Amino-modified MIL-68(In) with enhanced hydrogen and carbon dioxide sorption enthalpy

The amino modified MIL-68(In), hereafter denoted by MIL-68(In)_NH2, has been obtained by self-assembling from 2-amino-terephthalic acid and indium nitrate hydrate. The characterization of the modified material based on powder X-ray diffraction analysis, IR spectroscopy, 1H NMR spectroscopy and TG analysis demonstrates that this porous coordination network possesses the Kagomé topology of MIL-68(In) with amino modified pores walls. The Brunauer–Emmett–Teller surface area of 1230 ± 24 m2 g−1 for MIL-68(In)_NH2 compared to 1028 ± 29 m2 g−1 for MIL-68(In) exhibits an surface area improvement of approximate 200 m2 g−1 within MIL-68(In)_NH2. Moreover, for both hybrids, the hydrogen and carbon dioxide sorption properties have been studied at 77 K and 87 K, and at 273 K and 298 K, respectively. The comparison of the corresponding results of MIL-68(In) shows that the presence of amino group can effectively enhance the adsorption enthalpy of H2 and CO2, whereas, slightly effect on the integral sorption amount. Besides, to our knowledge, it is the first time that the CO2 adsorption of MIL-68(In) sample are reported.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► An amino modified MIL-68(In) (named MIL-68(In)_NH2) has been synthesized. ► Surface area gain approximate 200 m2 g−1 within MIL-68(In)_NH2 compared to MIL-68(In). ► The adsorption enthalpy of H2 and CO2 is enhanced by the modification of amino groups into MIL-68(In).