Highly dispersed Mo-doped graphite carbon nitride: potential application as oxidation catalyst with hydrogen peroxide†
A novel molybdenum-doped graphite carbon nitride (g-C3N4) catalyst was successfully prepared by simple calcination and applied to the oxidation of various substrates with hydrogen peroxide or tert-butylhydroperoxide (TBHP) as the oxidant. The morphology, structure, and chemical composition of the catalyst were characterized fully, demonstrating the presence of highly dispersed molybdenum species stabilized by the nitrogen atoms of g-C3N4. The Mo(VI) sites stabilized on the triazine ring of g-C3N4 interacted with H2O2 or TBPH, forming peroxo-Mo(VI) groups, which were active for oxidation. Mo-doped g-C3N4 exhibited significantly enhanced activity for the non-selective oxidation of methylene blue (MB) when compared with MoO3 or pure g-C3N4. Furthermore, the catalyst exhibited high efficiency for the selective oxidation of sulfides to sulfoxides, and N-compounds to the corresponding N-oxides, under mild conditions. The catalyst also showed potential application in the epoxidation of olefins. The effects of the homogeneous reaction of leached Mo and the recyclability of the catalyst were also evaluated. The data show that the catalyst exhibits great potential for various industrial applications.