Molybdenum electrode

Development of molybdenum electrodes in the 1950s permitted the use of electrically assisted melting in regenerative furnaces (81). In the 1990s, approximately one-half of all regenerative tanks ate electrically boosted. Operating practice has shown that effective use of electricity near the back end of the furnace, where the batch is added, can reduce fossil fuel needs. This lowers surface temperature and reduces batch volatilisation. 

There has been much interest in reducing C02 to methanol for use in fuel cells. In one of the earliest reports, when Summers et al. used molybdenum electrodes in C02-saturated acidic solutions (pH 4.2.) at-0.7 to -0.8 V (versus SCE), methanol was formed with faradaic efficiencies approaching 100% [62]. Such efficiencies were observed to increase to 370% when the electrode was cycled at-1.2 to +0.2 V (versus SCE), indicating that the electrode was being corroded and becoming unstable. 

Electric melting furnaces with molybdenum electrodes are unsuitable wherever glass melt interacts with molybdenum electrodes bringing about contamination of... 

Use of molybdenum electrodes for melting lead glasses may be considered in combination with anodic protection (passivation) which prevents separation of lead at the electrodes and suppresses corrosion (Susser et al., 1977). 

SERS (vW=0, vW-O-W) was used to study the effects of adsorption of a-[SiWi204o]4- on silver or molybdenum electrode surfaces.233 The decomposition of H3PWi2O40 in aqueous solution or in aqueous/EtOH or aqueous/ acetone solutions was followed by IR spectroscopy (vWO).234 The hybrid organic/inorganic hybrid system (dmaH2)2[Nd(dmf)4(H20)][ot-BWi204o].H20 was characterised by IR spectroscopy (dma = dimethylamine, dmf = dime-thy lformamide), 23 5... 

Cyclic voltammetric traces obtained with a molybdenum electrode in... 

Fig. 6.4. Threshold voltage as a function of electrode separation for memory material TegiGejsSbjS using molybdenum electrodes. After Buckley (1972).

In this 16X16 array each memory switch is in series with and thus isolated from the next by an integrated silicon p-n junction diode. The memory switches measuring about 30 ]U m in diameter consist of a film of amorphous memory material between two molybdenum electrodes. The x-address lines are seen to run over the round memory switches. The y-address lines are buried in the Si wafer in the form of an n silicon layer. 

Neutralization reactions have been followed by various techniques. A molybdenum electrode was found useful for potentiometric titrations in anhydrous thio-nyl chloride , but the mechanism of the electrode reaction has not been established. Likewise reactions between sulphur trioxide and various bases have been followed by conductometric and potentiometric titrations in solutions of acetyl chloride . Reactions in thionyl chloride can also be followed by the use of various colour indicators, such as methyl orange, methyl red, phenolphthalein, p-nitro-phenol, thymolphthalein or bromine thymolblue, which appear to be indicative of the chloride ion activities of the solutions. 

Table 2 presents the material balance obtained with three different combinations of electrodes material two nickel electrodes, two molybdenum electrodes, and a nickel facing a molybdenum electrode. 

In the LiCl-KCl mixture two associated anodic and cathodic peaks (O3 and R3 in Fig. 3) are obtained at -2.05 and -2.3 V on tungsten or molybdenum electrodes. Two bumps, O2 and R2 in Fig. 3, are visible on the anodic side of the two peaks. At high sweep rate the anodic peak becomes broader and overlaps the second peak. For high concentrations of titanium salt and low sweep rate, the cathodic peak suffers some distortion due probably to a dendritic growth. 

The addition of fluoride ions in chloride melts can stabilize the higher valences of cationic species, and thus, the intermediate step Eq. 9 is not pronounced in the fluoride-chloride melts [8]. Cyclic voltammetry [10] on a molybdenum electrode in LiF-NdF3 melts at 810 °C has proved that reduction of Nd " ions into Nd in a single step this is also confirmed by C. Hamela [11]. It is proved that the electrochemical reductiOTi process is controlled by the diffusirai of neodymium ions in the melts. 

In the AAS method a solution is vaporized in an acetylene-oxygen flame so that the atoms of the unknown element are present in the flame. If, for instance, the intention is to determine the molybdenum concentration, radiation emitted from a cathode ray lamp with a molybdenum electrode is allowed to pass through the flame. 

Gomez, E., Pellicer, E., and Valles, E. (2005) An approach to the first stages of cobalt—nickel—molybdenum electrode-position in sulphate—citrate medium. J. ElectroanaL Chem., 580 (2), 222—230. 

Figure 4.11.1 shows the cyclic voltammograms recorded at various reverse potentials on a molybdenum electrode in the NaCl-KCl-Li2C03 melt. These voltammetric curves have three cathodic waves (/ j, / 2, R ) and four electrooxidation peaks (Ox, OX2, OX2 , Ox ). The height of wave decreases monotonically with increasing polarization rate and almost vanishes at rate of 1.0 V-s . At the potential corresponding to wave we performed potentiostatic electrolysis on the molybdenum electrode to form M02C. 

Figure4.11.1 Cyclic voltammograms on a molybdenum electrode in the NaCI-KCI-Li2COj melt at various reverse potentials. The electrode area is 0.238 cm, the polarization rate is 0.1 V-s T T = 1023 K. Concentration ofLi2COj 2.37 0 mol-cm. The quasi-reference electrode platinum...

N.S. Xu, Y. Tzeng, R.V. Latham, Similarities in the cold electron-emission characteristics of diamond-coated molybdenum electrodes and polished bulk graphite surfaces. J. Phys. D-Appl. Phys. 26(10), 1776-1780 (1993)... 

A tungsten electrode may be used to indicate the hydrogen ion concentration in solution the E-pH curve for tungsten is linear over the pH range 4-9, but may be calibrated for use from pH 2-12. The E-pH curve for a molybdenum electrode, which behaves in a similar manner, is linear in the pH range 3-13. Both electrodes are poisoned reversibly by hydrogen and irreversibly by copper ions. They are reliable only when cleaned regularly. 

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