Engineering ZnMnCoO₄@Polyaniline nanowire hybrid electrodes for alkaline HER/OER electrocatalysis and durable...

This work presents the synthesis and investigation of a multifunctional ZnMnCoO₄@Polyaniline-nanowire (ZMCO@PANI-NW) electrode material for electrochemical hydrogen production and supercapacitor applications. ZnMnCoO₄ was prepared using a hydrothermal method, followed by the incorporation of conductive PANI nanowires to enhance the surface activity, electrical conductivity, and electrochemical stability of the electrode. The structural, morphological, compositional, optical, and thermal properties were characterized using SEM, TEM, EDAX, elemental surface mapping, TGA, FTIR, and UV-Vis spectroscopy. Electrochemical performance was evaluated in alkaline medium toward the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and capacitive energy storage using LSV, Tafel analysis, EIS, CV, GCD, and long-term stability measurements. The ZnMnCoO₄@PANI-NW electrode exhibited low overpotentials at 10 mA cm^-2 (η ₁₀) of 296 mV for HER and 194 mV for OER, with corresponding Tafel slopes of 84 and 116 mV dec^-1, for HER and OER respectively. Moreover, the electrode maintained stable performance after 15 h of continuous operation for both HER and OER, confirming its durability for water-splitting applications. For supercapacitor performance, the ZnMnCoO₄@PANI-NW electrode delivered a specific capacitance value of 410 F g^-1 at a current density of 0.5 A g^-1, respectively, with a rate capability of 59.3%. The electrode also retained 81.1% of its initial capacitance after 10 000 charge-discharge cycles, indicating excellent cycling stability.