Selective photoelectrocatalytic oxidation of 3-methylpyridine to vitamin B 3 by WO 3 decorated nanotube-structured TiO 2 .

Nanotube-structured TiO 2 electrodes on Ti plates were formed in ethylene glycol solution by the anodic oxidation method applied for different times and calcined at 500 °C. Different amounts of WO 3 were decorated on the nanotube surfaces electrochemically. The electrodes were characterized, and the effects of the nanotube length on the Ti plate, decorated WO 3 amount, electrolyte concentration, applied potential, and type of radiation source on the oxidation of 3-methylpyridine were investigated, together with the product distribution/selectivity. In a photoelectrocatalytic system, the vitamin B 3 yield increased significantly ( ca. 17 fold) under UVA by decorating nanotube-structured TiO 2 with WO 3 , whilst low reaction rates and no products were found under Vis irradiation, as only unselective photolytic reactions occurred. This unexpected result was clarified for the first time in the literature.