Exceptionally active iridium evolved from a pseudo-cubic perovskite for oxygen evolution in acid.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30718514.
- Also identified by DOI 10.1038/s41467-019-08532-3 and PMC identifier 6362036.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Exploring robust catalysts for water oxidation in acidic electrolyte is challenging due to the limited material choice. Iridium (Ir) is the only active element with a high resistance to the acid corrosion during water electrolysis. However, Ir is rare, and its large-scale application could only be possible if the intrinsic activity of Ir could be greatly enhanced. Here, a pseudo-cubic SrCo<sub>0.9</sub>Ir<sub>0.1</sub>O<sub>3-δ</sub> perovskite, containing corner-shared IrO6 octahedrons, is designed. The Ir in the SrCo<sub>0.9</sub>Ir<sub>0.1</sub>O<sub>3-δ</sub> catalyst shows an extremely high intrinsic activity as reflected from its high turnover frequency, which is more than two orders of magnitude higher than that of IrO<sub>2</sub>. During the electrochemical cycling, a surface reconstruction, with Sr and Co leaching, over SrCo<sub>0.9</sub>Ir<sub>0.1</sub>O<sub>3-δ</sub> occurs. Such reconstructed surface region, likely contains a high amount of structural domains with corner-shared and under-coordinated IrO<sub>x</sub> octahedrons, is responsible for the observed high activity.