Robust Mesoporous SiO2-Coated TiO2 Colloidal Nanocrystal with Enhanced Adsorption, Stability, and Adhesion for Photocatalytic Antibacterial and Benzene Removal.

The utility of nanostructured TiO2 in the degradation of organic compounds and the disinfection of pathogenic microorganisms represents an important endeavor in photocatalysis. However, the low photocatalytic efficiency of TiO2 remains challenging. Herein, we report a robust photocatalytic route to benzene removal rendered by enhancing its adsorption capacity via rationally designed mesoporous SiO2-coated TiO2 colloids. Specifically, amorphous, mesoporous SiO2-coated TiO2 nanoparticles (denoted T@S NPs) are produced via a precipitation-gel-hydrothermal approach, possessing an increased specific surface area over pristine TiO2 NPs for improved adsorption of benzene. Notably, under UV irradiation, the degradation rate of benzene by T@S NPs reaches 89% within 30 min, representing a 3.1-fold increase over that achieved by pristine TiO2. Moreover, a 99.5% degradation rate within 60 min is achieved and maintains a stable photocatalytic activity over five cycles. Surface coating of TiO2 with amorphous SiO2 imparts the T@S composite NPs nearly neutral characteristic due to the formation of Ti-O-Si bonds, while manifesting enhanced light harvesting, excellent stability, adhesion, and photocatalytic bacteriostatic effects. Our study underscores the potential of T@S composites for practical applications in photocatalysis over pristine counterparts.