新型纳米结构金催化剂的构筑及其催化性能研究

Catalysis by gold is one of the fastest growing subjects in catalytic science today and is also an interesting topic of research in nanotechnology. In this work, with the aim to improve the stability of gold nanoparticles and the catalytical activity and/or selectivity of gold catalysts, another metal M (such as Ag, Pt, and Pd) is added to Au to form binary Au-M nanocrystals, a series of novel gold catalysts with well-defined morphology and sizes were prepared by one pot synthesis using hydrothermal and microwave heating. Considering the similarities between the preparation conditions of metal-organic frameworks (MOFs) and metal nanoparticles with well-defined morphology, the synthesis of MOFs will couple with the synthesis of Au-M (M: Ag, Pt, Pd, etc.) alloy nanocrystals. A series of Au-M/MOFs catalysts with novel structures are prepared by a facile one-pot microwave irradiation and/or hydrothermal method. The novel structure may include the core-shell structure of Au-M@MOFs and MOFs stabilized Au-M clusters and/or Au-M alloy nanocrystals with ultrafine sizes (< 5 nm). Furthermore, the graphene supported Au-M alloy nanocrystals with well-defined morphology and controllable sizes are also prepared, in which much more attention is paid on fabrication of Au-M alloy nanocrystals with high-index facets and sizes less than 10 nm. Extensively physicochemical characterizations of the synthesized gold catalysts are carried out. The catalytic performances of activation of C-H, C-O, as well as electrical catalytical performance including methanol/formic acid electrooxidation, and oxygen reduction reaction are explored on the synthesized gold catalysts. Efforts will also be directed to understanding the structure-performance relationship as well as reaction mechanism. This work addresses novel strategies for preparation of advanced gold catalysts, providing an insightful guidance for developing novel and efficient gold catalysts.

纳米金催化剂的研究是当前催化科学创新的一个热点，本项目针对纳米金粒子的稳定性较差、负载型纳米金催化剂的催化性能不足（活性/选择性需要提升等）等关键科学问题，在Au中引入其他金属M（M：Ag、Pt、Pd等）形成Au-M合金纳米晶，选择适宜的新型载体（金属有机骨架与石墨烯），利用载体与金属前体离子的相互作用，采用微波和水热“一锅法”来制备新型高效纳米结构金催化剂，重点探索合成具有核壳结构的Au-M@MOFs与MOFs固载的Au-M超细及亚纳米粒子，以及石墨烯负载的具有高指数晶面且尺寸小于10 nm 的Au-M合金纳米粒子，综合多种理化表征手段和反应评价，探索其催化活化碳-氢、碳-氧及电催化性能，构建催化剂结构与性能的构效关系，揭示催化作用机制，为金催化剂的改造、优化和创新提供启示和指导。

基于金催化剂的科研开发是当前催化科学创新的热点领域之一，本项目是项目负责人在多年金催化剂的研究实践和体会中，为克服金催化剂催化性能的不足（比如稳定性较差，以及活性/选择性需要提升等），在Au中引入其他金属形成Au-M合金纳米晶，选择适宜的新型载体，并综合运用金催化剂研究中所采用的创新方法来创制新型纳米结构金催化剂，探索其催化性能，并构建其结构与催化性能的构效关系。通过本项目的实施，我们构建了金属有机骨架、氧化物、分子筛及裸露高指数晶面的纳米晶与金纳米粒子复合的系列新型纳米结构金催化剂，开发了制备高负载量，具有超细纳米金粒子尺寸（小于2 nm）的方法，并通过均相金催化多相化，实现了氧化物负载的Au(III)的多相催化剂，建立了催化醛、炔、胺三组分耦合反应、环己二酮与醇加成反应、4-硝基苯酚还原反应的高效催化体系。并展示了采用微波合成金属有机骨架负载的超细纳米金粒子的新方法，揭示了采用微波辅助进行有机合成反应催化反应，可以显著提高催化剂的催化活性。这些研究成果为金催化剂的改造、优化和创新将具有积极作用。此外，我们提出了一种制备裸露高指数Pt基合金的普适方法，并创新地提出以裸露高指数纳米晶为载体，引入金属/非金属调节其物化性质优化其催化性能的学术思想。具体地，通过在PtNi凹面立方体上引入纳米金粒子、PtMn凹面立方体引入Ru、Mo，构建了对电催化甲酸/甲醇/乙二醇氧化反应的高效催化剂。相关工作在Journal of Catalysis, ACS Catalysis, Applied Catalysis B，ACS Nano，Nano Energy，Nano Research等学术期刊发表SCI论文36篇，引用278次。