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研究报告

彭小明,吴健群,戴红玲,郭岑枫,李晨豪,许莉,许高平,胡锋平.Fe、N共掺杂原子级分散Fe-g-C₃N₄催化剂活化过硫酸盐降解亚甲基蓝的机制[J].环境科学学报,2022,42(5):225-236

Degradation mechanism of methylene blue by Fe-g-C₃N₄（600） catalyst activation peroxymonosulfate

基金项目：国家自然科学基金项目（No. 51908213， 61872141）；江西省重点研发项目（No. 20202BBGL73080）；江西省主要学科学术和技术带头人计划（ No.20204BCJL23038）

摘要：采用煅烧法制备了一种将孤立的Fe单原子和Fe团簇共同锚定在g-C₃N₄骨架上的原子级分散的催化剂Fe-g-C₃N₄（600）. 通过球差校正的高角度环形暗场扫描透射电子显微镜（AC-HAADF-STEM）对材料进行表征分析，证明了Fe单原子成功锚定在载体表面. 该催化剂在非均相活化过硫酸盐（PMS）催化降解亚甲基蓝中表现出高活性和高稳定性. 实验分析表明，Fe单原子比Fe团簇具有更高的催化活性，同时， N与孤立Fe原子形成的配位位点（Fe-N_x）是PMS活化的最主要活性中心. Fe-N_x反应位点可以直接激活PMS产生高价铁氧化物，这是亚甲基蓝高效降解的关键. 此外，Fe-g-C₃N₄（600）在湖水和自来水水源中对亚甲基蓝降解也展现出了卓越的催化效果，且当水源水为湖水时，亚甲基蓝的降解效率最高. 本工作证明了Fe-g-C₃N₄（600）/PMS体系能高效地降解被污染水体中的亚甲基蓝，且具有较好的应用潜力.

Abstract：A single-atom catalyst was prepared by calcination method. In this way， Fe atoms and Fe clusters were anchored on the framework of g-C₃N₄. The materials were characterized by spherical aberration corrected high angle annular dark field scanning transmission electron microscope （AC-HAADF-STEM）. The results indicated that Fe atoms were successfully anchored on the surface of the support. The Fe-g-C₃N₄（600） catalyst successfully， and high activity and stability in the methylene blue （MB） degradation by heterogeneous activated peroxymonosulfate （PMS） were exhibited. The results show that compared to Fe cluster， single Fe atom has higher catalytic activity than Fe cluster， and the N-coordinated single Fe atom （Fe-N_x） is the main active center for PMS activation. The Fe-N_x site can directly activate PMS to produce high-valent iron-oxo species， which is the key to efficient degradation of MB. Moreover， in lake water and tap water， Fe-g-C₃N₄（600） also showed excellent catalytic effect on MB degradation. This work proves that the Fe-g-C₃N₄（600）/PMS system can degrade MB efficiently and has potential application.

Key words：single-atom catalyst Fe-N_xsites peroxymonosulfate non-radical high-valent iron-oxo species