Speciation of adsorbed CO2 on metal oxides by a new 2-dimensional approach: 2D infrared inversion spectroscopy (2D IRIS)
| Autor: | Françoise Maugé, Philippe Bazin, Arnaud Travert, Paweł Stelmachowski, Sergey Sirotin |
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| Přispěvatelé: | Ecole Nationale Supérieure d'Art et de Design [Dijon] (ENSA), Laboratoire catalyse et spectrochimie (LCS), Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut de Chimie du CNRS (INC)-Université de Caen Normandie (UNICAEN), Normandie Université (NU), Roland, Pascal |
| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: |
Infrared
Chemistry Analytical chemistry General Physics and Astronomy Infrared spectroscopy Langmuir adsorption model 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Spectral line 0104 chemical sciences symbols.namesake Adsorption [CHIM] Chemical Sciences symbols Gravimetric analysis [CHIM]Chemical Sciences Physical and Theoretical Chemistry 0210 nano-technology Spectroscopy Monoclinic crystal system |
| Zdroj: | Physical Chemistry Chemical Physics Physical Chemistry Chemical Physics, Royal Society of Chemistry, 2013, 15 (23), pp.9335--9342 HAL |
| ISSN: | 1463-9076 1463-9084 |
| Popis: | International audience; A new methodology based on the inversion of adsorption isotherms obtained using infrared spectroscopy has been developed. It provides a description of coexisting surface species in terms of their individual IR spectra and surface affinities in a new two dimensional, 2D IR spectroscopic technique. When implemented with simultaneous gravimetric analysis, it further provides the quantification of adsorbed species. The adsorption of CO2 on monoclinic ZrO2 was investigated using this technique with temperature and pressure ranges of 353-673 K and 10(-4)-0.4 bar, respectively. The sets of spectra obtained at constant temperature and variable pressures (spectroscopic isotherms) were inverted assuming they obey a generalized Langmuir isotherm. This procedure yields a 2D map in which the IR spectra of the prominent surface species formed upon CO2 adsorption are resolved in one dimension - hydrogen carbonates, bidentate carbonates and polydentate carbonates - while these species are resolved according to their surface adsorption affinities (logarithm of adsorption equilibrium constants, ln K) on the other dimension. This technique also allows for the unambiguous determination of the thermodynamic stabilities of the various adsorbed species. The inversion of the gravimetric isotherms recorded simultaneously with the infrared spectra leads to a quantitative distribution function of CO2 adsorption sites whose components match those of the 2D infrared map and allows for a straightforward quantification of the corresponding sites, namely (i) weakly basic sites leading to bridged carbonates, hydrogen carbonates and bidentate carbonates (similar to 0.7 mu mol m(-2), Delta H-ads = -70 to 90 kJ mol(-1)), (ii) mild basic sites leading to a second type of bidentate carbonates (similar to 0.8 mu mol m(-2), Delta H-ads = -110 to 120 kJ mol(-1)) and (iii) strong basic sites leading to polydentate carbonate species (similar to 0.1 mu mol m(-2), Delta H-ads \textless -120 kJ mol(-1)). Finally, the advantages and limitations of the present methodology are discussed. Because this technique is not limited to a particular spectroscopy or physical process, it should find other applications in the field of spectroscopic characterization of surfaces. |
| Databáze: | OpenAIRE |
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