Tailoring hypervalent Nickel induced by oxygen vacancy toward enhanced oxygen evolution reaction performance in self-supporting NiFe-(oxy)hydroxides electrodes

Chun Kong; Chuang Zhi; Zirui Wu; Wenqiang Yang; Juan Yang; Zhongti Sun

doi:10.1016/j.jcis.2024.03.184

Tailoring hypervalent Nickel induced by oxygen vacancy toward enhanced oxygen evolution reaction performance in self-supporting NiFe-(oxy)hydroxides electrodes

J Colloid Interface Sci. 2024 Jul:665:863-870. doi: 10.1016/j.jcis.2024.03.184. Epub 2024 Mar 29.

Authors

Chun Kong¹, Chuang Zhi¹, Zirui Wu¹, Wenqiang Yang², Juan Yang¹, Zhongti Sun³

Affiliations

¹ School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China.
² Chemical Engineering, University of South Carolina, 301 S. Main Street, Columbia, SC 29208, USA.
³ School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China. Electronic address: ztsun@ujs.edu.cn.

PMID: 38564950
DOI: 10.1016/j.jcis.2024.03.184

Abstract

NiFe-(oxy)hydroxides are the most active transition metal oxide electrocatalysts for oxygen evolution reaction (OER) under the alkaline media. Herein, we controllably manipulated oxygen vacancy (V_O)-tunable NiFe-(oxy) hydroxides that their OER performances possessed a volcano-type relationship with V_O concentration, positively-correlated with Ni³⁺/Ni²⁺ ratio. Theoretical simulations further unearthed the enhanced activation and dissociation of H₂O by the inserting of V_O. As a result, the optimal sample featuring the Ni³⁺/Ni²⁺ ratio of 30.3 % and V_O of 23.8 % exhibited the overpotential of 243 mV at the current density of 100 mA cm^-2, simultaneously lasting 120 h durability without any attenuation, exceding the most reported NiFe-(oxy)hydroxides. This work offers an innovative view to understand the OER performance using hypervalent Ni ratio induced by V_O defects.

Keywords: Hypervalent Ni; NiFe-(oxy)hydroxides; Oxygen evolution reaction; Oxygen vacancy; Volcano-type relationship.