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Particle size effects for

An apparent particle size effect for the hydrodechlorination of 2-chlorophenol and 2,4-dichlorophenol was observed by Keane et al. [147], Investigating silica supported Ni catalysts (derived from either nickel nitrate or nickel ethane-diamine) with particles in the size range between 1.4 and 16.8 nm, enhanced rates for both reactions were observed with increased size over the full range (Figure 13). As electronic factors can be ruled out in this dimension, the observed behavior is traced back to some sort of ensemble effect, known from CFC transformations over Pd/Al203... [Pg.177]

Kinoshita K. 1990. Particle size effects for oxygen reduction on highly dispersed platinum in acid electrolytes. J Electrochem Soc 137 845-848. [Pg.338]

Kabbabi A, Gloaguen F, Andolfatto F, Durand R. 1994. Particle-size effect for oxygen reduction and methanol oxidation on Pt/C inside a proton-exchange membrane. J Electroanal Chem 373 251-254. [Pg.558]

The results can be understood in terms of the influence of an intrinsic particle size effect (independent of the support) and a support-induced particle size effect. For both reactions and both supported metals, the intrinsic effect manifests itself in a decrease in activity with decreasing particle size below about 3 nm. [Pg.583]

In this context, it should be mentioned that once the Pt surface really starts being oxidized, i.e. when the oxygen coverage becomes noticeable, the methanol oxidation rate goes down as well. This is the origin of a particle-size effect for this reaction [151] when the particle diameter falls below 4 nm, the increased strength of adsorption of 0(H), and by the way, also CO(H) [155], causes the specific MeOH electroxidation activity to decrease with decreasing Pt particle size. [Pg.281]

Fig, 6.7. a Site time yield in the processes described in the figure as a function of radius of the metal cluster involved in the catalytic processes. No particle size effect is observed down to small clusters, b Particle size effect for Pt clusters dispersed on Si02 in the recombination reaction of oxygen and hydrogen, c Particle size effect for Fe clusters dispersed on MgO for the ammonia synthesis at atmospheric pressure and 570° K. d Relationship between catalytic activity, dispersion of the metal cluster on support and bulk metal character of the cluster for metals of the group VIII... [Pg.83]

K. Kinoshita, Particle Size Effects for Oxygen Rednetion on Highly Dispersed Platinum in Acid Electrolytes, J. Electrochem. Soc., 137, 845 (1990). [Pg.38]

Greeley J, Rossmeisl J, Helbnann A, Norskov JK (2007) Theoretical trends in particle size effects for the oxygen reduction reaction. Z Phys Chem 221 1209—1220... [Pg.312]

Particle Size Effect For the moment, let it be assumed that the alkylation reaction is approximately first order in butene concentration. It then follows that the apparent order should also be unity in the presence of diffusional limitations. If it is assumed that our alkylation reactor can be modeled as a plug-flow reactor, then the apparent rate constant for each particle size can be readily estimated using equation 1. [Pg.111]

Tritsaris GA, Greeley J, Rossmeisl J, Norskov JK (2011) Atomic-scale modeling of particle size effects for the oxygtai reduction reaction on Pt. Catal Lett 141 909-913... [Pg.64]

Figure 2.22 illustrates the particle size effects for Au particles of nanometer size supported by Ti02. The catalytic properties of Au are altered in a rmique fashion. Au particles between 2 and 4 nm supported on titania show unique activity for the low temperature oxidation of CO, whereas large particles are non-reactive. [Pg.55]

Figure 9.4. Calculated mass averaged distribution (MAD, Figure 9.4(a)) and calculated surface-averaged distribution (SAD, Figure 9.4(b)) for edge (e) and comer (c) sites, and 100 and 111 crystal planes for cubo-octahedral Pt as a function of the particle size [59]. (Reproduced by permission of ECS—The Electrochemical Society, from Kinoshita K, Particle size effects for oxygen reduction on highly dispersed platinum m acid electrolytes.)... Figure 9.4. Calculated mass averaged distribution (MAD, Figure 9.4(a)) and calculated surface-averaged distribution (SAD, Figure 9.4(b)) for edge (e) and comer (c) sites, and 100 and 111 crystal planes for cubo-octahedral Pt as a function of the particle size [59]. (Reproduced by permission of ECS—The Electrochemical Society, from Kinoshita K, Particle size effects for oxygen reduction on highly dispersed platinum m acid electrolytes.)...
The model of diffusion-controlled grain burning of the ammonium nitrate is still a candidate however, the apparent absence of appreciable particle size effects for Amatex explosives in the studies of Hershkowitz and Rigdon or Craig is hard to reconcile with the diffusion model. Walker showed that ammonium perchlorate in nitromethane... [Pg.69]

Al-Rajhi, M.A., al-Shayeb, S.M., Seaward, M.R.D., and Edwards, H.G.M. 1996. Particle size effect for metal pollution analysis of atmospherically deposited dust. Atmospheric Environment 3Q y. A5- 53. [Pg.488]


See other pages where Particle size effects for is mentioned: [Pg.175]    [Pg.583]    [Pg.18]    [Pg.319]    [Pg.432]    [Pg.52]    [Pg.165]    [Pg.319]    [Pg.403]    [Pg.453]    [Pg.139]    [Pg.312]    [Pg.52]   
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