Preparation and standard molar enthalpy of formation of the ZnO nanotetrapods

ZnO nanotetrapods with uniform size and morphology were harvested by a gentle and facile microemulsion-mediated hydrothermal route. Each of the prepared nanotetrapods consisted of four legs about 110-130-nm in length and 20-nm in diameter, and their leg tips were somewhat pointed. Through designing a novel thermochemical cycle according to thermodynamic potential function method, the relationship between standard molar enthalpies of formation of nano ZnO and bulk ZnO was built. Combined with microcalorimetry, standard molar enthalpy of formation of the prepared ZnO nanotetrapods at 298.15-K was successfully acquired as (-317.41-0.29)-kJ/mol¹. The striking difference between standard molar enthalpies of formation of the ZnO nanotetrapods and bulk ZnO can be attributed to the surface effect of nanomaterials.