Low-Temperature Synthesis of Micro–Mesoporous TiO2–SiO2 Composite Film Containing Fe–N Co-Doped Anatase Nanocrystals for Photocatalytic NO Removal

Abstract

A simple low-temperature (< 100 °C) hot-water treatment was used to synthesize Fe–N co-doped anatase nanocrystals which were uniformly dispersed in micro–mesoporous SiO2 host film for the first time. The Fe–N co-doped TiO2–SiO2 (FNTS) film exhibited stable photocatalytic activities. A NO removal efficiency of 56.1% was achieved under simulated solar light irradiation without any obvious inactivation in 30 min. The transient photocurrent response of FNTS film is approximately six times higher than that of non-doped TiO2–SiO2 film, indicating the superior charge separation of photo-generated electron–hole pairs. Electron spin resonance analysis showed that the ·OH and ·O2− radicals were key species to remove NO. Combined with quantitative reaction intermediates, the possible photocatalytic degradation mechanism of NO over FNTS film was proposed. In addition, the FNTS thin films exhibited intrinsic super-hydrophilicity and durable self-cleaning property even after 6 months of storage in the dark. This work provides a facile method to load the catalyst on thermal labile substrates, such as soda–lime glass and organic polymer for more practical applications. A simple low-temperature (< 100 °C) hot-water treatment was used to synthesize micro–mesoporous TiO2–SiO2 composite film, which shows good self-cleaning ability and superior photodegradation activity for NO removal under solar light.