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Electron Correlations Engineer Catalytic Activity of Pyrochlore Iridates for Acidic Water Oxidation
Author(s) -
Shang Chunyan,
Cao Cong,
Yu Dayou,
Yan Yu,
Lin Yitao,
Li Hongliang,
Zheng Tingting,
Yan Xupeng,
Yu Wenchao,
Zhou Shiming,
Zeng Jie
Publication year - 2019
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201805104
Subject(s) - pyrochlore , catalysis , ionic radius , ionic bonding , materials science , transition metal , inorganic chemistry , oxygen , metal , chemical physics , ion , chemical engineering , chemistry , organic chemistry , engineering , metallurgy , phase (matter)
The development of highly efficient oxygen‐evolving catalysts compatible with powerful proton‐exchange‐membrane‐based electrolyzers in acid environments is of prime importance for sustainable hydrogen production. In this field, understanding the role of electronic structure of catalysts on catalytic activity is essential but still lacking. Herein, a family of pyrochlore oxides R 2 Ir 2 O 7 (R = rare earth ions) is reported as acidic oxygen‐evolving catalysts with superior‐specific activities. More importantly, it is found that the intrinsic activity of this material significantly increases with the R ionic radius. Electronic structure studies reveal that the increased R ionic radius weakens electron correlations in these iridate oxides. This weakening induces an insulator–metal transition and an enhancement of IrO bond covalency, both of which promote oxygen evolution kinetics. This work demonstrates the importance of engineering the electron correlations to rationalize the catalytic activity toward water oxidation in strongly correlated transition‐metal oxides.