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Spin Balance Over Janus Ir-Co Magnetic Atoms for Efficient Acidic Water Oxidation
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DOI：10.1007/s40820-026-02082-2.png)
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Abstract
En 中文
Herein, spin regulation of the low-spin Ir4+ in Ca2IrO4 is realized via a novel spin balance strategy through a Janus Ir–Co structure using high-spin Co3+ dopants, achieving the intermediate-spin state of Ir and Co atoms and enhancing the acidic oxygen evolution reaction (OER) performance of the obtained catalysts (Co–CIO). The optimized 0.2Co–CIO catalyst, with a nominal Co/(Co + Ir) metal atom percentage of 20%, displays exceptional electrochemical water oxidation activity with an ultrasmall overpotential of ~ 200 mV at 10 mA cm−2, ultralarge mass activity of 1110 A gIr−1, and high turnover frequency of 2050 h‒1 under an overpotential of 300 mV in 1 M HClO4, outperforming most recently reported Ir–based oxides catalysts. Molecular and atomic characterizations via in situ X-ray absorption near-edge and Raman spectroscopy demonstrate the acceleration of bridged O‒O formation over the Janus Ir–Co units, indicating a preference for the superoxide path mechanism for Co–CIO. Furthermore, density functional theory calculations rationalize the promotion of the superoxide *O‒O intermediate over the spin-regulated Ir‒O‒Co units, thanks to optimized eg1 orbital and reduced t2g orbital occupancy. The study presents a rare example of Ir spin regulation via a Janus Ir–Co magnetic structure, thereby promoting acidic OER activity.
Keywords:
Spin state
Superoxide path mechanism
Intermediate spin state
O K edge adsorption spectroscopy
In situ Raman
Journal
IF:
36.3
Papers:
2.6K
Citations:
3.6W
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