The thermodynamic stability and hydration enthalpy of strontium cerate doped by yttrium

TL;DR

This study determines the thermodynamic stability and hydration enthalpy of yttrium-doped strontium cerate, revealing its stability and favorable reaction with water through calorimetric measurements and enthalpy calculations.

Contribution

It provides the first comprehensive thermodynamic data for SrY0.05Ce0.95O2.975, including formation and hydration enthalpies, using solution calorimetry and literature data.

Findings

SrY0.05Ce0.95O2.975 is thermodynamically stable against decomposition.

The hydration reaction of SrY0.05Ce0.95O2.975 with water is thermodynamically favorable.

The derived enthalpy of formation is -1720.4 kJ/mol.

Abstract

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