Effect of annealing treatment on nanostructure and electrical conductivity of flame-made Ir-IrO2/TiO2 particles

Iridium-loaded titanium oxide (Ir − IrO₂/TiO₂) particles with unique structures have a potential to become an outstanding highly conductive material for various applications. In this paper, we investigated the effectiveness of annealing treatment of flame-made Ir − IrO₂/TiO₂ particles to enhance its electrical conductivity. Before annealing treatment, the Ir − IrO₂ species was amorphous even though the Ir − IrO₂ species uniformly covered the TiO₂ surface. After annealing treatment at temperature of 750 °C, the phase of IrO₂ changed from amorphous to crystalline phase, and the degree of crystallinity of IrO₂ increased. The electrical conductivity of the Ir − IrO₂/TiO₂ particles increased from 1.05 S.cm⁻¹ to 1.85 S.cm⁻¹ with increasing annealing temperature from before annealing to 750 °C, which demonstrates the improvement of the crystallinity of Ir − IrO₂/TiO₂ particles after annealing treatments.