Adsorption Properties of Hydrogen and Carbon Dioxide in Prussian Blue Analogues M3[Co(CN)6]2, M = Co, Zn
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- 作者：Sittichai Natesakhawat ; Jeffrey T. Culp ; Christopher Matranga ; Bradley Bockrath
- 刊名：Journal of Physical Chemistry C
- 出版年：2007
- 出版时间：January 18, 2007
- 年：2007
- 卷：111
- 期：2
- 页码：1055 - 1060
- 全文大小：202K
- 年卷期：v.111,no.2(January 18, 2007)
- ISSN：1932-7455
文摘
H2 and CO2 adsorption were studied in dehydrated Prussian blue analogues M3[Co(CN)6]2 (M = Co, Zn)using volumetric isotherm measurements. Both materials adsorbed 1.2-1.3 wt % of H2 at 77 K and 760 Torrwith isosteric heats of adsorption ranging from 5.9 to 6.8 kJ/mol. High-pressure H2 isotherms at 77 K showedthat Co3[Co(CN)6]2 started to saturate well above 6 atm with a saturation coverage of ~1.9 wt %. Thesematerials adsorbed approximately 17.6-19.7 wt % of CO2 at 253 K and 760 Torr with isosteric heats ofadsorption of ~25-28 kJ/mol. The CO2 saturation coverages from high-pressure isotherms at 263 K and 15atm were ~27.4-29.0 wt %. The displacement of CO2 by H2 in these compounds was investigated withFourier transform infrared spectroscopy (FTIR). The FTIR experiments showed that CO2 physisorption atcryogenic temperatures produced an infrared peak at 2335 cm-1. Co-adsorption experiments revealed that H2was able to displace preadsorbed CO2 if the PH2/PCO2 ratio was well above 100. The infrared results from theco-adsorption experiments also showed that H2 and CO2 competed for adsorption in the same pores underthese conditions.