Activity of Au/ZnO catalysts prepared by photo-deposition for the preferential CO oxidation in a H2-rich gas

•The precipitant concentration could affect both catalyst activity and selectivity.•The gold particle size over ZnO was between 1 and 2 nm with low distribution.•The difference on catalytic activity related to the amount of different states of gold.•The photodeposition was an effective method for gold catalyst preparation.

In this work, Au supported over ZnO prepared by photodeposition was applied to prepare nano-size Au catalysts by utilizing UV light for the preferential oxidation (PROX) of CO. The results demonstrated that Au can be dispersed homogeneously over ZnO in the size range of 1–2 nm with a narrow size distribution. It was clearly seen that the preparation parameters (i.e. irradiation time, precipitant concentration, calcination, and storage condition) had a significant effect on the catalytic activity. Among the variables studied, low concentrations of precipitant and long irradiation time were by far the most influential on the catalytic activity.

Graphical abstractAu/ZnO prepared by photo-deposition showed the highest catalytic activity because of the homogeneously dispersed Au over ZnO with diameters below 5 nm. However, the catalytic activities of Au/ZnO prepared by higher precipitating agent concentration can be enhanced by applying calcination.Figure optionsDownload full-size imageDownload as PowerPoint slide