【摘要】 水热合成钛酸钠是制备钛酸纳米管的关键步骤之一，但由于其水热过程处于高温高压状态，很难在线获得反应动力学信息，无法有效阐述其反应机制以及动力学机制。通过定制微型水热反应池，采用微量热技术，原位监测了TiO₂与NaOH水热反应过程中生成钛酸钠纳米材料的热流变化，探究了TiO₂晶相、NaOH浓度、升温速率对反应热流的影响，并使用ASTM E698法拟合动力学参数。水热反应过程的热流曲线呈现三阶段特征，分别对应TiO₂溶解、层状钛酸钠形成及钛酸钠致密重组。溶解锐钛矿型TiO₂的焓变为（8.329±0.453） kJ/mol;层状钛酸钠最低形成温度为59.1℃（外推法）,其标准生成吉布斯自由能为-2 545.4 kJ/mol;反应活化能为90.17 kJ/mol。本研究获得的水热合成钛酸钠热分析动力学结果，为深入研究水热过程提供了一种新的视角。更多还原

【Abstract】 Hydrothermal synthesis of sodium titanate is one of the key steps in preparing titanate nanotubes. However, due to the high temperature and high pressure conditions of the hydrothermal process, it is difficult to obtain real-time reaction kinetics information, making it challenging to effectively elucidate the reaction mechanism and kinetic behavior. A custom micro-hydrothermal reactor was used, and the heat flow changes during the hydrothermal reaction between TiO₂ and NaOH, resulting in the formation of sodium titanate nanomaterials, were monitored in situ using microcalorimetry. Effects of TiO₂ crystal phase, NaOH concentration, and heating rate on the reaction heat flow were investigated, and the kinetic parameters were fitted using the ASTM E698 method. The heat flow curve of the hydrothermal reaction exhibited three stages, corresponding to the dissolution of TiO₂, the formation of layered Na₂Ti₂O₅·H₂O, and the densification of Na₂Ti₂O₅·H₂O. The enthalpy change for the dissolution of anatase TiO₂ was（8.329±0.453） kJ/mol; the minimum formation temperature of layered Na₂Ti₂O₅·H₂O was 59.1 ℃（extrapolation method）, and its standard Gibbs free energy of formation was-2 545.4 kJ/mol. The activation energy of the reaction was 90.17 kJ/mol. The thermodynamic kinetic results obtained in this work for the hydrothermal synthesis of sodium titanate provide a new perspective for further research into the hydrothermal process.更多还原