An Up-Scalable Solid-State Approach to Synthesize Iridium Nanoparticles on ATO for Water Splitting
Ebrahim Sadeghi, Per Morgen, Darko Makovec, Sašo Gyergyek, Raghunandan Sharma, Shuang Ma Andersen
Abstract
Proton exchange membrane water electrolysis (PEMWE) technology commercialization strongly relies on developing efficient and cost-effective anode catalysts. One key challenge is the high cost associated with IrO 2, which can be mitigated by reducing iridium (Ir) loading. A promising approach to achieving this is using a conductive support material to anchor Ir/IrO 2 . In this study, we explored depositing metallic Ir on antimony-doped tin oxide (ATO) using a solid-state method. This approach is straightforward and time-efficient. Among four samples with 50 wt % Ir loading, one prepared with NaOH in 100% ethanol (Ir/ATO-NE) exhibited the highest specific oxygen evolution reaction (OER) performance. The Ir/ATO-NE catalyst achieved 340 A g Ir –1 at 1.6 V (versus RHE), surpassing a commercial IrO 2 catalyst, which showed 282 A g Ir –1 . Additionally, Ir/ATO-NE demonstrated the lowest Tafel slope, indicating enhanced oxygen evolution kinetics and long-term durability comparable to commercial catalysts. Electron microscopy revealed uniform Ir nanoparticle (NP) sizes and a complete layer of Ir NPs on the support, in contrast to other samples. This study introduces a synthesis protocol for Ir catalysts that is efficient, simple, and effective for oxygen evolution in acidic media.