Abstract
Tools for computer generation of reaction mechanisms were extended to handle heterogeneous catalytic reactions. Development of these generic capabilities was carried out by constructing a detailed kinetic model of Fischer-Tropsch synthesis on Ni(1 1 1) and Co(0 0 1) surfaces. To estimate rate constants during automatic mechanism generation for heterogeneous catalytic reactions, linear free energy relationships were applied using heat of reaction as the reactivity index, and theoretical approaches were used to estimate activation energies and preexponential factors. Calculation of heats of reaction involving surface species presented special challenges due to unknown heats of adsorption for many adsorbates. This problem was addressed by estimating heats of adsorption using a phenomenological approach which relates the chemisorption energy of multiatomic species to that of adatoms. To provide a basis set of values for adsorbed species on Ni(1 1 1) and Co(0 0 0 1) surfaces, the binding energies of key intermediates were calculated using an ab initio method developed for periodic systems. The energetics obtained were used in an automatically constructed reaction mechanism describing Fischer-Tropsch synthesis via carbene polymerization. The model predictions for Ni(1 1 1) and Co(0 0 0 1) surfaces successfully captured product selectivities observed experimentall over nickel and cobalt catalysts.
Original language | English (US) |
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Pages (from-to) | 3379-3389 |
Number of pages | 11 |
Journal | Chemical Engineering Science |
Volume | 54 |
Issue number | 15-16 |
DOIs | |
State | Published - Jul 1999 |
Event | Proceedings of the 1998 15th International Symposium on Chemical Reaction Engineering, ISCRE 15 - Newport Beach, CA, USA Duration: Sep 13 1998 → Sep 16 1998 |
Keywords
- Automatic mechanism generation
- Cobalt
- Fischer-Tropsch synthesis
- Microkinetic model
- Nickel
- Single crystal
ASJC Scopus subject areas
- General Chemistry
- General Chemical Engineering
- Industrial and Manufacturing Engineering