An algorithm for estimating kinetic parameters of atomistic rare events using finite-time temperature programmed molecular dynamics trajectories

2021 ◽  
Vol 262 ◽  
pp. 107828
Author(s):  
Saurabh Shivpuje ◽  
Manish Kumawat ◽  
Abhijit Chatterjee
Keyword(s):  
Molecular Dynamics ◽  
Kinetic Parameters ◽  
Finite Time ◽  
Rare Events ◽  
Temperature Programmed

Accelerating rare events using temperature programmed molecular dynamics: a review

2019 ◽  
Vol 45 (14-15) ◽  
pp. 1295-1303
Author(s):  
Saurabh Shivpuje ◽  
Methary Jaipal ◽  
Abhijit Chatterjee
Keyword(s):  
Molecular Dynamics ◽  
Rare Events ◽  
Temperature Programmed

Kinetics of temperature-programmed reactivation of a hydrodesulphurization catalyst

1983 ◽  
Vol 48 (12) ◽  
pp. 3340-3355 ◽  
Author(s):  
Pavel Fott ◽  
Pavel Šebesta
Keyword(s):  
Carbon Dioxide ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Thin Layer ◽  
Kinetic Parameters ◽  
Diffusion Region ◽  
Reaction Heat ◽  
Gaseous Products ◽  
Temperature Programmed ◽  
Kinetics Of

The kinetic parameters of reactivation of a carbonized hydrodesulphurization (HDS) catalyst by air were evaluated from combined thermogravimetric (TG) and differential thermal analysis (DTA) data. In addition, the gaseous products leaving a temperature-programmed reactor with a thin layer of catalyst were analyzed chromatographically. Two exothermic processes were found to take part in the reactivation, and their kinetics were described by 1st order equations. In the first process (180-400 °C), sulphur in Co and Mo sulphides is oxidized to sulphur dioxide; in the second process (300-540 °C), in which the essential portion of heat is produced, the deposited carbon is oxidized to give predominantly carbon dioxide. If the reaction heat is not removed efficiently enough, ignition of the catalyst takes place, which is associated with a transition to the diffusion region. The application of the obtained kinetic parameters to modelling a temperature-programmed reactivation is illustrated on the case of a single particle.

scholarly journals An alternative approach to kinetic analysis of temperature-programmed reaction data

RSC Advances ◽  
2018 ◽  
Vol 8 (6) ◽  
pp. 3286-3295 ◽  
Author(s):  
A. S. Portnyagin ◽  
A. P. Golikov ◽  
V. A. Drozd ◽  
V. A. Avramenko
Keyword(s):  
Particle Size ◽  
Kinetic Analysis ◽  
Kinetic Parameters ◽  
Isothermal Reaction ◽  
Alternative Approach ◽  
Reaction Data ◽  
Temperature Programmed ◽  
Temperature Programmed Reaction

Presented method of kinetic analysis of non-isothermal reaction data provides precise kinetic parameters for different materials with different morphology and particle size.

Structural relaxation in Ag-Ni nanoparticles: Atomistic modeling away from equilibrium

2021 ◽  
Author(s):  
Florent Calvo
Keyword(s):  
Molecular Dynamics ◽  
Structural Relaxation ◽  
Rare Events ◽  
Metal Vapor ◽  
Silver Concentration ◽  
Atomistic Modeling ◽  
Ni Nanoparticles ◽  
Vapor Mixture ◽  
Chemical Ordering ◽  
Fast Cooling

The out-of-equilibrium structural relaxation of Ag-Ni nanoparticles containing about 1000--3000 atoms was investigated computationally by means of molecular dynamics trajectories in which the temperature is decreased gradually over hundreds of nanoseconds. At low silver concentration of 10--30\%, the evolution of chemical ordering in Ni$_{\rm core}$Ag$_{\rm shell}$ nanoparticles with different surface arrangements is found to proceed spontaneously and induce some rounding of the nickel core and its partial recristallization. Fast cooling of an initially hot metal vapor mixture was also considered, and it is shown to disfavor silver aggregation at the surface. Silver impurities are also occasionally produced but remain rare events under the conditions of our simulations.

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