Solution mediated phase transformation (RHO to SOD) in porous Co-imidazolate based zeolitic frameworks with high water stability

Experimental hydrogen isotherms on several metal-organic frameworks (IRMOF-1, IRMOF-3, IRMOF-9, ZIF-7, ZIF-8, ZIF-9, ZIF-11, ZIF-12, ZIF-CoNIm, MIL-101 (Cr), NH2-MIL-101 (Cr), NH2-MIL-101 (Al), UiO-66, UiO-67 and HKUST-1) synthesized in-house and measured at 77 K and pressures up to 18 MPa are presented, along with N2 adsorption characterization. The experimental isotherms together with literature high pressure hydrogen data were analysed in order to search for relationships between structural properties of the materials and their hydrogen uptakes. The total hydrogen capacity of the materials was calculated from the excess adsorption assuming a constant density for the adsorbed hydrogen. The surface area, pore volumes and pore sizes of the materials were related to their maximum hydrogen excess and total hydrogen capacities. Results also show that ZIF-7 and ZIF-9 (SOD topology) have unusual hydrogen isotherm shapes at relatively low pressures, which is indicative of "breathing", a phase transition in which the pore space increases due to adsorption. This work presents novel correlations using the modelled total hydrogen capacities of several MOFs. These capacities are more practically relevant for energy storage applications than the measured excess hydrogen capacities. Thus, these structural correlations will be advantageous for the prediction of the properties a MOF will need in order to meet the US Department of Energy targets for the mass and volume capacities of on-board storage systems. Such design tools will allow hydrogen to be used as an energy vector for sustainable mobile applications such as transport, or for providing supplementary power to the grid in times of high demand.

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“…The materials were synthesised according to methods reported in the literature [22][23][24][25][26][27][28][29].…”

Section: Methodsmentioning

confidence: 99%

Structure–property relationships in metal-organic frameworks for hydrogen storage

Noguera-Díaz

Bimbo

Holyfield

et al. 2016

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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“…Evidence for the SOD phase in the M3 diffraction pattern include the intense reflection at 7.31°, as well as at 10.24°, and 12.65°, which overlay with the simulated SOD phase (ZIF-8) [33]. The RHO phase is evident from reflections at 4.30°, 6.08°, 7.45°, 8.60°, and 9.63°that overlay with the RHO topology seen for ZIFs [36]. The ratio of SOD to RHO was calculated to be 1:2.…”

Section: Sim-1 (Sod Rho) Fabrication Using Ex Situ Methods (M3)mentioning

confidence: 93%

“…The larger crystals had an average size of 370 ± 8.6 nm and the smaller crystals were *100 nm. Previously a SOD and RHO mixture was described for ZIF, CoNIm, and it was reported that RHO transforms into SOD over time [36]. However, the M3 synthesis does not seem to be affected by time, since after 48 h the SOD/RHO ratio did not change.…”

Section: Sim-1 (Sod Rho) Fabrication Using Ex Situ Methods (M3)mentioning

confidence: 95%

“…Thus in the case of M3, any unreacted starting materials Fig. 4 PXRD patterns of the simulated SOD ZIF phase (ZIF-8) from crystallographic information in reference [33] (black), simulated RHO ZIF phase from crystallographic information in reference [36] (red), and SIM-1 synthesized using M3 (blue) (Color figure online) [33] (black), simulated RHO phase from crystallographic information in reference [36], and SIM-1 synthesized using M4 (blue) (Color figure online) remaining in solution may crystallize in the RHO topology when methanol is added, resulting in the mixed phase. The SIM-1 (RHO) exhibited a type I N 2 adsorption isotherm as shown in Fig S5 where the volume of N 2 absorbed increased from *130 cm 3 /g for SIM-1 (SOD) (M2) to *220 cm 3 /g for SIM-1 (RHO) (M4).…”

Section: Sim-1 (Sod Rho) Fabrication Using Ex Situ Methods (M3)mentioning

confidence: 99%

“…The ratio of SOD to RHO was calculated to be 1:2. RHO crystallizes in the Im-3 m cubic space group with an overall framework of 8, 6, and 4 ring units, while SOD crystallizes in the I-43 m space group with only 6 and 4 ring units [33,36].…”

Section: Sim-1 (Sod Rho) Fabrication Using Ex Situ Methods (M3)mentioning

confidence: 99%

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Tuning the crystal size and morphology of the substituted imidazole material, SIM-1

2014

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Zeolitic imidazolate frameworks (ZIFs) are attractive materials for liquid and gas separations. They are chemically and thermally stable and their pores sizes/pore windows can be modified for enhanced performance. Substituted imidazolate material-1 (SIM-1) is a ZIF that crystallizes in the SOD and RHO topologies. Herein, we report a variety of new syntheses for SIM-1 in the SOD and RHO topologies using solvothermal in situ and ex situ reaction methods including microwave synthesis and linker exchange that result in nanoparticles with a narrow size distribution.

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Porous Metal Azolate Frameworks

Liao

Zhou

et al. 2016

The Chemistry of Metal-Organic Frameworks: Synthesis, Characterization, and Applications

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Solution mediated phase transformation (RHO to SOD) in porous Co-imidazolate based zeolitic frameworks with high water stability

Cited by 78 publications

References 15 publications

Structure–property relationships in metal-organic frameworks for hydrogen storage

Structure–property relationships in metal-organic frameworks for hydrogen storage

Tuning the crystal size and morphology of the substituted imidazole material, SIM-1

Porous Metal Azolate Frameworks

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