In situ FTIR study of the adsorption of formaldehyde, formic acid, and methyl formiate at the surface of TiO2 (anatase)

The catalytic properties of TiO2 (anatase) in the reactions of formaldehyde oxidation and formic acid decomposition are examined. At 100-150 degreesC, formaldehyde is converted into methyl formate with high selectivity regard less of the presence of oxygen in the reaction mixture. Formic acid is deco mposed to CO and water. Surface compounds formed in the reactions of formal dehyde, formic acid, acid methyl formate with TiO2 (anatase) are identified by in situ FTIR spectroscopy. In a flow of a formaldehyde-containing mixtu re at 100 degreesC, H-bonded HCHO, dioxymethylene species, bidentate format e, and coordinatively bonded HCHO are observed on the TiO2 surface. In the adsorption of formic acid, H-bonded HCOOH and two types of formates (bident ate and unsymmetrical formates) are formed. In the adsorption of methyl for mate, H-bonded HCOOCH3, HCOOCH3 coordinatively bonded via the carbonyl oxyg en, and bidentate formate are identified.