Photocatalytic degradation of organic pollutants with PT-CaFe₂O₄/TiO₂ composite under visible-light irradiation

In this study, visible-light active photocatalyst based on TiO₂ was designed using CaFe₂O₄ nanoparticle as an effective sensitizer. CaFe₂O₄ nanoparticles (CFO) were synthesized by Pechini method using calcium nitrate and iron nitrate. Then, the high crystalline CFO calcined at 800^oC was combined with TiO₂ in a simple sol-gel aging. In order to form coupled structure, CFO suspension and TiO₂-precursor solution were mixed in ethanol solution, and then heated at 80^oC while vigorously stirring. After 6 hrs, the coupled particles were filtered and dried, followed by calcination at 400^oC. The prepared composites were tested for photocatalytic oxidation of Salicylic acid, a model organic compound under visible-light (λ ≥ 420 nm) as monitored by UV-Visible Spectrophotometer. The origin of photoactivity of the heterojunction was found mainly due to the superoxide radical and generation of hydroxyl radical was negligible. The average photo-conversion performance was obtained because of unique energy band matching between CFO and TiO₂.