1. Unusual double ligand holes as catalytic active sites in LiNiO2.
- Author
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Huang, Haoliang, Chang, Yu-Chung, Huang, Yu-Cheng, Li, Lili, Komarek, Alexander C., Tjeng, Liu Hao, Orikasa, Yuki, Pao, Chih-Wen, Chan, Ting-Shan, Chen, Jin-Ming, Haw, Shu-Chih, Zhou, Jing, Wang, Yifeng, Lin, Hong-Ji, Chen, Chien-Te, Dong, Chung-Li, Kuo, Chang-Yang, Wang, Jian-Qiang, Hu, Zhiwei, and Zhang, Linjuan
- Subjects
OXYGEN evolution reactions ,TRANSITION metal oxides ,RARE earth oxides ,METALLIC oxides ,METAL catalysts ,TRANSITION metals - Abstract
Designing efficient catalyst for the oxygen evolution reaction (OER) is of importance for energy conversion devices. The anionic redox allows formation of O-O bonds and offers higher OER activity than the conventional metal sites. Here, we successfully prepare LiNiO
2 with a dominant 3d8 L configuration (L is a hole at O 2p) under high oxygen pressure, and achieve a double ligand holes 3d8 L2 under OER since one electron removal occurs at O 2p orbitals for NiIII oxides. LiNiO2 exhibits super-efficient OER activity among LiMO2 , RMO3 (M = transition metal, R = rare earth) and other unary 3d catalysts. Multiple in situ/operando spectroscopies reveal NiIII →NiIV transition together with Li-removal during OER. Our theory indicates that NiIV (3d8 L2 ) leads to direct O-O coupling between lattice oxygen and *O intermediates accelerating the OER activity. These findings highlight a new way to design the lattice oxygen redox with enough ligand holes created in OER process. Lattice-oxygen redox is pivotal for high oxygen evolution reaction (OER) activity. Here, LiNiO2 , a unary 3d-transition metal oxide catalyst, exhibits superefficient activity during the OER due to the creation of double O 2p holes states, according to operando XAS, XRD, and Raman spectroscopy observations. [ABSTRACT FROM AUTHOR]- Published
- 2023
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