The synthesis and characterization of copper-based metal–organic framework/graphite oxide composites

New composites of a copper-based metal–organic framework and graphite oxide were synthesized with different ratios of HKUST-1 (also called MOF-199) and graphite oxide. These compounds, as well as the parent materials, were characterized by X-ray diffraction, sorption of nitrogen, FT-IR spectroscopy, thermal analyses, scanning electron microscopy, and sorption of hydrogen. The composites exhibit features similar to HKUST-1 as well as an increased porosity compared to the parent materials. The formation of new small pores is demonstrated by an increase in the hydrogen uptake. The results suggest that the building process of the composites occurs via the reaction/binding of the copper dimers from the HKUST-1 with/to the functional groups in graphite oxide (epoxy, carboxylic, hydroxylic, sulfonic).

Composites of a copper-based metal–organic framework (MOF) and graphite oxide were synthesized in situ. As a result of chemical reactions between graphite oxide and MOF, new micropores are formed at the interface of the two phases. Their presence results in enhanced adsorption of nitrogen and hydrogen.Figure optionsDownload as PowerPoint slideResearch highlights
► Composites of graphite oxide (GO) and copper-based metal–organic framework (MOF) are prepared for the first time.
► The composites are formed by reactions between the oxygen groups of GO and the copper sites of the MOF.
► The composite exhibit an increased porosity compared to the parent materials.
► Hydrogen uptake is enhanced in the composites compared to the parent materials owing to an increase in the porosity and in the strength of dispersive forces.