Microkinetic model for CO oxidation on Cu

Contents

This folder contains the following scripts for simulating kinetics of carbon monoxide oxidation on copper.

1. solve_CO_oxidation_surface_only.m
2. solve_CO_oxidation_tanks_in_series.m
3. get_CO_oxidation_surface_odes.m
4. get_CO_oxidation_odes.m
5. get_CO_oxidation_rates.m
6. get_CO_oxidation_rate_constants.m
7. k_ads.m
8. k_des.m
9. k_arr.m
10. get_CO_oxidation_jac.m
11. solve_parameter_optimisation.m
12. parameter_optimisation.m

Running simulations

1. Surface only simulations

Files 1 and 3 are for surface kinetics only and assume constant bulk concentrations of CO, O2 and CO2.

Run file 1 to solve the ODEs provided in file 3.

2. Simulations with mass transport

Files 2 and 4 are for surface kinetics with a tanks-in-series model.

Run file 2 to solve the ODEs provided in file 4.

3. Changing the parameters

Simulation parameters can be modified in the Settings section of files 1 and 2.

Files 11 and 12 can be used to solve for parameters that meet certain conditions, for example to match experimentally observed phenomena.

Computing reaction rates

Files 5-9 are used to set up the ODEs:

• File 5 computes the surface reaction rates, using file 6 to obtain values for the rate constants.
• File 6 computes the reaction rate constants, using files 7-9 to obtain expressions for adsorption, desorption and Arrhenius reaction.
• The reaction barriers in file 6 are taken from Farsig et al. [1].
• The expressions in files 7-9 are taken from Filot (2018) [2].

File 10 supplies the analytic Jacobian for the tanks-in-series ODEs. This is suggested to improve efficiency of ode23s in the Matlab documentation. However, sufficient stability has been experienced using ode15s which is significantly faster than ode23s for the current cases.

[1] Falsig, H., Hvolbaek, B., Kristensen, I.S., Jiang, T., Bligaard, T., Christensen, C.H. and Norskov, J.K., 2008. Trends in the catalytic CO oxidation activity of nanoparticles. Angewandte Chemie International Edition, 47(26), pp.4835-4839.

[2] Filot, I. A. W., 2018, Introduction to Microkinetic Modeling, Technische Universiteit Eindhoven, Eindhoven.

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Astrid Boje, 17 April 2020.