Hydration-Effect-Promoting Ni-Fe Oxyhydroxide Catalysts for Neutral Water Oxidation.

Ning Wang, Zhen Cao, Xueli Zheng, Bo Zhang, Sergey M Kozlov, Peining Chen, Chengqin Zou, Xiangbin Kong, Yunzhou Wen, Min Liu, Yansong Zhou, Cao Thang Dinh, Lirong Zheng, Huisheng Peng, Ying Zhao, Luigi Cavallo, Xiaodan Zhang, E. Sargent

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

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 Mg2+ and hydration-effect-limiting Ba2+ 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 (IrO2 ) 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.
Original languageEnglish (US)
Pages (from-to)1906806
JournalAdvanced materials (Deerfield Beach, Fla.)
DOIs
StatePublished - Jan 16 2020

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