Microwave-Assisted Synthesis of Titania Nanocubes, Nanospheres and Nanorods for Photocatalytic Dye Degradation

TiO2nanostructures with fascinating morphologies like cubes, spheres, and rods were synthesized by a simple microwave irradiation technique. Tuning of different morphologies was achieved by changing the pH and the nature of the medium or the precipitating agent. As-synthesized titania nanostructures were characterized by X-ray diffraction (XRD), UV–visible spectroscopy, infrared spectroscopy (IR), BET surface area, photoluminescence (PL), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and atomic force microscopy (AFM) techniques. Photocatalytic dye degradation studies were conducted using methylene blue under ultraviolet light irradiation. Dye degradation ability for nanocubes was found to be superior to the spheres and the rods and can be attributed to the observed high surface area of nanocubes. As-synthesized titania nanostructures have shown higher photocatalytic activity than the commercial photocatalyst Degussa P25 TiO2

Photocatalytic Comparison of TiO 2

The development of a high-efficiency TiO2 photocatalyst is of great importance to a variety of solar light conversion and application fields; the desired high efficiency can be achieved by employing well-controlled TiO2 nanoarchitectures. In this study, we have successfully synthesized well-ordered and aligned high surface area mesoporous TiO 2 nanofibers (TiO2-NF) by electrospinning of TiO 2 powder dispersed in viscous polymer solution and subsequent calcination. For comparison, TiO2 nanoparticles (TiO2-NP) are also prepared from calcination of the same TiO2 powder. The TiO2-NF of ca. 500 nm in diameter and a few micrometers in length consist of compactly and densely packed spherical nanoparticles of ca. 20 nm in size and have mesopores of 3-4 nm in radius. Photocatalytic comparison between TiO2-NF and TiO2-NP indicated that the former had far higher photocatalytic activities in photocurrent generation by a factor of 3 and higher hydrogen production by a factor of 7. The photocatalytic superiority of TiO2-NF is attributed to effects of mesoporosity and nanoparticle alignment, which could cause efficient charge separation through interparticle charge transfer along the nanofiber framework. Finally, various surface characterization experiments were conducted and included to understand the photocatalytic behaviors of TiO2-NF and TiO2-NP. © 2010 American Chemical Society.1