The performance of monodispersed Ag/SBA-15 catalyst prepared by post-grafting method was studied. Compared with impregnation method, the catalyst prepared by post-grafting method exhibited higher metal dispersion, smaller silver particle size and better catalytic activity for formaldehyde oxidation. The HCHO can be completely oxidized into CO2 and H2O over the silver catalyst at about 100 degrees C. Temperature programmed surface reaction (HCHO-TPSR) and temperature programmed desorption (HCHO-TPD) experiments demonstrated that the catalyst prepared by post-grafting method exhibited better HCHO adsorption and activated performance at low temperatures. In situ FT-IR spectra revealed that DOM and formate species can be formed on all catalysts, but CO and CO2 species can only be found on silver supported catalysts and the post-grafting sample trended to form more intermediates. Dynamic test showed that the oxidation of HCHO with gas O-2 can be occurred at lower temperatures on post-grafting catalyst than on other catalysts, which was consistent with the activity test. (C) 2012 Elsevier B.V. All rights reserved.