Particle edges

We would also like to point out some essential differences in site geometry between particle edges and monoatomic steps, which may be crucial for some catalytic... 

An influence of particle size on the kinetics of COads electro-oxidation has been shown by Maillard and co-workers with FTIR spectroscopy. It has been suggested that the reaction starts on the terraces of large (> 3 nm) particles, and then propagates to the particle edges. Electro-oxidation of COads on small (<2nm) particles commences at more positive potentials, when COads on large particles is oxidized. 

Montmorillonite has some important characteristics that justify its use as a model substance for the study of the interfacial processes of rocks and soils. It is a dioctahedral three-layer clay (2 1 clays, TOT) an A10(0H) octahedral sheet is between two tetrahedral Si04 layers (Chapter 1, Table 1.2). The distance between the layers is not fixed (—O—O-bonds) the layers can be expanded. Because of the layered structure, it has two surface types external and internal surfaces. The external surface is the surface of the particles (edge surface), and its size depends on particle size distribution. Its area can be measured by the BET method, usually by the adsorption of nitrogen gas at the temperature of liquid nitrogen (Chapter 1, Section 1.1.3). The internal surface is the surface between the layers (interlayer surface), and its size can be determined by introducing substances into the interlayer space (e.g., water) (Chapter 1, Section 1.1.3). The internal surface area is independent of particle size distribution. 

Figure 1 shows measured Peak shifts (Peak shift is defined as the distance from the particle edge to the point of maximum Vanadium concentration, expressed as a fraction of the particle radius) for various catalysts vs. fractional distance from the top to the reactor. Qualitatively, the results are in full agreement with the theory that predicts ... 

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