6533b851fe1ef96bd12a960b

RESEARCH PRODUCT

Fine chemistry by TiO2 heterogeneous photocatalysis

subject

description

Abstract Heterogeneous TiO2 photocatalysis is a promising technology based on the capability of the semiconducting material to generate charges upon irradiation of suitable energy. The photogenerated electrons and holes, in turn, induce redox reactions involving species adsorbed on the surface of the photocatalyst, giving rise to chemical transformations. The presence of highly oxidizing radicals, thus generated, has long led to consider TiO2 photocatalysis only a nonselective oxidation process. In fact, so far it is possible to find in the literature many examples of its use in the field of environmental remediation aimed at the degradation of harmful molecules, although the studies are almost all limited to the laboratory scale. However, selective synthetic reactions can also be carried out both in organic solvents and in water, carefully tuning the crystallinity and surface physicochemical properties of the photocatalyst. Oxidation, reduction, and coupling reactions, together with fuels production, for example, have been reported under mild experimental conditions, using both artificial and sunlight. The efficiency of TiO2 photocatalysis for production of fine chemicals can be further improved by tuning some parameters such as the setup configuration and the reactor geometry and by coupling photocatalysis with a membrane separation unit. The present chapter reports various examples of photocatalytic reactions in the presence of TiO2 photocatalyst, and among them oxidation of alcohols to aldehydes, hydroxylation of aromatic compounds, epoxidation of alkenes, hydrogenation of carbon–carbon multiple bonds, and some types of alkylation reactions will be presented.