Interconnected Copper Cobaltite Nanochains as Efficient Electrocatalysts for Water Oxidation in Alkaline Medium

The present work is focused on the protective-agent-free synthesis of interconnected copper cobaltite (Cu_0.3Co_2.7O₄) nanochains by temperature-controlled solvothermal method followed by post-thermal treatment of the precursors. Furthermore, Cu_0.3Co_2.7O₄ interconnected nanochains are employed as electrocatalyst for water oxidation in alkaline medium for the first time. Extensive studies of physiochemical properties showed the formation of interconnected 1D nanochains of Cu_0.3Co_2.7O₄ exhibiting a larger specific surface area (139.5 m² g^-1) and enhanced electrochemical water oxidation ability. It delivered excellent mass activity (∼50.0 A g^-1), high anodic current density (∼124.9 mA cm^-2 at 1.75 V versus reversible hydrogen electrode), and turnover frequency (∼4.26 × 10^-2 s^-1) in 1.0 M KOH. These Cu_0.3Co_2.7O₄ nanochains also demonstrated low overpotential (∼351 mV) and good cycling stability (1000 cycles) in strong alkaline media. The fabricated Cu_0.3Co_2.7O₄ nanochains could be a good alternative to the commercial OER electrocatalysts (RuO₂ and IrO₂) and also advantageous to the development of efficient, cost-effective, and durable electrocatalysts for electrochemical water splitting.