TY - JOUR
T1 - Kinetically Controlled Aggregation in Reactive Adsorbate Overlayers
AU - Becker, Oren M.
AU - Silverberg, Marvin
AU - Ben‐Shaul, Avinoam
PY - 1990
Y1 - 1990
N2 - The kinetics of surface chemical reactions depend critically on the lateral distribution of the adsorbed reactants. In some cases, the adsorbates are aggregated into islands and the rate of reaction is strongly influenced by the structural (sizes and shapes) and energetic (lateral interaction potentials) characteristics of the aggregated overlayer. Adsorbate aggregation or segregation on surfaces may be induced by a variety of mechanisms, three important types of which are briefly discussed here. The first process is driven by strong lateral interactions between the adsorbed particles, which favor their organization in an ordered two‐dimensional phase, but because of kinetic constraints the system only reaches a long‐lived metastable state characterized by finite islands with highly ramified edges. A somewhat more complex aggregation‐segregation process, in a system comprised of two interacting adsorbate species, is also described, and the consequences with respect to surface reaction kinetics are demonstrated. The second aggregation process reflects (Eden‐type) island formation during adsorption of molecules from the gas phase. More specifically, these islands result from the so‐called (extrinsic) precursor‐mediated chemisorption mechanism. Finally, we discuss the segregation of adsorbed reactants induced by the bimolecular annihilation reaction A + B → 0, under steady‐state conditions. Unlike in the first example, this segregation process takes place even in the absence of adsorbate interactions (except for the reactive A‐B interaction) and is most pronounced in the absence of particle diffusion.
AB - The kinetics of surface chemical reactions depend critically on the lateral distribution of the adsorbed reactants. In some cases, the adsorbates are aggregated into islands and the rate of reaction is strongly influenced by the structural (sizes and shapes) and energetic (lateral interaction potentials) characteristics of the aggregated overlayer. Adsorbate aggregation or segregation on surfaces may be induced by a variety of mechanisms, three important types of which are briefly discussed here. The first process is driven by strong lateral interactions between the adsorbed particles, which favor their organization in an ordered two‐dimensional phase, but because of kinetic constraints the system only reaches a long‐lived metastable state characterized by finite islands with highly ramified edges. A somewhat more complex aggregation‐segregation process, in a system comprised of two interacting adsorbate species, is also described, and the consequences with respect to surface reaction kinetics are demonstrated. The second aggregation process reflects (Eden‐type) island formation during adsorption of molecules from the gas phase. More specifically, these islands result from the so‐called (extrinsic) precursor‐mediated chemisorption mechanism. Finally, we discuss the segregation of adsorbed reactants induced by the bimolecular annihilation reaction A + B → 0, under steady‐state conditions. Unlike in the first example, this segregation process takes place even in the absence of adsorbate interactions (except for the reactive A‐B interaction) and is most pronounced in the absence of particle diffusion.
UR - http://www.scopus.com/inward/record.url?scp=85005608061&partnerID=8YFLogxK
U2 - 10.1002/ijch.199000017
DO - 10.1002/ijch.199000017
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AN - SCOPUS:85005608061
SN - 0021-2148
VL - 30
SP - 179
EP - 188
JO - Israel Journal of Chemistry
JF - Israel Journal of Chemistry
IS - 1-2
ER -