Adsorption and surface reactions of HCOOH, CH3OH, and CH2O on siliceous mesoporous MCM-41 have been investigated by Fouriertransform infrared spectroscopy. CH2O decomposes on the surface to form adsorbed CH3O and HCOO (an analog of Cannizzaro disproportionation) which are identified by dissociative adsorption of CH3OH and HCOOH. In addition, CH3OH is sequentially oxidized to CH2O and HCOO on MCM-41. These types of reactions for CH2O and CH3OH on MCM-41 have not been observed on amorphous SiO2 without a mesoporous structure. (C) 2004 Elsevier Inc. All rights reserved.