Enhanced oxygen evolution of hexagonal nanosheet NixCo3-xO4 catalysts based on Co-Ni MOF derivatives in alkaline media

This study aimed to design and develop low-cost and highly adaptable non-noble metal catalysts. Co-Ni metal–organic frameworks (Co-Ni MOF)-derived Ni_xCo_3-xO₄ catalysts were successfully synthesized via ion exchange and thermal treatment. An 8-Ni_xCo_3-xO₄ catalyst with a stable hexagonal nanosheet morphology was obtained by optimizing the Ni content. The original structure of the Co-Ni MOF precursor was preserved. In 1 M KOH solution, the 8-Ni_xCo_3-xO₄ catalyst achieved current densities of 10 and 50 mA·cm⁻² at overpotentials of only 320 and 391 mV, respectively. After 32 h of long-term electrolysis, the overpotential decay rate was as low as 0.5%. These results demonstrate the superior activity and stability of the 8-Ni_xCo_3-xO₄ catalyst, attributed to its stable hexagonal nanosheet morphology and the multivalent synergy of cobalt and nickel bimetallic nodes induced by composition optimization.