Development of Highly Durable Electrocatalysts Using Porous Ceramic Supports

Abstract

The development of metal oxide supports with porous structure and high electrical conductivity has attracted considerable interest for diverse applications, including polymer electrolyte fuel cells (PEFCs) and water electrolysis. Among these supports, iridium oxide-titanium oxide (Ir–IrO₂/TiO₂) particles stand out due to their unique properties. In this study, we synthesized a porous catalyst support consisting of titanium oxide particles with a low loading of iridium–iridium oxide species (Ir–IrO₂) using a flame aerosol process. We examined the effect of annealing these flame-made Ir–IrO₂/TiO₂ particles to boost their electrical conductivity. Prior to annealing, a spherical morphology with a porous structure, and the Ir–IrO₂ species were amorphous but uniformly covered the TiO₂ surface. After annealing at 750°C, the Ir–IrO₂/TiO₂ particles retained their spherical morphology and porous structure, demonstrating their excellent thermal stability. By increasing the annealing temperature to 750°C, the electrical conductivity of Ir–IrO₂/TiO₂ particles improved significantly, rising from 1.05 S/cm before annealing to 1.85 S/cm, demonstrating the effectiveness of annealing treatment in enhancing conductivity. These findings provide valuable insights into optimizing the performance of catalysts for various applications.