Supported metal oxides for catalytic combustion of CO and VOCs emissions: Preparation of titania overlayers on a macroporous support

TiO2 (anatase), SiO2 and gamma-Al2O3 were used as supports for Co-, Cu-, Fe- and Mn-oxide with a loading of active phase corresponding to one theoretical layer. The catalysts were tested for the combustion of CO and toluene, and the best combinations with active phase and support were submitted to a deactivation test in a waste gas incinerator for 50 days. The catalyst screening showed that CuOx/TiO2 was the most promising system. To design a catalyst with good activity and transport properties, a macroporous substrate was coated with TiO2 for use as a support for Cu-oxide, Titania overlayers were prepared by precipitation from oxychloride, tetrachloride and alkoxide, and stabilisation with ZrO2 and SiO2 was tried. The results show that precipitation from oxychloride gives the best properties and that addition of ZrO2 gives enhanced activity to the catalyst, while SiO2 addition produces increased stability.