Hydrolysis synthesis of iridium oxide (IrOx) on carbon for acidic oxygen evolution: Influence of heat-treatment on structure and electrocatalytic activity

Le résumé fourni par la source

The development of efficient and durable oxygen evolution reaction (OER) electrocatalysts is critical for advancing proton exchange membrane water electrolyzers (PEMWEs). This study presents a nanostructured iridium oxide anchored on high-surface-area carbon (IrO x /C) OER electrocatalyst, synthesized through ultrasonication-assisted deposition of hydrolysis-derived colloidal IrO x nanoparticles onto the carbon support. The as-prepared IrO x /C exhibits a mass activity exceeding five times that of unsupported benchmark commercial IrO 2 , attributed to its uniform nanoparticle distribution and enhanced surface chemistry. Post-synthesis heat-treatments at two different temperatures (200 or 300 °C) were employed to stabilize the catalyst structure. Notably, the sample treated at 200 °C retained 84 % of its initial activity after accelerated stress testing, outperforming the commercial counterpart, which retained 67 % under identical conditions. Comprehensive structural and morphological analyses revealed that the heat-treatment increased the IrO x particle size and decreased the Ir³⁺/Ir⁴⁺ ratio while leaving the amorphous nature of IrO x unaffected, which combinedly led to the improved durability. These findings offer valuable insights into designing stable low-iridium OER electrocatalysts for acidic PEMWE applications.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.