Photocatalytic Degradation of Organic Pollutants Using Visible Light Responsive Photocatalysts

Abstract

Photocatalytic processes over semiconducting oxide surfaces have attracted worldwide attention as potentially efficient, environmentally friendly and low-cost methods for water/air purification as well as for renewable hydrogen production. However, some limitations to achieve high photocatalytic efficiencies have been found due to the fast recombination of the charge carriers and limited visible light absorption ability. Development of photocatalysts by depositing metals on the surface of semiconductors or by coupling two semiconductors with suitable band edge position can reduce recombination phenomena by vectorial transfer of charge carriers. To draw new prospects in this domain, four different kinds of heterostructures such as Au incorporated on B-doped TiO2 in the presence of rGO support, Ti3+ in TiO2 through incomplete hydrolysis of titanium precursor, rGO composited with rod-like g-C3N4 and CuWO4/g-C3N4 nanocomposite were successfully prepared by various process. Their composition, texture, optoelectronics, structure and morphology were thoroughly characterized by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, transmission electron microscopy (TEM), N2 sorption measurements, UV visible diffuse reflectance spectroscopy (DRS), and others. The as-prepared photocatalysts showed higher sonophotocatalytic efficiency for the degradation of organic dyes (i.e., methyl orange) and tetracycline antibiotics as a model contaminant present in aqueous environment through the production of reactive oxygen species. Moreover, these enhanced performances were rationalized in terms of suitable band alignment along with their improved visible light absorption ability and reduced charge recombination rate newline