Abstract: Formaldehyde is one of the most important carbonyl organic compounds. Heterogeneous reactions of formaldehyde on the surfaceof oxides of crustal elements could be an import sink for formaldehyde in atmosphere. In this study, the kinetics of the heterogeneous reaction of formaldehyde on the surface of α-Al₂O₃ were in situ investigated by diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS) over the temperature range of 273—333 K. The adsorbed species, formate(Ⅰ), dioxymehtylene(Ⅱ), polyoxymethylene(Ⅲ) and formaldyhyde(Ⅳ), on α-Al₂O₃ particles were identified with infrared spectrum: on the surface of α-Al₂O₃ particles, formaldyhyde was oxidized at first to dioxymehtylene which was further oxidized to formate. The reaction order was determined as 0.81±0.05, and the initial reactive uptake coefficients at 293 K were calculated with the geometric and the BET specific surface areas are(2.3±0.5)×10^-5 and (9.4±1.7)×10^-9, respectively. The apparent activation energy of the reaction was etermined as 33.5 kJ/mol.

Key words: Formaldyhyde, α-Al₂O₃, DRIFT S, Heterogeneous reaction