Open AccessReversible ternary nickel‐cobalt‐iron catalysts for intermittent water electrolysis
Author(s) -
Lu Xunyu,
Zhang Qingran,
Ng Yun Hau,
Zhao Chuan
Publication year - 2020
Publication title -
ecomat
Language(s) - English
Resource type - Journals
ISSN - 2567-3173
DOI - 10.1002/eom2.12012
Subject(s) - oxygen evolution , overpotential , water splitting , electrocatalyst , hydrogen production , materials science , catalysis , nickel , chemical engineering , electrolysis of water , electrolysis , cobalt , ternary operation , inorganic chemistry , electrode , chemistry , electrolyte , metallurgy , electrochemistry , photocatalysis , computer science , programming language , biochemistry , engineering
Global‐scale application of water splitting technology for hydrogen fuel production and storage of intermittent renewable energy sources such as solar and wind has called for the development of oxygen evolution catalysts and hydrogen evolution catalysts that are inexpensive, efficient, robust, and can withstand frequent power interruptions and shutdowns. Current water electrolyzers must operate with a protective current in stand‐by/idle modes to avoid a substantial catalyst degradation. Here, we show a hierarchically structured porous ternary composite catalyst of nickel, cobalt and iron (NiCoFe) hydroxides prepared via electrodeposition on three‐dimensional (3D) nickel foam (NF) substrates as reversible bifunctional electrodes for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The NiCoFe/NF electrode exhibits exceptionally high catalytic activity, requiring overpotentials as low as 220 and 50 mV, respectively, for OER and HER to occur. In a water electrolysis cell comprising of two NiCoFe/NF electrodes, an overall cell overpotential of merely 300 mV is required to deliver a stabilized current density of 3 mA cm −2 . The ternary electrocatalyst also exhibits prolonged stability under both continuous and intermittent electrolysis and can be used for oxygen evolution and hydrogen evolution reversibly without degradation.