Unraveling the Fundamentals of Axial Coordination FeN <sub>4+1</sub> Sites Regulating the Peroxymonosulfate Activation for Fenton‐Like Activity
Sijia Jin, Wenxian Tan, Xiaofeng Tang, Mengxuan Li, Xinyi Yu, Haiyan Zhang, Shuang Song, Tao Zeng
Abstract
Abstract Precise modulation of the axial coordination microenvironment in single‐atom catalysts (SACs) to enhance peroxymonosulfate (PMS) activation represents a promising yet underexplored approach. This study introduces a pyrolysis‐free strategy to fabricate SACs with well‐defined axial‐FeN 4+1 coordination structures. By incorporating additional out‐of‐plane axial nitrogen into well‐defined FeN 4 active sites within a planar, fully conjugated polyphthalocyanine framework, FeN 4+1 configurations are developed that significantly enhance PMS activation. The axial‐FeN 4+1 catalyst excelled in activating PMS, with a high bisphenol A (BPA) degradation rate of 2.256 min −1 , surpassing planar‐FeN 4 /PMS systems by 6.8 times. Theoretical calculations revealed that the axial coordination between N and the Fe sites forms an optimized axial FeN 4+1 structure, disrupting the electron distribution symmetry of Fe and optimizing the electron distribution of the Fe 3d orbital (increasing the d‐band center from −1.231 to −0.432 eV). Consequently, this led to an enhanced perpendicular adsorption energy of PMS from −1.79 to −1.82 eV and reduced energy barriers for the formation of the key reaction intermediate (O*) that generates 1 O 2 . This study provides new insights into PMS activation through the axial coordinated engineering of well‐defined SACs in water purification processes.