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 TiO2/CeO2 (m-TiO2/CeO2) nanocomposite aerogel was prepared and defect-engineered using a facile sol-gel method assisted solvent exchange and hydrogenated thermal treatment. The hydrogenated black m-TiO2/CeO2 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 similar to 96.4% in 60 min, and the hydrogen-evolution rate reached similar to 182 mmol h(-1)g(-1), which are far higher than those of air-annealed m-TiO2 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-TiO2/TiO2-x/CeO2-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.