For catalytic materials, if particle size reduces means activity increases, how about the thermal stability?
A lower particle size will make the material more reactive (as its surface area is higher), and more prone to coalescence (as the surface energy needs to be minimized). So for both cases, the material is more prone to change, i.e., is less stable.
Alain
When particle size decreases, the thermal stability decreases, i. e. : solubility increases, vapour pressure increases and melting point decreases.
This dependence is given by the Freundlich - Ostwald equation (also known as Kelvin equation and Gibbs - Thomson equation). It will only be significant for particles sizing less than roughly 100 nm.
For more information, you can read :
Cao, G. Nanostructures & Nanomaterials. Synthesis, properties & Applications. Imperial College Press (2004), pages 26-31
but also
A. S. MYERSON Handbook of Industrial Crystallization, 2nd Ed (2002), page 142
J. W. MULLIN. Crystallization, 4th Ed (2001), pages 108 -110
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