Morphology Effect on the Kinetic Parameters and Surface Thermodynamic Properties of Ag3 PO4 Micro-/Nanocrystals

Considerable effort has been exerted using theoretical calculations to determine solid surface energies. Nanomaterials with high surface energy depending on morphology and size exhibit enhanced reactivity. Thus, investigating the effects of morphology, size, and nanostructure on the surface energies...

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Bibliographic Details
Published in:Journal of nanomaterials 2015-01, Vol.2015
Main Authors: Huang, Zai-Yin, Li, Xing-Xing, Liu, Zuo-Jiao, He, Liang-Ming, Tan, Xue-Cai
Format: Article
Language:English
Subjects:
Activation energy
Entropy
Morphology
Nanocrystals
Nanomaterials
Reaction kinetics
Surface chemistry
Surface energy
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Summary:Considerable effort has been exerted using theoretical calculations to determine solid surface energies. Nanomaterials with high surface energy depending on morphology and size exhibit enhanced reactivity. Thus, investigating the effects of morphology, size, and nanostructure on the surface energies and kinetics of nanomaterials is important. This study determined the surface energies of silver phosphate (Ag sub(3) PO sub(4) ) micro-/nanocrystals and their kinetic parameters when reacting with HNO sub(3) by using microcalorimetry. This study also discussed rationally combined thermochemical cycle, transition state theory, basic theory of chemical thermodynamics with thermokinetic principle, morphology dependence of reaction kinetics, and surface thermodynamic properties. Results show that the molar surface enthalpy, molar surface entropy, molar surface Gibbs free energy, and molar surface energy of cubic Ag sub(3) PO sub(4) micro-/nanocrystals are larger than those of rhombic dodecahedral Ag sub(3) PO sub(4) micro-/nanocrystals. Compared with rhombic dodecahedral Ag sub(3) PO sub(4) , cubic Ag sub(3) PO sub(4) with high surface energy exhibits higher reaction rate and lower activation energy, activation Gibbs free energy, activation enthalpy, and activation entropy. These results indicate that cubic Ag sub(3) PO sub(4) micro-/nanocrystals can overcome small energy barrier faster than rhombic dodecahedral Ag sub(3) PO sub(4) micro-/nanocrystals and thus require lower activation energy.
ISSN:1687-4110
1687-4129
DOI:10.1155/2015/743121