Tuning the selectivity of CO2 conversion to CO on partially reduced Cu2O/ZnO heterogeneous interface

The development of stable and efficient low-cost electrocatalysts is conducive to the industrialization of CO₂. The synergy effect between the heterogeneous interface of metal/oxide can promote the conversion of CO₂. In this work, Cu₂O/ZnO heterostructures with partially reduced metal/oxide heterointerfaces in Zn plates (CZZ) have been synthesized for CO₂ electroreduction in different cationic solutions (K⁺ and Cs⁺). Physical characterizations were used to demonstrate the heterojunction of Cu₂O/ZnO and the heterointerfaces of metal/oxide; electrochemical tests were used to illustrate the enhancement of the selectivity of CO₂ to CO in different cationic solutions. Faraday efficiency for CO with CZZ as catalyst reaches 70.9% in K⁺ solution (current density for CO −3.77 mA cm⁻² and stability 24 h), and the Faraday efficiency for CO is 55.2% in Cs⁺ solution (−2.47 mA cm⁻² and 21 h). In addition, in situ techniques are used to elucidate possible reaction mechanisms for the conversion of CO₂ to CO in K⁺ and Cs⁺ solutions.