title: TiO2-NiO p-n nanocomposite with enhanced sonophotocatalytic activity under diffused sunlight.
abstract: TiO2-NiO composites with p-n junction were developed by assembling p-type NiO on n-type TiO2using ultrasound assisted wet impregnation method. The sonophotocatalytic efficiencies of pure TiO2and TiO2-NiO composites were evaluated under diffused sunlight using methyl orange (MO) as a model pollutant. The impregnation of NiO nanoparticles on TiO2considerably enhanced the optical absorption in visible region (500-800nm) due to the formation of p-n junctions at the interface between TiO2and NiO. The internal electric field induced by the p-n junction led to effective separation of electron-hole pairs and thereby generating a large amount of reactive species for the degradation of MO. The individual effect of ultrasound and diffused sunlight for the degradation of MO was found to be 30% and 6%, respectively. A synergy of 4.8 fold was achieved when ultrasound was combined with photocatalytic degradation process in the presence of diffused sunlight. The sonophotocatalytic activity of TiO2-NiO photocatalysts with different NiO loading was also evaluated and 10wt% NiO loading was found to be optimal. Moreover, 66% of Total Organic Carbon (TOC) removal was achieved with the optimized TiO2-NiO composite in 140min. In addition, the TiO2-NiO composite exhibited an enhanced photocurrent response under visible light illumination.
authors.affiliation: SRM Research Institute, SRM University, Kattankulathur, 603203 Chennai, Tamilnadu, India.
authors.forename: R
authors.initials: R
authors.lastname: Vinoth
authors.affiliation: SRM Research Institute, SRM University, Kattankulathur, 603203 Chennai, Tamilnadu, India.
authors.forename: P
authors.initials: P
authors.lastname: Karthik
authors.affiliation: Department of Chemistry, Madras Christian College, Tambaram, Chennai 600059, India.
authors.forename: K
authors.initials: K
authors.lastname: Devan
authors.affiliation: SRM Research Institute, SRM University, Kattankulathur, 603203 Chennai, Tamilnadu, India. Electronic address: neppolian.b@res.srmuniv.ac.in.
authors.forename: B
authors.initials: B
authors.lastname: Neppolian
authors.affiliation: The School of Chemistry, University of Melbourne, Parkville, Melbourne, Victoria 3010, Australia.
authors.forename: Muthupandian
authors.initials: M
authors.lastname: Ashokkumar
keywords: Diffused sunlight; Photocatalysts and synergistic effect; Sonophotocatalysts; TiO(2)–NiO