How adsorption and reaction influence on the equilibrium shape and surface morphology of the metal nanoparticles.

Evgenii V. Kovalyov Vladimir I. Elokhin 1Aleksandr V. Myshlyavtsev 

1. Boreskov Institute of Catalysis (BIC), pr. akad. Lavrentieva, 5, Novosibirsk 630090, Russian Federation

Abstract

The peculiarities of reaction performance over nanocatalysts dictate the special requirements to the models aimed at the simulating of catalytic properties of nanoparticles [1,2]. The goal of our study is the elaboration of the stochastic model of the supported particle taking into account the change of the shape and surface morphology of the particles under the influence of the reaction media. The analysis has been provided by means of the lattice model based on the Kossel crystal located on the inert support [3]. The morphology of the particle's surface is determined by the heights of the metal atom columns. The change of morphology caused by the diffusion of the surface atoms (the metal atoms attract each other and the atoms of support).

The influence of adsorption on the particles equilibrium shape and surface morphology has been studied. By taking into account of attraction "adsorbate-metal" the reshaping of the initial hemispheric particle into cone-shaped one occurs induced by adsorption, similar to the experimentally observed reversible reshaping of active nanoparticles [4]. The isotherms simulated with taking into account the attraction between atoms of metal and adsorbate differ noticeably from the ideal Langmuir isotherm. The simulation of oscillatory CO oxidation reaction over Pd nanoparticles has been provided. The influence of the particles shape and surface morphology, as well as spillover effects, on the characteristics of oscillations has been studied.

Acknowledgements: The study was partly supported by the NWO grant # 047.015.002

1. V.P. Zhdanov, B. Kasemo, Surf. Sci. Rep. 39 (2000) 25.

2. V.I. Elokhin, A.V. Myshlyavtsev, In: Dekker Encyclopedia of Nanoscience and Nanotechnology. Marsel Dekker, Inc.: New York, 2004; p. 621.

3. E.V. Kovalyov, e.a., Phys. Chem. Chem. Phys. 5 (2003) 784.

4. P.L. Hansen, e.a., Science 295 (2002) 2053.

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Presentation: Oral at E-MRS Fall Meeting 2006, Symposium B, by Vladimir I. Elokhin
See On-line Journal of E-MRS Fall Meeting 2006

Submitted: 2006-06-06 14:09
Revised:   2009-06-07 00:44
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