One Pot-Synthesized Ag/Ag-Doped CeO₂ Nanocomposite with Rich and Stable 3D Interfaces and Ce³⁺ for Efficient Carbon Dioxide Electroreduction

Electrochemical CO2 reduction (ECR) technology is promising to produce value-added chemicals and alleviate the climate deterioration. Interface engineering is demonstrated to improve the ECR performance for metal and oxide composite catalysts. However, the approach to form a substantial interface is still limited. In this work, we report a facile one-pot coprecipitation method to synthetize novel silver and silver-doped ceria (Ag/CeO2) nanocomposites. This catalyst provides a rich 3D interface and high Ce3+ concentration (33.6%), both of which are beneficial for ECR to CO. As a result, Ag/CeO2 exhibits a 99% faradaic efficiency and 10.5 A g–1 mass activity to convert CO2 into CO at an overpotential of 0.83 V. The strong interfacial interaction between Ag and CeO2 may enable the presence of surface Ce3+ and guarantee the improved durability during the electrolysis. We also develop numerical simulation to understand the local pH effect on the ECR performance and propose that the superior ECR performance of Ag/CeO2 is mainly due to the accelerated CO formation rate rather than the suppressed hydrogen evolution reaction.