Studies on Visible Active Transition Metal Doped Biphasic TiO2 Photocatalyst for Solar Energy Applications

Abstract

Solar photocatalysis has emerged as a promising solution to address the current energy environmental issues in a sustainable manner. Using sunlight or artificial light, photocatalytic processes can degrade organic pollutants, disinfect water, and even address emerging contaminants. These reactions are driven by semiconductors that act as photocatalysts, with titanium dioxide (TiO2) being one of the most extensively studied and applied material. The non-toxicity, easy availability and high stability have prompted using TiO2 as an ideal material for multifunctional applications such as photocatalysis and photovoltaics. However, the wide band gap of TiO2, poor charge carrier separation, and newlinecharge carrier dynamics limit its performance. Among the strategies adopted to improve the performance of TiO2, doping and biphasic heterojunctions are the two different techniques widely adopted to address the major limitations such as low absorption wavelength, high charge carrier recombination, and low charge carrier transport. Biphasic heterojunction has a prominent role in improving the charge carrier dynamics of TiO2. Accordingly, biphasic TiO2 samples with varying anatase-rutile(A/R) ratios via a facile sol-gel method are synthesized as an initial study. The influence of the A/R ratio on the physicochemical properties of TiO2 was studied using various structural, morphological, optical and photoelectrochemical characterization techniques. It was observed that the formation of biphasic heterojunction reduced the charge transfer resistance, thereby enhancing the charge carrier dynamics of TiO2. The photocatalytic performance of the synthesized samples was carried out under solar irradiation in a slurry batch-mode reactor. The biphasic TiO2 with higher anatase content exhibited superior photocatalytic performance.