Synthesis of Hydrogenated Titania and Its Photocatalytic Activity in Photodegradation of Phenol

Abstract

TiO2 is widely utilized in many applications, such as self-cleaning, antifogging properties and a favorable photocatalyst in solving environmental problem. However, TiO2 has a large bandgap of 3.0 – 3.3 eV that limits its optical absorption to ultraviolet (UV) spectrum, resulting in low photocatalytic efficiency. One way to solve these problems would be by synthesizing hydrogenated TiO2 using a simple hydrogenation method, which is a surface modification phenomenon and does not perturb the crystalline core of TiO2. Therefore, this study reports on the preparation of hydrogenated TiO2 from commercial TiO2 at different hydrogen gas pressure and hydrogenation duration, that give a bluish-grey colour of hydrogenated TiO2. The physicochemical properties of the synthesized hydrogenated TiO2 were characterized by TPR, FESEM-EDX, XRD, NIR UV-Vis and FTIR. TPR analysis measured the reducibility of commercial TiO2 is at 400 to 600 °C. FESEM images of hydrogenated TiO2 showed that the particles size of hydrogenated TiO2 is bigger than the commercial TiO2. EDX analysis confirmed the presence of titanium (Ti) and oxygen (O) element, while XRD patterns confirmed the synthesized hydrogenated TiO2 samples are in anatase phase. NIR-UV-Vis showed that the band gap energy of all samples was in the range of 3.23 – 3.26 eV, higher than the expected value. Most probably due to insufficient hydrogen gas supplied to the TiO2. The photocatalytic activity of the synthesized hydrogenated TiO2 was tested out in photodegradation of phenol under UV and visible light irradiations for 7 hours. It was found that the hydrogenated TiO2 were able to decompose phenol, although at lower degradation percentage of less than 50%.