Anode carbon electrolytic cell described

The electrolytic cells used are very similar to the cells used for the production of elemental fluorine [4, 5, 7] cf. Fluorine Suppl. Vol. 2,1980, pp. 4/10. An electrolytic cell suitable for NF3 production on a pilot-plant scale having a capacity of about 25 kg of electrolyte was described by Massonne [5]. The cell and the gas separation skirt were made of Monel the cell cover and the cathode were made of mild steel. The anode was composed of nickel or carbon with an efficient surface of ca. 800 cm. Thus, a current density of 0.15 A/cm was possible at a current of 120 A. On the top of the cell cover there were holes for the release of Hg, the anode gas, inlets for HF, NH3, and Ng, and for the electrodes. The cell was electrically heated and a water-cooling system was attached to remove the heat at high current densities. 

Two parts are treated one is the physical and chemical features of materials of molten carbonate fuel cells (MCFCs), and the other is performance analysis with a 100 cm class single cell. The characteristics of the fuel cell are determined by the electrolyte. The chemical and physical properties of the electrolyte with respect to gas solubility, ionic conductivity, dissolution of cathode material, corrosion, and electrolyte loss in the real cell are introduced. The reactirm characteristics of hydrogen oxidation in molten carbonates and materials for the anode of the MCFC are reviewed. The kinetics of the oxygen reduction reaction in the molten carbonates and state of the art of cathode materials are also described. Based on the reaction kinetics of electrodes, a performance analysis of MCFCs is introduced. The performance analysis has importance with respect to the increase in performance through material development and the extension of cell life by cell development. Conventional as well as relatively new analysis methods are introduced. 

The PAFC works in a similar fashion to the PEM fuel cell described in Chapter 4. The PAFC uses a proton-conducting electrolyte, and the reactions occurring on the anode and cathode are those given in Figure 1.3. In the PAFC, the electrochemical reactions take place on highly dispersed electrocatalyst particles supported on carbon black. As with the PEM fuel cells, platinum (Pt) or Pt alloys are used as the catalyst at both electrodes. The electrolyte is an inorganic acid, concentrated phosphoric acid (100%) which, like the membranes in the PEM cells, will conduct protons. 

I. 4-methoxyacetophenone (30 //moles) was added as an internal standard. The reaction was stopped after 2 hours by partitioning the mixture between methylene chloride and saturated sodium bicarbonate solution. The aqueous layer was twice extracted with methylene chloride and the extracts combined. The products were analyzed by GC after acetylation with excess 1 1 acetic anhydride/pyridine for 24 hours at room temperature. The oxidations of anisyl alcohol, in the presence of veratryl alcohol or 1,4-dimethoxybenzene, were performed as indicated in Table III and IV in 6 ml of phosphate buffer (pH 3.0). Other conditions were the same as for the oxidation of veratryl alcohol described above. TDCSPPFeCl remaining after the reaction was estimated from its Soret band absorption before and after the reaction. For the decolorization of Poly B-411 (IV) by TDCSPPFeCl and mCPBA, 25 //moles of mCPBA were added to 25 ml 0.05% Poly B-411 containing 0.01 //moles TDCSPPFeCl, 25 //moles of manganese sulfate and 1.5 mmoles of lactic acid buffered at pH 4.5. The decolorization of Poly B-411 was followed by the decrease in absorption at 596 nm. For the electrochemical decolorization of Poly B-411 in the presence of veratryl alcohol, a two-compartment cell was used. A glassy carbon plate was used as the anode, a platinum plate as the auxiliary electrode, and a silver wire as the reference electrode. The potential was controlled at 0.900 V. Poly B-411 (50 ml, 0.005%) in pH 3 buffer was added to the anode compartment and pH 3 buffer was added to the cathode compartment to the same level. The decolorization of Poly B-411 was followed by the change in absorbance at 596 nm and the simultaneous oxidation of veratryl alcohol was followed at 310 nm. The same electrochemical apparatus was used for the decolorization of Poly B-411 adsorbed onto filter paper. Tetrabutylammonium perchlorate (TBAP) was used as supporting electrolyte when methylene chloride was the solvent. 

In aluminium reduction cells the carbon anode is placed in the upper part of the bath parallel to the liquid aluminium layer at the bottom, which acts as the cathode. The electrolyte between these electrodes consists of cryolite melt Na3AlF6 and alumina A1203 dissolved in it it may also contain such admixtures as A1F3, CaF2 and others. Dissolving of alumina in the bulk of the cell may be described as follows ... 

The electrochemical intercalation of lithium into 3-ZrNCl was performed by constructing a cell with a pressed 3 ZrNCl cathode and a lithium metal anode in 1 M LiClO solutions in tetrahydrofuran or propylene carbonate. Lithium perchlorate was vacuum-dried at 200 C for 20 h prior to the preparation of the electrolytes. The solvents used were purified by the procedure described in the following paragraph. 

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