Microwave-assisted combustion synthesis of nanocrystalline Sm-doped La2Mo2O9 oxide-ion conductors for SOFC application

• Highly sinter-active La2−xSmxMo2O9 nanopowders were synthesis by combustion method.
• They were characterized by XRD, TEM and DSC analysis.
• They were capable of stabilizing the cubic β-phase at room temperature.
• La1.7Sm0.3Mo2O9 sample exhibited a high conductivity of 0.196 S cm−1 at 750 °C.

The synthesis of nanocrystalline La2−xSmxMo2O9 (0 ≤ x ≤ 0.6) oxide-ion conductors by a microwave assisted-combustion method using aspartic acid as a combustion fuel is presented. A single-phase Sm-doped La2Mo2O9 nanopowders (∼25 nm) were produced within 45 min. The Sm-doping (x ≥ 0.2) effectively suppressed the α → β phase transition of pure La2Mo2O9 and maintained the high temperature cubic phase at room temperature. The synthesized nanocrystalline Sm-doped samples had good sinterabilty and relatively a low sintering temperature of 800 °C for 5 h was sufficient to reach ∼98% of its theoretical density. Sm-doping effectively improved the oxide ion conductivity of La2Mo2O9 and the maximum oxide-ion conductivity of 0.196 S cm−1 was attained at 750 °C for of La1.7Sm0.3Mo2O9.

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