Direct Spectroscopy for Probing the Critical Role of Partial Covalency in Oxygen Reduction Reaction for Cobalt-Manganese Spinel Oxides

Xinghui Long; Pengfei Yu; Nian Zhang; Chun Li; Xuefei Feng; Guoxi Ren; Shun Zheng; Jiamin Fu; Fangyi Cheng; Xiaosong Liu

doi:10.3390/nano9040577

Direct Spectroscopy for Probing the Critical Role of Partial Covalency in Oxygen Reduction Reaction for Cobalt-Manganese Spinel Oxides

Nanomaterials (Basel). 2019 Apr 9;9(4):577. doi: 10.3390/nano9040577.

Authors

Xinghui Long^{1

2

3}, Pengfei Yu^{4

5}, Nian Zhang^{6

7}, Chun Li⁸, Xuefei Feng⁹, Guoxi Ren^{10

11

12}, Shun Zheng^{13

14

15}, Jiamin Fu^{16

17

18}, Fangyi Cheng¹⁹, Xiaosong Liu^{20

21

22}

Affiliations

¹ State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China. xhlong@mail.sim.ac.cn.
² CAS Center for Excellence in Superconducting Electronics (CENSE), Chinese Academy of Sciences, Shanghai 200050, China. xhlong@mail.sim.ac.cn.
³ University of Chinese Academy of Sciences, Beijing 100049, China. xhlong@mail.sim.ac.cn.
⁴ State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China. ypfaq@mail.sim.ac.cn.
⁵ CAS Center for Excellence in Superconducting Electronics (CENSE), Chinese Academy of Sciences, Shanghai 200050, China. ypfaq@mail.sim.ac.cn.
⁶ State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China. zhangn@mail.sim.ac.cn.
⁷ CAS Center for Excellence in Superconducting Electronics (CENSE), Chinese Academy of Sciences, Shanghai 200050, China. zhangn@mail.sim.ac.cn.
⁸ Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) and State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China. kemistlic@foxmail.com.
⁹ Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. xuefeifeng2013@gmail.com.
¹⁰ State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China. gxren@mail.sim.ac.cn.
¹¹ CAS Center for Excellence in Superconducting Electronics (CENSE), Chinese Academy of Sciences, Shanghai 200050, China. gxren@mail.sim.ac.cn.
¹² University of Chinese Academy of Sciences, Beijing 100049, China. gxren@mail.sim.ac.cn.
¹³ State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China. shunzheng@mail.sim.ac.cn.
¹⁴ CAS Center for Excellence in Superconducting Electronics (CENSE), Chinese Academy of Sciences, Shanghai 200050, China. shunzheng@mail.sim.ac.cn.
¹⁵ University of Chinese Academy of Sciences, Beijing 100049, China. shunzheng@mail.sim.ac.cn.
¹⁶ State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China. fujm@shanghaitech.edu.cn.
¹⁷ CAS Center for Excellence in Superconducting Electronics (CENSE), Chinese Academy of Sciences, Shanghai 200050, China. fujm@shanghaitech.edu.cn.
¹⁸ School of Physical Science and Technology, Shanghai Tech University, Shanghai 200031, China. fujm@shanghaitech.edu.cn.
¹⁹ Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) and State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China. fycheng@nankai.edu.cn.
²⁰ State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China. xliu3@mail.sim.ac.cn.
²¹ CAS Center for Excellence in Superconducting Electronics (CENSE), Chinese Academy of Sciences, Shanghai 200050, China. xliu3@mail.sim.ac.cn.
²² School of Physical Science and Technology, Shanghai Tech University, Shanghai 200031, China. xliu3@mail.sim.ac.cn.

Abstract

Nanocrystalline multivalent metal spinels are considered as attractive non-precious oxygen electrocatalysts. Identifying their active sites and understanding their reaction mechanisms are essential to explore novel transition metal (TM) oxides catalysts and further promote their catalytic efficiency. Here we report a systematic investigation, by means of soft X-ray absorption spectroscopy (sXAS), on cubic and tetragonal Co_xMn_3-xO₄ (x = 1, 1.5, 2) spinel oxides as a family of highly active catalysts for the oxygen reduction reaction (ORR). We demonstrate that the ORR activity for oxide catalysts primarily correlates to the partial covalency of between O 2p orbital with Mn⁴⁺ 3d t_2g-down/e_g-up, Mn³⁺ 3d e_g-up and Co³⁺ 3d e_g-up orbitals in octahedron, which is directly revealed by the O K-edge sXAS. Our findings propose the critical influences of the partial covalency between oxygen 2p band and specific metal 3d band on the competition between intermediates displacement of the ORR, and thus highlight the importance of electronic structure in controlling oxide catalytic activity.

Keywords: catalytic activity; oxygen reduction reaction; partial covalency; soft X-ray absorption spectroscopy; spinel oxides.

Grants and funding

21473235, U1632269 and 11227902/National Natural Science Foundation of China