Heats of Adsorption of Oxygen on Nickel, Platinum and Silver<sup>1</sup>

Gonzalez, O.; Parravano, G.

doi:10.1021/ja01599a007

Cited by 46 publications

(6 citation statements)

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“…Starting from the dissociative chemisorption of oxygen on Au catalysts, research activities reported on the necessity of a thermal activation in order to chemisorb O 2 on Au. 255 Using a static O 2 adsorption measurements in a pressure range of 4-8 mbar, Fukushima et al 256 reported that the amount of O 2 adsorbed on different Au based supports (silica, magnesia and alumina) increases concomitantly with the increase of temperature (from 170 1C to 450 1C). By increasing the temperature, the adsorption becomes reversible at 340 1C where the isobar reaches a maximum.…”

Section: Chemisorption Methodsmentioning

confidence: 99%

Characterisation of gold catalysts

et al. 2016

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Au-based catalysts have established a new important field of catalysis, revealing specific properties in terms of both high activity and selectivity for many reactions. However, the correlation between the morphology and the activity of the catalyst is not always clear although much effort has been addressed to this task. To some extent the problem relates to the complexity of the characterisation techniques that can be applied to Au catalyst and the broad range of ways in which they can be prepared. Indeed, in many reports only a few characterization techniques have been used to investigate the potential nature of the active sites. The aim of this review is to provide a critical description of the techniques that are most commonly used as well as the more advanced characterization techniques available for this task. The techniques that we discuss are (i) transmission electron microscopy methods, (ii) X-ray spectroscopy techniques, (iii) vibrational spectroscopy techniques and (iv) chemisorption methods. The description is coupled with developing an understanding of a number of preparation methods. In the final section the example of the supported AuPd alloy catalyst is discussed to show how the techniques can gain an understanding of an active oxidation catalyst.

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Section: Chemisorption Methodsmentioning

confidence: 99%

Characterisation of gold catalysts

et al. 2016

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“…Oxygen, however, readily adsorbs on Pt with a low activation energy, about 3 kcal/mole (40,41). The initial heat of adsorption for molecular oxygen is about 10-17 kcal/mole (38,42,43), and molecules readily dissociate into oxygen atoms, with a dissociative heat of adsorption of about 53-70 kcal/mole (44)(45)(46).…”

Section: Possible Rate-determining Steps--thermodynamicmentioning

confidence: 99%

Steady‐State D‐C Polarization Characteristics of the O 2, Pt/Stabilized Zirconia Interface

Gür

Raistrick

Huggins

1980

J. Electrochem. Soc.

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alaria parasites, Plasmodia , spend most of their asexual life cycle within red blood cells, where they proliferate and mature. The erythrocyte cytoplasm has very low [Ca 2 ϩ ] ( Ͻ 100 nM), which is very different from the extracellular environment encountered by most eukaryotic cells. The absence of extracellular Ca 2 ϩ is usually incompatible with normal cell functions and survival. In the present work, we have tested the possibility that Plasmodia overcome the limitation posed by the erythrocyte intracellular environment through the maintenance of a high [Ca 2 ϩ ] within the parasitophorous vacuole (PV), the compartment formed during invasion and within which the parasites grow and divide. Thus, Plasmodia were allowed to invade M erythrocytes in the presence of Ca 2 ϩ indicator dyes. This allowed selective loading of the Ca 2 ϩ probes within the PV. The [Ca 2 ϩ ] within this compartment was found to be ‫ف‬ 40 M, i.e., high enough to be compatible with a normal loading of the Plasmodia intracellular Ca 2 ϩ stores, a prerequisite for the use of a Ca 2 ϩ -based signaling mechanism. We also show that reduction of extracellular [Ca 2 ϩ ] results in a slow depletion of the [Ca 2 ϩ ] within the PV. A transient drop of [Ca 2 ϩ ] in the PV for a period as short as 2 h affects the maturation process of the parasites within the erythrocytes, with a major reduction 48 h later in the percentage of schizonts, the form that re-invades the red blood cells. *Abbreviations used in this paper: PV, parasitophorous vacuole; PVM, parasitophorous vacuole membrane; SERCA, sarco-endoplasmic reticulum Ca 2 ϩ ATPase; THG, thapsigargin.

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“…Ag has the capability of adsorbing oxygen-containing species, such as carbon dioxide, 20 phosphates, 21 and silicate, 22 and the oxygen-containing species adsorptions have been found to be much stronger on Ag than on Pt. 23 It is thus speculated that the nine oxygen atomscontaining quaternary phosphonium functional group in the TPQPOH ionomer may be more strongly attracted to the Ag surface than Pt, leading to the tighter and more efficient catalyst-ionomer interface. To verify this assumption, a small model phosphonium molecule, benzyl tris(2,4,6-trimethoxyphenyl) quaternary phosphonium chloride (BTQPCl, Scheme S1, ESI †), was synthesized and added into the supporting electrolyte to investigate its adsorption on both Ag and Pt bulk metal surfaces in ORR RDE tests (Fig.…”

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confidence: 99%