Characterization of hydrogen/deuterium adsorption sites in nanoporous Cu–BTC by low-temperature thermal-desorption mass spectroscopy

Hydrogen and deuterium adsorption sites in the crystalline MOF copper(II) benzene-1,3,5-tricarboxylate, Cu–BTC were studied by low-temperature thermal desorption spectroscopy. For a maximum loading of 218 D2 molecules per unit cell of Cu–BTC three desorption maxima were observed. The maxima could be separated by either interrupted desorption or partial loading. By comparing to neutron diffraction studies from the literature the maxima could be assigned to three different adsorption sites, i.e. coordinatively-unsaturated Cu2+ sites, tetrahedral side pockets and the large pores.

Successive filling of different adsorption sites in Cu-BTC by partical loading with deuterium.Figure optionsDownload as PowerPoint slideResearch highlights
► For the first time D2 desorption from Cu–BTC is investigated by TDS.
► The desorption maxima are assigned to three different sites in the Cu–BTC structure.
► Different maxima are separated by partial loading or interrupted desorption.
► By calibration the amount of deuterium adsorbed in Cu–BTC is determined.