析氧
无定形固体
氧化态
化学
铱
氧气
化学计量学
电泳剂
光化学
催化作用
氧化物
火用反应
亲核细胞
无机化学
化学物理
结晶学
物理化学
电化学
有机化学
生物化学
电极
作者
Verena Pfeifer,Travis E. Jones,Sabine Wrabetz,Cyriac Massué,Juan‐Jesús Velasco‐Vélez,Rosa Arrigo,Michael Scherzer,Simone Piccinin,Michael Hävecker,Axel Knop‐Gericke,Robert Schlögl
出处
期刊:Chemical Science
[The Royal Society of Chemistry]
日期:2016-01-01
卷期号:7 (11): 6791-6795
被引量:152
摘要
Tremendous effort has been devoted towards elucidating the fundamental reasons for the higher activity of hydrated amorphous IrIII/IV oxyhydroxides (IrO x ) in the oxygen evolution reaction (OER) in comparison with their crystalline counterpart, rutile-type IrO2, by focusing on the metal oxidation state. Here we demonstrate that, through an analogy to photosystem II, the nature of this reactive species is not solely a property of the metal but is intimately tied to the electronic structure of oxygen. We use a combination of synchrotron-based X-ray photoemission and absorption spectroscopies, ab initio calculations, and microcalorimetry to show that holes in the O 2p states in amorphous IrO x give rise to a weakly bound oxygen that is extremely susceptible to nucleophilic attack, reacting stoichiometrically with CO already at room temperature. As such, we expect this species to play the critical role of the electrophilic oxygen involved in O-O bond formation in the electrocatalytic OER on IrO x . We propose that the dynamic nature of the Ir framework in amorphous IrO x imparts the flexibility in Ir oxidation state required for the formation of this active electrophilic oxygen.
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