Photocatalytic oxidation of glycerol with red light employing quinacridone sensitized TiO2 nanoparticles

Photocatalytic nanomaterials combining organic dyes and inorganic semiconductor nanoparticles (NPs) are extensively investigated for light-driven production of solar fuels and for conversion of organic feedstocks. However, their applications for the valorization of abundant raw materials by exploiting low-energy visible light remain limited. In this study, we report a facile preparation of TiO2 nanoparticles sensitized with a quinacridone (QA) industrial pigment for the aqueous oxidation of glycerol to glyceraldehyde with red light (lambda = 620 nm), reaching 47.5 +/- 5.0 mu mol gNP-1 h-1 of productivity and 80% selectivity in the presence of TEMPO co-catalyst. The hybrid material outperforms the single components and shows recyclability up to at least 5 additional times under red light while maintaining intact productivity; furthermore, it demonstrates versatility by operating also under green, yellow or white light irradiation. We believe that this work will provide a new avenue for using industrial pigment-sensitized materials in photocatalysis exploiting low energy light, providing novel strategies for the future development of this field.