Solid solutions of oxides

Metal Oxide Photoelectrodes for Hydrogen Generation Using Solar Radiation Driven Water Splitting Topics reviewed include preparation of oxide electrodes, sensitization of wide band gap oxides, tandem cells, solid solutions of oxides and por-ous/nano-crystalline materials. 80... 

It is also worthwhile mentioning that Barbier et al. have prepared and characterized rutheniun-tin mixed oxide catalysts used in electro-oxidation of phenol. XRD of the calcined catalysts revealed the presence of RUO2, Sn02 and some trace amount of metallic ruthenium. However, there was no evidence of the formation of solid solutions of oxides. ... 

Upon heating in air at 500°, the coprecipitated gels gave products containing solid solutions of -oxides and y-oxides. The y-oxide pattern was observed in catalysts containing up to 45 mole % CrgOg and it was concluded that, up to about 14 wt % CrgOg, the y-oxide composition was the same as the over-all sample composition. Above this point, the y-oxide phase was alumina-rich. 

This holds for dilute alloys and dilute solid solution of oxides. 

Shc] Shchepetkin, A.A., Chufarov, G.I., Dissociation of Solid Solutions of Oxides in M-Fe-O Systems under Equilibrium Conditions , Russ. J. Inorg. Chem. (Engl Transl), 17(6), 792-794 (1972) (Experimental, Phase Relations, 14)... 

All authors agree on the fact, that other structures then those of the initial and of the oxidized polymer are not observed. In other words, intermediates as expected, if the intercalation was to proceed homogeneously to form a solid solution of oxidized segments in the lattice of the initial polymer, have never been observed. The only exception are recent reports by R. H. Baughman who reports the occurence of new diffraction peaks in iodinated samples annealed for a very long time... 

The solid solution of oxides of rare earth elements in the natural mineral loparite has the following composition Ce - 50 Avt. %, La - 25 wt. %, Nb - 12 wt. %, Pr - 6 wt. %, the rest - Sm, Eu, Gd. The content of elements in synthesized powders may differ from the original due to the use of various amounts of precipitators or to lanthanide binding in the fluorine-containing compoimds. 

We now study the oxidation of a single-phase alloy A/B when the formed product is a solid solution of oxide of the B element in A oxide, that is, the two formed oxides are miscible with each other. We will confine ourselves to the case of a pure diffusion mode in the oxide layer. The problem can be divided into two parts ... 

We now study the oxidation of a second alloy of M with a second metal A. The atomic fraction of M remains Xm- Oxidation nnder the same conditions as earlier led, according to a parabolic law, to the formation of a solid solution of oxide of metal A A2O3 in metal oxide MO. We keep the same assumption of the same parabolic mode as that of the above and assume that the concentration ratio of metal M to metal A is the same in oxide as in alloy. 

Lead Chromates and Molybdates. The lead chromates appear in several shades of yellow. The primrose and lemon are solid solutions of lead sulfate in the chromate and have the stable monoclinic stmcture. The medium shade contains no sulfate. Chrome orange is a compound with lead oxide (PbCrO TbO). Molybdate orange is a combination of lead chromate and sulfate with molybdate (PbMoO ). These pigments have the advantages of... 

The equation for the rate of oxidation of the transition metals at high temperatures, which form a solid solution of oxygen before the oxide appears at the surface has die same form as that derived for die carburizing of die metal, and... 

Evaluating the results a clear kinetic picture of the catalysts has been obtained. In the steady state the active sites in Fe- and Cu-ZSM-5 are nearly fully oxidized, while for Co only -50% of the sites are oxidized. The former catalysts oporate in an oxidation reduction cycle, Fe /Fe and CuVCu. Coi in zeolites is hardly oxidized or reduced, but ESR studies on diluted solid solutions of Co in MgO indicate that Co -0 formation is possible, rapidly followed by a migration of the deposited oxygen to lattice oxygen and reduction back to Co [36]. For Fe-ZSM-5 such a migration has been observed, so a similar model can be proposed for the zeolitic systems. Furthermore, it is obvious that application of these catalysts strongly depends on the composition of the gas that has to be treated. 

Magnesium oxide is always blended with the zinc oxide prior to ignition. Magnesium oxide promotes densification of the zinc oxide, preserves its whiteness and renders the sintered powder easier to pulverize (Crowell, 1929). The sintered mixed oxide has been shown to contain zinc oxide and a solid solution of zinc oxide in magnesium oxide (Zhuravlev, Volfson Sheveleva, 1950). Specific surface area is reduced compared with that of pure zinc oxide and cements prepared from the mixed oxides are stronger (Crowell, 1929 Zhuravlev, Volfson Sheveleva, 1950). 

The layer of titanium and ruthenium oxides usually is applied to a titanium substrate pyrolytically, by thermal decomposition (at a temperature of about 450°C) of an aqueous or alcoholic solution of the chlorides or of complex compounds of titanium and rathenium. The optimum layer composition corresponds to 25 to 30 atom % of ruthenium. The layer contains some quantity of chlorine its composition can be written as Ruq 2sTio 750(2- c)Cl r At this deposition temperature and Ru-Ti ratio, the layer is a poorly ordered solid solution of the dioxides of ruthenium and titanium. Chlorine is completely eliminated from the layer when this is formed at higher temperatures (up to 800°C), and the solid solution decomposes into two independent phases of titanium dioxide and ruthenium dioxide no longer exhibiting the unique catalytic properties. 

The XRD analyses revealed presence of AEO and Nd203, SrC03 (about 62 wt%) in SrNd-SG sample, CaC03 and Ca(OH)2 (about 5 wt%) in CaNd-SG. Solid solutions of Nd in AEO and of AEE in Nd203 were observed in all samples. The calculation of lattice constants and unit cell volumes (UCV) showed modification of the oxide lattice by foreign cations. The formation of solid solutions obviously depended of the relative ionic radii of the elements equal to 0.0995 nm for Nd3+, 0.072 for Mg2+, 0.1 for Ca2+,... 

For a number of reasons the TiS2 battery was not widely exploited commercially, but similar batteries based upon intercalation into transition-metal oxides LiJCTO2, where T is a 3d transition metal such as Ni, Co, or Mn (or a solid solution of these metals, LiJt.T1 yTj,02) are widely available. The first of these, the Sony cell, introduced in 1991, employs LixCo02 as the cathode and the intercalation of Li into graphite as the anode, to form LivC6. 

The oxide film formed in dry air at room temperature consists of a spinel phase, probably a solid solution of magnetite and maghemite. Such films form on magnetic tapes. They are around 1.5-2.0 nm thick, and in a dry atmosphere, can provide indefinite protection (e.g. the Delhi pillar). Ali and Wood (1969) found that with time and at a relative humidity of 46%, some hematite developed as well. At higher temperatures (200-300 °C) well defined duplex films with an inner layer of magnetite... 

Foster, P.K. Welch, A.J.F. (1956) Metal-oxide solid solutions. Part 1. Lattice constant and phase relationships in ferrous oxide (wiistite) and in solid solutions of ferrous oxide and manganous oxide. Trans. Faraday Soc. 52 1626-1635... 

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