Photocatalytic degradation of methylene blue with carbon coated tungsten trioxide nanoparticles

Abstract

Nanoparticles have attracted considerable attention recently because of their unique properties. Among various methods of producing nanoparticles, flame spray pyrolysis (FSP) has attracted great interest as a promising method of obtaining highly crystalline nanoparticles. In this study, tungsten trioxide (WO3) was successfully synthesized for use as a photocatalyst. Field emission scanning electron microscopy with energy-dispersive spectroscopy showed that carbon doping resulted in good coverage of the tungsten by carbon. Thermogravimetric analysis showed negligible mass loss in the WO3 nanoparticles, whereas the carbon-coated WO3 lost up to 20.3% of its mass at 900 °C. However, at this temperature, orthorhombic crystals were formed. To examine their potential application as photocatalysts, various types of WO3 nanoparticles (as-prepared WO3, WO3 annealed at 1000 °C, and carbon-coated WO3) were used to degrade methylene blue. A photodegradation test revealed that the carbon-coated WO3 nanoparticles had the best photodegradation performance, where the final concentration of methylene blue in solution was only approximately 3% of the initial concentration.