Reactive fractal surfaces

Dina Farin, David Avnir*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

112 Scopus citations

Abstract

We extend our finding that the surfaces of most materials are fractal on a molecular scale to chemically reactive surfaces: We report that in many cases the reaction rate, v, between a surface and reactant molecules diffusing to it from the bulk (Eley-Rideal type process) scales with particle radius, R, as v ∝ RDR-3, in which DR, the reaction dimension, is a characteristic parameter of the reaction. It is suggested that, quite often, DR can be interpreted as the fractal dimension of the subset of reactive sites of the surface. The relation between DR and the surface fractal dimension, D, reflects a rich mechanistic phenomenology of this type of reaction, such as the effects of diffusional screening and trapping, of chemical surface site selectivity, and of morphology changes during the reaction. Examples include reactive dissolution of various natural materials, dissolution of drugs, thermal decomposition, and coal gasification. Wenzel's very early law (1777) on surface reactivity is generalized. It is shown that the efficiency of a reaction can be increased by controlling the geometrical parameters of the reacting material.

Original languageEnglish
Pages (from-to)5517-5521
Number of pages5
JournalJournal of Physical Chemistry
Volume91
Issue number22
DOIs
StatePublished - 1987

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