Controllable synthesis of brookite/anatase/rutile TiO2 nanocomposites and single-crystalline rutile nanorods arrayElectronic supplementary information (ESI) available: FESEM images of the oriented rutile TiO2 nanorod array, relative components of anatase, brookite, and rutile phase, TEM images of sample T7, sample T2, and P25, FTIR spectra, photocatalytic comparative testing, calculated band structures and total density of states (DOS) and the projected density of states (PDOS) of brookite, anat

• Main Authors: Liao, Yulong, Que, Wenxiu, Jia, Qiaoying, He, Yucheng, Zhang, Jin, Zhong, Peng
• Format: Journal Article
• Language: English
• Published: 27.03.2012
• ISSN: 0959-9428; 1364-5501
• DOI: 10.1039/c2jm16628c

The synthesis of nano-TiO 2 materials have attracted intense interest due to their importance in a wide area of applications. In this study, we report a facile method to synthesize mixed-phase TiO 2 nanocomposites by using a one-step approach under mild solvothermal conditions. Differently from previous reports, this method not only yields rutile/brookite/anatase TiO 2 nanocomposites with high photocatalytic activities, but also can obtain highly oriented single-crystal rutile nanorod arrays selectively deposited on FTO. These products were characterized by XRD, FTIR, FESEM, TEM, HRTEM, and BET. Results indicate that in the brookite/anatase/rutile coexisting nanopowders, the brookite and anatase phases were crystallized into irregular nanoparticles <20 nm in diameter, whereas the rutile phase was crystallized into single-crystalline nanorods 20 nm in diameter and 100 to 500 nm in length. The single-crystalline rutile nanorods could form a film with controllable thickness up to 7 m. The sample with 29.9% anatase, 27.9% brookite, 42.2% rutile was shown to have the highest photocatalytic activity, yielding over 90% bleaching of methyl orange solution in 20 min. The degradation rate constant k of this sample was 0.10180 min 1 , almost twice as high as that of P25 ( k = 0.05397 min 1 ). DFT calculations were used to confirm the band structures and density of states in brookite, anatase, and rutile phases. Brookite/rutile/anatase TiO 2 nanocomposites with high photocatalytic activities and single-crystal rutile nanorods film are obtained.