立方体纳米Cu2O规定热力学函数的粒度效应研究

Particle size effect of specifically prescribed thermodynamic function of cubic nano-Cu2O

纳米材料的规定热力学函数是纳米材料本征性质,而粒径是其规定热力学函数值的重要影响因素之一.因此研究纳米材料的规定热力学函数的粒度效应对于指导预测纳米材料的规定热力学函数具有重要的科学意义.采用液相法合成了4种粒度在40~120 nm的立方体纳米Cu2O作为模型材料.利用原位微热量技术获取了Cu2O与HNO3反应过程的热力学参数,结合热化学循环热动力学原理及过渡态理论,计算得到不同粒径的纳米Cu2O的规定热力学函数,并讨论了粒度对标准摩尔生成焓、标准摩尔熵和标准摩尔生成吉布斯能的影响.结果表明:随着粒径的减小,标准摩尔生成吉布斯自由能、标准摩尔生成焓和标准摩尔熵均增大.

The prescribed thermodynamic function of nanomaterials is the intrinsic properties of nanomaterials, and the prescribed thermodynamic functions are different with different particle sizes of nanomaterials. Therefore, it is of great scientific significance to study the variation of the specified thermodynamic function with the particle size for guiding the prediction of the specified thermodynamic function of nanomaterials? In this paper, four cubic nano-Cu2O with a particle size of 40-120 nm was synthesized by liquid phase method. In situ microcalorimetry was used to obtain the prescribed thermodynamics function of the reaction between four nano-Cu2O and HNO3 systems in combination of thermo-chemical cycles, thermodynamic principles and transition state theory. And the effects of different particle sizes on standard molar formation enthalpy, standard molar entropy and standard molar generation Gibbs energy were discussed. Results showed that: all of the standard molar Gibbs energy of formation, the standard molar enthalpy of formation and standard molar entropy of formation increased with decreasing particle size.