Enhancement Of Photocatalytic Efficiency Research Articles

Photocatalytic efficiency enhancement of plasma-sprayed TiO 2 coatings under external bias voltage

TiO 2 coatings were prepared on stainless steel by plasma spraying. The photocatalytic efficiencies of as-sprayed coatings were evaluated through the photo mineralization of methylene blue. External bias voltages applied to the coatings have shown an enhancement of the photocatalytic efficiency reducing the recombination of photogenerated electron–hole pairs. A more efficient photocatalytic reaction would take place when a higher external bias is imposed, because the force of recombination suppression is strengthened when the external bias is higher. The highest photocatalytic efficiency enhancement was about 46%.

Photocatalytic activity of nanocrystalline TiO 2-based films produced by ESAVD method

Nanocrystalline TiO 2-based films have been deposited using a novel and cost-effective Electrostatic Spray Assisted Vapour Deposition (ESAVD) method for photocatalysis applications. The deposited films mainly have anatase phase with very small amounts of rutile or brookite. This paper reports the photocatalytic activity of the nanostructured TiO 2-based films under solar light irradiation. The influence of PEG additive and Fe doping on the film photocatalytic efficiency will be presented, as well as the structural changes with the additive and dopant. The results demonstrate that ESAVD process can produce nanocrystalline anatase films with good photocatalytic activity, and further enhancement of photocatalytic efficiency can be achieved by introducing appropriate Fe doping.

Structure and size distribution of TiO2 nanoparticles deposited on stainless steel mesh

Doped and undoped TiO2 nanoparticles with narrow size distribution were deposited on stainless steel mesh substrates by metalorganic chemical vapor deposition. The chemical composition of TiO2 nanoparticles was measured by energy dispersive x-ray spectroscopy and x-ray photoelectron spectroscopy. X-ray diffraction and transmission electron microscopy were performed to investigate the size and the size distribution of particles as well as the structural phase transitions. For pure TiO2, the results showed that anatase polycrystalline nanoparticles with average size from 23 to 31 nm were obtained for substrate temperatures between 350 and 600 °C. Particles deposited below 350 °C were x-ray amorphous and rutile began to precipitate at temperatures above 700 °C. The particles synthesized at 600 °C had the smallest size and narrowest size distribution. In order to study the dopant effects on the photocatalytic properties, growth temperature of 600 °C was selected to prepare 1 at. % Nd3+ doped TiO2 nanoparticles. The results of photodegradation of the pollutant 2-chlorophenol solution irradiated under ultraviolet light showed that 1 at. % of Nd3+ doped TiO2 had an enhanced degradation of the pollutant. The enhancement of photocatalytic efficiency by doped nanoparticles was ascribed to the large surface area and trapping induced prolonged lifetime of holes.