Efficient VOCs photodegradation through local ion substitution in TiO₂-C composites derived from MIL-125(Ti)

Volatile organic compounds (VOCs) are the main cause of environmental pollution and numerous respiratory diseases. Most VOCs molecules can be entirely converted into H₂O and CO₂ by photocatalytic technology without the demand for additional oxidants, making it an ideal choice for air purification. However, for conventional photocatalysts, a smaller specific surface area is not conducive to enriching VOCs molecules on the surface of catalyst. To address this, a functionalized porous C-TiO₂ composite was synthesized by a self-sacrificing template method. The resulting porous carbon layer can serve as an adsorption medium to enrich VOCs molecules, while the photocatalytic reaction occurs on the TiO₂ surface. On the basis of the experimental results, the remarkable properties of the catalysts can be attributed to the doping of carbon atoms into oxygen vacancies (OVs) and the formation of Ti@C bonds. Additionally, the study confirmed that C-TiO₂ possesses abundant surface defects and Ti-OH groups, which can facilitate the rapid generation of •OH groups on the catalyst surface, thus aiding in the catalytic oxidation process of VOCs molecules.