Calcium metal doping

In addition to the reactions described above which relate to the internal combustion engine emissions questions, the catalysed low temperature oxidative coupling of methane, the water gas shift reaction and many other catalytic reactions are also promoted by ceria [10-12]. A study of dkali and alkaline earth metal doped ceria catalysts has shown that barium or calcium doped ceria were the most active catalyst for the oxidative coupling of CH4 [ 13]. Zhang and Baems explained the observed dependence of selectivity on the Ca content in terms of oxygen-ion conductivity... 

In the vapor phase, acetone vapor is passed over a catalyst bed of magnesium aluminate (206), 2iac oxide—bismuth oxide (207), calcium oxide (208), lithium or 2iac-doped mixed magnesia—alumina (209), calcium on alumina (210), or basic mixed-metal oxide catalysts (211—214). Temperatures ranging... 

The anode material in SOF(7s is a cermet (rnetal/cerarnic composite material) of 30 to 40 percent nickel in zirconia, and the cathode is lanthanum rnanganite doped with calcium oxide or strontium oxide. Both of these materials are porous and mixed ionic/electronic conductors. The bipolar separator typically is doped lanthanum chromite, but a metal can be used in cells operating below 1073 K (1472°F). The bipolar plate materials are dense and electronically conductive. 

Samarium salts are used in optical glass, capacitors, thermoionic generating devices, and in sensitizers of phosphors. The metal is doped with calcium fluoride crystals for use in lasers. It also is used along with other rare earths for carbon-arc lighting. Its alloys are used in permanent magnets. 

Research chemists found that they could modify the conducting properties of solids by doping them, a process commonly used to control the properties of semiconductors (see Section 3.13). In 1986, a record-high Ts of 35 K was observed, surprisingly not for a metal, but for a ceramic material (Section 14.24), a lanthanum-copper oxide doped with barium. Then early in 1987, a new record T, of 93 K was set with yttrium-barium-copper and a series of related oxides. In 1988, two more oxide series of bismuth-strontium-calcium-copper and thallium-barium-calcium-copper exhibited transition temperatures of 110 and 125 K, respectively. These temperatures can be reached by cooling the materials with liquid nitrogen, which costs only about 0.20 per liter. Suddenly, superconducting devices became economically viable. 

Compared to the 6 mol-% La-doped membranes, calcium and gadolinium-doped membranes showed larger pores and more pore growth during SASRA treatment. This indicates that the stabilising effect of the latter metal ions is not of the same quality as that of lanthanum. These findings could be of interest, however, for the preparation of membranes with specific pore-... 

Ceo has also been doped with the alkaline earth metals calcium, strontium, and barium (Group 2)P Two discrete phases have been characterized CasCeo is simple cubic with the same cell parameters as pure Ceo, and BaeCeo is bcc. These compounds are reported to have superconducting transition temperatures (Tc) of 8.4 and 7 K, respectively. ... 

The design of highly selective catalysts for the hydrogenation of dienes and alkynes is an important problem. Among the transition metals palladium is well known as being the most selective of all for the production of mono-olefins. This selectivity can even be improved when doped, as in the so-called commercial Lindlar catalyst which is composed of palladium and lead supported on calcium carbonate. There is still a need for stable and highly selective catalysts, especially at high conversion. 

Samarium is used to dope calcium fluoride crystals for use in optical masers or lasers. Compounds of the metal act as sensitizers for phosphors excited in the infrared the oxide exhibits catalytic properties in the dehydration and dehydrogenation of ethyl alcohol. It is used in infrared absorbing glass and as a neutron absorber in nuclear reactors. The metal is priced at about 3.50/g (99.9%). Little is known of the toxicity of samarium therefore, it should be handled carefully. 

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