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Abstract:
In our days the catalytic CO-oxidation using Pd supported catalysts belongs to the most famous examples of synergetics in heterogeneous chemical systems. This reaction obeys periodic behaviour as well as chaos.
For macroscopic structure formation in this system the cooperation of a lot of small catalytic active palladium particles within the catalyst support is essential.
Which of the palladium particles are acting in synchrony depends on their particle sizes. The reason is that the exothermic CO-oxidation will heat up the small nano-meal particles extraordinarily. Although for small amounts of CO in the carrier gas the reaction can be executed isothermally with respect to the whole catalyst bulk. However, the catalytic active palladium particles can be heated up to several hundred degrees Celsius for very short times whereas their surrounding remains almost unaffected.
This very high temperature enables the phase transition from active palladium to catalytic inactive palladium oxide in the presence of oxygen. After fast cooling because of the large temperature gradient between the nano-metal particles and their surrounding the palladium oxide can be reduced by its adsorbed CO via solid state reactions.
The time discrete evolution equation for this system is solved numerically assuming that noise is added to the order parameters of the system.
