Dual-Acid Mesostructured Cellular Foams (SO3H and Mo) as Efficient Catalysts for Dibenzothiophene Oxidation

Mesostructured cellular foam (MCF) materials were modified with sulfonic acid (TPS) and molybdenum species to obtain dual-site catalysts containing both Brønsted and Lewis acid sites. The physicochemical properties of the materials were characterized using N₂ adsorption–desorption, XRD, SEM-EDX, XPS, pyridine adsorption combined with FT-IR and UV–vis spectroscopy. N₂ physisorption revealed that TPS and molybdenum incorporation led to pore blockage and surface area reduction, particularly for Mo/MCF. XRD and SEM-EDX analyses indicated that molybdenum species are well dispersed, although TPS presence promoted localized accumulation, suggesting interactions between the two components. The catalysts were evaluated in dibenzothiophene (DBT) oxidation using H₂O₂. Mo/TPS/MCF exhibited superior activity, achieving 100% DBT conversion within 30 min at 80 °C, outperforming TPS/MCF and Mo/MCF. Moreover, the dual-site catalyst maintained high activity over five consecutive cycles, whereas Mo/MCF showed significant deactivation due to molybdenum leaching. These results demonstrate that TPS plays a stabilizing role for molybdenum species and enhances catalytic performance. The interaction between Brønsted and Lewis acid sites in Mo/TPS/MCF offers a promising strategy for efficient and recyclable oxidative desulfurization catalysts.