Thermodynamic functions of the grain-like ZnO nanostructures

Grain-like ZnO nanostructures were prepared by a simple microemulsion-mediated hydrothermal route, and were characterized by X-ray powder diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM). In order to associate thermodynamic functions of nano ZnO with bulk ZnO, a novel thermochemical cycle was designed. Combined with in situ microcalorimetry, the standard molar enthalpy of formation, standard molar Gibbs free energy of formation and standard molar entropy of the obtained products at 298.15 K were successfully acquired as (− 322.36 ± 0.42) kJ mol− 1, (− 318.74 ± 0.03) kJ mol− 1 and (44.61 ± 1.02) J mol− 1 K− 1, respectively.