Improved hydrogen storage capacity by hydrogen spillover and fine structural characterization of MIL-100 metal organic frameworks

摘要

The MIL-100 metal organic framework was synthesized through solvothermal route, modified with Pt-loaded active carbon and H-2 adsorption capacity was evaluated. The maximum specific surface area of MIL-100 was obtained upto 1,960 m(2) g(-1) with a type I adsorption isotherm confirmed from N-2 adsorption isotherms. The pristine MIL-100 was modified with 5 wt% Pt-loaded activated carbon and the carbonyl bridge was established to facilitate the hydrogen spillover effect. The hydrogen storage capacity of modified MIL-100 was 0.41 wt% measured at 31 bar and 298 K. This value is much higher than that of pristine MIL-100. XANES spectra indicated that the valency of central chromium metal ions of MIL-100 structure was Cr(III). EXAFS data also revealed that MIL-100 had a first shell of Cr-O bonding with bond distance of 1.965 and the coordination number of 4.8.