Thermodynamic studies on LnCoO3(s) (Ln = Dy, Ho) by solid-state electrochemical cells

Ternary oxides, DyCoO3(s) and HoCoO3(s) have been synthesized by citrate–nitrate gel combustion method and characterized by X-ray powder diffraction method. The standard molar Gibbs energies of formation of DyCoO3(s) and HoCoO3(s) have been measured using solid oxide galvanic cell technique employing yttria-stabilized zirconia (YSZ) and calcia-stabilized zirconia (CSZ) as solid electrolyte tubes, respectively. The standard molar Gibbs energies of formation of DyCoO3(s) and HoCoO3(s) were calculated from the measured e.m.f. data and are given as:ΔfGm°(DyCoO3,s,T) kJ mol−1(±4)=−1211.3+0.2449∗(T K), (1013 K≤T≥1167 K),ΔfGm°(HCoO3,s,T) kJ mol−1(±4)=−1237.8+0.2590∗(T K).(964 K≤T≥1102 K),A set of self consistent thermodynamic functions for LnCoO3(s) (Ln = La, Nd, Sm, Eu, Gd, Dy, Ho) has been computed from available experimental data in the literature.