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采用室温反相微乳液法制备不同粒度的八面体钼酸镉CdMoO4,利用微量热技术获取不同粒径产物与盐酸反应过程的原位热动力信息,结合热动力学理论、过渡态理论和热化学循环法,获得了不同粒径八面体钼酸镉CdMoO4的反应动力学参数及表面热力学函数,并讨论粒度、温度对其化学反应动力学和表面热力学性质的影响规律及其原因.结果表明,速率常数、比表面Gibbs自由能、比表面焓、比表面熵和比表面能随粒径减小而增大,表观活化能、活化Gibbs自由能、活化焓和活化熵则均随粒径减小而减小;且速率常数、活化Gibbs自由能、比表面焓和比表面熵均随温度升高而增大,比表面Gibbs自由能随温度变化则相反.在30~200nm范围存在临界尺寸使钼酸镉材料表面热容性质发生突变,表现为区别于传统储能材料的独特热容性质.
The octahedral cadmium molybdate CdMoO4 with different particle size was prepared by RTV microemulsion method. The in-situ thermodynamic information of the reaction of different particle size products and hydrochloric acid was obtained by using microcalorimetry. Combining the thermodynamics theory, transition state theory and thermochemistry The reaction kinetics parameters and surface thermodynamic functions of octahedral cadmium molybdate CdMoO4 with different particle sizes were obtained, and the influence laws of particle size and temperature on their chemical reaction kinetics and surface thermodynamic properties were discussed. The results show that the rate The Gibbs free energy, specific surface enthalpy, specific surface entropy and specific surface area increased with the decrease of particle size. The apparent activation energy, activation Gibbs free energy, activation enthalpy and activation entropy decreased with the decrease of particle size While the Gibbs free energy, Gibbs free energy, specific surface enthalpy and specific surface entropy increase with increasing temperature, and Gibbs free energy changes with temperature on the specific surface. In the range of 30 ~ 200nm, The abrupt change in the surface heat capacity of the acid-cadmium material manifests itself as the unique heat capacity property that is different from the traditional energy storage materials.