Ni/Co-Based Bouquet-Like Electrocatalyst for Urea Oxidation and Supercapacitor Applications

Developing efficient, multifunctional electrocatalyst is essential for the advancement of sustainable energy conversion and storage technologies. In this work, we report a Ni/Co oxide/hydroxide electrocatalyst featuring a distinctive flower-bouquet-like nanostructure, which exhibits remarkable bifunctional performance for both the urea oxidation reaction (UOR) and supercapacitor applications. The catalyst demonstrates an impressive UOR onset potential of 1.3 V versus Ag/AgCl—≈ 250 mV lower than that of the oxygen evolution reaction—and maintains excellent operational stability for 5000 s. The catalyst also exhibited excellent performance in supercapacitor application, achieving a high specific capacitance of 116.25 F/g, an energy density of 10.33 Wh/kg and a power density of 200 W/kg. Remarkably, after 500 cyclic voltammetry cycles, the specific capacitance increased to 141.88 F/g, accompanied by an enhanced energy density of 12.61 Wh/kg, highlighting the material's exceptional cycling stability and self-activation behavior. This superior electrochemical performance is attributed to the activation of previously inaccessible active sites, deeper ion penetration, and the possible formation of defects or nanocracks, all of which collectively enhance the density of electrochemically active sites. Additionally, the expansion of the layered structure may facilitate more efficient ion intercalation pathways, thereby boosting the activity.