Fluctuation adsorption theory: quantifying adsorbate-adsorbate interaction and interfacial phase transition from an
Seishi Shimizu1, Nobuyuki Matubayasi
1York Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5DD, UK. seishi.shimizu@york.ac.uk.
Physical Chemistry Chemical Physics : PCCP
|December 9, 2020
Summary
Adsorbate-adsorbate interactions, crucial for adsorption isotherm shapes, can now be quantified using statistical thermodynamics. This method extends solution theories to interfaces, providing insights into multi-body interactions and cluster sizes.
Area of Science:
- Physical Chemistry
- Surface Science
- Thermodynamics
Background:
- Understanding adsorbate-adsorbate interactions is key to interpreting adsorption isotherm shapes.
- Existing isotherm models often lack direct validation of their underlying assumptions.
- Quantifying interfacial interactions from adsorption data remains a significant challenge.
Purpose of the Study:
- To develop a method for quantifying adsorbate-adsorbate interactions directly from adsorption isotherms.
- To link statistical thermodynamics principles to interfacial adsorption phenomena.
- To provide a theoretical framework for interpreting isotherm shapes beyond simple model fitting.
Main Methods:
- Extension of Kirkwood-Buff and McMillan-Mayer theories to interfacial adsorbates.
- Application of statistical thermodynamics principles to adsorption isotherms.
- Utilizing fitting parameters from established isotherm models (e.g., Langmuir, BET).
Main Results:
- Adsorbate-adsorbate interactions can be quantified from isotherms using Kirkwood-Buff integrals (in absence of capillary condensation).
- Virial coefficients provide insights into multi-body interactions between adsorbates.
- Isotherms can reveal the size of adsorbate clusters during capillary condensation and interfacial phase transitions.
Conclusions:
- The proposed method allows for direct quantification of adsorbate-adsorbate interactions from adsorption isotherms.
- This approach provides a deeper understanding of the physical basis of different isotherm shapes.
- The study connects macroscopic isotherm behavior to microscopic interaction mechanisms.
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