Oxygen vacancies on CuGa2 catalysts enhance CO2 reduction to CO

Abstract

Electroreduction of CO₂ into fuels and valuable chemicals is an effective way to alleviate the greenhouse effect. However, CO₂ is chemically inert owing to the highly stable CO bond. Thus, CO₂ activation is recognized as a critical reaction step in the process. As electron transfer to CO₂ is commonly accepted as the key step during the activation of CO₂, it is crucial to engineer the electronic properties of catalysts to enhance their performance in the electrochemical reduction of CO₂. Herein, we prepared a CuGa₂ catalyst with oxygen vacancies (O–CuGa₂) to effectively improve product selectivity. O–CuGa₂ exhibited a current density of 32.9 mA cm⁻² with a faradaic efficiency of 82.6% for CO production in a tetrabutylammonium chloride/acetonitrile (Bu₄NCl/AN) electrolyte, which is 2.5 times higher than that exhibited by CuGa₂. XPS and EPR results indicated that O_V concentration in O–CuGa₂ is much larger than that in the CuGa₂ catalysts. The results of electrokinetic studies indicated that the introduction of O_Vs facilitate electron transfer to CO₂.