Catalytic oxidation of formaldehyde over different silica supported platinum catalysts

Three kinds of silica materials, including fumed SiO2, porous granular SiO2 and mesoporous SBA-15, were adopted to prepare supported Pt catalysts by impregnation method. The catalytic properties of these silica supported Pt catalysts (Pt/SiO2) were investigated for the complete oxidation of formaldehyde (HCHO). Among them, fumed SiO2 supported Pt catalyst (Pt/f-SiO2) shows very high catalytic activity, which could completely oxidize HCHO even at ambient temperature. According to the results of catalyst characterization, it was proposed that the nature of silica supports could affect the particle size and the chemical states of platinum species and then further influence the redox property of Pt/SiO2 catalysts. Compared with other silica supported Pt catalysts, Pt/f-SiO2 catalyst possesses higher ratio of metallic Pt species, which might be a key factor in improving its capability to activate molecular oxygen and consequently to oxidize HCHO at low temperature.

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• The nature of silica supports can affect the chemical states and catalytic properties of Pt nanoparticles.
• Fumed silica supported platinum catalyst is highly active for HCHO oxidation.
• Fumed silica supported platinum catalyst contains more metallic Pt species.
• The activation of molecular oxygen can be achieved at room temperature.