A novel Nb2O5/Bi2WO6 heterojunction photocatalytic oxidative desulfurization catalyst with high visible light-induced photocatalytic activity

Abstract

A novel Nb₂O₅/Bi₂WO₆ heterojunction catalyst was successfully synthesized via a one-pot solvothermal process. The catalyst was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) with the corresponding XEDS energy mapping, UV-vis diffuse reflection spectra (UV-vis DRS), Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The photocatalytic oxidative desulfurization performances of the prepared samples were studied with DBT as the model sulfur compound under visible light irradiation. Results indicated that the Nb₂O₅/Bi₂WO₆ exhibited considerably higher activity than pure Nb₂O₅ and Bi₂WO₆ and the desulfurization rate achieved 99% after visible light irradiation for 120 min. The catalyst also possessed good stability so that the desulfurization rate remained about 90% after seven cycle times and then the crystal structure of the catalyst has barely changed. Such enhanced photocatalytic activity is mainly attributed to the effective separation of photogenerated electron–hole pairs on Nb₂O₅/Bi₂WO₆ heterojunction. Moreover, the synergistic effects of this photocatalytic oxidation and the extraction with the methanol as the solvent played an indispensable role in the desulfurization.