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Matériaux fonctionnels carbonés
(19) Production(s) de l'année 2021
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Comment on the paper “Improving Poor Man’s Kramers-Kronig analysis and Kramers-Kronig constrained variational analysis”
Auteur(s): Rousseau E., Izard N., Bantignies J.-L., Felbacq D.
(Article) Publié:
-Spectrochimica Acta Part A Molecular And Biomolecular Spectroscopy [1994-...], vol. 259 p.119849 (2021)
Texte intégral en Openaccess :
Ref HAL: hal-03228703_v1
DOI: 10.1016/j.saa.2021.119849
Exporter : BibTex | endNote
Résumé: We clarify some analytical expressions existing in the literature, • Within the correct formulae we conclude that there is no need for an ad hoc improvement on the opposite to the title paper, • We highlight the symmetry properties of the function to be integrated in order to agree with the usual assumptions made to derive the Kramers-Kronig relations, • The analytical formula we provide may be used to increase the accuracy of the "Poor Man's Kramers-Kronig analysis" method and the "Kramers-Kronig constrained variational analysis" method.
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Phonons and Adsorption-Induced Deformations in ZIFs: Is It Really a Gate Opening?
Auteur(s): Formalik F., Mazur Bartosz, Fischer Michael, Firlej L., Kuchta Bogdan
(Article) Publié:
The Journal Of Physical Chemistry C, vol. 125 p.7999-8005 (2021)
Texte intégral en Openaccess :
Ref HAL: hal-03226590_v1
DOI: 10.1021/acs.jpcc.1c01342
Exporter : BibTex | endNote
Résumé: We report a microscopic model of the phonon-adsorption correlations in flexible metal−organic framework materials. We analyze the mechanism of the gate opening deformation using the notion of coupled phonon- and adsorption-induced structural transformation. Using the ZIF-8 structure as an example, we perform an analysis of transformation-related, low-frequency phonon modes of the framework.On the basis of structure-related quantities such as pore limiting diameter, void fraction, and adsorption uptake, we determine the conditions which lead to the gate opening transformation in ZIF-8. Energetic landscape of the deformation process is analyzed using grand thermodynamic potential of adsorption. We generalize our conclusions to other flexible ZIF structures with the same topology.
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SERS detection and comprehensive study of p-nitrophenol: towards pesticide sensing
Auteur(s): Hostert Leandro, Blanc C., Zarbin Aldo J. G., Anglaret E., Orth Elisa S.
(Article) Publié:
New Journal Of Chemistry, vol. 45 p.3886-3891 (2021)
Texte intégral en Openaccess :
Ref HAL: hal-03194024_v1
DOI: 10.1039/d0nj05933a
WoS: WOS:000623596600015
Exporter : BibTex | endNote
Résumé: Pesticide sensing is an important object of study due to its increasing use worldwide. Herein, we report a SERS study of 4-nitrophenol (PNP), which is product of neutralization processes of various pesticides such as Paraoxon, and can be used as a target molecule for monitoring. PNP is also widely used in the chemical industry and due to its high toxicity is considered a concerning pollutant. The sensing was carried out with a reduced graphene oxide nanocomposite functionalized with cysteamine and Ag nanoparticles (rGOSHAg), and compared with raw reduced graphene oxide and a commercial SERS substrates (SERStrate (TM)). A mechanistic evaluation was also carried out, focused in the degradation of PNP caused by the different exciting laser lines, evidencing the PNP dimerization in substrates containing Ag NPs (under 532 nm laser), which has important outcomes for sensing purposes. The nanocomposite rGOSHAg presented the highest sensitivity towards PNP, detecting concentrations as low as 10(-6) mol L-1 and with a high potential for field applications and real-time measurements of molecules commonly present in pesticides and industrial contaminants.
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Raman resonance tuning of quaterthiophene in filled carbon nanotubes at high pressures
Auteur(s): Alencar R. S., Aguiar A. L., Ferreira R. S., Chambard R., Jousselme B., Bantignies J.-L., Weigel C., Clement S., Aznar R., Machon D., Souza Filho A. G., San-Miguel A., Alvarez L.
(Article) Publié:
Carbon, vol. 173 p.163-173 (2021)
Texte intégral en Openaccess :
Ref HAL: hal-03163018_v1
DOI: 10.1016/j.carbon.2020.10.083
WoS: WOS:000613132200003
Exporter : BibTex | endNote
Résumé: Filling carbon nanotubes with molecules is a route for the development of electronically modified one-dimensional hybrid structures for which the interplay between the electronic structure of molecules and nanotubes is a key factor. Tuning these energy levels with external parameters is an interesting strategy for the engineering of new devices and materials. Here we show that the hybrid system composed by quaterthiophene (4T) molecules confined in single-walled carbon nanotubes, presents a piezo-Raman-resonance of the molecule vibrational pattern. This behavior manifests as a rapid pressure induced enhancement of the 4T Raman mode intensities compared to the tubes G-band Raman modes. Density functional theory calculations allow to explain the spectral behaviour through the pressure-enhanced quaterthiophene resonance evolution. By increasing pressure, the tube cross-section deformation leads to a reduction of the intermolecular distance, to the splitting of the molecular levels and then to an increase of resonance channels. Calculations and experiments converge to the 4T piezo-resonance scenario associated with the pressure-induced nanotube radial collapse observed at about 0.8 GPa. Our findings offer possibilities for the development of pressure transducers based on molecule-filled carbon nanotubes.
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High-throughput screening of metal - Organic frameworks for CO2 and CH4 separation in the presence of water
Auteur(s): Rogacka J., Seremak Agnieszka, Luna-Triguero Azahara, Formalik F., Matito-Martos Ismael, Firlej L., Calero Sofia, Kuchta Bogdan
(Article) Publié:
Chemical Engineering Journal, vol. 403 p.126392 (2021)
Texte intégral en Openaccess :
Ref HAL: hal-03118302_v1
DOI: 10.1016/j.cej.2020.126392
WoS: WOS:000579752500109
Exporter : BibTex | endNote
Résumé: Competitive adsorption of water is an important issue in the adsorption-based industrial processes of bio- and flue gases separation. The dehumidification of gases prior to separation would increase process complexity and lower its economic interest. In this work, large-scale computational screening was applied to identify Metal-Organic Frameworks (MOFs) structures which exhibit high CO2/CH4 selectivity and total loading higher than 0.5 mol/kg (in the presence of water). High-throughput Grand Canonical Monte Carlo (GCMC) screening of nearly 3000 existing MOF materials was carried out. Initial selection assumed fixed values of pore limiting diameter (PLD) and Henry's constant for water and allowed one to preselect 764 structures. After GCMC simulations carried for 50/50 CO2/CH4 mixture, at ambient conditions (p = 1 bar, T = 298 K), and variable gas humidity (0%, 5%, 30% and 40%) the final selection revealed 13 most promising MOFs structures. We focused on analysis of the correlations between the properties of the selected MOFs and the separation selectivity. We show that the selectivity is a complex function of the porous materials characteristics and finding selective sorbent, performing well in dry and wet conditions requires careful analysis of available MOFs.
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