Influences of annealing atmosphere on phase transition temperature, optical properties and photocatalytic activities of TiO2 phase-junction microspheres

• Published in: Journal of alloys and compounds Vol. 789; pp. 1015 - 1021
• Main Authors: Liu, Ruidi, Li, Hui, Duan, Libing, Shen, Hao, Zhang, Qian, Zhao, Xiaoru
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15.06.2019; Elsevier BV
• Subjects: Anatase; Annealing; Annealing atmospheres; Current carriers; Holes (electron deficiencies); Microspheres; Morphology; Optical properties; Phase transition; Phase transitions; Photocatalysis; Photocatalytic performance; Rhodamine; Synergistic effect; Temperature; TiO2 mixed phase microspheres; Titanium dioxide; Transition temperature; X ray photoelectron spectroscopy; Annealing atmospheres; TiO2 mixed phase microspheres; Photocatalytic performance; Phase transition
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2019.02.198

TiO2 microspheres were successfully fabricated and subsequently annealed in air and N2 atmosphere under different temperatures. The morphologies, phase transition temperatures, optical properties were investigated by SEM, XRD, PL and XPS. The photocatalytic performances of these products were also evaluated toward Rhodamine B (RhB) degradation. The experimental data implied that the anatase phase could gradually transform to rutile phase with the temperature increasing from 450 °C to 600 °C under air atmosphere. However, the phase transition was inhabited to the range of 500–650 °C under N2 atmosphere. Analysis showed that the synergistic effect of the phase-junction could separate photo-generated electron-hole pairs to improve the photocatalytic activities. Moreover, N2 annealing could bring about the formation of charged oxygen vacancies and Ti3+, which further prolonged the life time of charge carriers and optimized the photocatalytic performance. [Display omitted] •A facile way has been carried out to synthesize TiO2 microspheres.•The annealing atmosphere could influence the transition temperature and optical properties.•N2 annealing could bring about the formation of charged oxygen vacancies and Ti3 for as-prepared TiO2 microspheres.•Phase-juntion TiO2 annealed at 550 °C under N2 atmosphere exhibited the optimum photocatalytic performance.