Chen Fei, Liu Lian-Lian, Wu Jing-Hang, Rui Xian-Hong, Chen Jie-Jie, Yu Yan
Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science & Technology of China, Hefei, 230026, China.
Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, College of Environment and Ecology, Chongqing University, Chongqing, 400045, China.
Adv Mater. 2022 Aug;34(31):e2202891. doi: 10.1002/adma.202202891. Epub 2022 Jul 1.
Single-atom catalysts have emerged as an efficient oxidant activator for eliminating organic pollutants in Fenton-like systems. However, the complex preparation, single active site, lack of understanding of the fundamental mechanism, and harsh pH conditions currently limit their practical applications. In this work, single-atom iron anchored nitrogen-rich g-C N nanotubes (FeCNs) are designed and synthesized by a facile approach, and eco-friendly peracetic acid (PAA) is selected as the oxidant for Fenton-like reactions. The constructed heterogenous system achieves an enhanced degradation of various organic contaminants over a wide pH range of 3.0-9.0, exhibiting an ultrahigh and stable catalytic activity, outperforming equivalent quantities of pristine g-C N by 75 times. The O isotope-labeling technique, probe method, and theoretical calculations demonstrate that the efficient catalytic activity relies on the high-valency iron-oxo species coupled with organic radicals generated by PAA. An increase in electron transport from the contaminant to the formed "metastable PAA/FeCN catalyst surface complex" is detected. A double driving mechanism for the tubular g-C N regulated by a single Fe site and PAA activation is proposed. This work opens an avenue for developing novel catalysts with the coexistence of multiple active units and providing opportunities for significantly improving catalytic efficiency.
单原子催化剂已成为一种高效的氧化剂活化剂，用于在类芬顿体系中消除有机污染物。然而，复杂的制备过程、单一的活性位点、对基本机理的缺乏了解以及苛刻的pH条件目前限制了它们的实际应用。在这项工作中，通过一种简便的方法设计并合成了单原子铁锚定的富氮石墨相氮化碳纳米管（FeCNs），并选择了环境友好的过氧乙酸（PAA）作为类芬顿反应的氧化剂。构建的异质体系在3.0 - 9.0的宽pH范围内实现了对各种有机污染物的增强降解，表现出超高且稳定的催化活性，比等量的原始石墨相氮化碳性能高出75倍。氧同位素标记技术、探针方法和理论计算表明，高效催化活性依赖于高价铁氧物种与PAA产生的有机自由基的耦合。检测到从污染物到形成的“亚稳PAA/FeCN催化剂表面络合物”的电子传输增加。提出了由单个铁位点调控的管状石墨相氮化碳和PAA活化的双重驱动机制。这项工作为开发具有多个活性单元共存的新型催化剂开辟了一条途径，并为显著提高催化效率提供了机会。
