限域镍基催化体系的构建及其在甲烷二氧化碳重整反应中的应用

The present work proposes to design the confined Ni-based catalysts by combining material nanotechnology and surface chemistry for the CO2 reforming of CH4. The outcome of this work is expected to broaden the scope of confinement theory in catalysis and shed more insights into the preparation of highly efficient catalytic systems. To achieve these goals, two kinds of confined Ni-based catalysts will be configured. Electro-spinning technique will be employed to prepare a spatially confined Ni-based catalytic system in which Ni nanoparticles will be confined inside the channels of the SiO2 nanofibers. The composite support N-C-SiC consisting of N-doped porous C layers on the SiC surface will be synthesized via surface functionalization and used as the substrate for the electronically confined Ni-based catalytic system. The configured Ni-based catalysts with various confinement effects will be tested in CO2 reforming of CH4 and the structure-activity relationship of this reaction will be acquired with the aid of in-situ and dynamic characterizations. In addition, density function theory calculations will be applied for further understanding of the confinement effects and better design of the highly efficient catalytic systems. The present work focuses on the confinement theory in catalysis and the preparation of highly efficient catalysts, showing great importance in fundamental science. The implement of this work will benefit the supply of clean energy, the mitigation of emissions of greenhouse gases and the optimization of the energy structures in our country. Therefore, this unique and creative work is of great significance in both academic researches and industrial applications.

项目在限域催化理论的指导下，采用材料合成与表面化学相结合的策略分别构建具有空间和电子限域效应的镍（Ni）基催化体系，并探索其在甲烷二氧化碳重整反应中的应用，以拓展限域催化理论并指导高效催化体系的设计。具体为基于静电纺丝技术在SiO2纳米纤维孔道内合成Ni纳米粒子，构建空间限域Ni基催化体系；通过表面功能化方法合成N掺杂的N-C-SiC复合载体，构建电子限域Ni基催化体系。通过评价以上限域催化体系对应的催化性能，结合原位动态表征技术，建立催化反应的构－效关系，且借助密度泛函理论计算对建立的构－效关系进行验证，加深对限域理论的理解并为高效催化体系的制备提供思路。项目涉及限域催化理论的拓展和高效催化体系的设计，是一个科学价值显著的研究课题。同时，项目的实施对于我国清洁能源生产、温室气体减排以及能源结构优化等方面具有重大的现实意义。因而，本项目是一个科学意义与应用前景并重，特色性强的创新性课题。

近年来基于模型催化体系的研究表明，催化剂在限域条件下的催化性能将得到显著提高。目前限域催化剂的构建及限域效应的作用机理仍待进一步拓展。本项目以甲烷二氧化碳重整为探针反应，采用材料合成与表面化学相结合的策略，构建了具有空间、电子和界面限域的新型高效Ni基催化剂，考察具有不同限域效应的催化剂在重整反应中的活性与稳定性，并研究了其构-效关系。本项目取得了以下突破：1）采用静电纺丝技术获得了SiO2或Al2O3纳米纤维空间限域的Ni基催化剂，这些空间限域效应作用下的催化剂较常规负载的催化剂表现出更好的抗积碳性能和稳定性；2）通过卤素抽提和杂原子掺杂的方法，获得了N-CDC-SiC （CDC: carbide-derived carbon）载体电子限域的Ni基催化剂，该催化剂Ni金属粒子的尺度得到控制，催化剂表面的碱性位得到增强，进而显著提高催化剂的重整活性； 3)通过引入高度分散的CeO2纳米粒子，构建大量的Ni-CeO2界面，利用界面限域效应促进CO2在Ni-CeO2界面的活化，加快消碳过程，抑制积碳现象，进而提高催化剂的稳定性能。以上研究结果为新型高效负载型金属催化剂的制备提供了新的思路，为限域催化理论的丰富拓展供了实验基础。研究结果将加深对CH4-CO2重整催化反应机理的认识，促进新型高效Ni基催化剂的设计制备，对我国温室气体减排和清洁能源生产等领域带来积极影响。本项目已发表SCI论文7篇，其中TOP期刊3篇，申请专利3项，已经获得授权1项，参加国际国内会议10次，做口头报告5次。项目负责人应邀担任Topics in Catalysis期刊客座编辑。