Spatiotemporal patterns during CO oxidation on Pt(100) at elevated pressures

• Published in: AIChE journal Vol. 47; no. 6; pp. 1418 - 1424
• Main Authors: Lele, Tanmay P., Pletcher, Timothy D., Lauterbach, Jochen
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.06.2001; Wiley Subscription Services; American Institute of Chemical Engineers
• Subjects: Catalysis; Catalytic reactions; Chemistry; Conventional optical microscopes; Exact sciences and technology; General and physical chemistry; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Optical instruments, equipment and techniques; Physics; Polarimeters and ellipsometers; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Catalytic reaction; Surface reaction; Transition metal; Experimental study; Reaction rate; Ellipsometry; High pressure; Heterogeneous catalysis; Optical microscopy; Pressure effect; Platinum; Selfoscillation; Oxidation; Carbon monoxide; Kinetics; Platinoid; Mass spectrometry; Oscillating reaction
• ISSN: 0001-1541; 1547-5905
• DOI: 10.1002/aic.690470617

CO oxidation on Pt(100) was investigated at reactant pressures of 8 Pa using ellipsomicroscopy for surface imaging to monitor spatiotemporal pattern formation on the catalyst surface and mass spectroscopy to monitor the integral reaction rate. Three distinct temperature regions showing nonlinear phenomena were found. The first region, at 540–615 K, is characterized by macroscopic, regular reaction‐rate oscillations with spatially uniform, instantaneous transitions between CO and oxygen covered states. Regular, periodic oscillations were not observed on Pt(100) before. The second region, 480–540 K, exhibited continuous dynamic pattern formation with no visible macroscopic kinetic oscillations. Front speeds measured indicated a decrease in oxygen front velocity and an increase in CO front velocity with an increasing CO/O2 partial pressure ratio. The third region, 390–430 K, is characterized by macroscopic rate oscillations, which continued for several oscillation periods and then ceased with the onset of pattern formation.