Forging Fenton-like system to functionalize electron/hole enrichment regions for ATZ photocatalytic degradation

Abstract

Independent functional regions for electrons and holes enrichment are usually driven by the construction of multiple heterostructures, which is difficult to achieve fine-controlling, resulting in the limited photocatalytic activity. TiO2-based photocatalysts with suitable forbidden band widths are promising for wide application prospects, where the construction of Schottky heterojunctions is the trick to achieve directional migration of electrons and holes. Here, a regionalized surface modification method of H–TiO2 with oxygen vacancy (Ov) and defects for efficient carrier separation was reported, in which interspersed Ag nanoparticles and SiO2 layers serve as electron/hole enrichment regions, respectively. Meanwhile, SiO2 can be served as adsorption sites for photocatalytic oxidation of small-molecule pollutants, while Ag nanoparticles with H+ adsorption capacity and reasonable guide band position can be used as an engine of Fenton-like reactions to cyclically generate the active substance H2O2 to participate in the reduction reaction. The degradation efficiency of Ag–SiO2–H–TiO2 (ASHT) can be increased by 159% for pesticide atrazine (ATZ). The superoxide radicals generated by electrons and oxygen in ASHT also generate H2O2, which promotes the centralized generation of hydroxyl radicals to improve photocatalytic performance. The structural design strategy of ASHT provides a new concept for the process of ring-opening reactions of benzene-containing contaminants in water and conversion to small molecules which will eventually be rapidly mineralized.