Nickel Foam‐Supported Amorphous FeCo(Mn)−O Nanoclusters with Abundant Oxygen Vacancies through Selective Dealloying for Efficient Electrocatalytic Oxygen Evolution

Abstract Developing earth‐abundant, cost‐effective and high‐performance electrocatalyst towards the oxygen evolution reaction (OER) is a great challenge for large‐scale hydrogen production from electrochemical water splitting. Nickel‐foam‐supported amorphous hierarchical nanoclusters of metal/metal (hydr)oxides with abundant oxygen defects (FeCo(Mn)−O/NF) were prepared from an FeCoMn/NF precursor through chemical dealloying. The FeCo(Mn)−O/NF electrode exhibits enhanced OER activity in alkaline electrolyte with an overpotential of only 235 mV to drive a current density of 10 mA cm −2 , a small Tafel slope of 44.5 mV dec −1 and excellent durability over 100 h. The superior OER performance is attributed to the synergistic effect of abundant oxygen vacancies, hierarchical morphology and amorphous structure, which essentially modulate the electronic structures and create more active sites. These interesting findings highlight the significance of dealloying strategy on the structural defects and improved catalytic performance of the electrocatalysts.