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

Abstract

The unique catalytic activity of supported Au catalysts for CO oxidation has been reported to depend strongly on the particle size of the Au which is related to the preparation technique and the nature of the metal oxide support. Au supported over ZnO was an appropriate candidate catalyst in the preferential oxidation (PROX) of CO with high catalytic activity, even at room temperature. Recently, photodeposition was used to prepare supported nano-size Au catalysts for PROX by utilizing u v light. The results demonstrated that Au can be dispersed homogeneously over ZnO in the size range of 1 to 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. The uncalcined catalyst with a low concentration of the precipitant and a long irradiation time was by far the most active catalyst. Furthermore, the Au/ZnO catalyst showed high durability at a reaction temperature of 30°C for 100 h. To elucidate the performance of the catalysts, they were characterized by using XRD, TEM, TPR, N₂ adsorption, and A AS.