Oxidative desulfurization of dibenzothiophene over highly dispersed Mo-doped graphitic carbon nitride

Mo-doped graphitic carbon nitride (Mo/g-C 3 N 4 ) was successfully prepared by thermal condensation of a Mo/melamine precursor in a semi-closed alumina crucible at 550 °C without atmosphere. Thermogravimetric analysis (TGA) was used to evaluate the polymerization route of the precursor, and theoretical and experimental investigations revealed that the Mo species were likely dispersed and anchored to the pyridinic groups of g-C 3 N 4 . As a result, the obtained Mo/g-C 3 N 4 displayed exceptional catalytic activity in the oxidative desulfurization of dibenzothiophene (DBT) with H 2 O 2 . The effects of catalyst dosage, O/S ratio, and temperature on the catalytic properties of Mo/g-C 3 N 4 were investigated. The kinetic studies revealed a pseudo-first-order kinetic process for DBT oxidation with an apparent activation energy of 43.6 kJ mol −1 . Experimental and theoretical evaluation of the Mo/g-C 3 N 4 stability suggests that catalytically active Mo species are progressively leached from the g-C 3 N 4 structure. The decrease in the Mo–N bond order after forming reactive peroxo-Mo(VI) groups was associated with catalyst deactivation.