Bridge Bonded Oxygen Ligands between Approximated FeN4 Sites Confer Catalysts with High ORR Performance

Liyuan Gong; Hao Zhang; Ying Wang; Ergui Luo; Kui Li; Liqin Gao; Yuemin Wang; Zhijian Wu; Zhao Jin; Junjie Ge; Zheng Jiang; Changpeng Liu; Wei Xing

doi:10.1002/anie.202004534

Bridge Bonded Oxygen Ligands between Approximated FeN₄ Sites Confer Catalysts with High ORR Performance

Angew Chem Int Ed Engl. 2020 Aug 10;59(33):13923-13928. doi: 10.1002/anie.202004534. Epub 2020 Jun 22.

Authors

Liyuan Gong^{1

2}, Hao Zhang³, Ying Wang⁴, Ergui Luo^{1

2}, Kui Li¹, Liqin Gao¹, Yuemin Wang^{1

2}, Zhijian Wu⁴, Zhao Jin¹, Junjie Ge^{1

2}, Zheng Jiang³, Changpeng Liu^{1

2}, Wei Xing^{1

2}

Affiliations

¹ State Key Laboratory of Electroanalytical Chemistry, Jilin Province Key Laboratory of Low Carbon Chemical Power, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, 130022, P. R. China.
² School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China.
³ Shanghai Synchrotron Radiation Facility, Zhangjiang Lab, Shanghai Advanced Research Institute, Chinese Academy of Science, Shanghai, 201210, P. R. China.
⁴ State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, 130022, P. R. China.

PMID: 32436324
DOI: 10.1002/anie.202004534

Abstract

The applications of the most promising Fe-N-C catalysts are prohibited by their limited intrinsic activities. Manipulating the Fe energy level through anchoring electron-withdrawing ligands is found effective in boosting the catalytic performance. However, such regulation remains elusive as the ligands are only uncontrollably introduced oweing to their energetically unstable nature. Herein, we report a rational manipulation strategy for introducing axial bonded O to the Fe sites, attained through hexa-coordinating Fe with oxygen functional groups in the precursor. Moreover, the O modifier is stabilized by forming the Fe-O-Fe bridge bond, with the approximation of two FeN₄ sites. The energy level modulation thus created confers the sites with an intrinsic activity that is over 10 times higher than that of the normal FeN₄ site. Our finding opens a novel strategy to manage coordination environments at an atomic level for high activity ORR catalysts.

Keywords: O ligands; electronic structure; iron; oxygen reduction; single-atom catalysts.

Abstract

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