粒径对纳米氧化锌颗粒电极电势和热力学性质的影响

Effect of Particle Size on Electrode Potential and Thermodynamics of Nano-ZnO Particles

为探究纳米颗粒粒径对电极电化学热力学的影响规律,从理论上分析了纳米电极电化学热力学函数对粒径的依赖关系。以纳米氧化锌为例,通过测定不同温度下、不同粒径纳米氧化锌的电极电势,得到标准电极电势、温度系数和电极反应热力学函数随粒径的变化规律。理论和实验结果都表明,当纳米氧化锌粒径减小时,标准电极电势和相应电极反应的平衡常数增大,而温度系数、摩尔吉布斯能变、焓变和熵变减小。同时,在实验范围内,这些量都与粒径的倒数存在线性关系。

In order to explore the influences of particle size on electrochemical thermodynamics of the electrodes, the size-dependent electrochemical thermodynamics has been theoretically investigated. Experimentally, taking ZnO nanoparticles electrode as an example, the standard electrode potentials, the temperature coefficients, and the thermodynamic functions of electrode reaction were obtained by determining the electrode potentials of the electrodes constructed by ZnO nanoparticles with different sizes at different temperatures. Both the theoretical and the experimental results indicated that with the particle size of nanoparticles decreasing, the standard electrode potential and the equilibrium constants of the corresponding electrode reactions increased, while the temperature coefficient, the molar reaction Gibbs energy, enthalpy and entropy decreased. Moreover, all these physical quantities were linearly related with the reciprocal of particle radius in the experimental range.