材料科学
尖晶石
催化作用
铱
氧化物
溶解
析氧
无机化学
物理化学
电化学
化学
冶金
电极
生物化学
作者
Ashwani Kumar,Marcos Gil‐Sepulcre,Jinsun Lee,Viet Q. Bui,Yue Wang,Serena DeBeer,Min Gyu Kim,Serena DeBeer,Harun Tüysüz
标识
DOI:10.1002/adma.202401648
摘要
Abstract Exploring single‐atom‐catalysts for the acidic oxygen evolution reaction (OER) is of paramount importance for cost‐effective hydrogen production via acidic water electrolyzers. However, the limited durability of most single‐atom‐catalysts and Ir/Ru‐based oxides under harsh acidic OER conditions, primarily attributed to excessive lattice oxygen participation resulting in metal‐leaching and structural collapse, hinders their practical application. Herein, an innovative strategy is developed to fabricate short‐range Ir single‐atom‐ensembles (Ir SAE ) stabilized on the surface of Mn‐substituted spinel Co 3 O 4 (Ir SAE ‐CMO), which exhibits excellent mass activity and significantly improved durability (degradation‐rate: ≈2 mV h −1 ), outperforming benchmark IrO 2 (≈44 mV h −1 ) and conventional Ir single‐atoms on pristine‐Co 3 O 4 for acidic OER. First‐principle calculations reveal that Mn‐substitution in the octahedral sites of Co 3 O 4 substantially reduces the migration energy barrier for Ir single‐atoms on the CMO surface compared to pristine‐Co 3 O 4 , facilitating the migration of Ir single‐atoms to form strongly correlated Ir SAE during pyrolysis. Extensive ex situ characterization, operando X‐ray absorption and Raman spectroscopies, pH‐dependence activity tests, and theoretical calculations indicate that the rigid Ir SAE with appropriate Ir–Ir distance stabilized on the CMO surface effectively suppresses lattice oxygen participation while promoting direct O─O radical coupling, thereby mitigating Ir‐dissolution and structural collapse, boosting the stability in an acidic environment.
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