Catalytic conversion reactions mediated by single-file diffusion in linear nanopores: Hydrodynamic versus stochastic behavior

TitleCatalytic conversion reactions mediated by single-file diffusion in linear nanopores: Hydrodynamic versus stochastic behavior
Publication TypeJournal Article
Year of Publication2011
AuthorsAckerman DM, Wang J, Wendel JH, Liu DJ, Pruski M, Evans JW
Journal TitleJournal of Chemical Physics
Volume134
Pages114107
Date Published02/21
ISBN Number0021-9606
Accession NumberISI:000288597700007
Keywordskinetics, lattice-gas models, noninteracting particles, systems, tracer exchange, ZEOLITES
Abstract

We analyze the spatiotemporal behavior of species concentrations in a diffusion-mediated conversion reaction which occurs at catalytic sites within linear pores of nanometer diameter. Diffusion within the pores is subject to a strict single-file (no passing) constraint. Both transient and steady-state behavior is precisely characterized by kinetic Monte Carlo simulations of a spatially discrete lattice-gas model for this reaction-diffusion process considering various distributions of catalytic sites. Exact hierarchical master equations can also be developed for this model. Their analysis, after application of mean-field type truncation approximations, produces discrete reaction-diffusion type equations (mf-RDE). For slowly varying concentrations, we further develop coarse-grained continuum hydrodynamic reaction-diffusion equations (h-RDE) incorporating a precise treatment of single-file diffusion in this multispecies system. The h-RDE successfully describe nontrivial aspects of transient behavior, in contrast to the mf-RDE, and also correctly capture unreactive steady-state behavior in the pore interior. However, steady-state reactivity, which is localized near the pore ends when those regions are catalytic, is controlled by fluctuations not incorporated into the hydrodynamic treatment. The mf-RDE partly capture these fluctuation effects, but cannot describe scaling behavior of the reactivity. (C) 2011 American Institute of Physics. [doi:10.1063/1.3563638]

URL<Go to ISI>://000288597700007http://scitation.aip.org/getpdf/servlet/GetPDFServlet?filetype=pdf&id=JCPSA6000134000011114107000001&idtype=cvips&doi=10.1063/1.3563638&prog=normal
DOI10.1063/1.3563638
Alternate JournalJ Chem PhysJ Chem Phys