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Formation of FeOOH Nanosheets Induces Substitutional Doping of CeO 2− x with High‐Valence Ni for Efficient Water Oxidation
Author(s) -
Yu Jun,
Wang Jian,
Long Xia,
Chen Lei,
Cao Qi,
Wang Jian,
Qiu Chen,
Lim Jongwoo,
Yang Shihe
Publication year - 2021
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.202002731
Subject(s) - overpotential , materials science , oxygen evolution , catalysis , valence (chemistry) , electrocatalyst , doping , oxide , nickel , transition metal , water splitting , inorganic chemistry , metal , oxygen , chemical engineering , chemistry , metallurgy , electrode , photocatalysis , electrochemistry , biochemistry , optoelectronics , organic chemistry , engineering
Transition metal elements such as Ni in high oxidation states can promote oxygen evolution reaction (OER) activity, but it is difficult to prepare dispersed Ni 3+ or even Ni 4+ species under mild conditions. Herein, a one‐step synthesis of high‐valence nickel‐doped CeO 2− x covered with FeOOH nanosheets in the presence of Ni 2+ /Fe 3+ is reported. A series of ex situ and in situ experiments reveal the etching effect on ceria of the H + species from the hydrolysis of Fe 3+ , which induces substitutional doping of Ni 2+ ions into the etched sites and their further oxidation to the high‐valance Ni 3+ /Ni 4+ by coupling to the Ce 4+ /Ce 3+ pair in the oxygen‐vacancy‐rich CeO 2− x . Concomitantly, Fe 3+ is deposited on the surface of ceria as FeOOH nanosheets. The dispersed high‐valent Ni 3+ /Ni 4+ coupled with the decorated FeOOH nanosheets on CeO 2− x leads to efficient OER electrocatalysis with a low overpotential of 195 mV cm −2 at a current density of 10 mA cm −2 and a high turnover frequency (TOF) of 0.99 s −1 , which, to the best of the authors’ knowledge represents the best Ce‐containing OER catalyst reported to date, and comparable to other top OER catalysts. This work opens an avenue for engineering high‐valence metal ions in an oxide matrix for the OER or other oxidation reactions.