Au particle size manipulated Au/ZnO interface and its performance in selective oxidation of glycerol

The gold (Au)/oxide interface has been shown to be an effective active site in many oxidation reactions due to its unique structural features. However, several issues arise in research on these active sites, such as the effective control of Au particle size, the correlation between Au particle size and the formation of interface sites, and the promoting effect of effective interface sites on the reaction. In this work, we achieved precise control of Au particle size through a series of methods, and using high-resolution transmission electron microscopy, we demonstrated the correlation between surface energy and the formation of the interface between Au particles and ZnO. Catalyst evaluation results showed that the Au/ZnO interface formed by Au particles of 3.5-4 nm can achieve an approximately 25%-30% increase in glycerol conversion while maintaining the same dihydroxyacetone (DHA) selectivity. We used O 1s X-ray photoelectron spectroscopy (XPS) and in situ Fourier transform infrared spectroscopy (FTIR) to investigate the mechanism by which oxygen vacancies at the interface promote glycerol selective oxidation. Based on the above results, we conclude that the enhanced activity of the small Au nanoparticles (NPs) originates from the abundance of oxygen vacancies at the Au/ZnO interface. Our studies provide a new insight for the Au particle size manipulated Au/ZnO interface and the performance in hydroxyl oxidation.