Influence of particle size on the interfacial thermodynamic properties of cubic nanoparticles: theoretical and experimental research

Abstract

The special properties of nanoparticles significantly differ from those of their corresponding bulk substances, which are determined on the basis of their interfacial thermodynamic properties. It is well known that the interfacial thermodynamic properties of nanomaterials are related to their morphology and particle size. It has been reported in the literature that cubic nanoparticles exhibit excellent properties, but the quantitative influence of particle size regularities on the interfacial thermodynamic properties of cubic nanoparticles has not been reported previously. In this paper, theoretically, the relational expressions of the interfacial thermodynamic properties and particle sizes of cubic nanoparticles were derived; additionally, an electrochemical method to measure the interfacial thermodynamic properties of cubic nanoparticles was proposed. Experimentally, cubic In₂O₃ nanoparticles were taken as a system, and the electrode potential and temperature coefficient of the cubic In₂O₃ nanoparticles with different particle sizes were measured at different temperatures. In addition, the interfacial thermodynamic properties of the cubic In₂O₃ nanoparticles were calculated. Results show that the interfacial electrode potential, interfacial molar Gibbs energy, interfacial molar enthalpy, interfacial molar entropy and interfacial molar internal energy increase with a decrease in the side length of the cubic In₂O₃ nanoparticles. When the side length exceeds 20 nm, these physical quantities are linearly related to the reciprocal of the mean side length, and the experimental results are in good agreement with theoretical predictions. Results obtained in the study can quantitatively describe the relationship between the interfacial thermodynamic properties and the side length of the cubic nanoparticles as well as can provide significant insights for the research and application of cubic nanoparticles.