The Standard Molar Enthalpies of Formation of Nano-ZnO Particles with Different Morphologies

• Main Authors: Ya Li, Xinmin Wu
• Format: Article
• Language: English
• Published: Hindawi Limited 2015-01-01
• Series: Journal of Nanomaterials
• Online Access: http://dx.doi.org/10.1155/2015/738909

The thermodynamic properties of nano-ZnO particles with different morphologies were studied. First, based on the measurements of XRD and SEM, the morphologies of the five nano-ZnO products were determined as sheet, block, sieve, column, and rod, and their particle size was about 40 nm. Then, based on a designed thermodynamic cycle, the standard molar enthalpies of formation ΔfHmӨ of the nano-ZnO particles were determined by the RD496-2000 microcalorimeter, and they are ΔfHmӨ(sheet) = (-337.43 ± 0.47) kJ·mol−1, ΔfHmӨ(block) = (-336.57 ± 0.43) kJ·mol−1, ΔfHmӨ(sieve) = (-337.04 ± 0.57) kJ·mol−1, ΔfHmӨ(column) = (-343.56 ± 0.39) kJ·mol−1, and ΔfHmӨ(rod) = (-341.43 ± 0.41) kJ·mol−1. The results show that the bigger difference of the morphologies of nano-ZnO, the bigger difference of the standard molar enthalpies of formation.