In Situ Synthesis of Ag/Ag2O on CeO2 for Boosting Electron Transfer in Photocatalytic Hydrogen Production

A simple and effective photocatalytic system has always been the goal of photocatalytic research. In this study, Ag/Ag2O was grown in situ on a CeO2 substrate by a one-step method to form a Ag/Ag2O/CeO2 photocatalyst. The close combination of the two made the composite catalyst have more effective hydrogen evolution sites. The Ag/Ag2O/CeO2 composite catalyst has a wide light absorption wavelength, low overpotential, and small electrochemical impedance, which are favorable for the development of a photocatalytic system. CeO2 and Eosin Y continue to provide photogenerated electrons as electron donors, while the heterostructure of the Ag/Ag2O/CeO2 system enables the separation of electrons on the conduction band of CeO2. The ingenious coordination of the two can effectively isolate the photogenerated electron–hole pairs, thus supporting the continuous progress of photocatalytic hydrogen evolution. Importantly, Ag/Ag2O/CeO2 has excellent photocatalytic performance for hydrogen production; in particular, Ag/Ag2O/CeO2-30 has the highest hydrogen production efficiency, which is much higher than those of Ag/Ag2O and CeO2. Therefore, Ag/Ag2O/CeO2 can be considered as a photocatalyst worth developing.