Synthesis of TiO2 Nanoparticles Doped with Transition Metals via CVS Method and Characterization of Their Photocatalytic Activity

Photocatalytic nanoparticles have achieved great attention due to their ability to remove environmental pol-lutants [1]. Among various kinds of photocatalysts, TiO2 has been found of great interest owing to its low cost, high chemical stability, non-toxicity and high oxidation power [2]. One of the most important chal-lenges of using TiO2 as a photocatalytic material is its wide band gap and a near UV absorption edge that leads to a poor activity under visible light. Doping of TiO2 with anions [2], transition metals [3] and rare earth metals [4] is a well-known method to introduce a shift in the absorption edge and improve photocata-lytic activity. Chromium and vanadium are the most common transition metals that impose a great impact on the efficiency of TiO2 [5]. Most researches have a focus on the synthesis of TiO2 via liquid procedure, e.g. sol-gel, hydrothermal, etc. Gas phase synthesis of TiO2 has the advantages of high production capacity, minimizing the contaminations and the ability to produce narrow particle size distribution in a high quantity [6]. A few reports have been available in open literature on doping of TiO2 nanoparticles with transition metals during gas phase synthesis. In the present work, doped TiO2 nanoparticles have been synthesized via chemical vapor synthesis (CVS) method. The effect of Cr and V elements on the performance of TiO2 nanoparticles in degradation of methylene blue is presented