Defect Engineering Modulated Iron Single Atoms with Assist of Layered Clay for Enhanced Advanced Oxidation Processes
Xiangwei Zhang, Chunquan Li, Xinlin Wang, Shanshan Yang, Ye Tan, Fang Yuan, Shuilin Zheng, Dionysios D. Dionysiou, Zhiming Sun
Abstract
Abstract Single‐atom catalysts (SACs) feature maximum atomic utilization efficiency; however, the loading amount, dispersibility, synthesis cost, and regulation of the electronic structure are factors that need to be considered in water treatment. In this study, kaolinite, a natural layered clay mineral, is applied as the support for g‐C 3 N 4 and single Fe atoms (FeSA‐NGK). The FeSA‐NGK composite exhibits an impressive degradation performance toward the target pollutant (>98% degradation rate in 10 min), and catalytic stability across consecutive runs (90% reactivity maintained after three runs in a fluidized‐bed catalytic unit) under peroxymonosulfate (PMS)/visible light (Vis) synergetic system. The introduction of kaolinite promotes the loading amount of single Fe atoms (2.57 wt.%), which is a 14.2% increase compared to using a bare catalyst without kaolinite, and improved the concentration of N vacancies, thereby optimizing the regulation of the electronic structure of the single Fe atoms. It is discovered that the single Fe atoms successfully occupied five coordinated N atoms and combined with a neighboring N vacancy. Consequently, this regulated the local electronic structure of single Fe atoms, which drives the electrons of N atoms to accumulate on the Fe centers. This study opens an avenue for the design of clay‐based SACs for water purification.