Electrochemical Isoperibolic Calorimetry for D2O Electrolysis

Equations developed for isoperibolic electrochemical calorimetry were tested for the electrolysis of D2O in an open calorimetric cell. The derivatives of these equations gave correct values within the experimental error range for the important rate of change of the cell temperature with time (dT/dt). In addition, these calorimetric equations were also tested directly in determining the enthalpy change (ΔH) for the D2O electrolysis reaction. The mean experimental value at 298.15 K was ΔH = 294.4 ± 0.3 kJ/mole. This compares favorably (within 0.10%) with the literature value of ΔH = 294.600 kJ/mole. The accuracy of these ΔH measurements could be even further improved by more accurate cell voltage and cell temperature measurement.