铜基非均相类Fenton催化剂降解有机污染物反应机理研究

The development of high-performance heterogeneous Fenton-like catalysts is highly desired for resolving the pollution of water resource. The lack of understandings of the structure-performance relationship of catalysts and the reaction mechanism restrains the development of highly active heterogeneous Fenton-like catalysts. This project is to study the structure-performance relationship of Cu-based heterogeneous Fenton-like catalysts and the reaction mechanism of the degradation of the organic pollutants by combining the Operando techniques and density functional theory calculations. Firstly, a series of Cu-based catalysts will be prepared and studied for the degradation of benzene, phenol, nitrobenzene, and Rhodamine B. Then, Operando techniques such as UV-visible, IR, and Raman spectroscopy will be combined to probe the surface structure of Cu-based catalysts during reaction and establish the structure-performance relationship under reaction conditions. Meanwhile, kinetics study and operando techniques will be combined to deduce the possible reaction pathway. The formation mechanism of hydroxyl radical and the degradation mechanism of organic pollutants on Cu-based catalysts will then be obtained using density functional theory studies. Finally, based on the reaction mechanism and the structure-performance relationship, high-reactivity and high-stability Cu-based Fenton-like catalysts will be prepared by tuning the preparation methods and the pretreatment conditions, thus improving the utilization ratio of hydrogen peroxide and the degradation efficiency of pollutants.

发展非均相类Fenton技术对解决水资源污染问题具有重要意义。反应机理不明确限制了非均相类Fenton催化剂的研发。本项目拟结合动态现场原位表征技术及密度泛函理论（DFT）计算方法，探究铜（Cu）基非均相类Fenton催化剂降解有机污染物的反应机理及催化剂构-效关系。首先制备一系列Cu基催化剂，并研究其用于降解苯、苯酚、硝基苯及罗丹明B等有机污染物的活性；然后使用动态现场原位紫外、红外及拉曼等表征技术获得Cu基催化剂在反应过程中的结构信息，建立反应条件下的Cu基催化剂构-效关系，同时结合反应动力学预测可能的反应路径，通过DFT计算阐明铜基催化剂上过氧化氢（H2O2）分解产生羟基自由基及有机污染物降解的反应机理；基于反应机理及反应条件下的催化剂构-效关系，调控催化剂制备方法及预处理手段，定向制备高活性及高稳定性的Cu基催化剂，提高H2O2利用率及有机污染物降解效率。

非均相类Fenton技术是解决水资源污染问题最有潜力的技术之一。阐明非均相类Fenton催化剂构-效关系及催化反应机理，是实现高性能非均相类Fenton催化剂理性设计与可控制备的基础。与传统类Fenton催化剂相比，Cu基类Fenton催化剂具有可应用pH范围宽的优点，揭示其活性位点本质、构-效关系及催化反应机理是进一步提升催化性能的关键。本项目聚焦Cu基类Fenton催化剂用于降解罗丹明B及硝基苯等有机污染物的研究，通过结合先进催化剂材料制备方法、动态现场原位表征方法及第一性原理计算方法，阐明催化剂构-效关系及催化反应机理。本项目取得的重要研究进展和成果总结如下：（1）使用改进的Stöber法制备出结构可控的Cu@SiO2催化剂，通过结合原位表征及第一性原理计算方法，揭示了一价Cu物种是活化H2O2产生·OH及降解有机污染物的主要活性位，阐明非均相Cu基Fenton催化剂活化H2O2产生·OH的反应机理；（2）使用溶胶-凝胶法制备了一系列Cu-Fe双金属催化剂，发现5Fe2.5Cu-Al2O3对硝基苯具有最优的催化降解效率，阐明Fe与Cu之间的协同作用是提高·OH的生成速率及硝基苯降解效率的关键，·OH对硝基苯的主要降解机理为直接氧化；（3）构筑了高性能Cu基成型催化剂，研究其用于连续固定床的反应动力学，阐明了催化剂型态、流速、双氧水浓度及反应温度等因素对传质特性及双氧水利用率的影响。本项目共发表SCI收录论文8篇，申请中国发明专利2件，培养研究生4人。本项目可以为催化氧化反应体系机理研究及工业催化剂的开发提供理论指导。