Effect of temperature on hydrogen and carbon dioxide adsorption hysteresis in an ultramicroporous MOF

• We show genuine and non-genuine hysteresis through temperature-dependent H2 and CO2 adsorption of an ultramicroporous MOF.
• We demonstrate that structure-induced adsorption hysteresis can be closed when temperature reaches to a “critical” point.
• We stress that reliable isosteric heats should be obtained only from fully equilibrated and reversible adsorption isotherms.

Different types of hysteresis commonly observed in gas adsorption isotherms of metal-organic frameworks (MOFs) and possible reasons are discussed. The temperature effect of hydrogen (H2) and carbon dioxide (CO2) adsorption/desorption hysteresis in an ultramicroporous MOF and a method to obtain accurate isosteric heats of adsorption in small-pore adsorbent materials are presented.

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