Synthesis of Z-scheme heterostructure FeWO₄/rGO/g-C₃N₄ as a visible-light photocatalyst for removal of organic pollutant

Abstract

Photocatalysts have been effectively applied for water treatment. Narrow bandgap energy semiconductors show good photocatalytic performance at visible light. However, high recombination rate of the photogenerated electrons and holes leads to their low photocatalytic activity. Moreover, the conduction and valence band potentials of these materials are not suitable for the redox reactions with water and oxygen to generate HO• and •O2⁻ radicals, respectively. Therefore, the development of new photocatalyst systems to overcome these disadvantages is necessary. This study investigated the photocatalytic activity of FeWO4/rGO/g-C3N4 Z-scheme photocatalytic system via the degradation of Rhodamine B in water. The photocatalyst was synthesized by simple hydrothermal method and characterized by X-ray diffraction method (XRD), fluorescence spectroscopy (PL) and diffuse reflectance spectra (UV-vis). The results showed that after 150 minutes illumination, the Rhodamine B decomposition efficiency on FeWO4/g-C3N4 and FeWO4/rGO/g-C3N4 were 93.07 and 99.21%, respectively. These values were significantly higher than that of g-C3N4 under the same catalytic concentration of 0.1g/L. In the FeWO4/rGO/g-C3N4 heterostructure, rGO acted as electron mediator and transporter between two semiconductors, resulting in a lower recombination rate of photogenerated charges. As the results, the photocatalytic performance was enhanced.