Asymmetric Exchange Interaction Induces Highly Efficient Alkaline Hydrogen Evolution in RhFe Bimetallene

Kun Yan; Tingting Wei; Hengdong Ren; Jianghua Wu; Xiaoqing Pan; Xiaobing Xu; Lizhe Liu; Xinglong Wu

doi:10.1002/smll.202204456

Asymmetric Exchange Interaction Induces Highly Efficient Alkaline Hydrogen Evolution in RhFe Bimetallene

Small. 2022 Oct;18(42):e2204456. doi: 10.1002/smll.202204456. Epub 2022 Sep 18.

Authors

Kun Yan¹, Tingting Wei¹, Hengdong Ren¹, Jianghua Wu², Xiaoqing Pan³, Xiaobing Xu⁴, Lizhe Liu¹, Xinglong Wu¹

Affiliations

¹ National Laboratory of Solid States Microstructures and Key Laboratory of Modern Acoustics, MOE, Institute of Acoustics, Nanjing University, Nanjing, 210093, P. R. China.
² National Laboratory of Solid States Microstructures, College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, P. R. China.
³ Department of Materials Science and Engineering, University of California Irvine, Irvine, CA, 92697, USA.
⁴ College of Electronic Engineering, Nanjing Xiaozhuang University, Nanjing, 211171, P. R. China.

PMID: 36116118
DOI: 10.1002/smll.202204456

Abstract

An RhFe bimetallene with Fe atoms doped into Rh host for efficient hydrogen evolution reaction (HER), is constructed. When two doped Fe atoms occupy neighboring asymmetric spatial positions, their asymmetric exchange interaction drives electron hopping between the d_xy orbital of a Fe atom and the d_z ₂ orbital of its neighboring Fe atom to push the d band center closer to the Fermi level as a result of electronic state reconstruction. The designed bimetallene with thickness of 0.77 nm (5 atomic layers), possesses excellent HER performance. The low overpotentials of 24.4 and 34.6 mV are achieved at the 10 and 100 mA cm^-2 current densities in 1 m KOH solution, respectively. An ultra-low Tafel slope of 8.9 mV dec^-1 shows that this kind of RhFe bimetallene is of an ultrafast kinetic process. This work provides a strategy for designing HER catalysts with double metal composites.

Keywords: RhFe bimetallene; asymmetric exchange interaction; d band center; electron hopping; hydrogen adsorption energy; hydrogen evolution reaction.

Abstract

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