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A nanoporous metal phosphide catalyst for bifunctional water splitting

Xu, Wence, Zhu, Shengli, Liang, Yanqin, Cui, Zhenduo, Yang, Xianjin, Inoue, Akihisa
Journal of materials chemistry 2018 v.6 no.14 pp. 5574-5579
anodes, catalysts, catalytic activity, cathodes, electrochemistry, electrolysis, hydrogen production, iron, nanopores, nickel, oxygen production, phosphides, potassium hydroxide
The development of high-performance earth-abundant bifunctional electrocatalysts for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is highly desirable, but remains a significant challenge. Herein, a type of content-controllable amorphous Ni–Fe–P catalyst with a bicontinuous nanostructure has been reported to be useful as a bifunctional electrocatalyst for overall water splitting. np-(NiₓFe₁₋ₓ)₄P₅ is prepared simply by an electrochemical dealloying method. Owing to the bicontinuous nanostructure, amorphous atomic arrangement, metallic nature, and the substitution of Ni by Fe, np-(Ni₀.₆₇Fe₀.₃₃)₄P₅ exhibits excellent catalytic performance with the overpotentials of 245 mV and 120 mV at the current density of 10 mA cm⁻² for OER and HER in 1 M KOH, respectively. Furthermore, the np-(Ni₀.₆₇Fe₀.₃₃)₄P₅ catalyst as both an anode and a cathode shows a high current density of 10 mA cm⁻² at a low potential of 1.62 V in a two-electrode water electrolysis system with excellent stability for 20 h.