Isolated Pt single atomic sites anchored on nanoporous TiO2 film for highly efficient photocatalytic degradation of low concentration toluene

Single atom catalysts with atomically distributed active metal centers have attracted great attention owing to their maximum atom efficiency and excellent activity. Herein, we report a novel photocatalyst with isolated Pt single atomic sites anchored on nanoporous TiO2 film prepared by a facile immersion and reduction method. HAADF-STEM, XPS, XANES and EXAFS results confirmed the anchoring of Pt single atomic sites on nanoporous TiO2 film. The effects of immersion concentration of Pt, reduction temperature, relative humidity, inlet toluene concentration and residence time on photocatalytic degradation of low concentration toluene under UV and VUV irradiation were investigated. The results showed that the as-prepared catalyst had considerably high photocatalytic activity. The removal rate of toluene reached 45.88% under VUV irradiation when the inlet toluene concentration and residence time were 200 ppb and 0.3 s, respectively, which was 5.94 times that of pristine nanoporous TiO2 film. The by-product ozone removal was greatly improved and the corresponding energy consumption was 0.01 kW·h/m3. While the removal rate of toluene increased with the decrease of inlet toluene concentration under UV irradiation. The Pt single atom catalyst exhibits significant potential for photocatalytic degradation of low concentration VOCs in indoor environments.