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Amorphous Cobalt–Iron Hydroxide Nanosheet Electrocatalyst for Efficient Electrochemical and Photo‐Electrochemical Oxygen Evolution
Author(s) -
Liu Wei,
Liu Hu,
Dang Lianna,
Zhang Hongxiu,
Wu Xiaolin,
Yang Bin,
Li Zhongjian,
Zhang Xingwang,
Lei Lecheng,
Jin Song
Publication year - 2017
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201603904
Subject(s) - oxygen evolution , tafel equation , materials science , overpotential , nanosheet , cobalt hydroxide , water splitting , amorphous solid , electrochemistry , electrocatalyst , chemical engineering , cobalt , photocurrent , hydroxide , reversible hydrogen electrode , catalysis , nanotechnology , electrode , working electrode , metallurgy , optoelectronics , chemistry , photocatalysis , crystallography , biochemistry , engineering
Finding efficient electrocatalysts for oxygen evolution reaction (OER) that can be effectively integrated with semiconductors is significantly challenging for solar‐driven photo‐electrochemical (PEC) water splitting. Herein, amorphous cobalt–iron hydroxide (CoFeH) nanosheets are synthesized by facile electrodeposition as an efficient catalyst for both electrochemical and PEC water oxidation. As a result of the high electrochemically active surface area and the amorphous nature, the optimized amorphous CoFeH nanosheets exhibit superior OER catalytic activity in alkaline environment with a small overpotential (280 mV) to achieve significant oxygen evolution ( j = 10 mA cm −2 ) and a low Tafel slope (28 mV dec −1 ). Furthermore, CoFeH nanosheets are simply integrated with BiVO 4 semiconductor to construct CoFeH/BiVO 4 photoanodes that exhibit a significantly enhanced photocurrent density of 2.48 mA cm −2 (at 1.23 V vs reversible hydrogen electrode (RHE)) and a much lower onset potential of 0.23 V (vs RHE) for PEC‐OER. Careful electrochemical and optical studies reveal that the improved OER kinetics and high‐quality interface at the CoFeH/BiVO 4 junction, as well as the excellent optical transparency of CoFeH nanosheets, contribute to the high PEC performance. This study establishes amorphous CoFeH nanosheets as a highly competitive candidate for electrochemical and PEC water oxidation and provides general guidelines for designing efficient PEC systems.