scholarly journals Molecular behaviour of phenol in zeolite Beta catalysts as a function of acid site presence: a quasielastic neutron scattering and molecular dynamics simulation study

2019 ◽  
Vol 9 (23) ◽  
pp. 6700-6713 ◽  
Author(s):  
Carlos Hernandez-Tamargo ◽  
Alexander O'Malley ◽  
Ian P. Silverwood ◽  
Nora H. de Leeuw
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Simulation Study ◽  
Acid Site ◽  
Dynamic Behaviour ◽  
Acid Sites ◽  
Zeolite Beta ◽  
Dynamics Simulation ◽  
Quasielastic Neutron ◽  
Quasielastic Neutron Scattering

The dynamic behaviour of phenol in zeolite Beta is strongly influenced by the presence of Brønsted acid sites.

scholarly journals Methanol diffusion in zeolite HY: a combined quasielastic neutron scattering and molecular dynamics simulation study

2016 ◽  
Vol 18 (26) ◽  
pp. 17294-17302 ◽  
Author(s):  
Alexander J. O'Malley ◽  
Victoria García Sakai ◽  
Ian P. Silverwood ◽  
Nikolaos Dimitratos ◽  
Stewart F. Parker ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Neutron Scattering ◽  
Simulation Study ◽  
Md Simulations ◽  
Dynamics Simulation ◽  
Quasielastic Neutron ◽  
Quasielastic Neutron Scattering

The diffusion of methanol in zeolite HY is studied using tandem quasielastic neutron scattering (QENS) experiments and molecular dynamics (MD) simulations at 300–400 K.

scholarly journals Quasielastic Neutron Scattering and Molecular Dynamics Simulation Study on the Molecular Behaviour of Catechol in Zeolite Beta

2020 ◽  
Author(s):  
Carlos Hernandez-Tamargo ◽  
Ian P. Silverwood ◽  
Alexander J. O’Malley ◽  
Nora H. de Leeuw
Keyword(s):  
Molecular Dynamics ◽  
Neutron Scattering ◽  
Md Simulations ◽  
Acid Sites ◽  
Zeolite Beta ◽  
Dynamics Simulation ◽  
Oh Groups ◽  
Quasielastic Neutron ◽  
Quasielastic Neutron Scattering ◽  
Dynamics Simulations

AbstractThe dynamics of catechol in zeolite Beta was studied using quesielastic neutron scattering (QENS) experiments and molecular dynamics simulations at 393 K, to understand the behaviour of phenolic monomers relevant in the catalytic conversion of lignin via metal nanoparticles supported on zeolites. Compared to previous work studying phenol, both methods observe that the presence of the second OH group in catechol can hinder mobility significantly, as explained by stronger hydrogen-bonding interactions between catechol and the Brønsted sites of the zeolite. The instrumental timescale of the QENS experiment allows us to probe rotational motion, and the catechol motions are best fit to an isotropic rotation model with a $$D^{rot}$$ D rot of 2.9 × 10$$^{10}$$ 10 s$$^{-1}$$ - 1 . While this $$D^{rot}$$ D rot is within error of that measured for phenol, the fraction of molecules immobile on the instrumental timescale is found to be significantly higher for catechol. The MD simulations also exhibit this increased in ‘immobility’, showing that the long-range translational diffusion coefficients of catechol are lower than phenol by a factor of 7 in acidic zeolite Beta, and a factor of $$\sim$$ ∼ 3 in the siliceous material, further illustrating the significance of Brønsted site H-bonding. Upon reproducing QENS observables from our simulations to probe rotational motions, a combination of two isotropic rotations was found to fit the MD-calculated EISF; one corresponds to the free rotation of catechol in the pore system of the zeolite, while the second rotation is used to approximate a restricted and rapid “rattling”, consistent with molecules anchored to the acid sites through their OH groups, the motion of which is too rapid to be observed by experiment.

scholarly journals Comparing ammonia diffusion in NH3-SCR zeolite catalysts: a quasielastic neutron scattering and molecular dynamics simulation study

2018 ◽  
Vol 20 (17) ◽  
pp. 11976-11986 ◽  
Author(s):  
A. J. O'Malley ◽  
M. Sarwar ◽  
J. Armstrong ◽  
C. R. A. Catlow ◽  
I. P. Silverwood ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Neutron Scattering ◽  
Zeolite Catalysts ◽  
Dynamics Simulation ◽  
Simulation Studies ◽  
Nh3 Scr ◽  
Small Pore ◽  
Quasielastic Neutron ◽  
Quasielastic Neutron Scattering

Neutron scattering and simulation studies reveal important consistencies and differences in ammonia mobility in small pore NH3-SCR zeolite catalysts.

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