The role of fluctuations in bistability and oscillations during the H2 + O2 reaction on nanosized rhodium crystals.
A combined experimental and theoretical study is presented of fluctuations observed by field ion microscopy in the catalytic reaction of water production on a rhodium tip. A stochastic approach is developed to provide a comprehensive understanding of the different phenomena observed in the experiment, including burst noise manifesting itself in a bistability regime, noisy oscillations, and nanopatterns with a cross-like oxidized zone separating the surface into four quadrants centered on the {111} facets. The study is based on a stochastic model numerically simulating the processes of adsorption, desorption, reaction, and transport. The surface diffusion of hydrogen is described as a percolation process dominated by large clusters corresponding to the four quadrants. The model reproduces the observed phenomena in the ranges of temperature, pressures, and electric field of the experiment.
Center for Nonlinear Phenomena and Complex Systems (CENOLI), Université libre de Bruxelles (ULB), Campus Plaine Code Postal 231, B-1050 Brussels, Belgium.
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Grosfils
Center for Nonlinear Phenomena and Complex Systems (CENOLI), Université libre de Bruxelles (ULB), Campus Plaine Code Postal 231, B-1050 Brussels, Belgium.
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Gaspard
Center for Nonlinear Phenomena and Complex Systems (CENOLI) and Chemical Physics of Materials-Catalysis and Tribology, Université libre de Bruxelles (ULB), Campus Plaine Code Postal 243, B-1050 Brussels, Belgium.
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Visart de Bocarmé