Ultralow-Iridium Oxygen Evolution Catalyst with Dual-Site Oxide Pathway for Proton Exchange Membrane Water Electrolysis.
basic_science · Level V
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- Record sourced from PubMed, PMID 41159608.
- Also identified by DOI 10.1021/acs.nanolett.5c04543.
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Abstract
Developing cost-effective low-iridium catalysts for the acidic oxygen evolution reaction (OER) is essential for the advancement of proton exchange membrane (PEM) water electrolyzers. Here, we report a cerium oxide-supported iridium cluster catalyst (Ir@CeO<sub>2</sub>) that features ultrafine Ir clusters dispersed within a CeO<sub>2</sub> matrix, achieving low noble metal loading and favorable activity-stability balance. The Ir@CeO<sub>2</sub> exhibits a small overpotential of 197 mV at 10 mA cm<sup>-2</sup> and a large mass activity of 247 A g<sub>Ir</sub><sup>-1</sup> at 300 mV, surpassing commercial IrO<sub>2</sub> by more than 38 times. The enhanced OER kinetics is attributed to the dual-site oxide pathway mechanism enabled by increased Ir-O covalency and a shortened Ir-Ir distance at chelation interfaces within Ir@CeO<sub>2</sub>. Utilizing the Ir@CeO<sub>2</sub> catalyst in an actual PEM electrolyzer with a minimal Ir loading of 0.3 mg cm<sup>-1</sup> demonstrated durable water electrolysis for over 1000 h at a current density of 1 A cm<sup>-2</sup> under a cell voltage of 1.68 V.