Carbon oxidation activity of complex oxides (Part 2)—Characteristics of La_0.9Ag_0.1FeO_α synthesized at low temperature using co-precipitation method—

Abstract

The perovskite oxide, LaFeO₃, was synthesized by different preparation methods, i.e., the calcination of co-precipitated precursors [La(Ag)–Fe–CO₃ and La–Fe–CO₃] and a mixture of La₂O₃ and Fe₂O₃ (La–Fe–O). By using the solution of Ag, the formation temperature (600°C) of the LaFeO₃ single phase obtained by the calcining of La(Ag)–Fe–CO₃ was about 500°C lower than that of La–Fe–CO₃. The formation temperature of the LaFeO₃ single phase of La–Fe–O was 1100°C as well as that of La–Fe–CO₃. Their carbon oxidations were investigated by DSC (differential scanning calorimetry) measurements. The DSC exothermic peak of La_0.9Ag_0.1FeO_α obtained by the calcining of La(Ag)–Fe–CO₃ at 700°C occurred at 409°C and showed a higher carbon oxidation activity when compared to LaFeO₃ (477 and 562°C) obtained by the calcining of La–Fe–CO₃ and La–Fe–O at 1100°C. The carbon oxidation activation energies observed for the non-catalyzed and catalyzed reactions (mixture of La_0.9Ag_0.1FeO_α) were 160 and 130 kJ·mol⁻¹, respectively.