Oxidation of CO and C3 hydrocarbons on gold dispersed on oxide supports

Catalysts containing Au nanoparticles (1 wt.% Au) dispersed on oxides of main group elements, MGO (Mg, Si, Sn) and on transition metal oxides, TMO (Fe, Ti, Ce) were obtained by deposition–precipitation method, characterized by TPR, TEM, XPS and tested in oxidation of CO, C3H8 and C3H6. The catalysts with TMO as supports were considerably more active in the CO oxidation than those with MGO supports. The propane oxidation occurred at temperatures >250 °C, yielding only carbon oxides. In propene oxidation in the presence of H2, the Au/MGO catalyst were active at temperatures >200 °C, giving mainly selective oxidation products (propanal, ethanal, acrolein), whereas total combustion was the main reaction in these conditions for Au/TMO catalysts. High selectivities to propene oxide (∼70%) were observed only for catalysts containing Ti in the support oxide at temperatures 100–150 °C. No clear correlations have been observed between the activity of the catalysts in the oxidation reactions and reducibility of the catalysts studied by H2TPR, nor the dominating Au particle size.