Mo framework-substituted Beta zeolite hydrothermally synthesized by interzeolite transformation for oxidative desulfurization

Oxidative desulfurization (ODS) is regarded as a viable carbon–neutral way to produce sulfur-free fuels. Mo framework substituted zeolite is considered to be a potential heterogeneous catalyst to achieve this goal. Nonetheless, the hydrothermal synthesis of Mo-containing zeolite remains a challenging task in terms of theses aspects including the difficulty in isomorphous substitution of Si with Mo due to the large ionic radius of Mo (59 pm), the tendency of Mo species to precipitate in the alkaline medium, and the prolonged crystallization time. Herein, Mo-Beta zeolites were synthesized via interzeolite transformation within a short time of 24 h. The crystallization process followed the dissolution–recrystallization mechanism. Various techniques were used to confirm that Mo species was isomorphously substituted into zeolite framework. Mesopore was also created over Mo-Beta zeolite with different Mo contents. This Mo-Beta zeolites were employed as heterogeneous catalysts in oxidative desulfurization, where framework Mo species was found to be the catalytic active sites. The process parameters (catalyst dosage, reaction temperature, and H 2 O 2 amounts), reaction kinetics, and reusability were also investigated. Mo-Beta exhibited remarkably high catalyst-weight-based space–time-yield and active-site-based turnover frequency, surpassing the zeolite catalysts in the literatures. This work paves an avenue to the hydrothermal synthesis of metallosilicate zeolites for catalytic oxidations.