Facile Formation of Anatase/Rutile TiO2 Nanocomposites with Enhanced Photocatalytic Activity

• Published in: Molecules (Basel, Switzerland) Vol. 24; no. 16; p. 2996
• Main Authors: He, Jing, Du, Yi-en, Bai, Yang, An, Jing, Cai, Xuemei, Chen, Yongqiang, Wang, Pengfei, Yang, Xiaojing, Feng, Qi
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 19.08.2019; MDPI
• Subjects: anatase/rutile nanocomposites; Morphology; Nanocomposites; Nanocrystals; Nanoparticles; Photocatalysis; photocatalytic activity; Solar energy; Titanium; {101} facets; {110} facets
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules24162996

Anatase/rutile mixed-phase TiO2 nanoparticles were synthesized through a simple sol-gel route with further calcination using inexpensive titanium tetrachloride as a titanium source, which effectively reduces the production cost. The structural and optical properties of the prepared materials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and UV-vis adsorption. The specific surface area was also analyzed by Brunauer–Emmett–Teller (BET) method. The anatase/rutile mixed-phase TiO2 nanocomposites containing of rod-like, cuboid, and some irregularly shaped anatase nanoparticles (exposed {101} facets) with sizes ranging from tens to more than 100 nanometers, and rod-like rutile nanoparticles (exposed {110} facets) with sizes ranging from tens to more than 100 nanometers. The photocatalytic activities of the obtained anatase/rutile mixed-phase TiO2 nanoparticles were investigated and compared by evaluating the degradation of hazardous dye methylene blue (MB) under ultraviolet light illumination. Compared to the commercial Degussa P25-TiO2, the mixed-phase TiO2 nanocomposites show better photocatalytic activity, which can be attributed to the optimal anatase to rutile ratio and the specific exposed crystal surface on the surface. The anatase/rutile TiO2 nanocomposites obtained at pH 1.0 (pH1.0-TiO2) show the best photocatalytic activity, which can be attributed to the optimal heterojunction structure, the smaller average particle size, and the presence of a specific exposed crystal surface. The enhanced photocatalytic activity makes the prepared anatase/rutile TiO2 photocatalysts a potential candidate in the removal of the organic dyes from colored wastewater.