Hydrogen Adsorption on MOFs

Parameters obtained such as pore volumes, surface areas and pore size distributions are estimates for relative comparisons. 

Measurements of BET nitrogen surface area at 77 K are frequently used as a standard procedure for characterisation of porous materials. Studies suggested that BET surface area correlates with MOE surface areas determined from crystallographic data. However, heterogeneous surfaces are found in MOEs and it is best to describe the BET surface area as an apparent surface area. If a Type I isotherm has a plateau at high relative pressure, the micropore volume is given by the amount adsorbed (converted to a liquid volume) since the mesopore volume and external surface are both relatively small. Porous structure characterisation parameters (Eangmuir and BET surface areas and pore volumes) obtained from gas adsorption studies of MOEs have interrelated correlations. 

Isoreticular metal organic framework (IRMOF) materials were part of the series of MOF materials used in the identification of the correlation between hydrogen saturation amount and Langmuir surface area determined from nitrogen adsorption at 77Hydrogen adsorption on 

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Similar correlations were not observed for hydrogen adsorption at 1 bar pressure. 

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In 2003, Yaghi and colleagnes reported the first measurements of hydrogen adsorption on MOF-5 and topologically... 

The hydrogen sulfide adsorption on the HKUST-l/GO composites was only studied in moist conditions [44]. The choice was based on the presence of water in the ambient air and on the extensive studies of H2S reactive adsorption on carbonaceous materials where water was important for dissociation of hydrogen sulfide before its further reaction with surface active sites [5]. Here up to 20 wt% of H2S was adsorbed in the composite with the smallest content of GO. [44]. An increase in the GO content resulted in a decrease in the capacity but nevertheless it was higher than that on MOF... 

Figure 5.19 Hydrogen adsorption isotherm at room temperature (left) and at liquid nitrogen temperature (right) on metal organic frameworks (MOFs).

The comparison of hydrogen uptake in the same MOFs with and without unsaturated metal sites will directly demonstrate how the open metal sites affect the hydrogen adsorption, e.g., SNU-5, Cu2(abtc), with open metal sites can store 2.87wt% H2 at 77K and Ibar, compared to 1.83 wt% on SNU-5, Cu2(abtc)(dmf)2, without open metal site [131]. The capacity of Mn-BTT with available Mn + sites (1 m ) was 6.9 wt% v.s. 3.9 wt% of Mn-BTT with Mn " sites passivated by DMF (1 ) [126] (Figure 6.12). Pretreatment processes and alignment of the open... 

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