA/cm2. This work provides a new perspective on regulating the local microenvironment to modify the selectivity of multi-carbon products.