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OP-I-7NON-STEADY-STATE CATALYST CHARACTERISATION WITHTHIN-ZONE TAP EXPERIMENTSEvgeniy Redekop 1 , Gregory Yablonsky 2 , John T. Gleaves 1 , Xiaolin Zheng 1 ,Denis Constales 31 EECE Dept., Washington University in Saint Louis, MO, er2@cec.wustl.edu2 Parks College, Department of Chemistry, Saint Louis University, MO3 Department of Mathematical Analysis, Ghent University, Gent, BelgiumIntroductionThe non-steady-state kinetic characterization of the heterogeneous catalysts isvery informative for elucidating the structure-activity relationships and measuring thereaction rate, R(t), as a function of gas composition, C(t), which is vital for successfulcatalyst development and improvement of industrial catalytic technologies. TheTemporal Analysis of Products (TAP) reactor system is an advanced instrument forthe kinetic study of the heterogeneous catalysts which bridges the material andpressure gaps between applied kinetics and surface science [1]. In this work wedevelop a kinetically model free framework for non-steady-state TAP data analysisusing Y-Procedure, the algorithm for the reconstruction of R(t) and C(t) from the exitfluxes recorded in a Thin-Zone TAP experiment [2]. The Y-Procedure was applied toexperimental data obtained for carbon monoxide (CO) oxidation catalyzed by silicasupported gold nanoparticles. The characteristic patterns in the rate/concentrationdata obtained in the experiment are compared to the patterns modeled by a simplereversible adsorption on the surface.Thin Zone TAP experiments and Y-ProcedureIn the Thin Zone (TZ) configuration of the TAP reactor the thickness of thecatalytic zone is made small in comparison with the reactor length (Fig. 1) to ensurethat the concentration and temperature gradients within the catalytic material can beneglected for conversions as high as 75 % in a non-steady-state experiment [3].Recently, the Y-Procedure was developed for the reconstruction of the gasconcentrations and the surface reaction rates from the exit flux measured in a TZTAP experiment [2]. Mathematically, the Y-Procedure is based on the Laplacedomain solution of the diffusion equation forthe inert zones in the TZ TAP reactor. Thenumerical algorithm utilizes the equivalent ofthis solution in the Fourier domain. The keyfeature of the Y-Procedure is that the nonsteady-stategas concentrations and thereaction rates are extracted from theexperimental data without any a prioriFigure 1. Thin Zone TAP microreactor. assumptions about the reaction mechanism.49