基于微量热技术研究双微乳液体系纳米MnMoO₄的原位生长过程的热动力学及机理
Thermokinetic Study on Growth Process of MnMoO₄ Nanocrystals on Double Microemulsion System by In Situ Microcalorimetry

本工作利用高精度、高灵敏度的RD496-III型微量热计获取了在双微乳液体系内不同生长参数下纳米MnMoO₄生长过程的原位特征热谱信息，结合热动力学方程获取了其生长过程的热动力学特征生长参数，并与电镜表征技术相结合讨论了反应参数对其原位生长热动力学机理及其形貌、尺寸的影响规律。结果表明：1) 在双微乳体系中纳米MnMoO₄在不同生长参数下原位生长过程的热谱曲线具有相同的热变趋势：均经历了一个快速的放热–吸热–放热过程。2) 由热谱曲线整个生长过程分为三个阶段：反应成核阶段、结晶形成阶段、晶体生长阶段。3) 反应成核阶段的反应吉布斯自由能与反应速率常数成反比。本文为纳米钼酸盐材料的制备提供了理论基础与实验依据同时为纳米材料生长机理的研究提供新的思路和技术方法。

Abstract: In this paper, we use a RD 496-III microcalorimeter with high precision and high sensitivity to obtain the in situ heat flow information in the growth process of MnMoO₄. The growth parameters of MnMoO₄ acquired by thermodynamics equation were combined with the electron microscopy technique to discuss the growth mechanism and the influence of reaction parameters on mor-phology evolution and size of MnMoO₄. Experimental results show that：1) The thermogram curve has the same varying tendency in the growth process of MnMoO₄ exothermic chemical process, endothermic process, exothermic chemical process, Respectively. 2) The whole process contained three periods’ reaction respectively; nucleation, crystal crystallization and the secondary growth. 3) The gibbs free energy of reaction nucleationis is inversely proportional to the reaction rate constant. This paper will provide experimental basis and theoretical support for the controlled preparation and in situ growth of molybdate nanomaterials, also provide a new idea and method for the preparation and process characterization of nanomaterials, which is of great scientific significance for the controllable preparation of nanomaterials.

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