Oxidized surfaces, oxygen content

Fe203-Sb204 has been shown to be an excellent catalyst for the allylic oxidation of olefins. The surface oxygen content and the ratio of Fe/Sb are believed to be important for catalysis (Aso et al 1980). The active surface is shown to be an Sb-enriched surface layer, as found in the Sb-Sn oxide systems. 

Oxygen-containing functional groups on the carbon black surface can also be created through specific oxidative aftertreatment. Oxygen content levels of 15% and higher are possible. 

The surface oxygen content also affects the resistivity of the carbon particles. Thus active carbon oxidation, as in other powdered carbon materials, enhances, whereas heat treatment in an oxygen-free atmosphere diminishes electrical resis-... 

An essential feature of these films is that they are prone to oxidation. The surface oxygen content, with a few exceptions, varies between 10 and 20 at%. This surface oxide contamination could be removed completely (to a trace level of 1-2 at % of O) by applying a short (10 min) IkeV Ar+ ion etch. As calculated by the TRIM 95 program [21] the penetration of Ar+ ions into Ni and Ni-C (Ni/C=l 1) alloy is ranging from 1.2 to 2 nm only. On this basis we consider that Ar+ bombardment would not alter significantly neither the bulk composition of the layers, nor the chemical states of the constituent elements. 

Ethilenevinylalcohol (EVAL) is used to prepare hydrophihc symmetric low-flux membranes, usually sterilized by means of gaseous ethylene oxide (EtO) or y-ray irradiation. Details on membrane preparation are not available. Their surface oxygen content has been reported to reduce protein adsorption and activation of the humoral system as compared to RC membranes. 

Upon storage, the amount of ted phosphoms in soHd white or Hquid phosphoms may increase if the material is exposed to light or contains contaminants such as iodine, sulfur, selenium, or sodium that catalyze the conversion from white to ted. Also, because white phosphoms is generally stored under water, some surface oxidation to form viscous white or colored polymeric oxyacids also occurs, especially if the oxygen content of the water can be replenished by exposure to air. 

Od-fumace blacks used by the mbber iadustry contain over 97% elemental carbon. Thermal and acetylene black consist of over 99% carbon. The ultimate analysis of mbber-grade blacks is shown ia Table 2. The elements other than carbon ia furnace black are hydrogen, oxygen, and sulfur, and there are mineral oxides and salts and traces of adsorbed hydrocarbons. The oxygen content is located on the surface of the aggregates as C O complexes. The... 

The nickel supported catalysts formed in this way have some specific features (144)- The catalysts containing about 3% of Ni are paramagnetic. When varying the nickel content from 0.1 to 20%, all the nickel the reduced catalyst (the exposed surface area of nickel was about 600 m2/g Ni) is oxidized by oxygen. The activity in benzene hydrogenation is very high and increases in proportional to the nickel content in the catalyst. 

All boiler system waterside surfaces need the protection given by the smooth, hard, tenaciously adherent magnetite layer. The magnetite film sometimes may sparkle because of the precipitation of fine magnetite crystals onto the metal-oxide surface. Magnetite film formation is best achieved under stable, low-oxygen content operating conditions at a pH level of 10.5 to 11.5 (possibly up to 12.0). 

A typical result for DPV In Fig. 4a shows the presence of two redox couples with peak potentials of 0.25 V and 0.19 V ( lOmV). Similar results have also been obtained with SWV. The relative Intensities of the two peaks vary from sample to sample but are always present with activated electrodes. The similarities between the potentials found for the surface species and for the oxidation of ascorbic acid suggest that an ec catalytic mechanism may be operative. The surface coverage of the o-qulnone Is estimated to be the order of 10 mol cm . It Is currently not possible to control the surface concentration of the o-qulnone-llke species or the oxygen content of the GCE surface. 

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