基于谐振微悬臂梁的纳米铜基硫化物原位生长热力学和动力学研究

The nanostructured metal sulfides have aroused extensive attentions among various areas such as photoelectronics, sensors, energy-storage and so on, due to their outstanding physical and chemical properties as well as relatively low-cost fabrication. However, it is very challenging to illuminate the growth mechanism in the essence of thermodynamics and kinetics for accurately and repetitively designing a kind of nanostructured metal sulfide satisfying a special application. This project aims to investigate the in-situ thermodynamics and kinetics (changes of enthalpy, entropy and Gibbs free energy, activation energy, etc.) of molecular interaction at the interface of gas-solid reaction for the growth of nanostructured copper-based sulfides by using the highly precise and sensitive resonant microcantilever as the analyzing and measuring tool. Additionally, the cantilever chip integrated with a micro-cavity for chemical reaction and in-situ TEM observation will be used to explore the structure-function relationship between the size, morphology and crystal structure and the thermodynamic and kinetic parameters for the growth of nanostructured copper-based sulfides. Furthermore, the project focuses on investigating the influence of reaction temperature, sulfur-containing reactant gas (type and concentration), precursor (size, morphology and crystal structure) and other factors on the thermodynamics and kinetics of nucleation, crystallization and growth in the gas-solid reaction processes. Therefore, the mechanism of gas-solid reaction for the growth of copper-based sulfide nanostructures can be clarified. The results of this project will enrich the scientific connotation for the fabrication of nanomaterials and provide novel routes for the accurate and controllable growth of nanostructured metal sulfides.

纳米金属硫化物因具有优异的物理、化学性能及较低的制备成本，在光电、传感、储能等众多领域引起了广泛的关注。然而，从热/动力学本质上厘清其生长机理，实现高精度、可重复地生长出满足某种特定需求的金属硫化物纳米结构仍面临巨大挑战。本项目以纳米铜基硫化物的气固反应生长为研究对象，采用高精度、高灵敏度的谐振微悬臂梁为分析测量工具来原位研究气固界面分子作用的热力学和动力学（焓变、熵变、吉布斯自由能变、活化能等）；并通过集成了TEM原位观测微反应腔的悬臂梁芯片来探究纳米铜基硫化物在生长过程中的尺寸、形貌及晶体结构与热/动力学参数的构效关联；重点研究反应温度、含硫反应性气体（类型及浓度）、前驱体（尺寸、形貌及晶体结构）等因素对气固反应成核、结晶及生长热/动力学的影响；从而阐明铜基硫化物纳米结构的气固反应生长机理。本项目的研究成果将丰富纳米材料制备的科学内涵，为金属硫化物纳米结构的精确可控生长提供新思路。

纳米金属硫化物因具有优异的物理、化学性质，在传感、光电、储能等众多领域引起了广泛关注。本项目以亚皮克级分辨率谐振微悬臂梁为测量工具，通过实时记录H2S与铜基纳米材料气固界面分子吸附/脱附作用过程质量变化引起的频率响应，结合经典热力学/动力学理论，成功实现纳米铜基硫化物气固反应生长过程热力学/动力学参数（焓变、活化能、反应速率等）的定量提取，并厘清其成核、结晶及生长的热力学/动力学规律。通过将谐振微悬臂梁传感器集成到气相原位TEM芯片中，开发了一种能同时实现纳米形貌/结构观察与热力学/动力学参数提取的原位定量构效关联表征技术。实现了以纳米铜为前驱体，H2S气氛中气固反应生长CuxS过程的纳米形貌与动力学参数的构效关联表征，并发现了其基于柯肯达尔效应的三阶段硫化反应空心化过程。重点研究了纳米形貌、晶体结构及暴露晶面对气固界面分子作用热力学/动力学机制的影响，提出了H2S气体分子与纳米铜晶面竞争性气固反应机理。本项目的研究成果将丰富纳米材料制备的科学内涵，为金属硫化物纳米结构的精确可控生长提供理论依据。