Insight into the influence of defect sites in mixed phase of mesoporous titania nanoparticles toward photocatalytic degradation of 2‐chlorophenol: Effect of light source

Abstract

The impact of different light irradiation was studied on photocatalytic degradation of 2‐chlorophenol (2‐CP) using mesoporous titania nanoparticles (MTNs) prepared by microwave‐assisted methods. The photoactivity of MTNs was also compared with pretreated commercial TiO2 and Degussa P25 (P25). The reactions were conducted for 2.5 hr under UV‐A, UV‐C, sunlight, and visible light using a batch reactor. The catalysts were characterized by X‐ray powder diffractometer, UV–Vis diffuse reflectance spectroscopy, photoluminescence, Brunauer–Emmett–Teller method, field‐emission scanning electron microscopy, transmission electron microscopy, and X‐ray photoelectron spectroscopy. The characterization results confirmed that MTN consisted a composition of 21% rutile phase and 79% anatase phase with Ti3+ site defects (TSDs) and oxygen vacancies (OVs) in their structures because of their anionic surfactant nature, microwave heating, and high calcination temperature during the catalyst preparation. Besides, the photoactivity of MTN upon degradation of 2‐CP under sunlight has exhibited the best performance with 100% degradation followed by UV‐A, visible light, and UV‐C with degradation of 96, 52, and 39%, respectively. MTNs showed a remarkable performance due to their mixed‐phase crystalline structures as well as the formation of TSDs and OVs, which improved the charge migration, lowered the band gap energy, and reduced the rate of electron–hole recombination, thus succeeded to be activated under a wide range of light responses.