Heat capacity by differential scanning calorimetry and thermodynamic functions of BaCe_0.8Gd_0.1Y_0.1O_2.9 in the temperature range of 166–790 K

In the present study, the heat capacities of barium cerate doped by gadolinium and yttrium oxides were measured for the first time in the temperature range of 166–790 K. The differential scanning calorimeter was used for investigation. There was reproducible anomaly with maximum at 601 K and minimum at 679 K. The experimental results were used to calculate the thermodynamic functions: smoothed heat capacities, enthalpy increment (H_m ^o(T) − H_m ^o(298.15)), and entropy (S_m ^o(T)). The heat capacity in the temperature range of 166–602 K was described by a polynomial of the form: C_p,m ^o(T) = 83.140 + 0.14943 T − 1.1537 × 10⁻⁴T²− 3.6358 × 10⁵/T² (J mol⁻¹ K⁻¹). Heat capacity of BaCe_0.8Y_0.1Gd_0.1O_2.9 in the temperature range of 602–680 K was described by a polynomial: C_p,m ^o(T) = − 118.18 + 0.71961 T − 5.5387 × 10⁻⁴T² + 5.6948 × 10⁺⁶/T² (J mol⁻¹ K⁻¹). The heat capacity in the temperature range of 680–790 K was well described by the equation: C_p,m ^o(T) = 1987.1 − 6.9263 T + 8.3407 × 10⁻³T²− 3.1992 × 10⁻⁶T³ (J mol⁻¹ K⁻¹).