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Iowa State University

2006

Reaction kinetics

Articles 1 - 2 of 2

Full-Text Articles in Physics

Chemical Diffusion Of Co In Mixed Co+O Adlayers And Reaction-Front Propagation In Co Oxidation On Pd(100), Da-Jiang Liu, James W. Evans Aug 2006

Chemical Diffusion Of Co In Mixed Co+O Adlayers And Reaction-Front Propagation In Co Oxidation On Pd(100), Da-Jiang Liu, James W. Evans

Physics and Astronomy Publications

Within the framework of a realistic atomistic lattice-gas model, we present the theoretical formulation and simulation procedures for precise analysis of the chemical diffusion flux of highly mobile CO within a nonuniform interacting mixed CO+O adlayer on a Pd(100) surface. The approach applies in both regimes of relatively immobile unequilibrated and fairly mobile near-equilibrated O adlayer distributions. Spatiotemporal behavior in surface reactions is controlled by chemical diffusion in mixed adlayers. Thus, we naturally integrate the above analysis with a previously developed multiscale modeling strategy to describe mesoscale reaction front propagation in CO oxidation on Pd(100). This treatment ...


Atomistic Lattice-Gas Modeling Of Co Oxidation On Pd(100): Temperature-Programed Spectroscopy And Steady-State Behavior, Da-Jiang Liu, James W. Evans Apr 2006

Atomistic Lattice-Gas Modeling Of Co Oxidation On Pd(100): Temperature-Programed Spectroscopy And Steady-State Behavior, Da-Jiang Liu, James W. Evans

Physics and Astronomy Publications

We have developed an atomistic lattice-gas model for the catalytic oxidation of CO on single-crystal Pd(100) surfaces under ultrahigh vacuum conditions. This model necessarily incorporates an detailed description of adlayer ordering and adsorption-desorption kinetics both for CO on Pd(100), and for oxygen on Pd(100). Relevant energetic parameters are determined by comparing model predictions with experiment, together with some guidance from density functional theory calculations. The latter also facilitates description of the interaction and reaction of adsorbed CO and oxygen. Kinetic Monte Carlo simulations of this reaction model are performed to predict temperature- programed reaction spectra, as well ...