In Situ/Operando Capturing Unusual Ir6+ Facilitating Ultrafast Electrocatalytic Water Oxidation. (3rd August 2021)

• Record Type: Journal Article
• Authors: Li, Lili; Sun, Hainan; Hu, Zhiwei; Zhou, Jing; Huang, Yu‐Cheng; Huang, Haoliang; Song, Sanzhao; Pao, Chih‐Wen; Chang, Yu‐Chung; Komarek, Alexander C.; Lin, Hong‐Ji; Chen, Chien‐Te; Dong, Chung‐Li; Wang, Jian‐Qiang; Zhang, Linjuan
• Is Part Of: Advanced functional materials. Volume 31:Number 43(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-08-03
• Subjects: operando X‐ray absorption spectroscopy -- oxygen evolution reaction -- synergistic effects, ordered multi‐active sites, high‐valence elements; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202104746
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Identifying real active sites and understanding the mechanism of oxygen evolution reaction (OER) are still a big challenge today for developing efficient electrochemical catalysts in renewable energy technologies. Here, using a combined in situ/operando experiments and theory, the catalytic mechanism of the ordered OER active Co and Ir ions in Sr2 CoIrO6− δ is studied, which exhibits an unprecedented low overpotential 210 mV to achieve 10 mA cm –2, ranking the highest performance among perovskite‐based solid‐state catalysts. Operando X‐ray absorption spectroscopies as a function of applied voltage indicates that Ir 4+ ion is gradually converted into extremely high‐valence Ir 5+/6+, while the part of Co 3+ ion is transferred into Co 4+ under OER process. Density functional theory calculations explicitly reveal the order Co‐O‐Ir network as an origin of ultrahigh OER activity. The work opens a promising path to overcome the sluggish kinetics of OER bottleneck for water splitting via proper arrangements of the multi‐active sites in catalyst. Abstract : Operando experimental observation of a gradual oxidation state transition from Ir 4+ to Ir 5+ and further to Ir 6+ and theoretical simulation expatiates the origin of ultrafast electrocatalytic water oxidation of the Sr2 CoIrO6− δ catalyst with Co‐O‐Ir ordered arrangement.