Oxygen ion transfer

Figure 6 indicates a change in the charge transfer mechanism at a pH between 9 and 9.5, corresponding to the pH of zero charge of aluminum oxide.33,34 Experimental results on the slopes enabled speculation on the values of transfer coefficients and reaction orders. From that, Valand and Heusler concluded that the most probable mechanism of oxygen ion transfer [reaction (21)] is... 

The practical usefulness of these electrochemical converters is partly a function of their volume power densities. This parameter is composed of the oxygen ion transfer area per unit reactor 2 3... 

In principle, parallel connection doubles the effective oxygen ion transfer surface area when compared with series connection, since the entire geometric electrolyte surface is utilized for oxygen ion transfer. This is a consequence of the geometry of the cross-flow monolith configuration. 

Oxygen Ion Transfer Area per Unit Reactor Volume. As discussed above, the prime attraction of the cross-flow monolith configuration is its potentially high oxygen ion transfer area per unit reactor volume. From our unit cell (Figure 2), this volume-specific area computes as... 

S = Oxygen ion transfer area per unit reactor volume,... 

This paper describes the development and performance of a 16 mol% ceria stabilised zirconia supported palladium-zinc catalyst in vehicle exhaust after treatment. The main aspects of the novel catalytic system are i) the low temperature preparation of a thermally stable solid solution of tetragonal phase ceria stabilised zirconia, ii) the role of zinc in the dispersion of the palladium component and its synergetic interaction with palladium in an oxygen ion transfer mechanism, iii) the in situ perfomance of the catalyst under close-coupled engine conditions in producing... 

Solution Since oxygen ions transfer from the (Ni,NiO) electrode to the... 

The authors have often commented on the thermochemical importance of metallic calcium condensation near the cathode from the bulk, while oxygen ion transfer from the cathode to the anode is also reported in the electrochemical viewpoint of oxidation and reduction [4-6]. However, the ionic transport number and the dominant species for charge carrier are not known well. The purpose of this work is to study the ionic transport behavior of oxygen and calcium in a molten CaO-CaCl2 salt, and to know their contributions to the direct oxide reduction at the cathode. 

The transfer annealing of I , in iodates and periodates, " has been investigated. As much as 80% of the I can be lost as I2. A reaction mechanism has been postulated involving successive electron and oxygen ion transfer. ... 

The mechanism of enolization involves two separate proton transfer steps rather than a one step process m which a proton jumps from carbon to oxygen It is relatively slow m neutral media The rate of enolization is catalyzed by acids as shown by the mechanism m Figure 18 1 In aqueous acid a hydronium ion transfers a proton to the carbonyl oxygen m step 1 and a water molecule acts as a Brpnsted base to remove a proton from the a car bon atom m step 2 The second step is slower than the first The first step involves proton transfer between oxygens and the second is a proton transfer from carbon to oxygen... 

Electrical Conduction by Proton Jumps. As mentioned in Sec. 24, a hydroxyl ion may be regarded as a doubly charged oxygen ion 0 , containing a proton inside the electronic cloud of the ion, which has the same number of electrons as a fluoride ion. The radius of the hydroxyl ion cannot be very different from that of the fluoride ion. But it will be seen from Table 2 that the mobility of the hydroxyl ion is about four times as great. This arises from the fact that a large part of the mobility is undoubtedly due to proton transfers.1 Consider a water molecule in contact with a hydroxyl ion. If a proton jumps from the molecule to the ion,... 

Nickel(IV) complexes react with dimethyl sulphoxide in acidic solution to give the sulphone and nickel(II) ions. The kinetics of this reaction have been studied and found to be very complex in nature. The reaction probably proceeds by initial complexation of the dimethyl sulphoxide to the nickel(IV) species followed by electron transfer and oxygen atom transfer producing the observed products149. 

On the other hand, the electrochemical potentials of electrons, pe, oxygen ions, jIo2, and gaseous oxygen, po2 are related via the charge transfer equilibrium at the three-phase-boundaries (tpb) metal-support-gas38"40 ... 

Within each group relatively simple molecules will be discussed first. In some cases a given substrate may be reduced by modes (i) and (ii) depending on the reductant and in other cases the mechanism is unknown, for example the reduction of perchlorate ion may involve either electron-acceptance or oxygen atom transfer. 

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