Co-CoO/ZnFe₂O₄ encapsulated in carbon nanowires derived from MOFs as electrocatalysts for hydrogen evolution

Transition metals are increasingly attracting interest in electrocatalysts for use in water decomposition due to their excellent catalytic activity and stability. Simultaneously, metal-organic frameworks with designable metal ion centers and organic ligands are the promising precursors for the one-step synthesis of metal encapsulated in carbon composites for alkaline hydrogen evolution reaction (HER). Herein, we report the successful construction of Co-CoO/ZnFe₂O₄ encapsulated in carbon nanowires (Co-CoO/ZnFe₂O₄@CNWs) by annealing as-synthesized nanowire Co/Zn/Fe-MOF at 400 °C in N₂. This structure provides the rich defect sites and active centers, and the synergy of Co, CoO and ZnFe₂O₄ lead to efficient hydrogen evolution when the composite is used as a catalytic electrode for HER in 1.0 M KOH. The catalyst shows a low initial overpotential (97 mV) and a small Tafel slope (138 mV dec^-1), and the overpotential at 10 mA cm^-2 is only 226 mV. In addition, this composite material exhibits excellent long-term durability even after 1000 cycles. It is expected that it is a potential alternative catalyst for rational utilization in the field of electrolytic water decomposition.