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Hydration‐Effect‐Promoting Ni–Fe Oxyhydroxide Catalysts for Neutral Water Oxidation
Author(s) -
Wang Ning,
Cao Zhen,
Zheng Xueli,
Zhang Bo,
Kozlov Sergey M.,
Chen Peining,
Zou Chengqin,
Kong Xiangbin,
Wen Yunzhou,
Liu Min,
Zhou Yansong,
Dinh Cao Thang,
Zheng Lirong,
Peng Huisheng,
Zhao Ying,
Cavallo Luigi,
Zhang Xiaodan,
Sargent Edward H.
Publication year - 2020
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201906806
Subject(s) - overpotential , catalysis , oxygen evolution , electrolyte , dissociation (chemistry) , inorganic chemistry , electrocatalyst , adsorption , oxide , materials science , water splitting , metal , electrolysis of water , chemical engineering , electrochemistry , chemistry , electrode , photocatalysis , organic chemistry , engineering , metallurgy , electrolysis
Oxygen evolution reaction (OER) catalysts that function efficiently in pH‐neutral electrolyte are of interest for biohybrid fuel and chemical production. The low concentration of reactant in neutral electrolyte mandates that OER catalysts provide both the water adsorption and dissociation steps. Here it is shown, using density functional theory simulations, that the addition of hydrated metal cations into a Ni–Fe framework contributes water adsorption functionality proximate to the active sites. Hydration‐effect‐promoting (HEP) metal cations such as Mg 2+ and hydration‐effect‐limiting Ba 2+ into Ni–Fe frameworks using a room‐temperature sol–gel process are incorporated. The Ni–Fe–Mg catalysts exhibit an overpotential of 310 mV at 10 mA cm −2 in pH‐neutral electrolytes and thus outperform iridium oxide (IrO 2 ) electrocatalyst by a margin of 40 mV. The catalysts are stable over 900 h of continuous operation. Experimental studies and computational simulations reveal that HEP catalysts favor the molecular adsorption of water and its dissociation in pH‐neutral electrolyte, indicating a strategy to enhance OER catalytic activity.