Photocatalytic oxidative-extractive desulfurization of dibenzothiophene under simulated solar light with MoS2-CeO2/Al2O3-SiO2 nano photocatalyst: effect of CeO2 content

Abstract

In this paper, a visible light-driven nanophotocatalyst of MoS2 with different amounts of CeO2 (0%, 8%, 16%, 24%, and 32% wt.) was impregnated on SiO2-Al2O3. The physicochemical properties of synthesized photocatalysts were investigated by XRD, FESEM, TEM, UV-Vis DRS, PL, BET-BJH, ICP-OES, EDX, and FTIR analyses. While the size of particles in all samples was in the nanoscale range, the sample with 8% wt. of CeO2 indicated the narrowest particle size distribution. UV-Vis DRS and PL analyses confirmed that adding CeO2 to the MoS2/SiO2-Al2O3 photocatalyst increased the amount of light absorption and decreased the recombination rate of charge carriers. Among CeO2-containing samples, the sample with 8% wt. of CeO2 illustrated the lowest recombination rate and the narrowest bandgap energy of 2.9 eV. The MoS2-CeO2/SiO2-Al2O3 photocatalyst with 8% wt. of CeO2 had the highest adsorption of DBT in dark conditions (29.93%), the highest photodegradation (96.9%) after 3 h of visible light irradiation and good stability after five consecutive runs. Meanwhile, total sulfur measurement indicated that using this sample and the extraction afterward, the model fuel has lost 96% of its sulfur content which confirms the excellent ability of acetonitrile-assisted extraction in gathering desulfurization products from the fuel.