Development of hierarchically porous LaVO4 for efficient visible-light-driven photocatalytic desulfurization of diesel

Abstract Aerobic photocatalytic oxidative desulfurization (APODS) is a rapidly growing organosulfur compound conversion technique that operates at mild temperature and ambient pressure and, eliminating the requirement of expensive hydrogen gas as required in industrial hydrodesulfurization technology. In this study, mesoporous LaVO4 was synthesized hydrothermally using a KIT-6-based template etching for deep desulfurization. The as-synthesized photocatalyst was characterized by several techniques, including SEM, STEM, FTIR, UV–Vis DRS, Raman, PL, and N2 physisorption analyses. The synthesized material offered a large surface area and enlarged pore size with a narrow bandgap (2.05 eV) and reduced particle size with a dominant monoclinic phase of LaVO4, making it suitable for capturing more light photons, offering plentiful active sites, and reducing electron-hole recombination rate compared with standard techniques; this results in an enhanced visible-light-driven APODS performance. The optimum parameters such as reaction temperature, solution pH, oxygen flow rate, solvent/oil ratio, catalyst dosage, and agitation rate for APODS were determined to be 20 °C, pH 4, 100 mL/min, 1:5 (v/v), 3 g/L, and 750 rpm, respectively. Mesoporous LaVO4 was tested on commercial diesel fuel containing 410 ppm sulfur over a visible-light irradiation period of three hours, exhibiting excellent performance in desulfurizing diesel up to 88.17%, which was more than twice that of conventional LaVO4. The kinetic study demonstrated a good fit with the pseudo-first-order kinetic reaction model, and the reaction mechanism was suggested. The developed photocatalytic material also exhibited excellent regeneration and recyclability.