Facet Dependent Activity of Fe(III) Species Modified TiO₂ for Simulated Sunlight Driven Fenton-like Reactions

TiO2 crystals with different exposed facets are synthesized and modified facilely by depositing Fe(III) species. With more (101) facets exposed, the photoactivity of Fe-TiO2 is obviously enhanced with peroxymonosulfate (PMS) as oxidant. The degradation rate for 20 ppm Bisphenol A (BPA) on Fe-TiO2 (101) can achieve 0.219 min–1, ∼8.5 times faster than that of pure TiO2 under simulated sunlight irradiation. Photoelectrochemical measurements and density functional theory (DFT) calculations confirm that the interfacial charge transfer (IFCT) on Fe-TiO2 (101) is stronger than that on Fe-TiO2 (001) and a faster Fe(III)/Fe(II) transformation rate can be therefore achieved. As a result, the generation of ·OH and 1O2 will be accelerated with more (101) facets exposed, thus obtaining better photoactivity. Under the Fe-TiO2/PMS/Light system, BPA can be effectively degraded in a wide pH range or in the presence of multiple inorganic anions. After five cycles, 100% BPA can still be degraded within 60 min. The study provides new photocatalysts design strategy based on Fe(III)/Fe(II) redox for PMS based photocatalytic oxidation.