Study of carbon dioxide adsorption on a Cu-nitroprusside polymorph

Journal Article · Sat Mar 26 00:00:00 EDT 2011 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2011.02.029· OSTI ID:1335960

Roque-Malherbe, R. ^[1]; Lozano, C. ^[1]; Polanco, R. ^[1]; Marquez, F. ^[1]; Lugo, F. ^[1]; Hernandez-Maldonado, A. ^[2]; Primera-Pedrozo, J. N. ^[2]

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1. Univ. of Turabo, Gurabo (Puerto Rico). Inst. for Physical Chemical Applied Research, School of Science
2. Univ. of Puerto Rico, Mayaguez (Puerto Rico). Dept. of Chemical Engineering

A careful structural characterization was carried out to unequivocally determine the structure of the synthesized material. The TGA, DRIFTS and a Pawley fitting of the XRD powder profiles indicate that the hydrated and in situ dehydrated polymorph crystallizes in the orthorhombic space group Pnma. Meanwhile, the CO₂ isosteric heat of adsorption appears to be independent of loading with an average value of 30 kJ/mol. This translates to a physisorption type interaction, where the adsorption energy corresponding to wall and lateral interactions are mutually compensated to produce, an apparently, homogeneous adsorption energy. The somewhat high adsorption energy is probably due to the confinement of the CO₂ molecules in the nitroprusside pores. Statistical Physics and the Dubinin theory for pore volume filling allowed model the CO₂ equilibrium adsorption process in Cu-nitroprusside. A DRIFTS test for the adsorbed CO₂ displayed a peak at about 2338 cm^-1 that was assigned to a contribution due to physical adsorption of the molecule. Another peak found at 2362 cm^-1 evidenced that this molecule interacts with the Cu²⁺, which appears to act as an electron accepting Lewis acid site. In conclusion, the aim of the present paper is to report a Pnma stable Cu-nitroprusside polymorph obtained by the precipitation method that can adsorb carbon dioxide.

• Research Organization: Univ. of Turabo, Gurabo (Puerto Rico)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: NA0000672; CHE-0959334
• OSTI ID: 1335960
• Journal Information: Journal of Solid State Chemistry, Vol. 184, Issue 5; ISSN 0022-4596
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Adsorption space
Cu-nitroprusside
Molecular interaction
Confinement
Lewis acid