RETRACTED ARTICLE: Preparation of hollow Au_x-Cu₂O nanospheres by galvanic replacement to enhance the selective electrocatalytic CO₂ reduction to ethanol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 H₂ on Au_0.51-Cu₂O is the lowest (∼19.5%) and the Faraday efficiency of ethanol can reach ∼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.