Visible-light-active TiO2-based hybrid nanocatalysts for environmental applications

Photocatalytic nanomaterials such as TiO2 are receiving a great deal of attention owing to their potential applications in environmental remediation. Nonetheless, the low efficiency of this class of materials in the visible range has, so far, hampered their large-scale application. The increasing demand for highly efficient, visible-light-active photocatalysts can be addressed by hybrid nanostructured materials in which two or more units, each characterised by peculiar physical properties, surface chemistry and morphology, are combined together into a single nano-object with unprecedented chemical–physical properties. The present review intends to focus on hybrid nanomaterials, based on TiO2 nanoparticles able to perform visible-light-driven photocatalytic processes for environmental applications. We give a brief overview of the synthetic approaches recently proposed in the literature to synthesise hybrid nanocrystals and discuss the potential applications of such nanostructures in water remediation, abatement of atmospheric pollutants (including NOx and volatile organic compounds (VOCs)) and their use in self-cleaning surfaces.