Gibbs energy zirconia electrolyte

Figure 6.15 Schematic cell using a stabilized zirconia electrolyte to measure the Gibbs energy of formation of an oxide MO. The cell voltage, E, is measured under open-circuit conditions when no current flows.

The standard Gibbs energy of formation of NiO has been experimentally determined over the temperature range from 900 to 1400 K using a galvanic cell with the solid electrolyte made of 15% calcia-stabilised zirconia. The measured value of AfG (NiO) at 1300 K was - 123.555 kJmol with a precision of+0.057 kJ-mof and an estimated accuracy not worse than 0.200 kJ-mol. This precision is equivalent to an error of only 0.2 - 0.3 mV in the cell potential (emf). In comparison, most previous studies have reported a precision of 1 - 2 mV. Using the third law analysis, the authors obtained for the enthalpy of formation of NiO, Af//° (NiO, 298.15 K) = - 240.110 kJ-mol. ... 

Thermodynamic data of high accuracy and reliability for the Ni - NiO system at high temperatures were obtained from electrochemical cells with yttria- or calcia-stabilised zirconia electrolytes. The experimental results are in excellent agreement with available calorimetric data as well as emf measurements of previous publications. The recommended Gibbs energy equation for the reaction ... 

With the advent of solid electrolytes, such as the stabilized forms of zirconia, the field of solid-state electrochemistry has grown. Galvanic cells utilizing this material as an electrolyte for anionic (0 ) conduction have been used in conjunction with the Nernst equation to measure within various ceramic systems (1) the Gibbs free energy of formation, (2) the activity of, and (3) the kinetics of solid-state reactions. Electrolytic cells can be used to drive reactions in the non-equilibrium direction by the application of an electrical current. The reader is again referred to Schmalzried. ... 

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