Superhydrophobic self-floating TiO2-silicone composite aerogels and their air–liquid-solid triphase photocatalytic system

Semiconductor photocatalysis is as a promising method for water pollution remediation. However, the recycling and light capture of powder photocatalysts in traditional suspension systems are bottlenecks for their practical application in photocatalysis. Moreover, the large-scale application of traditional immobilized photocatalytic systems immersed in solution is limited due to the electron-hole recombination and slow reaction rate. Herein, we have successfully prepared superhydrophobic self-floating TiO 2 -silicone composite aerogels by condensation polymerization of γ-methacryloxypropyl trimethoxysilane (KH570) modified anatase TiO 2   and methyltriethoxysilane (MTES). The air–liquid-solid triphase photocatalytic system was constructed using the air layer formed by the superhydrophobic self-floating composite aerogel and the solution interface, which solved the above-mentioned limitation. The floating characteristics of the system effectively avoided the absorption of light by the solution, thereby significantly enhancing the light utilization of the catalyst. The air–liquid-solid interface allows oxygen to be quickly transported from the air to the reaction interface, and oxygen, which is a natural electron scavenger, can effectively remove photoelectrons from the catalyst surface and the recombination of electron-holes is minimized. The new self-floating photocatalyst with triphase catalytic system presented high practical application value for the degradation of suspended pollutants in a natural environment.