Nitrogen-rich carbon for catalytic activation of peroxymonosulfate towards green synthesis

Abstract

Nitrogen-doped carbon (NC) materials have demonstrated exceptional performances in activating peroxymonosulfate (PMS) for environmental remediation. However, accommodating higher nitrogen contents remains challenging in NC due to the thermodynamic instability of CN skeleton. In this study, we proposed an innovative epitaxial growth approach to synthesize two-dimensional NC nanosheets. Leveraging the abundant amino groups supplied by the polymer dots as growing sites, we successfully attained a high nitrogen level and spontaneously introduced abundant structural defects in the carbon framework. The resulting NC nanosheets exhibited outstanding catalytic activity for the activation of PMS toward selective oxidation of diethyl 1,4-dihydro-2,6-dimethyl-3,5-pyridinedicarboxylate (1,4-DHP) into diethyl 2,6-dimethylpyridine-3,5-dicarboxylate, which serves as a valuable intermediate in the synthesis of various pharmaceutical compounds. Comprehensive experimental and characterization investigations verified that the nitrogen sites and defects are the primary active sites for PMS activation and selective oxidation of 1,4-DHP. This work offered an efficient approach for the fabrication of high-nitrogen-loading carbon materials for catalytic oxidation reactions.