Kinetic oscillations in the catalytic CO oxidation on Pt(100): Periodic perturbations

Abstract

Periodic modulations of oxygen pressure or temperature were applied in the catalytic oxidation of CO on a Pt(100) surface under isothermal, low pressure conditions. Transitions from aperiodic autonomous oscillations to regular phase-locked behavior could be observed. Computer simulations using a stochastic cellular automaton model yielded qualitatively similar results. The spatial distribution in both experiment and simulation varies essentially in phase over the whole surface area under the influence of the periodic perturbation, while wave propagation in the autonomous system causes more irregular overall behavior.

Periodic perturbation of the kinetics of heterogeneous catalytic reactions

“…[84] and references therein). In surface science, a good example illustrating this rule was presented by Ertl and co-workers [85] in their study of CO oxidation on the Pt(1 0 0) surface at UHV conditions. In this case, kinetic oscillations are related to the interplay of conventional catalytic steps (1)-(3) (Section 2) and adsorbate-induced surface restructuring.…”

“…To clarify the physics behind the oscillations, Ertl et al [86] used periodic modulation of CO pressure. Later on, Ertl and co-workers [85] studied in detail the effect of sinusoidal modulation of O 2 pressure, P O 2 ¼ hP O 2 i½1 þ A cosðvtÞ, on the reaction kinetics. In particular, the natural and forced oscillations were probed by work function and LEED measurements.…”

Dynamic response of an irreversible catalytic reaction to periodic variation of the reactant’s pressure

“…11,15 Single crystal experiments have been performed for catalytic CO oxidation on Pt͑100͒ and Pt͑110͒. 16,17 Therefore, the aim of this work is to report and discuss Monte Carlo simulation results on the dynamic response of a reaction system ͑namely the oxidation of carbon monoxide͒ to a periodic forcing. In Sec.…”

Pulsed activation in heterogeneous catalysis

“…This improvement is considered trivial and does not give periodic operation an advantage over steady state operation at the highest available temperature C. Therefore the authors concluded that there is no advantage of periodic temperature forcing operation in this regime. In 1987 a study showed that forced oscillations of temperature or pressure can be used to influence the spontaneous oscillations, specifically making them more regular [93]. More recently, several forced temperature studies have been performed in microreactor setups by two separate groups.…”