OXIDATION OF VOLATILE ORGANIC-COMPOUNDS ON A AG AL2O3 CATALYST/

Temperature-programmed desorption (TPD) and oxidation (TPO) were used to study decomposition and oxidation of methanol, ethanol, acetaldehyd e, formic acid, and acetic acid on an Ag/Al2O3 catalyst. The volatile organic compounds (VOCs) were adsorbed on the alumina support. Silver was inactive for decomposition of adsorbed VOCs; all dehydration and d ehydrogenation products evolved from reaction on the Al2O3 support dur ing TPD. Silver was active for oxidation of VOCs during TPO, however, and a portion of the VOCs reacted on Al2O3 sites in parallel. Adsorbed VOCs reacted at silver sites with adsorbed oxygen; oxygen was supplie d to silver sites from the gas phase, and surface diffusion on Al2O3 t ransported adsorbed VOCs to the silver sites. Adsorbed oxygen also act ivated neighboring silver sites for alcohol dehydrogenation in paralle l with oxidation. Dehydrogenation was not observed for the aldehyde an d acids.