The oxidation of HCHO at room temperature was studied on Pt/TiO2 catalysts prepared by wet impregnation. The catalytic activity was dependent on the type of the TiO2 support and HCHO feeding rate. The surface carbon monoxide species were the main intermediate for HCHO oxidation, which was examined using in situ DRIFTS. XPS analysis confirmed that the catalytic performance and valence states of the catalyst were closely related. However, XRD analysis showed that the number of active sites decreased due to Pt agglomeration during reduction treatment at temperatures higher than 873 K. (C) 2011 Elsevier B.V. All rights reserved.