TiO2(B)/anatase heterostructure nanofibers decorated with anatase nanoparticles as efficient photocatalysts for methanol oxidation

TiO2(B) nanofibres, TiO2(B)/anatase heterostructure nanofibres, TiO2(B)/anatase heterostructure nanofibres decorated with anatase nanoparticles, and thermally highly stable anatase TiO2 nanorods have been prepared by hydrothermal treatment of TiO2 P25 in aqueous NaOH solution followed by controlled ion exchange and thermal annealing processes. The obtained TiO2 nanomaterials were characterized by x-ray diffraction, scanning electron microscopy, transmission electron microscopy, diffuse reflectance spectroscopy, electrochemical impedance spectroscopy, and nitrogen adsorption. The photocatalytic activities of the prepared materials were quantified by measuring the photocatalytic methanol oxidation under UV vis illumination. The results indicated that TiO2(B)/anatase heterostructure nanofibres decorated with anatase nanoparticles (84% anatase and 16% TiO2(B)) exhibit 3.5-fold higher photocatalytic activity towards methanol oxidation than TiO2(B) nanofibres and anatase TiO2 nanorods. These nanofibres even showed higher photocatalytic activity than TiO2 P25. This is explained by a better-separation of the photogenerated charge carriers and, most likely, by the facile interfacial charge transfer between TiO2(B) and anatase structures as confirmed by impedance spectroscopy measurements. (C) 2016 Elsevier B.V. All rights reserved.