Abstract: The photoinduced electron transfer and photocatalytic reaction processes of fivc kinds of amides at the surfaee of silver-modified titanium dioxide(Ag-TiO₂) particles have been studied by ESR method.The used amides include fo formamide(FA),dimethylformamide(DMFA),acetamide(AA),dimethylacetamide(DMAA) and propionamide(PA).Results show that the photocatalysis ability of Ag-TiO₂ particles is much greater than that of the unmodified TiO₂.As without TiO₂,the ESR signal of the adduct[DMPO-CONH₂] was observcd only in photolysis of formamide system,and no ESR signal was detected for other four kinds of amides.However,the clear ESR signals could be observed for five kinds of amides in the presence of TiO₂ particles.Two kinds of carbon centered radicals and hydroxyl radical were detected.ESR signals were obviously enhanced by silver-modified TiO₂ particles.At the same condition,the enhancing effect of Ag-TiO₂ containing 10% Ag is greater than that of the Ag-TiO₂ containing 1% Ag.

Key words: Amide, Titanium dioxide, Photocatalysis, ESR