Oxygen vacancies on CuGa2 catalysts enhance CO2 reduction to CO

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 OV concentration in O–CuGa2 is much larger than that in the CuGa2 catalysts. The results of electrokinetic studies indicated that the introduction of OVs facilitate electron transfer to CO2.