▎ 摘　　要

High yield of vitamin B-3 is produced using Ag/ZnO/graphene nanocomposite (1 wt%) as a nanocatalyst after its activation by a silicon precursor such as trimethylsilyl chloride(TMSCl) or tert-butyldimethylsilyl chloride (TBSCl) under visible light. TBSCl has been proved as more efficient activating agent than TMSCl in the oxidation of heterocyclic alcohol derivatives to afford their corresponding carboxylic acids. 3-Pyridinemethanol was selected to be a model substrate to test the ability of Ag/ZnO/graphene-Si nanocatalysts. The oxidation reaction of alcohols was completed in short reaction time (30-60 min) at ambient condition to yield vitamin B-3 and other heterocyclic carboxylic acids in excellent yields (86-99 %). A catalytic oxidation mechanism that is based on the generation of highly active catalytic oxidation species (oxygen radicals) has been proposed. The utility of this inexpensive and recyclable catalytic system without using molecular oxygen or any oxidants make this procedure interesting from a green chemistry point of view.