Syntheses, structures, and hydrogen adsorption properties of microporous metal-organic frameworks incorporating 3,5-dipyridyl-1,2,4-triazole

Hydrothermal reactions of Co(II)/Ni(II) salts with the ligands 3,5-dipyridyl-1,2,4triazole (4-Hbpt) and 3,3′,4,4′-biphenyltetracarboxylic acid (H4bptc) generated the robust, microporous metal-organic frameworks {[Co2(4-Hbpt)2(bptc)(H2O)2]·10H2O}n (I) and {[Ni3(4-Hbpt)2(Hbptc)2(H2O)6]·8H2O}n (II). The two coordination frameworks were performed to absorb hydrogen at low and high pressures, respectively. Experimental and theoretical analyses indicate that the high enthalpy of adsorption for H2 benefit the high hydrogen absorption capacity.

Two microporous MOFs {[Co2(4-Hbpt)2(bptc)(H2O)2]·10H2O}n (I) and {[Ni3(4-Hbpt)2(Hbptc)2(H2O)6]·8H2O}n (II) were hydrothermally synthesized and structurally characterized. The hydrogen uptakes in I and II were investigated, indicating that the hydrogen uptakes were 1.33 and 0.78 wt% at 77 K under 20 bar, respectively. Theoretical analysis reveals that the high binding energy of interaction between H2 and the framework benefit the high hydrogen uptakes.Figure optionsDownload as PowerPoint slideHighlights
► Two microporous MOFs have been hydrothermally synthesized.
► The compounds were employed for hydrogen adsorption.
► The enthalpy of adsorption with the adsorption amount has been correlated.