Theoretical and experimental studies on the size- and morphology-dependent thermodynamics of nanoparticle electrodes

The morphology and size of nanoparticles have a significant effect on the thermodynamics of nanoparticle electrodes due to the nanometer effect. However, the influencing mechanism and regularity of morphology and particle size on electrochemical thermodynamics of nanometer electrodes are still unclear. Herein, the universal thermodynamics equations of nanometer electrodes which consisting of nanoparticles with different morphologies and particle sizes are deduced theoretically and we discuss the influencing mechanism and regularity of morphology and size on electrochemical thermodynamics. Experimentally, we adopt a hydrothermal method to prepare nanometer In2O3 particles with different particle sizes and morphologies and make them into nanometer electrodes. The electrode potentials at different temperatures are measured by a potentiometer, the standard electrode potentials, temperature coefficients of electrode potential, reaction equilibrium constants, reaction thermodynamic properties, and reversible reaction heats are obtained for the nanometer electrode with diverse particle morphologies and sizes. The effects of particle size and morphology on these thermodynamic properties are discussed and we find that the experimental results conform to the corresponding theoretical relations. The electrochemical thermodynamics theory of nanoparticle electrodes can quantitatively describe the electrochemical thermodynamic behavior of nanometer electrodes with different morphologies and particle sizes, explain relevant experimental phenomena, and provide theoretical guidance and support reference to design, research, and apply various nanometer electrode.