铂基双金属纳米晶的形貌控制、电催化性质及第一性原理计算

Pt based metal nanoparticles are the key catalytic materials in oil refinement, fine chemicals, fuel cells, and automobile exhaust gas treatment, etc.. Currently, it has remained a challenge how to improve their catalytic performances together with reducing the consumption of Pt resources, by manipulating the compositions, sizes, shapes and surface structures of the nanoparticles through developing new liquid controlled synthetic protocols. In this project, we will adopt some facile, controllable, general, and scalable solution synthesis strategies, and introduce some shape-selective agents such as small molecules and ions into the synthetic reactions, so as to finely tune the coordination interaction and shape-selective capability between the agents and nuclei/facet during nanocrystal growth, and finally to obtain size- and composition-controlled Pt bimetallic nanocrystals with high shape selectivities. In addition, we will use some electro-catalytic probe reactions such as methanol oxidation and oxygen reduction to reveal their function-structure relationships. Furthermore, we will investigate the underlying chemical principles of the shape-selective synthesis and the function-structure relationships by combining experimental characterizations and first-principles calculations, so as to realize the optimization of the catalytic properties of the Pt based bimetallic nanomaterials. In all, through this project, we expect to achieve new promising Pt based metal nanocatalysts with high performance at reduced cost.

铂基金属纳米颗粒是石油炼制、精细化工、燃料电池、汽车尾气治理等领域的关键催化材料。目前，如何通过发展新的液相控制合成方法对铂基金属纳米晶的组成、尺寸、形貌和表面结构进行调控，以提高它们的催化性能、同时实现铂元素的部分替代和减量化使用是一个挑战性问题。本项目将采用温和可控、通用性强、易于放大的液相制备方法，通过在合成反应中引入小分子或离子晶面选择试剂，精细调节其在纳米晶生长过程中与晶核/晶面间的配位及晶面选择作用，以获得具有高的形貌选择性同时尺寸和组成可控的铂基双金属纳米晶。此外，我们将利用电催化探针反应（如甲醇氧化和氧还原反应），揭示它们的电催化构效关系。进一步，我们还将把实验表征与第一性原理计算相结合，以理解铂基金属纳米晶的形貌选择性控制合成以及电催化构效关系的内在化学原理，并实现它们的催化性能的最优化。期望最终能获得催化性能好、经济性强、有应用前景的新型铂基金属纳米催化材料。

铂系金属纳米催化材料在清洁能源、环境修复、精细化工等领域有重要的应用。本课题围绕铂系金属纳米催化材料的形貌控制合成化学及其电催化性质进行研究。获得的主要研究结果为：(1)通过发展铂基双金属和三金属纳米晶、钌基、铑基、铱基金属纳米晶的形貌控制的温和液相合成方法，获得了一系列新型铂族金属纳米催化材料（包括纳米多面体、纳米立方体、纳米八面体、纳米片、纳米线、纳米框架结构等）； (2) 利用电催化（如氧还原反应、乙醇电氧化反应）、气相（如CO氧化反应）、液相（如硝基苯氢化还原反应等）探针反应，揭示了所制备纳米材料的催化构效关系；(3) 结合第一性原理计算，探索了金属纳米晶的形貌选择性机制及分子催化机理。四年来，本项目共发表论文22篇，包括3篇J. Am. Chem. Soc.、3篇ACS Catal、3篇Chem. Commun.、2篇Nanoscale.、1篇J. Phys. Chem. C 等论文。相关成果对开发新型低成本、高性能的铂系金属纳米催化材料具有启发意义。鉴于本课题组在金属纳米催化领域内的贡献，应邀为英国皇家化学学会的 《化学学会评论》撰写了一篇关于双金属纳米催化剂的液相形貌控制合成方法的指南性综述（Chem. Soc. Rev. 2012, 41(24), 8050–8065）；应邀为Springer公司2013年出版的《Current Trends of Surface Science and Catalysis》一书撰写了关于“Shape-Controlled Bimetallic Nanocatalysts in Fuel Cells: Synthesis and Electrocatalytic Studies” 专章（Chapter 6, pp. 121–142）。