Computational approach to new catalytic reactions: rates of surface reactions

Samenvatting

Chemical reactivity has become one of the most important issues in computational chemistry for the last few years and several papers have been published reporting activation energies for elementary surface reactions calculated within density functional theory (DFT). However, this is not sufficient to predict the overall rate of a catalytic reaction since entropy changes need to be accounted for. Therefore, if we want to understand chemical reactivity in depth, we have to go one step further and investigate the effect of time and temperature on the reaction. Time can be included in the calculations as a variable by means of the Newton&8217;s equations in molecular dynamics calculations (MD). Unfortunately, the state-of-the-art methods based on ab-initio molecular dynamics are very time-consuming and only small systems can be studied. On the other hand, the effect of temperature has been rarely incorporated as a variable and the calculation of equilibrium constants and rate constants, key issues in chemical reactivity, has been only occasionally reported for gas-phase reactions.
The goals of this research proposal are: (1) Expanding the use of statistical thermodynamics to surface reactivity in order to be able to calculate thermodynamic functions of a reaction. (2) Exploring various possible reaction pathways and use the transition state theory to determine the rate constants of elementary steps. (3) Suggesting mechanisms for catalytic surface reactions and determining the overall rate equation. In addition to theory, various experimental techniques will be used in a collaborative project in order to validate the formulated reaction mechanism and its corresponding rate equation.
The perspective of this approach is to explore new reaction pathways to desirable products. A suitable reaction of interest both from a fundamental and applied point of view is the formation of HCN from dinitrogen and hydrocarbon fragments obtained from the dissociation of ethylene on metallic surfaces.

Kenmerken

Projectnummer

700.53.403

Hoofdaanvrager

Dr. D. Curulla Ferré

Verbonden aan

Total France S.A.

Uitvoerders

Dr. D. Curulla Ferré

Looptijd

01/04/2004 tot 18/12/2007