Active Sites of Single-Atom Iron Catalyst for Electrochemical Hydrogen Evolution

Lan Wang; Xiaokang Liu; Linlin Cao; Wei Zhang; Tao Chen; Yue Lin; Huijuan Wang; Yi Wang; Tao Yao

doi:10.1021/acs.jpclett.0c01943

Active Sites of Single-Atom Iron Catalyst for Electrochemical Hydrogen Evolution

J Phys Chem Lett. 2020 Aug 20;11(16):6691-6696. doi: 10.1021/acs.jpclett.0c01943. Epub 2020 Aug 6.

Authors

Lan Wang^{1

2}, Xiaokang Liu¹, Linlin Cao¹, Wei Zhang¹, Tao Chen^{1

2}, Yue Lin³, Huijuan Wang⁴, Yi Wang⁵, Tao Yao¹

Affiliations

¹ National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, P.R. China.
² School of National Defense Science and Technology, Southwest University of Science and Technology, Mianyang 621010, P.R. China.
³ Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, P.R. China.
⁴ Experimental Center of Engineering and Material Science, University of Science and Technology of China, Hefei 230026, P.R. China.
⁵ Department of Engineering and Applied Physics, University of Science and Technology of China, Hefei 230026, P.R. China.

PMID: 32787221
DOI: 10.1021/acs.jpclett.0c01943

Abstract

Electrochemical water splitting in alkaline media is an attractive way to produce the clear and renewable hydrogen fuel H₂. In this work, we report a single-atom Fe₁/NC catalyst, where the Fe-N_x moiety works as the active site, for high-efficiency alkaline hydrogen evolution reaction (HER). The Fe₁/NC electrocatalyst exhibits a low overpotential of 111 mV at the current density of 10 mA cm^-2, with a Tafel slope of 86.1 mV dec^-1 in 1 M KOH solution. Operando X-ray absorption spectroscopy reveals that, under the working states, the Fe-support interaction weakened as the Fe-N coordination number and Fe oxidation state decreased. As such, the evolved single-atom Fe site with more d electrons provides a favorable structure for boosting HER performance. This work gives insight into the structural evolution of the active site under the alkaline HER and provides a strategy for the design of non-noble metal electrocatalysts.