Hierarchically Mesoporous Titanosilicate Single-Crystalline Nanospheres for Room Temperature Oxidative–Adsorptive Desulfurization

Hierarchically mesoporous titanosilicate single-crystalline nanospheres were synthesized by using a polyelectrolyte–surfactant mesomorphous complex templating method. The titanosilicate nanospheres possessed highly ordered mesopores (∼3 nm), interstitial secondary mesopores (6–20 nm), and a titanium content as high as 4.8 wt %. Owing to the nanoscale size, hierarchically mesoporous structure, and high Ti content, the hierarchically mesoporous titanosilicate nanospheres exhibited excellent oxidative desulfurization activity at room temperature (25 °C), with 100% conversion of dibenzothiophene (DBT) achieved within 5 min. More importantly, the titanosilicate nanospheres exhibited a strong adsorptive capacity toward the oxidation product, achieving an oxidative–adsorptive process for one-pot desulfurization of liquid hydrocarbon fuels. The oxidation desulfurization reaction at different temperatures followed pseudo-first-order kinetics, corresponding to an Arrhenius activation energy of 35.53 kJ/mol. Catalytic oxidation of benzothiophene (BT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT), as well as thiophene (T) and 4-methyldibenzothiophene (4-MDBT), was also performed for which the catalyst exhibited excellent activity. The hierarchically mesoporous nanospherical titanosilicate catalyst can serve as a promising candidate for use in a one-pot oxidation–adsorption desulfurization process.