New correlations to analyze isothermal critical phenomena in heterogeneous catalysis reactions (“Critical simplification”, “hysteresis thermodynamics”)

Yablonskii, G. S.; Lazman, Mark

doi:10.1007/bf02068003

Cited by 11 publications

(9 citation statements)

References 2 publications

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“…The oxidation of CO over noble metal containing demonstrates nonlinear kinetics resulting in observed temperature/concentration hysteresis, steady-state multiplicity and long-lasting self-sustained isothermal oscillations [6][7][8][9][10].…”

Section: Co Oxidationmentioning

confidence: 99%

Glass fiber catalysts for total oxidation of CO and hydrocarbons in waste gases

et al. 1999

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Different glass fibers in woven forms were used as supports for Pt and Pd catalysts and were tested in toluene and CO total oxidation at atmospheric pressure. The catalytic activity and the ignition-extinction temperatures were investigated in relation to chemical composition of the supports, the types of active metal used (Pt, Pd), and the surface concentration of the metal. The experimental results suggest the modified glass fibers as suitable supports for efficient catalysts for complete oxidation. The catalysts can be used at moderate temperatures (150-250 • C) and at high gas hourly space velocity (GHSV = 30 000 h −1 ). The main design parameters of structured catalytic bed reactors, based on glass fiber catalyst, are discussed.

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Section: Co Oxidationmentioning

confidence: 99%

Glass fiber catalysts for total oxidation of CO and hydrocarbons in waste gases

et al. 1999

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Section: Effect Of Catalysts and Reaction Parameters/conditions On Hymentioning

confidence: 99%

“…In a catalytic reactor, inlet temperature, gas pressure, particle size, type and nature, inlet gas composition and reactant concentration affect the performance of a catalyst [126]. Casapu et al investigated Pt particle size distribution on the hysteresis during CO oxidation over Pt/Al2O3 and found that hysteresis is strongly dependent on the particle size of the catalyst.…”

Section: Effect Of Catalysts and Reaction Parameters/conditions On Hymentioning

confidence: 99%

“…Increasing CO concentration in inlet gas causes a higher light-off temperature or ignition point, the hysteresis loop increases upon increasing the CO concentrations [52,56,74,77,87,126,142] Inlet Temperature Ignition and extinction shifted to higher temperatures with rapid increase in CO conversion [77,[128][129][130][131][132][133][134] Surface Contamination and Aging Increase in the hysteresis width due to the removal of contamination that blocks active sites [75,94,141] [55, 94,140] Rate of temperature ramp-up Increase in the temperature ramp-up result in shifting the ignition curve to higher temperatures [72,92] Inhibition parameters Different inhibiting species accumulation on catalyst surface can change the shape of hysteresis curves and increase the width of the hysteresis. [141,142].…”

Section: Parameter Effect On Hysteresis Curve Referencementioning

confidence: 99%

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Critical Review of Low-Temperature CO Oxidation and Hysteresis Phenomenon on Heterogeneous Catalysts

2018

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There is a growing demand for new heterogeneous catalysts for cost-effective catalysis. Currently, the hysteresis phenomenon during low-temperature CO oxidation is an important topic in heterogeneous catalysis. Hysteresis provides important information about fluctuating reaction conditions that affect the regeneration of active sites and indicate the restoration of catalyst activity. Understanding its dynamic behavior, such as hysteresis and self-sustained kinetic oscillations, during CO oxidation, is crucial for the development of cost-effective, stable and long-lasting catalysts. Hysteresis during CO oxidation has a direct influence on many industrial processes and its understanding can be beneficial to a broad range of applications, including long-life CO2 lasers, gas masks, catalytic converters, sensors, indoor air quality, etc. This review considers the most recent reported advancements in the field of hysteresis behavior during CO oxidation which shed light on the origin of this phenomenon and the parameters that influence the type, shape, and width of the conversion of the hysteresis curves.

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confidence: 99%

About Bifurcational Parametric Simplification

Gol’dshtein

Krapivnik

Yablonsky

2015

Math. Model. Nat. Phenom.

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A concept of "critical" simplification was proposed by Yablonsky and Lazman (1996) for the oxidation of carbon monoxide over a platinum catalyst using a Langmuir-Hinshelwood mechanism. The main observation was a simplification of the mechanism at ignition and extinction points. The critical simplification is an example of a much more general phenomenon that we call a bifurcational parametric simplification. Ignition and extinction points are points of steady state multiplicity bifurcations, i.e., they are points of a corresponding bifurcation set for parameters.Any bifurcation produces a dependence between system parameters. This is a mathematical explanation and/or justification of the "parametric simplification". It leads us to a conjecture that "maximal bifurcational parametric simplification" corresponds to the "maximal bifurcation complexity."This conjecture can have practical applications for experimental study, because at points of "maximal bifurcation complexity" the number of independent system parameters is minimal and all other parameters can be evaluated analytically or numerically.We illustrate this method by the case of the simplest possible bifurcation, that is a multiplicity bifurcation of steady state and we apply this analysis to the Langmuir mechanism. Our analytical study is based on a coordinate-free version of the method of invariant manifolds by Bykov, Goldfarb, Gol'dshtein (2006). As a result we obtain a more accurate description of the "critical (parametric) simplifications."With the help of the "bifurcational parametric simplification" kinetic mechanisms and reaction rate parameters may be readily identified from a monoparametric experiment (reaction rate vs. reaction parameter).

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New correlations to analyze isothermal critical phenomena in heterogeneous catalysis reactions (“Critical simplification”, “hysteresis thermodynamics”)

Cited by 11 publications

References 2 publications

Glass fiber catalysts for total oxidation of CO and hydrocarbons in waste gases

Glass fiber catalysts for total oxidation of CO and hydrocarbons in waste gases

Critical Review of Low-Temperature CO Oxidation and Hysteresis Phenomenon on Heterogeneous Catalysts

About Bifurcational Parametric Simplification

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