Strong visible absorption and excellent photocatalytic performance of brown TiO2 nanoparticles synthesized using one-step low-temperature process

• Published in: Chinese journal of catalysis Vol. 38; no. 7; pp. 1184 - 1195
• Main Authors: Wang, Ting, Li, Wanwen, Xu, Dandan, Wu, Xuanmin, Cao, Liwei, Meng, Jianxin
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2017
• Subjects: Broadband absorption; Oxygen vacancy; Photocatalytic degradation; Titanium dioxide; Visible light; Photocatalytic degradation; Visible light; Broadband absorption; Titanium dioxide; Oxygen vacancy
• ISSN: 1872-2067; 1872-2067
• DOI: 10.1016/S1872-2067(17)62855-9

We report a facile and modified sol-gel approach to synthesize brown TiO2 nanoparticles at low temperature (100–600 °C). The TiO2 nanoparticles dried at 180 °C (TiO2-180°C) possessed a small particle size (5.0 nm), large specific surface area (213.45 m2/g), and efficient response to broadband light over the entire ultraviolet-visible spectrum with a narrow band gap of 1.84 eV. In addition, TiO2-180°C exhibited the optimal reaction rate constant for the degradation of methylene blue (0.08287 mg/(L·min)), which is six times higher than that of the mixed rutile/anatase phase TiO2 photocatalytic standard P25 (0.01342 mg/(L·min)). Furthermore, cycling photodegradation experiments confirmed the stability and reusability of this catalyst. The unique physicochemical properties resulting from the low-temperature preparation of TiO2-180°C, including its broadband visible absorption associated with a high concentration of oxygen vacancies, large surface area, and enriched surface –OH/H2O may be responsible for this excellent photocatalytic performance. The use of as-prepared TiO2-180°C for practical applications is expected after further optimization. Brown TiO2 nanoparticles synthesized using a modified sol-gel approach at 180 °C exhibited small particle size, large surface area, enhanced visible-light response, and enriched surface –OH/H2O, leading to the enhancement of their photocatalytic activity.