Synthesis and characterization of porous HKUST-1 metal organic frameworks for hydrogen storage

Hydrogen storage capacity has been investigated on a copper-based metal organic framework named HKUST-1 with fine structural analyses. The crystalline structure of HKUST-1 MOF has been confirmed from the powder X-ray diffraction and the average particle diameter has been found about 15–20 μm identified by FE-SEM. Nitrogen adsorption isotherms show that HKUST-1 MOF has approximately type-I isotherm with a BET specific surface area of 1055 m2g−1. Hydrogen adsorption study shows that this material can store 0.47 wt.% of H2 at 303 K and 35 bar. The existence of Cu (II) in crystalline framework of HKUST-1 MOF has been confirmed by pre-edge XANES spectra. The sharp feature at 8985.8 eV in XANES spectra represents the dipole-allowed electron transition from 1s to 4pxy. In addition, EXAFS spectra indicate that HKUST-1 MOF structure has the Cu–O bond distance of 1.95 Å with a coordination number of 4.2.

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► The as-synthesized HKUST-1 MOF was highly pure with almost no impurity.
► Average diameter of HKUST-1 MOF particles was about 15–20 μm.
► Gravimetric H2 uptake of HKUST-1 was 1.95 wt.% carried out at 77 K and 1 bar.
► The Cu–O bond distance in HKUST-1 was 1.95 Å with a coordination number of 4.20.
► HKUST-1 MOF can be used in high temperature systems as it is stable up to 250 °C.