Employment of the electrical arc discharge method to prepare Titania nanoparticles in oxygen bubbled water: Synthesis, characterization and photocatalytic activity

Titanium dioxide is the most popular photocatalyst among the common photocatalysts such as TiO₂, ZnO, ZrO₂, SnO₂, WO₃, CeO₂, Fe₂O₃, Al₂O₃, ZnS and CdS as it is relatively inexpensive, stable chemically, and the photogenerated holes are highly oxidizing. In general, synthesis of TiO₂ usually results in amorphous structures, but electrical arc discharge in water has the advantage in this regard as it produces self-crystallized nanoparticles due to high temperature caused by joule heating. Moreover, compared with other techniques, electrical arc discharge in water is an attractive method because of simplicity of experimental set up, low impurity, less production steps leading to a high-throughput and cost-effective procedure to generate a high yield of nanoparticles. Also the simplicity of this method allows scaling up for mass production. This paper investigates the effect of arc current on size distribution and the photocatalytic activity of the produced nanoparticles. The nanoparticles are fabricated by applying electrical arc discharge between titanium electrodes in oxygen bubbled deionized (DI) water followed by heat treatment. XRD patterns demonstrate formation of TiO₂ phase in oxygen bubbled water after heat treatment and dominance of rutile to anatase phase. The size and morphology of TiO₂ nanoparticles are studied using different arc currents as a crucial parameter in properties of final product. Photodegradation of Rhodamine B (Rh. B) as a standard pollution shows that heat treated samples in oxygen bubbled water for 2 hours at 500°C, have more photocatalytic activity due to enhancement in crystallinity.