Nickel foam supported CuCo-MOF/g-C₃N₄ composite electrode for efficient overall water splitting

Abstract Developing electrocatalysts that are efficient, durable, and economically viable is essential for promoting sustainable hydrogen generation via water splitting. In the present study, a novel CuCo-MOF/g-C₃N₄ composite electrode supported on three-dimensional nickel foam (CuCo-MOF/g-C₃N₄-NF) was fabricated via a straightforward in situ synthesis approach for bifunctional electrocatalytic applications. The integration of a bimetallic copper–cobalt metal–organic framework (CuCo-MOF) with graphitic carbon nitride (g-C₃N₄) on a 3D nickel foam substrate results in a highly porous architecture with abundant electroactive sites, enhanced electrical conductivity, and improved mass transport characteristics. The CuCo-MOF/g-C₃N₄ composites, synthesized through a solvothermal route, exhibited remarkable bifunctional electrocatalytic activity toward overall water splitting. The CuCo-MOF/g-C₃N₄-NF electrode exhibited low onset potentials of 1.47 V for OER and − 0.10 V for HER at a current density of 10 mAcm⁻², showing superior performance compared to the individual Cu-MOF, Co-MOF, and CuCo-MOF catalysts in 1 M KOH solution. Furthermore, the composite displayed low Tafel slopes (87.9 mV dec⁻¹ for OER and 159 mV dec⁻¹ for HER), minimal charge-transfer resistance, and excellent stability over 60 h of continuous operation. These results demonstrate that the CuCo-MOF/g-C₃N₄-NF composite is a highly promising, scalable, and cost-effective electrocatalyst for green hydrogen generation via overall water splitting.