Defect Engineering of MOF-Derived Carbon for Peroxymonosulfate Activation to Degrade Sulfadiazine: Roles of Carbon Vacancies and Edge Defects

The significance of defects in carbon materials for activating peroxymonosulfate (PMS) has garnered significant attention, and enhancing the heteroatom content of carbon materials is critical in defect engineering. In this study, defect-rich carbon-based catalysts (NOCs) were synthesized through one-step pyrolysis by utilizing metal–organic frameworks (MOFs) MIL-101-NH2(Fe) as precursors. These catalysts were employed as PMS activators for the degradation of sulfadiazine (SDZ). The design and regulation of organic ligands in MOFs facilitated the introduction of high levels of oxygen- and nitrogen-containing groups, which decomposed under a regulated pyrolysis temperature gradient, to result in the formation of defects. Furthermore, both experimental and theoretical calculations confirmed that edge defects (armchair edges and zigzag edges) and carbon vacancies played specific active roles by promoting adsorption and electron absorption from PMS. Consequently, this process led to the generation of O2•– and 1O2, which played a dominant role in the degradation of SDZ. The NOC-1000/PMS system demonstrated universal applicability to various antibiotics, anions, and water matrices. Notably the defects could be regenerated through secondary calcination, thereby highlighting their excellent potential for practical applications. This study introduces an innovative approach utilizing MOFs for defect engineering of carbon materials.