热力学亚稳态纳米晶的形成机制与可控合成—化学势的作用

纳米晶体除了热力学最稳定态外，多种形式的热力学亚稳态也可以稳定存在。但目前对亚稳态纳米晶生长机制缺乏深入的了解，相关理论和合成方法学研究已经严重滞后。本项目拟从全新的化学势视角研究“湿”化学合成中亚稳态纳米晶的形成机制，发展亚稳态纳米晶合成新方法。选择在催化等领域具有重要应用前景的无机纳米晶等为研究对象，在大量合成的基础上，评估各种反应因素对晶体生长基元化学势的贡献及其对最终产物纳米晶结构的影响；充分利用原位光谱和原位电镜等技术，探讨亚稳态纳米晶的成核及生长过程，综合热力学和动力学因素，结合理论推导和计算模拟，揭示其形成机理和本质规律，进而发展出亚稳态纳米晶可控合成方法。另外，研究各类亚稳态纳米晶的构效关系，厘清亚稳结构对相关物理化学性能的影响规律。该研究可为亚稳态纳米晶的可控合成及进一步的开发应用研究提供基础，完善无机亚稳态纳米晶合成相关领域的理论，切实推动相关领域取得突破。

The theory of chemical reactions of molecules is relatively comprehensive. Unlike isolated molecules, especially small molecules, that usually take most thermodynamically stable structures, various thermodynamically metastable structures for nanocrystals (NCs) may exist. However, the knowledge of corresponding formation mechanisms of metastable NCs still very lacks at present, which greatly impedes the development of related disciplines. It is urgent to develop relevant theories and synthetic methodologies. In this proposed project, we will study the formation mechanism of metastable NCs by wet chemical synthesis from a new perspective of chemical potential, and develop a new methodology for the rationally controlled synthesis of metastable NCs. Functional inorganic NCs, having important application prospects in the field of catalysis, will be selected as research objects. On the basis of tremendous endeavors on the synthesis, various experimental parameters effecting the chemical potential of growth units and final crystal structures are carefully evaluated. By taking advantage of state-of-the-art techniques, such as in-situ spectroscopy and in-situ electron microscopy, we will explore the nucleation and growth process of metastable NCs. Meanwhile, by comprehensively considering thermodynamics and kinetic factors, and combining theoretical derivation and computational simulation, we will try to figure out the intrinsic formation mechanism of metastable NCs, and finally develop the methodology for the rationally controlled synthesis of metastable NCs. Moreover, we will study the corresponding catalytic properties of thermodynamically metastable NCs by taking several typical catalytic reactions as benchmark. We believe that the studies will provide guidance in the rational design and large-scale synthesis of thermodynamically inorganic metastable NCs, deepen our knowledge of the control synthesis of inorganic metastable nanocrystals and effectively make breakthroughs in related fields.