Morphology-Controlled Nickel Oxide and Iron-Nickel Oxide for Electrochemical Oxygen Evolution Reaction

Morphology engineering is an attractive method for controllingthe activity of metal and metal oxide catalysts. However, there havebeen only a few studies on nickel oxide regarding the shape controland observation of its catalytic properties. Here, we synthesizedvarious morphologies of nickel oxide nanoparticles, namely octahedral((111) facet exposed), hexagonal ((110) facet exposed), and donut-shaped(via Kirkendall effect). Additionally, a small amount of iron wasadded to the nanoparticles by two methods: doping and post-deposition.The hexagonal and donut-shaped nickel oxides exhibited higher oxygenevolution reaction (OER) activity than the octahedral nickel oxide.In addition, the hexagonal and donut-shaped Fe-post-deposited samplesshowed superior OER activity compared to the other iron-nickeloxide samples.