Photocatalytic enhancement using defect-engineered black mesoporous TiO2/CeO2 nanocomposite aerogel.

Developing effective catalysts for the degradation of organic pollutants in the water as well as water-splitting for hydrogen production by using solar energy is a promising and green route for utilization and protection of water resources. In this study, a mesoporous TiO 2 /CeO 2 (m- TiO 2 /CeO 2) nanocomposite aerogel was prepared and defect-engineered using a facile sol-gel method assisted solvent exchange and hydrogenated thermal treatment. The hydrogenated black m -TiO 2 /CeO 2 nanocomposite aerogel exhibits the enhanced photocatalytic activity in the degradation of Rhodamine B (Rh B) and water splitting under visible-light irradiation. The degradation rate of Rh B reached ~96.4% in 60 min, and the hydrogen-evolution rate reached ~182 mmol h−1g−1, which are far higher than those of air-annealed m -TiO 2 sample. The photocatalytic enhancement mechanisms can be attributed to multiple strategies, such as the large specific surface area, the enhanced conductivity, the generation of self-doped defects in Z-scheme m -TiO 2 /TiO 2- x /CeO 2- x heterojunction, which are beneficial for providing more active sites, extending the absorption range of solar light, and suppressing the recombination of photo-excited carriers. [Display omitted] • The defect-engineered m -TiO 2 /CeO 2 aerogel was prepared using sol-gel method and hydrogenated thermal treatment. • The self-doped defects extend the visible light absorption of black m -TiO 2 /CeO 2 aerogel. • The migration of photoexcited charges in the m -TiO 2 /TiO 2- x /CeO 2- x heterojunction follow Z-scheme mechanism. [ABSTRACT FROM AUTHOR]