Tuning interfacial electronic properties of carbon nitride as an efficient catalyst for ultra-deep oxidative desulfurization of fuels

Regulation of electronic properties has been found to be an effective strategy to boost catalytic performance. In this paper, boron doped graphene-analogous carbon nitride (B-C3N4) was prepared and applied in aerobic oxidative desulfurization (ODS) as a metal-free catalyst. Detailed characterizations showed that B atoms have been doped into the framework of carbon nitride, which redistributes the electron structures and appears a stronger Lewis acidity. The B-C3N4 exhibited an impressive sulfur removal to aromatic sulfides, especially to 4,6-dimethyldibenzothiophaene, and the catalytic ability of different sulfides was 4,6-dimethyldibenzothiophene > 4-methyldibenzothiophene > dibenzothiophene. A stronger adsorption progress was constructed between Lewis acid B-C3N4 and Lewis basic aromatic sulfides by the Lewis acid-base interaction, which benefits the next oxidation reaction during the ODS process. After recycling 5 times, the sulfur removal of B-C3N4 could still remain higher than 90%. The current method provides a potential application of B-C3N4 for the removal of 4,6-dimethyldibenzothiophene.