Effect of Zirconium Substitution in Thiospinel Cobalt‐Ferrite Nanoparticles Decorated over Nitrogen‐Doped Graphene Oxide Sheet as an Oxygen Evolution Reaction Electrocatalysts

The oxygen evolution reaction performance of spinel cobalt iron sulfide (CoFe 2 S 4 ) is constrained by its inferior charge transfer capabilities compared to RuO 2 . Herein, partial substitution of zirconium (Zr 4+ ) into the octahedral Fe site of CoFe 2 S 4 is explored to enhance its electrocatalytic performance. The structural and electronic characterization reveals that Zr 4+ incorporation induces lattice distortion and modulates the electronic environment, resulting in an enhanced charge distribution. Notably, the optimized Zr‐doped catalyst (Zr 0.1 CFS/N‐RGO) exhibits a significantly improved oxygen evolution reaction performance, achieving a low overpotential of 470 mV at 10 mA cm −2 and a small Tafel slope of 55 mV dec −1 in 1 M KOH. Furthermore, the catalyst demonstrates remarkable durability, retaining 91% of its initial current density after 12 h of continuous operation. These findings underscore the potential of strategic transition metal doping to optimize nonprecious metal‐based catalysts for sustainable electrochemical water splitting applications.