skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Infrared Spectroscopic Study of the Adsorption of HCN by gamma-Al2O3: Competition with Triethylenediamine for Adsorption Sites

Abstract

The adsorption and vibrational properties of chemisorbed HCN on Lewis acid sites, Lewis base sites, and Brønsted Al-OH acid sites on a partially hydroxylated [gamma]-Al2O3 surface have been obtained by a combination of FTIR and density functional theory studies. The vibrational modes from the molecular and dissociative adsorption of HCN were assigned by using deuterium and 13C-labeled D13CN molecules at 170 K. In addition, [eta]2(C, N)-HCN bonding is also found from the [nu](CdN) vibrational spectra. Good correlation of the calculated vibrational frequencies for the adsorbed species with experimental data is found. The effect of triethylenediamine (TEDA) (also called 1, 4-diazabicyclo [2.2.2]octane, DABCO) on the adsorption of hydrogen cyanide (HCN) on the high area [gamma]-Al2O3 surface has been investigated using transmission FTIR spectroscopy. During HCN adsorption on TEDA-functionalized surfaces, there is no spectral change or emerging feature in either the TEDA or HCN spectral regions, indicating that no direct interaction occurs between these two molecules. Instead, we found that TEDA competes with HCN for the active sites on [gamma]-Al2O3. The observed [nu](C [identical with] N) mode on a TEDA-precovered surface is due to the HCN adsorption on Lewis base sites (Al-O-Al) which are less affected by TEDA preadsorption.

Authors:
; ;
Publication Date:
Research Org.:
National Energy Technology Laboratory (NETL), Pittsburgh, PA, and Morgantown, WV
Sponsoring Org.:
USDOE - Office of Fossil Energy (FE)
OSTI Identifier:
913403
Report Number(s):
DOE/NETL-IR-2007-128
Journal ID: ISSN 1932-7447; TRN: US200802%%645
DOE Contract Number:
None cited
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Physical Chemistry C; Journal Volume: 111; Journal Issue: 14
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CHEMISORPTION; HYDROCYANIC ACID; LEWIS ACIDS; LEWIS BASES; INFRARED SPECTRA; ALUMINIUM OXIDES; SORPTIVE PROPERTIES; VIBRATIONAL STATES; DENSITY FUNCTIONAL METHOD; AMINES

Citation Formats

Kim, S., Sorescu, D.C., and Yates, J.T., Jr. Infrared Spectroscopic Study of the Adsorption of HCN by gamma-Al2O3: Competition with Triethylenediamine for Adsorption Sites. United States: N. p., 2007. Web. doi:10.1021/jp065570l.
Kim, S., Sorescu, D.C., & Yates, J.T., Jr. Infrared Spectroscopic Study of the Adsorption of HCN by gamma-Al2O3: Competition with Triethylenediamine for Adsorption Sites. United States. doi:10.1021/jp065570l.
Kim, S., Sorescu, D.C., and Yates, J.T., Jr. Thu . "Infrared Spectroscopic Study of the Adsorption of HCN by gamma-Al2O3: Competition with Triethylenediamine for Adsorption Sites". United States. doi:10.1021/jp065570l.
@article{osti_913403,
title = {Infrared Spectroscopic Study of the Adsorption of HCN by gamma-Al2O3: Competition with Triethylenediamine for Adsorption Sites},
author = {Kim, S. and Sorescu, D.C. and Yates, J.T., Jr.},
abstractNote = {The adsorption and vibrational properties of chemisorbed HCN on Lewis acid sites, Lewis base sites, and Brønsted Al-OH acid sites on a partially hydroxylated [gamma]-Al2O3 surface have been obtained by a combination of FTIR and density functional theory studies. The vibrational modes from the molecular and dissociative adsorption of HCN were assigned by using deuterium and 13C-labeled D13CN molecules at 170 K. In addition, [eta]2(C, N)-HCN bonding is also found from the [nu](CdN) vibrational spectra. Good correlation of the calculated vibrational frequencies for the adsorbed species with experimental data is found. The effect of triethylenediamine (TEDA) (also called 1, 4-diazabicyclo [2.2.2]octane, DABCO) on the adsorption of hydrogen cyanide (HCN) on the high area [gamma]-Al2O3 surface has been investigated using transmission FTIR spectroscopy. During HCN adsorption on TEDA-functionalized surfaces, there is no spectral change or emerging feature in either the TEDA or HCN spectral regions, indicating that no direct interaction occurs between these two molecules. Instead, we found that TEDA competes with HCN for the active sites on [gamma]-Al2O3. The observed [nu](C [identical with] N) mode on a TEDA-precovered surface is due to the HCN adsorption on Lewis base sites (Al-O-Al) which are less affected by TEDA preadsorption.},
doi = {10.1021/jp065570l},
journal = {Journal of Physical Chemistry C},
number = 14,
volume = 111,
place = {United States},
year = {Thu Apr 12 00:00:00 EDT 2007},
month = {Thu Apr 12 00:00:00 EDT 2007}
}
  • The effect of triethylenediamine (TEDA) (also named 1,4-diazabicyclo [2.2.2]octane, DABCO) on the adsorption of ClCN on a y-Al2O3 absorbent has been investigated. Both Fourier transform infrared (FTIR) and theoretical studies indicate that no direct interaction between amine groups of TEDA and ClCN molecules takes place. Instead, we found that TEDA competes with ClCN for active surface sites on y-Al2O3. In addition, the adsorption behavior of cyanogen chloride (ClCN) on a clean y-Al2O3 surface has been studied. The sequence of the thermally activated processes of diffusion, adsorption, desorption, and decomposition of ClCN molecules on the clean y-Al2O3 surface following icelike ClCNmore » layer formation at lower temperature was observed. One of the decomposition products, Al-NCO, was assigned by using an Al-18OH labeled surface for reaction with ClCN. In addition, Al-CN and Al2-OCN species were also detected upon ClCN decomposition. Good correlation of the calculated vibrational frequencies for the adsorbed species with experimental data is found.« less
  • Silica-supported catalysts containing 16.7 and 30% copper were prepared by deposition-precipitation and a catalyst containing 10% copper was prepared by a conventional impregnation technique. The catalysts were calcined at 400/sup 0/C for 15 hr in oxygen. An interpretation of the IR spectra of carbon monoxide adsorbed on the calcined, reduced, and reoxidized catalysts suggested that in the catalyst preparation by deposition-precipitation a substantial amount of the copper is incorporated into the silica surface as accessible isolated copper(II) ions and in the bulk as inaccessible isolated copper ions and that these copper ions are mobilized and coalesce on the surface asmore » copper particles during reduction, and are reoxidized to copper(II) oxide during reoxidation. The catalyst prepared by impregnation incorporated a small amount of isolated copper ions into the surface but none into the bulk.« less
  • Adsorption of carbon monoxide at room temperature (0.1 to 50 Torr) on silica-supported copper oxide was studied by infrared spectroscopy. Catalysts were prepared by deposition-precipitation or impregnation. After calcination two types of adsorbed CO were identified showing absorption bands at 2136 +- 3 and 2204 +- 1 cm/sup -1/, which are ascribed to CO adsorbed on copper(II) oxide and on isolated copper(II) ions in the silica surface, respectively. Reduction and reoxidation removed the band at 2204 cm/sup -1/ with all samples and raised the intensity of the 2136-cm/sup -1/ band with the precipitated catalysts but not with the impregnation catalyst.more » Evidence is brought forward that the isolated copper ions are mobilized during reduction and generate new copper (oxide) surface. The change in background transmission of the samples could be used to obtain further information about the interaction of O/sub 2/ and CO with copper oxide.« less