Optimized Ternary Heterostructure Zirconium/Polyaniline‐Nickel Disulfide Served as Electrocatalyst for Efficient Water Oxidation and Supercapacitor Applications

Abstract Currently, electrochemical study is the main focus of global research for green energy production and storage applications. Among transition metal sulfide family, nickel disulfide (NiS ₂ ) has a large number of redox‐active sites and high theoretical specific capacity, making it a potential material for high‐performance electrode materials for supercapacitors and water oxidation applications. A facile co‐precipitation approach is employed to prepare zirconium/polyaniline‐nickel disulfide (Zr/PANI‐NiS ₂ ) with highly active Zr (1 and 3 weight percentage (wt.%) doped into a fixed quantity (2 wt.%) of PANI. Optimized sample 3 wt.% Zr/PANI‐NiS ₂ exhibits superior oxygen evolution reaction (OER) kinetics at a current density of 10 mA cm ⁻² with a Tafel slope of 68 mV dec ⁻¹ in 1 M KOH. Brunauer–Emmett–Teller (BET) technique indicates 3 wt.% Zr sample has a higher surface area of 53.305 m ² g ⁻¹ , resulting in more active sites with adequate charge transfer capability and better long‐term stability. For supercapacitor performance, 3 wt.% Zr/PANI‐NiS ₂ sample demonstrates a specific capacitance (1362 Fg ⁻¹ at 2 Ag ⁻¹ ), retention (96%), and coulombic efficiency (98%), respectively. Zr and PANI boost the efficiency of NiS ₂ via a synergistic effect, making it a promising material for supercapacitors and OER applications.