贵金属单原子催化剂的电弧法制备探索及其催化选择加氢研究

Controlled preparation of noble metal single-atom catalyst (SAC) with catalytic properties of high activity, high selectivity, high stability, and high metal loading shows great significance for studying the important chemical processes in micro-environment and further developing new catalysts for industrial application. Based on our recent discovery that the controlled preparation of supported metal catalyst with (sub)nanoclusters, the primary objective of the current proposal is to systematically discuss and try to develop the new and efficient preparation method under extreme conditions for SACs of Pt, Au, Ir, Ru, etc, with the aim to overcome the crucial scientific issues of inherent low efficiency, poor stability, and unclear structure-activity relationship associated with the existing catalytic systems for selective hydrogenation of unsaturated groups involved C=C, C=O, C=N, and C≡C. Herein, we propose to use the arc-discharge process under extreme conditions to modulate the series of micro chemical environment, including the active metal loading, coordination environment of noble metal ion, support, location of metal atom, metastable state, etc, and finally to construct the special noble metal SACs with unique electronic and/or geometric structure and excellent catalytic properties at atomic scale. Efforts will also be directed to thorough understanding of the structure-activity relationship, real active sites, key intermediates by analysis of catalyst characterization and micro-structure. Furthermore, fruitful demonstrations will be focused on in situ characterizations as well as disclose the essence of unsaturated desired product synthesis at molecular scale over SAC surface, thus providing fundamental data and guidance for developing new SAC with viable and practical application potential.

可控制备具有高活性、高选择性、高稳定性和高担载量的贵金属单原子催化剂对研究微观环境下的重要化学反应过程和拓展新型工业应用催化剂具有重要意义。基于我们在可控制备贵金属（亚）纳米团簇催化剂方面的发现，针对现有材料催化涉及C=C、C=O、C=N、C≡C等不饱和基团选择加氢体系中存在的反应效率偏低、稳定性不足、构效关系模糊不清等关键基础问题，进行系统深入的探索，试图发掘极端条件下制备高效Pt、Au、Ir、Ru等单原子催化剂的方法。拟采用电弧法对金属负载量、金属中心配位环境、载体类别、金属负载位点、亚稳态等一系列微观化学环境进行调控，在原子尺度上定向构筑具有特定电子/几何结构和特异催化性质的贵金属单原子催化剂。系统研究催化剂的构效关系、真实活性中心、关键中间体，在分子尺度上揭示不饱和目标物合成过程的本质，为发展具有实际应用潜力的单原子催化剂提供基础数据和理论指导。

在涉及C=C、C=O、C=N和C≡C等不饱和基团的化学选择催化加氢反应中存在活性金属正尺寸效应，可拓展至很多贵金属在更小尺度范围甚至原子级分散状态下展现出更佳的催化能力。在本项目的支持下，申请者采用电弧法对金属负载量、金属中心配位环境、载体类别、金属负载位点、亚稳态等一系列微观化学环境进行调控，在原子尺度上定向构筑具有特定电子/几何结构和特异催化性质的贵金属单原子催化剂。主要研究内容包括：（1）贵金属单原子催化剂的设计和电弧法制备探索；（2）单原子催化剂的性能测试和表征；（3）稳定性测试和动力学同位素效应实验及原位表征；（4）光谱表征和构效关系研究及反应机理探究，并取得了重要结果。