Thermodynamic stability and hydration enthalpy of strontium cerate doped with yttrium

摘要

The standard molar enthalpy of formation of SrY0.05Ce0.95O2.975 has beenderived by combining the enthalpy of solution of this compound in 1 M HCl + 0.1KI obtained by us and auxiliary literature data. The following value has beenderived: DfH (SrY0.05Ce0.95O2.975, s, 298.15 K) = -1720.4 (3.4) kJ/mol. Theobtained value has been used to obtain the formation enthalpy ofSrY0.05Ce0.95O2.975 from the mixture of binary oxides (DoxH (298.15 K) = -45.9(3.4) kJ/mol) and formation enthalpy of reaction of SrY0.05Ce0.95O2.975 withwater forming Sr(OH)2, CeO2, Y2O3 (DrH (298.15 K) = -85.5 (3.4) kJ/mol). Dataobtained by solution calorimetry and additional information on the entropies ofdifferent substances have shown that SrY0.05Ce0.95O2.975 is thermodynamicallystable with respect to a mixture of SrO, Y2O3, CeO2 and that the reaction ofSrY0.05Ce0.95O2.975 with water is thermodynamically favourable.