ZnO-Templated Selenized and Phosphorized Cobalt-Nickel Oxide Microcubes as Rapid Alkaline Water Oxidation Electrocatalysts

Graphical Selenized and phosphorized cobalt-nickel oxide microcubes formed by a novel strategy using a sacrificial ZnO spherical template are employed as an oxygen evolution reaction (OER) electrocatalyst. The selenized samples manifest desirable and robust OER performance, with comparable overpotential at 10 mA cm −2 (312 mV) as RuO 2 (308 mV) and better activity when the current reaches 13.7 mA cm −2 . Oxygen electrocatalysis is of remarkable significance for electrochemical energy storage and conversion technologies, together with fuel cells, metal-air batteries, and water splitting devices. Substituting noble metal-based electrocatalysts by decidedly effective and low-cost metal-based oxygen electrocatalysts is imperative for the commercial application of these technologies. Herein, a novel strategy is presented to fabricate selenized and phosphorized porous cobalt-nickel oxide microcubes by using a sacrificial ZnO spherical template and the resulting microcubes are employed as an oxygen evolution reaction (OER) electrocatalyst. The selenized samples manifest desirable and robust OER performance, with comparable overpotential at 10 mA cm −2 (312 mV) as RuO 2 (308 mV) and better activity when the current reaches 13.7 mA cm −2 . The phosphorized samples exhibit core–shell structure with low-crystalline oxides inside amorphous phosphides, which ensures superior activity than RuO 2 with the same overpotential (at 10 mA cm −2 ) yet lower Tafel slope. Such a surface doping method possibly will provide inspiration for engineering electrocatalysts applied in water oxidation.