A highly dispersed Pt/γ-Al2O3 catalyst prepared via deposition-precipitation method for preferential CO oxidation

Highly dispersed Pt/γ-Al2O3 catalysts were prepared by deposition-precipitation (DP) method with precursor solutions of various pH. The pH was controlled from 6.5 to 9.5 with 5 wt% NaOH solution. As the pH of precursor solution increases over pH 7.5, the metal dispersion and surface PtOx species decrease and the Pt particle size increases. PrOx test was carried out with a space velocity of 60,000 mL/h gcat in temperature ranges from 100 to 200 °C. The [O2]/[CO] ratio was adjusted between 1 and 2 and the effect of H2O and CO2 was examined at [O2]/[CO] = 2. It is interesting that the CO conversion has good agreement with the Pt metal dispersion. In addition, highly dispersed Pt/γ-Al2O3 catalyst prepared by DP with pH 7.5 exhibited good catalytic activity below 150 °C in PrOx due to the improvement of the metal dispersion and reducibility of surface PtOx species at low temperatures compared with the catalyst prepared by impregnation method.