Analysis of the adsorption state and desorption kinetics of NO2 over Fe–zeolite catalyst by FT-IR and temperature-programmed desorption

2010 ◽  
Vol 12 (10) ◽  
pp. 2365 ◽  
Author(s):  
Masaoki Iwasaki ◽  
Hirofumi Shinjoh
Keyword(s):  
Zeolite Catalyst ◽  
Temperature Programmed Desorption ◽  
Desorption Kinetics ◽  
Adsorption State ◽  
Ft Ir ◽  
Temperature Programmed ◽  
Kinetics Of

scholarly journals Engineering of TMDC-OSC Hybrid Interfaces: The Thermodynamics of Unitary and Mixed Acene Monolayers on MoS2

2020 ◽  
Author(s):  
Stefan R. Kachel ◽  
Pierre Martin Dombrowski ◽  
Tobias Breuer ◽  
Michael Gottfried ◽  
Gregor Witte
Keyword(s):  
Monte Carlo ◽  
Molecular Mobility ◽  
Temperature Programmed Desorption ◽  
Model System ◽  
Desorption Kinetics ◽  
Temperature Programmed ◽  
Kinetics Of

Here, we use temperature-programmed desorption (TPD) and Monte Carlo (MC) simulations<br>of TPD traces to characterize the desorption kinetics of pentacene (PEN) and perfluoropentacene (PFP) on MoS2 as a model system for OSCs on TMDCs. We show that the monolayers of PEN and PFP are thermally stabilized compared to their multilayers, which allows to prepare nominal monolayers by selective desorption of multilayers. This stabilization is, however, caused by entropy due to a high molecular mobility rather than an enhanced molecule-substrate bond. Consequently, the nominal monolayers are not densely packed films.

scholarly journals Engineering of TMDC-OSC Hybrid Interfaces: The Thermodynamics of Unitary and Mixed Acene Monolayers on MoS2

2020 ◽  
Author(s):  
Stefan R. Kachel ◽  
Pierre Martin Dombrowski ◽  
Tobias Breuer ◽  
Michael Gottfried ◽  
Gregor Witte
Keyword(s):  
Monte Carlo ◽  
Molecular Mobility ◽  
Temperature Programmed Desorption ◽  
Model System ◽  
Desorption Kinetics ◽  
Temperature Programmed ◽  
Kinetics Of

Here, we use temperature-programmed desorption (TPD) and Monte Carlo (MC) simulations<br>of TPD traces to characterize the desorption kinetics of pentacene (PEN) and perfluoropentacene (PFP) on MoS2 as a model system for OSCs on TMDCs. We show that the monolayers of PEN and PFP are thermally stabilized compared to their multilayers, which allows to prepare nominal monolayers by selective desorption of multilayers. This stabilization is, however, caused by entropy due to a high molecular mobility rather than an enhanced molecule-substrate bond. Consequently, the nominal monolayers are not densely packed films.

Competitive Pairing and the Chemistry of Coadsorbed Hydrogen and Halogens on Ge(100)

1992 ◽  
Vol 282 ◽  
Author(s):  
Yuemei L. Yang ◽  
Stephen M. Cohen ◽  
Mark P. D'Evelyn
Keyword(s):  
Epitaxial Growth ◽  
Atomic Layer ◽  
Temperature Programmed Desorption ◽  
Model System ◽  
Atomic Layer Epitaxy ◽  
Desorption Kinetics ◽  
First Order ◽  
First Order Kinetics ◽  
Temperature Programmed ◽  
Kinetics Of

ABSTRACTThe chemistry of coadsorbed H and X (X=C1, Br) on semiconductor surfaces is important in epitaxial growth of silicon from chlorosilanes and of SixGe1−x alloys, in hydrogenating/ halogenating cycles in atomic layer epitaxy, and also provides an interesting model system, yet has received little attention to date. We have investigated the interaction of HC1 and HBr with Ge(100) by temperature-programmed desorption, and find that H2, HCl and HBr each desorb with near-first-order kinetics near 570–590 K and that GeCl2 and GeBr2 desorb with near-second-order kinetics near 675 K and 710 K, respectively. Analysis of the desorption kinetics of H2 and HX provides evidence that adsorbed H and X atoms pair preferentially in a qualitatively similar way as H atoms adsorbed alone on Ge(100)2×1 or Si(100)2×1 and that pairing of H+X occurs in competition with pairing of H+H.

