Adsorption and Desorption of HD on the Metal-Organic Framework Cu2.97Zn0.03(Btc)(2) Studied by Three-Pulse ESEEM Spectroscopy

作者：Simenas Mantas; Jee Bettina; Hartmann Martin; Banys Juras; Poeppl Andreas

来源：Journal of Physical Chemistry C, 2015, 119(51): 28530-28535.

DOI：10.1021/acs.jpcc.5b11058

Cu2.97Zn0.03(btc)(2) is a structural analogue of the well-known HKUST-1 metal organic framework. In this compound 1% of the Cu2+ ions in the paddle-wheel units are substituted by Zn2+, resulting in the formation of Cu/Zn paddle-wheel units in low concentration. The paramagnetic Cu2+ ions of these mixed Cu/Zn pairs allow to perform pulsed electron paramagnetic resonance experiments at low temperatures. Here we report on the three-pulse electron spin echo envelope modulation (3p ESEEM) study of the deuterated hydrogen gas HD adsorption and desorption in Cu2.97Zn0.03(btc)(2). The HD adsorption sites in this modified, compound were identified by precisely simulating experimentally observed 3p ESEEM time domain pattern. To elucidate the HD desorption process, the 3p ESEEM experiments were performed at different temperatures. Employing this method, the detachment of HD from the Cu2+ binding sites is found to already occur slightly above 6 K temperature. Hereby 3p ESEEM spectroscopy reveals to be a powerful method to study adsorption of small molecules in the local environment of Cu2+ ions.

• 出版日期2015-12-24