Novel approach to synthesise MoO3-TiO2 nanocomposites for the photo-assisted oxidation of benzyl alcohol to benzaldehyde

Nowadays, there is a significant interest in the development of environment friendly catalysts for alcohols oxidation. Aiming to produce improved catalytic materials, here, the synthesis of new TiO2-MoO3 nanocomposites, using distinct approaches is described. The samples were obtained by hydrothermal treatment of a molybdenum oxide precursor in the presence of TiO2 using a step-by-step procedure (sample TM3) or using a one-pot approach (sample PTM3). Depending on the synthesis route, distinct morphologies, surface area and optical properties for the prepared samples, were obtained. The photocatalytic activity of the nanocomposite samples was evaluated for benzyl alcohol oxidation, under visible and UV-visible radiation. The results indicate that both materials are catalytic, presenting high selectivity for benzaldehyde production. Using UV-vis radiation, the best photocatalyst was PTM3 with 98% selectivity and under visible irradiation was TM3 with 99% of selectivity, with this performance being better than the one presented by either TiO2 or MoO3 separately.