Photocatalytic Comparison of TiO₂ Nanoparticles and Electrospun TiO₂ Nanofibers: Effects of Mesoporosity and Interparticle Charge Transfer

Abstract

The development of a high-efficiency TiO 2 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 TiO 2 nanoarchitectures. In this study, we have successfully synthesized well-ordered and aligned high surface area mesoporous TiO 2 nanofibers (TiO 2 -NF) by electrospinning of TiO 2 powder dispersed in viscous polymer solution and subsequent calcination. For comparison, TiO 2 nanoparticles (TiO 2 -NP) are also prepared from calcination of the same TiO 2 powder. The TiO 2 -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 TiO 2 -NF and TiO 2 -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 TiO 2 -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 TiO 2 -NF and TiO 2 -NP.

Ultrasensitive Gas Sensors Based on Electrospun TiO2 and ZnO

“…Electrospinning represents a new, simple and versatile method for generating ceramic porous nanofibers with interconnective pores and high specific surface area [2]. The sol-gel synthesis is a traditional method to prepare nanopowders with tailored properties, in terms of purity, morphology and grain size homogeneity.…”

Perspective of electrospun nanofibers in energy and environment

“…This superiority was mainly ascribed from the reduced band gap combined with a larger surface area . Compared with its nanoparticle counterparts, nanofibers demonstrate much better mesoporosity, enlarged surface area, tunable fiber morphology and aspect ratios which can significantly enhance the light scattering effect (Choi et al, 2010). Chen et al (2012) have reported that the preferred scattering wavelength and intensity was linearly proportional to the fiber diameter and the fiber deposition density.…”

Highly Sensitive Biofunctionalized Mesoporous Electrospun TiO2 Nanofiber Based Interface for Biosensing

“…10 Lee et al used electrospun TiO 2 nanorod photoelectrodes to investigate charge transport characteristics of high efficiency dyesensitized solar cells. 21 Yu et al reported a crystalline mesoporous TiO 2 that shows high photocatalytic activity due to the synergistic effect, mesoporous structure, and crystallization. 22 The electrospinning of TiO 2 −NF is known to be a low cost and mass production technique that can be used to create electrically charged jets from polymer solutions or melts by application of an electric field (∼kilovolts).…”