Research On The Catalyst Of Gold Supported On ZrO₂ Pillared Clay For Oxidizing HCHO

Gold is loaded onto ZrO₂ pillared-clay by ion exchange. The obtained Au/ZrO₂-pillared clay is found to be superior catalysts for removal of formaldehyde from indoor air at moderate temperature by oxidation. Interestingly, gold in the as-prepared catalyst is well dispersed and in an oxidized state of Au³⁺; but it is converted into metallic crystals (Au°) during the use as catalyst. Nonetheless, the gold species in the two states strongly adsorb HCHO molecules at ambient temperature, and the adsorbed HCHO molecules convert rapidly into formate species, as observed by Infrared spectra. Temperature program desorption (TPD) and temperature program reaction (TPR) study reveals that HCHO is adsorbed on surface of catalyst and HCHO oxidation involves reaction between adsorbed formate species and adsorbed oxygen molecules. Base on the fact of these experiments, the mechanism of HCHO oxidation on catalyst Au/ZrO₂-pillared clay has been suggested.