Direct Determination of Enthalpies of Sorption Using Pressure‐Gradient Differential Scanning Calorimetry: CO2 Sorption by Cu‐HKUST

Enthalpy of sorption (ΔH) is an important parameter for the design of separation processes using adsorptive materials. A pressure‐ramped calorimetric method is described and tested for the direct determination of ΔH values. Combining a heatflow thermogram with a single sorption isotherm enables the determination of ΔH as a function of loading. The method is validated by studying CO2 sorption by the well‐studied metal–organic framework Cu‐HKUST over a temperature range of 288–318 K. The measured ΔH values compare well with previously reported data determined by using isosteric and calorimetric methods. The pressure‐gradient differential scanning calorimetry (PGDSC) method produces reliable high‐resolution results by direct measurement of the enthalpy changes during the sorption processes. Additionally, PGDSC is less labor‐intensive and time‐consuming than the isosteric method and offers detailed insight into how ΔH changes over a given loading range. When a guest meets a host: A fast and reliable calorimetric method is described for the determination of enthalpies of sorption for porous materials. The method is validated by using Cu‐HKUST and offers higher resolution plots of ΔH as a function of loading as compared to the isosteric method.