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Observation of reduced thermal conductivity in a metal-organic framework due to the presence of adsorbates

Whether the presence of adsorbates increases or decreases thermal conductivity in metal-organic frameworks (MOFs) has been an open question. Here we report observations of thermal transport in the metal-organic framework HKUST-1 in the presence of various liquid adsorbates: water, methanol, and etha...

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Detalles Bibliográficos
Autores principales: Babaei, Hasan, DeCoster, Mallory E., Jeong, Minyoung, Hassan, Zeinab M., Islamoglu, Timur, Baumgart, Helmut, McGaughey, Alan J. H., Redel, Engelbert, Farha, Omar K., Hopkins, Patrick E., Malen, Jonathan A., Wilmer, Christopher E.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7421542/
https://www.ncbi.nlm.nih.gov/pubmed/32782252
http://dx.doi.org/10.1038/s41467-020-17822-0
Descripción
Sumario:Whether the presence of adsorbates increases or decreases thermal conductivity in metal-organic frameworks (MOFs) has been an open question. Here we report observations of thermal transport in the metal-organic framework HKUST-1 in the presence of various liquid adsorbates: water, methanol, and ethanol. Experimental thermoreflectance measurements were performed on single crystals and thin films, and theoretical predictions were made using molecular dynamics simulations. We find that the thermal conductivity of HKUST-1 decreases by 40 – 80% depending on the adsorbate, a result that cannot be explained by effective medium approximations. Our findings demonstrate that adsorbates introduce additional phonon scattering in HKUST-1, which particularly shortens the lifetimes of low-frequency phonon modes. As a result, the system thermal conductivity is lowered to a greater extent than the increase expected by the creation of additional heat transfer channels. Finally, we show that thermal diffusivity is even more greatly reduced than thermal conductivity by adsorption.