Catalytic properties of γ-Al2O3 supported Pt–FeOx catalysts for complete oxidation of formaldehyde at ambient temperature

Abstract

A series of γ-Al₂O₃ supported Pt–FeO_x catalysts (Pt–FeO_x/Al₂O₃) with different Fe/Pt atom ratios were prepared, and their catalytic properties were investigated in the oxidation of formaldehyde. It was found that the catalytic activities of Pt–FeO_x/Al₂O₃ catalysts are varied with the change of Fe/Pt ratios. Among them, the sample with a Fe/Pt ratio of 1.0 exhibits the highest activity, which can efficiently convert formaldehyde to CO₂ at ambient temperature. The catalytic activity of the Pt–FeO_x/Al₂O₃ catalyst can be further improved by the addition of water vapor into the feed stream. A variety of characterization results showed that both Pt nanoparticles and FeO_x species are highly dispersed on the surface of the γ-Al₂O₃ support. Changing Fe/Pt ratios could influence the chemical states and the redox properties of Pt and Fe species. The catalysts with appropriate Fe/Pt ratios have more accessible active sites, i.e., the Pt–O–Fe species, which are located at the boundaries between FeO_x and Pt nanoparticles, thus showing high activity for the oxidation of formaldehyde under ambient conditions.