Jahn-Teller Distortions Induced by in situ Li Migration in λ-MnO2 for Boosting Electrocatalytic Nitrogen Fixation

Zijian Gao; Zhi-Hao Zhao; Haifan Wang; Yiling Bai; Xuehua Zhang; Zeyu Zhang; Hui Mei; Menglei Yuan; Guangjin Zhang

doi:10.1002/anie.202318967

Jahn-Teller Distortions Induced by in situ Li Migration in λ-MnO₂ for Boosting Electrocatalytic Nitrogen Fixation

Angew Chem Int Ed Engl. 2024 Feb 19;63(8):e202318967. doi: 10.1002/anie.202318967. Epub 2024 Jan 18.

Authors

Zijian Gao^{1

2

3}, Zhi-Hao Zhao⁴, Haifan Wang^{2

3}, Yiling Bai^{5

6}, Xuehua Zhang^{3

7}, Zeyu Zhang⁸, Hui Mei⁴, Menglei Yuan⁴, Guangjin Zhang^{2

3

9}

Affiliations

¹ Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, 610041, P. R. China.
² Center of Materials Science and Optoeletronics Engineering, Chinese Academy of Sciences, Beijing, 100049, P. R. China.
³ CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, P. R. China.
⁴ State Key Laboratory of Solidification Processing and School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an, 710072, P. R. China.
⁵ State Key Laboratory of Coal Conversion, CAS Key Laboratory of Carbon Materials, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, 030001, P. R. China.
⁶ National Energy Center for Coal to Liquids, Synfuels China Technology Co. Ltd, Beijing, 101400, P. R. China.
⁷ State Key Laboratory of Petroleum Molecular & Process Engineering(RIPP, SINOPEC), Beijing, 101407, P. R. China.
⁸ Queen Mary University of London Engineering School, Northwestern Polytechnical University, Xi'an, 710129, P. R. China.
⁹ Key Laboratory of Green and High-value Utilization of Salt Lake Resources, Chinese Academy of Sciences, Beijing, 100190, P. R. China.

PMID: 38153676
DOI: 10.1002/anie.202318967

Abstract

Lithium-mediated electrochemical nitrogen reduction reaction (Li-NRR) completely eschews the competitive hydrogen evolution reaction (HER) occurred in aqueous system, whereas the continuous deposition of lithium readily blocks the active sites and further reduces the reaction kinetics. Herein, we propose an innovative in situ Li migration strategy to realize that Li substitutes Mn sites in λ-MnO₂ instead of evolving into the dead Li. Comprehensive characterizations corroborate that the intercalation of Li⁺ at high voltage breaks the structural integrity of MnO₆ octahedron and further triggers unique Jahn-Teller distortions, which promotes the spin state regulation of Mn sites to generate the ameliorative e_g orbital configuration and accelerates N≡N bond cleavage via e_g -σ and e_g -π* interaction. To this end, the resulted cationic disordered LiMnO₄ delivers the recorded highest NH₃ yield rate of 220 μg h^-1 cm^-2 and a Faradaic efficiency (FE) 83.80 % in organic electrolyte.

Keywords: Cationic Disordered LiMn2O4; Electrocatalytic Nitrogen Reduction; Jahn-Teller Distortions; Spin State Regulation; in Situ Li Migration.

Abstract

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