One-step synthesis of novel Fe₃C@nitrogen-doped carbon nanotubes/graphene nanosheets for catalytic degradation of Bisphenol A in the presence of peroxymonosulfate

Developing novel carbocatalysts with available strategies for peroxymonosulfate (PMS) activation has become a popular topic in environmental remediation and protection fields. Herein, using commercial K₄Fe(CN)₆ as the precursor, Fe₃C@nitrogen-doped carbon nanotubes/graphene nanosheets (Fe₃C@NCNTs/GNS) is synthesized by a direct high-temperature pyrolysis. Characterization results prove that Fe₃C@NCNTs/GNS has a relatively high graphitization degree and rich nitrogen doping content, which endow it with excellent catalytic efficiency in PMS activation for powerful removal of Bisphenol A (BPA). Influences of catalyst/oxidant dosages, some inorganic anions, humic acid, and practical sewages are investigated in detail. For mechanism studies, it is found that tert-butyl alcohol (TBA)/methanol fails to inhibit BPA degradation, and the primary reactive oxidative species (ROS) are superoxide radical (O₂ ^[rad]−) and singlet oxygen (¹O₂). Discussion on the origin of ¹O₂ confirms that moderate modification of N atoms in graphitic carbon frameworks plays an essential role in inducing the non-radical mechanism. This work will provide new insights for the preparation of high-performance carbocatalysts in PMS activation and exploring critical roles of N-doping during non-radical processes.