Grigoriy Yablonsky (or Yablonskii) (Russian: Григорий Семенович Яблонский) is a Russian expert in the area of chemical kinetics and chemical engineering, particularly in catalytic technology of complete and selective oxidation, which is one of the main driving forces of sustainable development. His theory of complex steady-state and non-steady-state catalytic reactions is widely used by research teams in many countries of the world (the USA, UK, Belgium, Germany, France, Norway, and Thailand). Yablonsky previously served as an associate research professor of chemistry at Saint Louis University's Parks College of Engineering, Aviation and Technology and college of arts and sciences. Since 2017, he has served as a Senior Researcher and Adjunct Professor at the McKelvey School of Engineering at Washington University in St. Louis, as part of the Department of Energy, Environmental and Chemical Engineering. Since 2006, Yablonsky has also been an editor of the Russian-American Middle West.
Scientific contributions Yablonsky, together with Lazman, developed the general form of steady-state kinetic description (the kinetic polynomial'), which is a non-linear generalization of many theoretical expressions proposed previously (the Langmuir –Hinshelwood and Hougen–Watson equations). Yablonsky also created a theory of precise catalyst characterization for the advanced worldwide experimental technique (temporal analysis of products) developed by John T. Gleaves at Washington University in St. Louis. In 2008–2011, Yablonsky, together with Constales and Marin (Ghent University, Belgium), and Alexander Gorban (University of Leicester, UK), obtained new results on coincidences and intersections in kinetic dependences and found a new type of symmetry relation between the observable and initial kinetic data. Together with Alexander Gorban, Yablonsky developed the theory of chemical thermodynamics and detailed balance in the limit of irreversible reactions. Yablonsky is a world recognized expert in chemical kinetics and chemical engineering, in particular Temporal analysis of products (TAP) studies. He has authored six monographs and more than 300 peer-reviewed papers on these topics. His research spans heterogeneous catalysis, kinetics of complex chemical reactions (see chemical kinetics), mathematical modeling of chemical reactors and technological processes (see chemical reactor), and the history and methodology of science.
Catalytic trigger and catalytic oscillator A simple scheme for the nonlinear kinetic oscillations in heterogeneous catalytic reactions has been proposed by Bykov, Yablonsky, and Kim in 1978. The authors have started with the catalytic trigger (1976), the simplest catalytic reaction without autocatalysis that allows multiplicity of steady states.
Then they have supplemented this classical adsorption mechanism of catalytic oxidation by a "buffer" step
Here, A2, B, and AB are gases (for example, O2, CO, and CO2), Z is the "adsorption place" on the surface of the solid catalyst (for example, Pt), AZ and BZ are the intermediates on the surface (adatoms, adsorbed molecules, or radicals), and (BZ) is an intermediate that does not participate in the main reaction. Let the concentration of the gaseous components be constant. Then the law of mass action gives for this reaction mechanism a system of three ordinary differential equations that describe kinetics on the surface.
where z = 1 − (x + y + s) is the concentration of the free places of adsorption on the surface ("per one adsorption center"), x and y are the concentrations of AZ and BZ, correspondingly (also normalized "per one adsorption center"). and s is the concentration of the buffer component (BZ). This three-dimensional system includes seven parameters. The detailed analysis shows that there are 23 different phase portraits for this system, including oscillations, multiplicity of steady states, and various types of bifurcations.
Reactions without the interaction of different components Let the reaction mechanism consist of reactions.
α r A i r → ∑ j β r j A j , {\displaystyle \alpha _{r}A_{i_{r}}\to \sum _{j}\beta _{rj}A_{j}\,,}
where A i {\displaystyle A_{i}} are symbols of components, r is the number of the elementary reaction and α r , β r j ≥ 0 {\displaystyle \alpha _{r},\beta _{rj}\geq 0} are the stoichiometric coefficients (usually they are integer numbers). (The components that are present in excess and the components with almost constant concentrations are not included.) The Eley–Rideal mechanism of CO oxidation on PT provides a simple example of such a reaction mechanism without interaction of different components on the surface:
… excerpt ends here. Continue reading the full article.
