Promoting Effects of Iron on CO Oxidation over Au/TiO2 Supported Au Nanoparticles

Fe-doped TiO2 supported gold nanoparticles as high-performance CO oxidation catalysts were prepared. XRD data revealed that TiO2 support was in an anatase phase. After calcination at 300 °C, the sample showed nanotube structure, and the size of gold nanoparticles was 3.1 nm. When calcined at 500 °C, most nanotubes broke, and gold nanoparticles grew up to 5.9 nm. XPS spectrum indicated the presence of Fe in the +3 oxidation state. Au/Fe-TiO2(Au: 1.44%, Fe: 1.35%) calcined at 300 °C possessed the best catalytic activity, and it could completely convert CO at 25 °C. The temperature of 100% CO conversion(T100%) of Fe-free catalyst was 40 °C. After the catalysts were stored at room temperature for 7 d, T100% of Au/Fe-TiO2 increased from 25 °C to 30 °C, while T100% of Fe-free catalyst increased from 40 °C to 80 °C. The catalytic activity and storage stability of Au/TiO2 could be improved by Fe-doping. The increase of specific surface area, generation of oxygen vacancies and new adsorption sites, depression of the growth of gold nanoparticles, and strong metal-support interaction were responsible for the promoting effect of iron on the catalytic performance of Au/TiO2 for CO oxidation.