TY - JOUR
T1 - Surface acid-base properties of Cu-BTC and Fe-BTC MOFs. An inverse gas chromatography and n-butylamine thermo desorption study
AU - Autié-Castro, Giselle
AU - Reguera, Edilso
AU - Cavalcante, Celio L.
AU - Araujo, Antonio S.
AU - Rodríguez-Castellón, Enrique
N1 - Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2020/7/1
Y1 - 2020/7/1
N2 - Catalytic activity is usually related to the acid-base properties of the catalyst material. Metal-organic frameworks (MOFs) have been evaluated as potential catalysts for several reactions. Cu-BTC (with a well-defined crystalline structure) and Fe-BTC (with a gel-like porous structure) have both shown the presence of Lewis surface acid sites based on the observed performance in different catalytic reactions. In this work, experiments of Inverse Gas Chromatography (IGC) and n-butylamine thermo desorption analysis were carried out in order to determine the acid-base properties of both materials. The IGC measurements allow to access the acid-base properties of the material surface by using acidic, basic and amphoteric molecules. Otherwise the n-butylamine thermo desorption measurements allow the quantification of those acid and basic sites from the n-butylamine desorption curves of a sample previously saturated with that probe molecule. The Lewis acid properties obtained by both methodologies showed to be more pronounced for the Fe-BTC MOF sample. The IGC measurements exhibited values of acidity constants (KA) of 0.81 and 0.60 for Fe-BTC and Cu-BTC, respectively. Furthermore the n-butylamine thermo desorption experiments indicate total acidities of 2.06 and 0.49 mmol g−1 for Fe-BTC and Cu-BTC, respectively.
AB - Catalytic activity is usually related to the acid-base properties of the catalyst material. Metal-organic frameworks (MOFs) have been evaluated as potential catalysts for several reactions. Cu-BTC (with a well-defined crystalline structure) and Fe-BTC (with a gel-like porous structure) have both shown the presence of Lewis surface acid sites based on the observed performance in different catalytic reactions. In this work, experiments of Inverse Gas Chromatography (IGC) and n-butylamine thermo desorption analysis were carried out in order to determine the acid-base properties of both materials. The IGC measurements allow to access the acid-base properties of the material surface by using acidic, basic and amphoteric molecules. Otherwise the n-butylamine thermo desorption measurements allow the quantification of those acid and basic sites from the n-butylamine desorption curves of a sample previously saturated with that probe molecule. The Lewis acid properties obtained by both methodologies showed to be more pronounced for the Fe-BTC MOF sample. The IGC measurements exhibited values of acidity constants (KA) of 0.81 and 0.60 for Fe-BTC and Cu-BTC, respectively. Furthermore the n-butylamine thermo desorption experiments indicate total acidities of 2.06 and 0.49 mmol g−1 for Fe-BTC and Cu-BTC, respectively.
KW - Acid-base properties
KW - Cu-BTC MOFs
KW - Fe-BTC MOFs
KW - Inverse Gas Chromatography
KW - n-butylamine thermo desorption
UR - http://www.scopus.com/inward/record.url?scp=85082723041&partnerID=8YFLogxK
U2 - 10.1016/j.ica.2020.119590
DO - 10.1016/j.ica.2020.119590
M3 - Artículo
SN - 0020-1693
VL - 507
JO - Inorganica Chimica Acta
JF - Inorganica Chimica Acta
M1 - 119590
ER -