The catalytic oxidation of dichloromethane (DCM, 1000 ppm) in wet air was carried out in a fixed bed reactor over a range of Pt/gamma-Al2O3 catalysts. The dichloromethane oxidation occurs following a bifunctional mechanism. DCM is disproportionated over gamma-Al2O3 into a 1/1/3molar mixture of CO, CH3Cl, and HCl; the DCM transformation is followed by CH3Cl and CO oxidation into CO2. A mechanism of DCM disproportionation is proposed involving, as intermediates, formate species as well as alumina hydroxyl groups formed by water adsorption. (C) 2012 Elsevier Inc. All rights reserved.