scholarly journals Thermal Transformation of Caffeic Acid on the Nanoceria Surface Studied by Temperature Programmed Desorption Mass-Spectrometry, Thermogravimetric Analysis and FT–IR Spectroscopy

2019 ◽  
Vol 3 (1) ◽  
pp. 34 ◽  
Author(s):  
Nataliia Nastasiienko ◽  
Borys Palianytsia ◽  
Mykola Kartel ◽  
Mats Larsson ◽  
Tetiana Kulik
Keyword(s):  
Mass Spectrometry ◽  
Thermogravimetric Analysis ◽  
Cerium Dioxide ◽  
Temperature Programmed Desorption ◽  
Hydroxyl Groups ◽  
Surface Complexes ◽  
Desorption Mass Spectrometry ◽  
Ft Ir ◽  
Temperature Programmed ◽  
Ft Ir Spectroscopy

The studies of pyrolysis of caffeic acid (CA) and its surface complexes is important for the development of technologies of heterogeneous catalytic pyrolysis of plant- and wood- based renewable biomass components. In this work, the structure and thermal transformations of the surface complexes of CA on the surface of nanoceria were investigated using Fourier transform–infrared (FT–IR) spectroscopy, thermogravimetric analysis (TGA) and temperature-programmed desorption mass spectrometry (TPD MS). It was found that CA on the surface of cerium dioxide forms several types of complexes: bidentate carboxylates, monodentate carboxylates and complexes formed as a result of interaction with phenolic hydroxyl groups. This is due to the ability of nanosized cerium dioxide to generate basic hydroxyl groups that can deprotonate phenolic groups to form phenolates on the surface. The main pyrolysis products were identified. The possible ways of forming 3,4-dihydroxyphenylethylene, acetylene carboxylic acid, pyrocatechol and phenol from surface complexes of CA were suggested. It was established that on the nanoceria surface effectively occur the decarboxylation, decarbonylation, and dehydration reactions of the CA, which are the desirable processes in biomass conversion technologies.

Adsorption of Silicon Tetrachloride on Si(111) 7×7

1988 ◽  
Vol 131 ◽  
Author(s):  
P. Gupta ◽  
P. A. Coon ◽  
B. G. Koehler ◽  
S. M. George
Keyword(s):  
Surface Temperature ◽  
Thermal Desorption ◽  
Temperature Programmed Desorption ◽  
Silicon Tetrachloride ◽  
Sticking Coefficient ◽  
Adsorption Model ◽  
Temperature Programmed ◽  
Kinetics Of

ABSTRACTThe kinetics of SiCl4 adsorption on Si(lll) 7×7 were studied using laser induced thermal desorption (LITD) and temperature programmed desorption (TPD) techniques. The initial reactive sticking coefficient of SiCl4 on Si(lll) 7×7 was observed to decrease with increasing surface temperature. This decrease was consistent with a precursor-mediated adsorption model. Both LITD and TPD experiments monitored SiCl2 as the main desorption product. These results suggest that SiC12 may be the stable chlorine species on the Si(lll) 7×7 surface.

The Characterization of Hydrocarbon Intermediates in H-ZSM-5

1987 ◽  
Vol 111 ◽  
Author(s):  
T. J. Gricus Kofke ◽  
R. J. Gorte ◽  
W. E. Farneth
Keyword(s):  
Infrared Spectroscopy ◽  
Thermogravimetric Analysis ◽  
Acid Site ◽  
Adsorbed Molecule ◽  
Temperature Programmed Desorption ◽  
Acid Sites ◽  
Adsorption State ◽  
Brönsted Acid ◽  
Temperature Programmed

AbstractWe have examined the adsorption of simple alcohols and 2-propanamine on H-ZSM-5 zeolites with Si/Al2 ratios between 38 and 520. Thermogravimetric analysis (TGA) demonstrated that most of the molecules display a clearly defined adsorption state corresponding to a coverage of one molecule per Al site. Temperature programmed desorption (TPD) and transmission infrared spectroscopy results for each of the molecules in this 1:1 adsorption state are consistent with adsorption being due to the transfer of a proton from the zeolite to the adsorbed molecule. These results provide additional evidence that carefully prepared H-ZSM-5 is a Bronsted acid, with one acid site per framework Al atom, in which all of the acid sites are identical in strength.

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