In Situ Electrochemical Activation of a Codoped Heterogeneous System as a Highly Efficient Catalyst for the Oxygen Evolution Reaction in Alkaline Water Electrolysis

Abstract

Highly active electrocatalysts for the oxygen evolution reaction (OER) hold a key to water splitting, particularly in the development of cost-effective and highly efficient oxygen evolution electrodes (OEEs) with prolonged stability to meet industrial requirements, where the reliable withstanding of large current densities (≥500 mA cm-2) is highly desired. This report shows how a hybrid NF@CGO with a catalytic layer codoped by nickel crystals, cobalt tetroxide (Co3O4), graphene oxide (GO), and in-situ-generated Ni(OH)2/NiOOH, via codeposition in combination with in situ electrochemical activation, acts as a promising OEE for alkaline water electrolysis. Notably, this hybrid catalyst shows excellent electrocatalytic performance toward OER in 1.0 M KOH with 212 mV low overpotentials to achieve a catalytic current density of 10 mA cm-2, which is comparable to the state-of-the-art noble catalysts. The NF@CGO as an electrocatalytically active and robust OER electrode also exhibits strong long-term electrochemical durability with release of a large current density of 800 mA cm-2 at 350 mV without degradation after 100 h. Such a remarkable performance can benefit from the self-assembly of the introduced OER catalysts deposited on NF, in-situ-generated Ni(OH)2/NiOOH nanoflakes, and their synergistic effects. Collectively, so far, the hybrid NF@CGO is one of the most efficient OEEs in alkaline electrolytes, which could potentially be implemented in large-scale water electrolysis systems.