Guoyu Shi, Hironori Osada, Donald A. Tryk, Helena Valle Casara, Akihiro Iiyama, Makoto Uchida, Mehtap Oezaslan, Katsuyoshi Kakinuma
High Resolution Image Download MS PowerPoint Slide Iridium oxide (IrO x ) catalysts supported on Nb-doped SnO 2 (Nb dopant content of 4 at. %) were prepared with different Ir loadings. The microstructure of IrO x on this support material transforms from dispersed nanoparticles into interconnected nanoparticle networks, accompanied by improved conductivity and reduced work function. These electronic and structural evolutions enhance the oxygen evolution reaction (OER) activity, with both mass and specific activities nearly doubling as the Ir loading increases from less than 10 wt % to over 30 wt %. The results highlight how tuning IrO x morphology and interfacial energetics enable efficient OER catalysis at optimized Ir loadings, offering a pathway toward cost-effective and scalable proton exchange membrane (PEM) water electrolysis.