掺氮碳内嵌非贵金属单原子可控制备及N-杂芳烃选择加氢性能研究

In recent years, the non-noble metals have drawn great attention in the academic and industrial fields because of their abundance and easy availability. However, the main bottleneck of their development is the harsh reaction conditions, low catalytic activity and poor stability. The lastest researches have shown that the non-noble metal single-atom catalysts can effectively overcome the aforementioned shortcomings of traditional catalysts owing to their isolated active sites, controllable chemical microenvironment and stable structure. Nevertheless, there are still many problems in the existing preparation methods, such as low specific surface area or porosity of the support, unsatisfying adjustment of metal loading, expensive precursors as well as relatively cumbersome preparation process. To this end, the present project intends to prepare a series of N-doped hierarchical porous carbon embedded non-noble metal single-atom catalysts with high specific surface area and high nitrogen doping level via high-temperature pyrolysis and in situ self-assembly strategy. The resulting catalysts are very likely to resolve the problems of high dosage, poor selectivity and stability of the noble metal-based catalysts in N-heteroarenes selective hydrogenation through the regulation of electronic configuration of non-noble metals, hierarchical porous characteristic of support as well as the enhanced synergistic effect between the metal and support. Meanwhile, we will explore the structure-activity relationship of the catalysts by investigating how the support surface property, pore-size distribution, different metal types and loading amount influence the catalytic activity of the selective hydrogenation of N-heteroarenes, and further grasp the corresponding regulation techniques. By means of the combination of experiment and theoretical calculation, it is promising to clarify the intrinsic relationship between the macroscopic reaction properties and microscopic interface catalytic effect, and also to lay a solid scientific foundation for the design and preparation of high performance non-noble metal single-atom catalysts.

非贵金属因廉价易得而引起学术和工业界的高度重视，但反应条件苛刻、催化活性低和稳定性差是制约其发展的主要瓶颈。最新研究表明，非贵金属单原子催化剂由于活性位孤立、微环境可控及结构稳定等优越性能可有效克服传统催化剂的上述缺点。然而，现有制备策略存在载体比表面或孔隙率低、金属负载量调控难度高、前驱体昂贵和制备过程复杂等问题。为此，本项目拟采用高温热解-原位组装策略合成一系列高比表面、高氮掺杂多级孔碳镶嵌的非贵金属单原子催化剂。通过调控非贵金属电子构型、载体多级孔特性及强化金属-载体间协同作用来解决N-杂芳烃选择加氢反应中贵金属用量大、选择性和稳定性差的问题。与此同时，调变载体表面性质、孔道尺寸分布、不同金属类型与负载量等因素探索催化剂的构效关系，并掌握相应调控技术。采取实验与理论计算相结合的手段，阐明宏观反应性能与微观界面催化效应的内在联系，为高性能非贵金属单原子催化剂的设计与制备奠定科学基础。

该项目实施以来，紧密围绕高比表面、高氮掺杂多级孔碳镶嵌的非贵金属单原子催化剂的制备及N-杂芳烃选择加氢反应，开展了系统性的研究工作。将酞菁钴、菲啰啉钴等金属有机配合物作为前驱体，通过调控高温热解参数成功制备了高催化活性的Co基纳米颗粒及单原子催化剂，对此类催化材料进行了系统表征与催化性能评价。以壳聚糖等可持续碳源作为前驱体制备的Pd@CIL-900催化剂在室温和1 atm H2下对喹啉类衍生物的选择性加氢反应展现了最优催化性能以及合成的氮掺杂多孔碳镶嵌高分散Co催化剂在苯甲醇衍生物直接氧化酯化等反应中表现出良好的应用前景。此外，申请人与国内相关领域课题组合作通过电弧放电策略首次合成了从Pt NPs@C到Pt1@C不同尺度Pt基催化剂的连续调控，发现稳定在洋葱碳骨架中的Pt单原子在对氯硝基苯加氢反应表现出优越的催化选择性和稳定性。同时，在共价有机框架和微孔聚合物等多孔催化材料的可控构筑与催化选择性加氢领域进行了初步探索。