Highly active Ag/SBA-15 catalyst using post-grafting method for formaldehyde oxidation

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 °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 O2 can be occurred at lower temperatures on post-grafting catalyst than on other catalysts, which was consistent with the activity test.

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► Highly active Ag/SBA-15 catalyst using post-grafting method for HCHO oxidation.
► HCHO can be completely oxidized into CO2 and H2O at 100 °C on the novel catalyst.
► Appropriate adsorption intensity between HCHO and silver sites was necessary.
► Silver particles highly dispersed on SBA-15 were active for HCHO oxidation.
► The formed intermediates can be easily activated on smaller silver particles.