Gaochao Fan

Size effect on thermodynamic parameters for the peanut-like CaMoO4 micro/nano reaction systems

Peanut-like CaMoO4 micro/nano structures with three different sizes were harvested by a simple reverse-microemulsion method at room temperature. Employing synthesized micro/nano CaMoO4 and HCl as reaction systems, thermodynamic parameters such as standard molar enthalpy of reaction ΔrHmθ, standard molar Gibbs free energy of activation Δr≠Gmθ, standard molar enthalpy of activation Δr≠Hmθ, and standard molar entropy of activation Δr≠Smθ were successfully acquired for the first time by in situ microcalorimetry. Furthermore, change regularities of the thermodynamic parameters for the micro/nano reaction systems were obtained and discussed. It demonstrated that size effect has significant influence on thermodynamic parameters of micro/nano material reaction systems.

Impact of Size Effects on the Thermodynamic Properties of Zinc Oxide Micro/nano System

Grenade-like ZnO micro/nano structures with three different sizes were prepared by microemulsion-mediated hydrothermal route. Through designing a thermochemical cycle, the relationship between thermodynamic properties of nano ZnO and bulk ZnO systems was built. Combined with microcalorimetry, thermodynamic properties of the ZnO micro/nano systems with different sizes were calculated. The results revealed that size effect has significant influences on thermodynamic properties of micro/nano systems. Along with the size of reactants decreasing, the standard molar enthalpy of reaction, standard molar Gibbs free energy of reaction and standard molar entropy of reaction of micro/nano systems decreased, but the standard molar enthalpy of formation, standard molar Gibbs free energy of formation and standard molar entropy of themselves increased.

Preparation of Sb2O3 Submicron Rod Arrays by the Carbothermal Reduction Method

Sb2O3 submicron rod arrays were fabricated by carbothermal reduction method using antimony doped tin oxide (ATO) nanoparticles and graphite powder as source materials. The obtained products were characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). The results demonstrated that the samples were single-crystal Sb2O3 submicron rod arrays. The room-temperature photoluminescence (PL) measurement exhibited two violet emission peaks which could be indexed to oxygen vacancies related defect emission. Also, blue shift and intensity decrease were observed when the excitation wavelength changed from 365 nm into 325 nm.