The role of support on the performance of platinum-based catalysts for the total oxidation of polycyclic aromatic hydrocarbons

A range of Pt supported catalysts have been evaluated for the total oxidation of naphthalene. Catalysts contained 0.5 wt% Pt on a range of supports (γ-Al2O3, TiO2, SiO2, SnO2, and CeO2). SiO2 was the best support, the 0.5%Pt/SiO2 catalyst showing a conversion to carbon dioxide of over 90% at 200 °C (100 vppm naphthalene, GHSV = 45,000 h−1). The catalyst also showed a considerably higher activity (in the temperature range 100–175 °C) than a CeO2 catalyst recently reported to be one of the most effective catalysts for the total oxidation of naphthalene. The high activity of the 0.5%Pt/SiO2 catalyst has been attributed to the relatively low dispersion and relatively large size of Pt particles. Furthermore, due to the acidic and non-reducible nature of the SiO2, platinum is expected to have a weak interaction with the support. XPS data identified the presence of Pt0 on the surface and this contributes to the high activity.