单原子铁限域氮掺杂碳纤维表界面调控及类Fenton催化反应机制研究

Persistent organic pollutants are relatively difficult to be eradicated from the water with traditional treatment processes due to highly biological toxicity and biological resistance. To solve these issues, single iron atoms confined N-doped porous carbon fiber composite catalysts (Fe-N @ CNF) have been prepared to build new type of heterogeneous Fenton catalytic reaction system (Fe-N@CNF/Oxone) to generate reactive species such as sulfate radicals for realizing environmental remediation. This proposal is focused on the key scientific issues such as the confined single-atom interface structure control and Fenton-like catalytic reaction mechanism. Combined experimental and theoretical research model, and used the advanced means of in situ and surface/interface science research, the single iron and nitrogen atoms are successfully embedded in carbon fibers to prepare Fe-N@CNF catalysts with high activity and high stability. The confined structure formation, evolution, and control mechanisms are revealed in detail to obtain Fe-N@CNF catalyst with excellent catalytic ability. The critical characteristic parameters of preparation with confined effects are given, and the precise control of surface/interface properties are realized. The influences of the confined structure, and micro-environment and other different means on the Fenton-like reaction are comprehensively studied. The form laws of active radical groups in Fenton-like system have been clarified, and the possible oxidative pathway and mineralization mechanism are also investigated. Finally, the new Fenton-like theory is built, which is based on the above information. The relevant research results will provide the important theoretical and technical supports to solve the pollution problems for environmental remediation.

针对持久性有机污染物生物毒性强、可生化性差等技术难题，通过研制单原子铁限域氮掺杂多孔碳纤维复合催化剂（Fe-N@CNF）催化活化新型氧化剂Oxone，构建基于硫酸根自由基的新型异相类Fenton催化反应体系净化污染物，解决“限域型”单原子催化表界面调控以及类Fenton催化反应机制等关键科学问题。采取实验和理论研究相结合的模式，利用先进的原位和表界面科学的研究手段，将单原子铁和氮元素嵌入到碳纤维中，研制出高活性和高稳定性的Fe-N@CNF催化剂。通过研究Fe-N@CNF限域结构的形成、演化和控制机制，给出催化剂制备关键特征参数，实现表界面性质精准调控，阐明单原子限域结构、反应微环境及外场等不同调控手段对类Fenton催化反应的调控规律，诠释活性自由基基团的形成规律，探明污染物的矿化历程及机理，构建系统的类Fenton氧化理论，相关研究成果将为解决环境污染问题提供重要的理论和技术支持。

本项目针对持久性有机污染物难以治理的技术难题，采用热解法、水热法、相转化法、共沉淀法、原位刻蚀法等技术，开发了系列铁限域氮掺杂多孔碳基复合类Fenton催化剂（如CP-Fe-N、Fe0@NC、Fe-N@BC、Fe-NC、Fe, Cu@NC、FeS2/C@PVDF、MoFe-NC@PVDF等），并构建基于自由基与非自由基的新型异相类Fenton催化反应体系净化污染物。通过调控过渡金属与非金属的掺杂方式等关键制备技术参数尽可能暴露催化剂活性位点，实现了微观结构的精准调控，阐明了催化剂合成机制。采用XRD、FTIR、XPS、TEM、Raman、EPR、LC-MS等分析表征手段，探究了污染物在催化剂上的去除行为及水化学条件的影响规律，探索了类Fenton催化反应的调控规律，诠释了自由基基团的形成规律，探明了污染物的矿化历程及机理，实现了自由基等活性组分的大量生成，揭示了复合催化剂中各组元素之间的协同作用机理，剖析了污染物-材料界面反应机理及降解机制，构建了系统的类Fenton氧化理论。通过采用碳包裹活性铁金属形成独特的空间限域效应，在稳定铁原子的同时又充分暴露铁催化活性中心，同时避免了有害组分对催化剂的毒化，提高了催化剂的稳定性。同时，被限域的铁金属活性价电子与碳层的相互作用“穿透”到外表面，实现了高效类Fenton催化反应。本项目的完成为工业废水净化处理提供了重要的实验依据与理论基础。以上研究在Appl. Catal. B: Environ.、Chem. Eng. J.和J. Hazard. Mater.等国际著名刊物上发表了系列论文；申请发明专利11项，已获授权国家专利4项、国际专利1项，转化专利技术1项；出版学术专著1本。指导学生获得“挑战杯”课外学术科技竞赛全国二等奖、全国研究生环境论坛优秀论文特等奖、全国化工设计竞赛一等奖等系列奖项。项目负责人担任Journal of Analytical, Bioanalytical and Separation Techniques、Journal of Chemical Engineering & Process Techniques、洁净煤技术，石油化工高等学校学报等期刊编委，连续入选爱思唯尔（Elsevier）中国高被引学者、全球顶尖前10万科学家排名榜，并获得全国石油和化工教育青年教学名师称号。