Study on Photocatalytic Properties of TiO₂ Nanoparticle in various pH condition

Titanium dioxide has been widely studied for its ability to photocatalytic and applications have high performance for photovoltaic applications. In this paper TiO₂ nanoparticle was investigated for the degradation of methylene blue under UV light in various pH condition. The TiO₂ nanoparticle was characterized by SEM and XRD. The results showed that TiO₂ nanoparticle has the structure of anatase and have a particle size of 27 nm. The photocatalytic activity of TiO₂ nanoparticle show that the degradation of methylene blue under UV light have dye removal of 97% dye was degraded in 3 h, but the degradation of methylene blue without UV light have dye removal of 15% dye was degraded in 3 h. It indicated that The photocatalytic activity of TiO₂ nanoparticle could occur if there the UV light. If not UV light the photocatalytic activity cannot occurs, the degradation of Methylene Blue 15% is not a photocatalytic activity but it is adsorption of Methylene Blue by TiO₂ nanoparticle. The photocatalytic activity of TiO₂ nanoparticle has pH-sensitive. The photocatalytic activity of TiO₂ nanoparticle in acid condition (pH 4.1) is 40%, in neutral condition (pH 7.0) is 90%, and in base condition (pH 9.7) is 97%. The highest photocatalytic activity occurs in base condition, it causes in base condition OH- can be direct reaction with a hole to produce hydroxyl radical (OH*).