Facile Synthesis of a Ternary Metal Hydroxide with Acid Treatment as an Effective and Durable Electrocatalyst in Water Oxidation

Abstract

Developing low‐cost, effective, and durable oxygen‐evolution catalysts (OECs) is still a huge challenge owing to the uphill thermodynamic reaction and the involvement of a four‐electron and four‐proton kinetics process. Herein, a facilely prepared NiCoFe(OH)x/NiOOH/NF electrode affords current densities of 10 and 100 mA cm−2 at overpotentials of 223 and 254 mV, respectively, and a Tafel slope as low as 33.5 mV dec−1 in 1 m KOH, which is superior to NiCoFe(OH)x/NF electrodes electrodeposited with a traditional method. This electrode also displays surprisingly high durability at a current density of 50 mA cm−2 for over 50 hours under alkaline conditions. Component analysis and an electrochemical study revealed that the catalytic activity enhancement of this newly prepared electrode is mainly attributed to the formation of the electrically conductive NiOOH interlayer.

Construction of Self-Supporting NiCoFe Nanotube Arrays Enabling High-Efficiency Alkaline Oxygen Evolution

“…In Figure b, the calculated value of NiCoFe-NTs is 37 mV dec –1 , obviously lower than that of NiCoFe-s (66 mV dec –1 ), RuO 2 (75 mV dec –1 ), and NF (190 mV dec –1 ), demonstrating the promoted OER kinetics. Noteworthy, NiCoFe-NTs is also comparable to the representative non-noble metal catalysts reported to date ,,− (Figure c and Table S2).…”

Precipitating Metal Nitrate Deposition of Amorphous Metal Oxyhydroxide Electrodes Containing Ni, Fe, and Co for Electrocatalytic Water Oxidation

“…Subsequently, further oxidation occurs under potential scanning or in situ electrocatalytic OER in alkaline medium forming a transition metal oxyhydroxide (MO y (OH) z ). This oxidation process has been commonly used to form an oxyhydroxide phase via electrodeposition. , Anodic deposition applying a positive potential to drive precipitation of an oxyhydroxide on the electrode surface and cyclic voltammetry activation further oxidizes metal hydroxide to metal oxyhydroxide Figure e displays a flake morphology of the catalyst uniformly formed on the entire surface.…”

“…30,46 Anodic deposition applying a positive potential to drive precipitation of an oxyhydroxide on the electrode surface 30 and cyclic voltammetry activation further oxidizes metal hydroxide to metal oxyhydroxide. 46 Conventional transition metal precipitation methods by electrodeposition induce the hydroxide ion (OH − ) by an electrochemical reduction of nitrate 47 or water 27 applying a specific voltage on the electrode, and combine it with a metal cation. Unlike these methods, we use OH − in the electrolyte by immersing the electrode in a basic solution.…”