Preparation of hollow Au-x-Cu2O nanospheres by galvanic replacement to enhance the selective electrocatalytic CO2 reduction to ethanol

Electrocatalytic CO2 reduction to fuel is one of the important ways to solve energy and environmental problems. In this work, the preparation of hollow Au-x-Cu2O electrocatalyst and the performance of electrocatalytic CO2 reduction to ethanol were studied. Hollow Cu2O nanospheres were prepared by a soft template method, and Au-x-Cu2O composites were prepared by galvanic replacement. The characterization results of XRD and XPS reveal that Cu+ is the main chemical state of Cu in the catalysts. The results of electroactive surface area demonstrate that the electroactive surface area of Au-0.51-Cu2O is the largest. The performance evaluation of electrocatalytic CO2 reduction shows that the Faraday efficiency of H-2 on Au-0.51-Cu2O is the lowest (similar to 19.5%) and the Faraday efficiency of ethanol can reach similar to 18.8% at -1.2 V vs. RHE. Compared with hollow Cu2O nanospheres, Au-x-Cu2O catalysts have an earlier onset for ethanol production and promote the CO2 reduction to ethanol with high efficiency, while the hydrogen evolution reaction is significantly inhibited. Our study demonstrates an effective approach to develop Cu-based electrocatalysts favourable toward ethanol in electrocatalytic CO2 reduction.