Influence of the method of platinum deposition on activity and stability of Pt/TiO2 photocatalysts in the photocatalytic oxidation of dimethyl methylphosphonate

Abstract: Gas-phase photocatalytic oxidation of organophosphorous compound dimethyl methylphosphonate was carried out in a flow reactor on platinized TiO2 Degussa P25. Platinization was performed by soft chemical reduction (SCR) and photodeposition (PD) techniques. Dispersion and chemical state of platinum were studied by X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HRTEM). It was found that SCR gave mostly metallic platinum, whereas PD gave only Pt2+ form. During the oxidation, the state of platinum on a SCR catalyst remained unchanged, which determined its good stability. The catalyst with PD platinum deactivated quite fast due to aggregation of Pt particles. The SCR technique was found to provide better stability and activity. [Copyright &y& Elsevier]