Tuning on Highly\nDispersed Iridium on Antimony-Doped\nTin Oxide with Strong Metal–Support Interaction for Oxygen\nEvolution Reaction

In the present study, we used a simple and efficient\nmicrowave-assisted\nNaBH<sub>4</sub> reduction method to generate unsupported and antimony-doped\ntin oxide (ATO)-supported metallic iridium nanoparticles (Ir-NPs).\nThe effects of pretreatment on the support and iridium precursor oxidation\nstate in two different salts (IrCl<sub>3</sub>·<i>n</i>H<sub>2</sub>O and (NH<sub>4</sub>)<sub>2</sub>IrCl<sub>6</sub>)\nwere investigated to produce efficient and stable electrocatalysts\nfor oxygen evolution reaction (OER) in acidic electrolysis. Electrocatalysts\nwith an Ir loading of 40 wt % supported on pristine ATO and acid-treated\nATO were synthesized, and the performance was compared with the unsupported,\nsynthesized, and commercial electrocatalysts. The Ir-NPs loaded on\nthe support surface with 98% reaction yield and narrow size distribution,\nwhile without the support, somewhat agglomerated Ir-NPs were generated.\nA strong metal–support electron interaction at the junction\nof the Ir support, promoting the electrocatalyst stability and activity,\nwas achieved for the supported electrocatalysts obtained from both\nprecursors. The best electrocatalyst has demonstrated an excellent\nOER activity of 597 A g<sub>Ir</sub><sup>–1</sup> compared\nto that of 305 A g<sub>Ir</sub><sup>–1</sup> for a commercial\nIrO<sub>2</sub> benchmark and a high potentiodynamic accelerated stress\ntest stability (OER activity retention: 76% compared to 31% for commercial\nIrO<sub>2</sub>). The superior electrochemical performance can be\nattributed to the prereaction strong adsorption of the iridium precursor\non the support surface, resulting in postreaction highly dispersed\nsmall NPs over the support surface generating strong metal–support\ninteraction at the junction of Ir-ATO.AT.