Adsorption properties of hydrogen and carbon dioxide in Prussian blue analogues M-3[Co(CN)(6)](2), M = Co, Zn

作者：Natesakhawat Sittichai^*; Culp Jeffrey T; Matranga Christopher; Bockrath Bradley

来源：Journal of Physical Chemistry C, 2007, 111(2): 1055-1060.

DOI：10.1021/jp065845x

H-2 and CO2 adsorption were studied in dehydrated Prussian blue analogues M-3[Co(CN)(6)](2) (M = Co, Zn) using volumetric isotherm measurements. Both materials adsorbed 1.2-1.3 wt % of H-2 at 77 K and 760 Torr with isosteric heats of adsorption ranging from 5.9 to 6.8 kJ/mol. High-pressure H-2 isotherms at 77 K showed that CO3[Co(CN)(6)](2) started to saturate well above 6 atm with a saturation coverage of similar to 1.9 wt %. These materials adsorbed approximately 17.6-19.7 wt % of CO2 at 253 K and 760 Torr with isosteric heats of adsorption of similar to 25-28 kJ/mol. The CO2 saturation coverages from high-pressure isotherms at 263 K and 15 atm were similar to 27.4-29.0 wt %. The displacement of CO2 by H-2 in these compounds was investigated with Fourier transform infrared spectroscopy (FTIR). The FTIR experiments showed that CO2 physisorption at cryogenic temperatures produced an infrared peak at 2335 cm(-1). Co-adsorption experiments revealed that H-2 was able to displace preadsorbed CO2 if the P-H2/P-CO2 ratio was well above 100. The infrared results from the co-adsorption experiments also showed that H-2 and CO2 competed for adsorption in the same pores under these conditions.

• 出版日期2007-1-18