Heylen, S

Joos, Lennart

Kirschhock, CEA

Martens, JA

Parac-Vogt, T

Van Speybroeck, Veronique

English

Ghent University Academic Bibliography

 COMP Emilio Esposito, Scott Wildman Thursday, August 14, 2014 514 - Entropy-driven chemisorption of NOx on phosphotungstic acidLennart Joos1, lennart.joos@ugent.be, Steven Heylen2, Tatjana Parac-Vogt3, Veronique Van Speybroeck1, Christine E.A.Kirschhock2, Johan A. Martens2. (1) Center for Molecular Modeling, Ghent University, Ghent, Belgium, (2) Centre for SurfaceChemistry and Catalysis, KU Leuven, Leuven, Belgium, (3) Molecular Design and Synthesis, KU Leuven, Leuven, BelgiumNitrogen oxides (NOx) -mostly caused by the combustion of fossil fuels- contribute to the formation of ozon, smog and acid rain,so lowering NOx emissions to the atmosphere is desired. [1] Phosphotungstic acid is a selective NOx adsorbent with highadsorption capacity that could be used to capture NOxmolecules from exhaust gases and later release them for processing. [2]A variety of experimental and computational approaches - including ex-situ and in-situ X-ray diffraction, neutron diffraction, NMRand DFT calculations - determined the nature of the chemisorbed NOxspecies and elucidated the reaction behavior.Experiments show that at high temperature, NOx adsorption occurs, while at low temperature, the reverse reaction takes place.DFT calculations could assign this behavior to the entropy change during the reaction. Upon chemisorption of 3 NO molecules and3 NO2molecules, 15 water molecules are released from the phosphotungstic acid hexahydrate (See Figure). This gives rise to apositive reaction entropy whereas the reaction energy is also positive. The free energy is negative -and thus chemisorptionoccurs- when the temperature are sufficiently high.The insights from this study will allow optimization of the adsorbent material for application in after-treatment systems forNOxelimination.[1] TEDxGhent talk: http://youtu.be/SvhLtiBDJ3s[2] Heylen, S., Joos, L., Parac-Vogt, T. N., Van Speybroeck, V., Kirschhock, C . E. A. and Martens, J. A., Angew. Chem. Int. Ed.2012 , 51 (44), 11010-11013Thursday, August 14, 2014 10:45 AMMaterial Science (08:30 AM - 12:15 PM)Location: Moscone Center, West Bldg.Room: 2016 *ACS does not own copyrights to the individual abstracts. For permission, please contact the author(s) of the abstract. C lose WindowResult Content View 6/23/2015http://acselb-529643017.us-west-2.elb.amazonaws.com/chem/248nm/program/view.php?pub_num=514&par=COMP 1 / 1

Entropy-driven chemisorption of NOx on phosphotungstic acid

https://biblio.ugent.be/publication/6842339/file/6842804.pdf

Entropy-driven chemisorption of NOx on phosphotungstic acid

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Ghent University Academic Bibliography