Fabrication of Graphitic Carbon Nitride-Doped Quaternary Metallic NiCuCoFe Perovskite Composite as a Highly Efficient Electrocatalyst for the Oxygen Evolution Reaction

A variety of perovskite oxide-based electrocatalysts have been reported for the oxygen evolution reaction (OER) due to their tunable electronic structure and abundance of transition metals. However, mostly reported composites often suffer from intrinsic limitations such as poor electrical conductivity and limited exposure of catalytically active sites, thus significantly impeding their practical application in scalable hydrogen production. To overcome these challenges, herein we report a novel hybrid electrocatalyst comprising a quaternary NiCuCoFe-based perovskite oxide doped with graphitic carbon nitride (g-C 3 N 4 ). This hybrid electrocatalyst has leveraged the synergistic redox interactions of different metals with a large number of catalytically active sites. Simultaneously, defects-rich g-C 3 N 4 as a conductive polymeric framework has effectively mitigated conductivity bottlenecks and offer smooth ways to catalytically active sites. The synthesized g-C 3 N 4 -doped NiCuCoFeO x catalyst has shown promising electrocatalytic efficacy by exhibiting a low overpotential of 280 mV at 10 mA cm –2 and a Tafel slope of 123.8 mV dec –1 . This improved electrochemical performance of g-C 3 N 4 -doped NiCuCoFeO x can be attributed to the synergistic interplay between metal oxides, and the conductive g-C 3 N 4 matrix underscores the effectiveness of this dual-engineering approach. These findings position g-C 3 N 4 -doped NiCuCoFeO x as a highly promising electrocatalyst for next-generation, nonprecious metal-based OER electrocatalysts suitable for large-scale alkaline water electrolysis.