Modeling dynamic CO oxidation over Pt/Al2O3: Effects of intrapellet diffusion and site heterogeneity

Measurement of Gas Composition at the Center of a Porous Pellet during Adsorption and Catalytic Reaction under Dynamic Conditions

“…This is a sample of one of the catalyst materials ("chloride sample") whose preparation and characterization were described in Refs. (1,2). The bulk CO signal in Fig.…”

“…In previous work, we measured CO oxidation over a single pellet under steady-state and dynamic conditions (1) and performed numerical simulations of reaction and diffusion in the pellet using a detailed kinetic model (2). CO oxidation is important in emission control and is a model reaction whose behavior exhibits many important characteristics of surface reactions: competitive adsorption, adsorbate-adsorbate interactions, adsorbate islands, surface reconstruction, subsurface oxygen incorporation, structure sensitivity of some steps, nonlinear kinetics, and spatio-temporal pattern formation (3)(4)(5)(6)(7)(8)(9).…”

Scaling Parameters for Dynamic Diffusion-Reaction over Porous Catalysts

“…6 We developed microkinetic di↵usion-reaction models, which we fit to time-resolved experimental measurements of CO oxidation. [7][8][9][10] Peter Silveston would sometimes visit the Michigan Catalysis Society from nearby Waterloo University in Ontario, Canada. Peter later edited the book Composition Modulation of Catalytic Reactors.…”

“…13,[15][16][17][18] 2 Models with equations that describe dynamic di↵usion and reaction in porous catalysts during composition forcing have been developed for specific reactions to explain experimental measurements. Many of these works have studied CO oxidation [6][7][8][9][10]19 or three-way automotive catalytic reactions 20 with rather complex models.…”

A quantitative analysis of transient kinetic experiments: The oxidation of CO by O2 over Pt

“…At high temperatures CO islands are not present any more on the Pt surface, due to a higher CO surface diffusion. Wicke et al [11] described a simple molecular level approach to show how islands may arise on a surface, which can be used in Monte Carlo simulations to predict the formation of both carbon monoxide and oxygen islands under both steady-state and transient conditions [12,13]. Zhou et al [14] suggested that CO2 can be formed on Pd via two pathways, involving either CO adsorption on sites adjacent to oxygen or diffusion of adsorbed CO over the surface to an oxygen island.…”