TiO2/graphene-like photocatalysts for selective oxidation of 3-pyridine-methanol to vitamin B3 under UV/solar simulated radiation in aqueous solution at room conditions: The effect of morphology on catalyst performances

Graphene-like layers, synthesized through a two-step oxidation/reduction wet treatment of a highsurface carbon black, have been used to prepare composites with TiO2 nanoparticles by liquid phase depo-sition, followed by calcination at 200oC. The photocatalytic activity of the TiO2/graphene-like compositeshas been tested for the selective conversion of 3-pyridine methanol to 3-pyridine carboxyaldehyde and nicotinic acid (vitamin B3), under de-aerated and UV/solar simulated conditions, in the presence of cupricions. Two different composite morphologies have been explored and a dependence of the photocat-alytic activity has been assessed. An enhanced photocatalytic activity, with respect to the neat TiO2, hasbeen observed and attributed to the broader variety of stable free-radical species generated, at a givenphoto-catalyst morphology, within the delocalized -electron systems.