Regulating the Spin State of FeIII Enhances the Magnetic Effect of the Molecular Catalysis Mechanism

Zemin Sun; Liu Lin; Jinlu He; Dajie Ding; Tongyue Wang; Jie Li; Mingxuan Li; Yicheng Liu; Yayin Li; Mengwei Yuan; Binbin Huang; Huifeng Li; Genban Sun

doi:10.1021/jacs.2c01153

Regulating the Spin State of Fe^III Enhances the Magnetic Effect of the Molecular Catalysis Mechanism

J Am Chem Soc. 2022 May 11;144(18):8204-8213. doi: 10.1021/jacs.2c01153. Epub 2022 Apr 26.

Authors

Zemin Sun^{1

2}, Liu Lin², Jinlu He³, Dajie Ding², Tongyue Wang¹, Jie Li¹, Mingxuan Li¹, Yicheng Liu¹, Yayin Li², Mengwei Yuan², Binbin Huang¹, Huifeng Li², Genban Sun^{1

2}

Affiliations

¹ Center for Advanced Materials Research, Beijing Normal University, Zhuhai 519087, China.
² Beijing Key Laboratory of Energy Conversion and Storage Materials Institution, College of Chemistry, Beijing Normal University, Beijing 100875, China.
³ School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021, China.

PMID: 35471968
DOI: 10.1021/jacs.2c01153

Abstract

Aqueous-phase oxygen evolution reaction (OER) is the bottleneck of water splitting. The formation of the O-O bond involves the generation of paramagnetic oxygen molecules from the diamagnetic hydroxides. The spin configurations might play an important role in aqueous-phase molecular electrocatalysis. However, spintronic electrocatalysis is almost an uncultivated land for the exploration of the oxygen molecular catalysis process. Herein, we present a novel magnetic Fe^III site spin-splitting strategy, wherein the electronic structure and spin states of the Fe^III sites are effectively induced and optimized by the Jahn-Teller effect of Cu²⁺. The theoretical calculations and operando attenuated total reflectance-infrared Fourier transform infrared (ATR FT-IR) reveal the facilitation for the O-O bond formation, which accelerates the production of O₂ from OH^- and improves the OER activity. The Cu₁-Ni₆Fe₂-LDH catalyst exhibits a low overpotential of 210 mV at 10 mA cm^-2 and a low Tafel slope (33.7 mV dec^-1), better than those of the initial Cu₀-Ni₆Fe₂-LDHs (278 mV, 101.6 mV dec^-1). With the Cu²⁺ regulation, we have realized the transformation of NiFe-LDHs from ferrimagnets to ferromagnets and showcase that the OER performance of Cu-NiFe-LDHs significantly increases compared with that of NiFe-LDHs under the effect of a magnetic field for the first time. The magnetic-field-assisted Cu₁-Ni₆Fe₂-LDHs provide an ultralow overpotential of 180 mV at 10 mA cm^-2, which is currently one of the best OER performances. The combination of the magnetic field and spin configuration provides new principles for the development of high-performance catalysts and understandings of the catalytic mechanism from the spintronic level.