OP-II-3

OP-I-5SPECIFICITY OF THE OSCILLATIONS PERFORMANCE OVER THEFLEXIBLE SURFACES OF THE METAL NANOPARTICLES:MONTE-CARLO APPROACHVladimir Elokhin 1,2 , Konstantin Kalgin 2,3 , Evgenii Kovalyov 1 , Andrei Matveev 1,2 ,Vladimir Gorodetskii 11 Boreskov Institute of Catalysis SB RAS, Novosibirsk, Russia, elokhin@catalysis.ru2 Novosibirsk State University, Novosibirsk, Russia3 Institute of Computational Mathematics and Mathematical Geophysics SB RAS,Novosibirsk, RussiaThe properties of the metal nanoparticles serving often as commercial catalystsdiffer significantly from those of similar systems with large dimensions. Particularlythe shape and the surface morphology of supported nanoparticles are not fixed(flexible) and can appreciably change in the course of reaction. Besides, spillover bydiffusion of reactants between the particle and its support can induce changes incatalytic behavior. The theoretical models aimed at the simulating of catalyticproperties of nanometer scale particles requires the use of atomic-scale computersimulations taking into account the intrinsic heterogeneity of nanoparticles. The mosteffective tool for the simulation of the spatiotemporal dynamics of adsorbed specieson the flexible catalytic surfaces are now the stochastic methods based on theMonte-Carlo technique permitting one to obtain qualitatively new results [1-3].We studied the model of oscillatory dynamics of the CO + O 2 reaction over thesupported Pd nanoparticles by means of Monte-Carlo technique. For that wecombine the kinetic Monte-Carlo (kMC) approach to model the CO + O 2 reaction overthe Pd(110) single crystal [4] and the stochastic model for the imitating the supportednanoparticle with dynamically changing shape and surface morphology [5]. Accordingto [6,7], it is necessary to take into account the contribution of CO ads diffusion overthe support onto the active metal particle surface (reverse spillover) giving theadditional source of CO ads flux to the particle through its perimeter. The amount ofCO ads reaching a nanoparticle is defined through the collection zone, which dependson the mean diffusion length of CO ads on the support and on the density of particles.The following mechanism of the reaction [4] has been used for the simulations1) O 2(gas) + 2∗ → 2O ads ; 4) O ads + ∗ v → [∗O ss ];2) CO gas + ∗ ↔ CO ads ; 5) CO ads + [∗O ss ] → CO 2(gas) + 2∗ + ∗ v ;3) CO ads + O ads → CO 2(gas) + 2∗; 6) CO gas + [∗O ss ] → [CО ads ∗O ss ];7) [CО ads ∗O ss ] → CO 2(gas) + ∗ + ∗ v ,45