MXenes负载金属纳米催化剂的限域构筑及其高效催化氯代苯酚加氢脱氯机理研究

Development of catalysts with high activity and stability for catalytic hydrodechlorination of chlorinated phenol is one of the international frontiers and challenges in the field of water pollution control of persistent organic pollutants. By using the space confinement effects of the 2D layered nanomaterial MXenes, the purpose of this proposal is to synthesize high-performance supported metal nanocatalysts for the hydrodechlorination of chlorinated phenols under mild conditions. The size, microstructure, physicochemical properties of the confined inter-lamellar space in 2D MXenes nanomaterials, and the interaction between the 2D supports and active sites will be tuned by surface modification, chemical intercalations and ion exchanges. Based on above modifications, the particle size, structure and surface properties of the metal nanoparticles will be controlled, yielding MXenes supported metal nanoparticles with narrow size distribution, high dispersion and adjustable size. According to the in-situ characterization of catalytic reaction process and related theoretical calculation, this project will investigate the relationship between the structure and catalytic property of the catalysts, study the mechanism of catalytic hydrodechlorination of chlorinated phenol by high performance nanocatalysts, and explore the key factors affecting the activity and stability of the hydrodechlorination of chlorinated phenols. Moreover, this proposal will provide a scientific evidence and theoretical guidance for the design and construction of high-performance catalysts in the hydrodechlorination of chlorinated phenols.

兼具高活性和高稳定性的氯代苯酚加氢脱氯催化剂的研制是持久性有机污染物的水污染控制研究领域的国际前沿和挑战之一。本项目基于二维层状MXenes材料的空间限域效应，设计与可控构筑具有高活性、高稳定性的氯代苯酚加氢脱氯负载金属纳米催化剂。通过表面修饰及改性、化学插层和离子交换等措施来有效调控MXenes的限域微空间（包括结构与尺寸）、物理化学性质及其与催化活性中心的相互作用，进而调控其负载金属纳米粒子的颗粒尺寸、体相结构和表面特性，获得单分散、颗粒尺寸可控的高活性和高稳定性的氯代苯酚加氢脱氯金属纳米催化剂。依据催化反应过程的原位表征和相关理论计算结果，阐明催化剂的结构特性与催化性能之间的构效关系，探索高效纳米催化剂催化氯代苯酚加氢脱氯的作用机理，解决影响氯代苯酚加氢脱氯的活性和稳定性的关键科学问题，为高性能加氢脱氯催化剂的设计与构筑提供科学依据和理论指导。

氯苯酚类污染废水的催化降解处理具有重要的生态和经济价值。构筑具有高活性和高稳定性的金属纳米催化剂催化降解氯苯酚类污染物对于持久性有机物水污染控制具有非常重要的意义。项目利用二维层状材料MXenes的层间微空间、微介孔及表面官能团的限域作用构筑了一系列高活性和高稳定性的金属纳米催化剂。通过表面修饰及改性、化学插层和离子交换等策略调控了其层间属性，从而有效控制了金属纳米颗粒的成核及生长过程。通过调控催化剂合成方法构筑了具有不同颗粒尺寸、微观结构和表面性质的负载金属纳米催化剂，探究了其颗粒尺寸、晶体结构与微观结构、表面状态和化学环境的改变对催化活性中心上反应物及产物的吸、脱附能力，进而研究了上述调控对氯代苯酚加氢脱氯活性与稳定性的影响机制；通过对催化剂物化结构表征以及催化剂动力学研究，揭示了载体材料的组成、结构、表面性质的调控与催化性能的构效关联机制；获得了氯苯酚类持久性污染物加氢脱氯性能的关键影响因素及其催化加氢反应机制。与现有的催化体系相比，本项目开发的催化体系实现了氯苯酚类污染物的高效加氢脱氯；有效的避免了加入碱助剂引起的二次污染等问题。本研究成果将为有效控制氯苯酚类环境污染物提供实验依据和理论基础，所提出的研究思路和技术方法具有一定的科学意义和潜在的应用价值。