Enhanced Oxygen Evolution Reaction Catalytic Properties of Novel Nanowire Structures from FeCo-MOFs/GO via Low-Temperature Annealing

Abstract

Metal-organic frameworks (MOFs) often suffer from poor stability, making them suitable precursors for metal oxides/porous carbon catalysts in the oxygen evolution reaction via pyrolysis. High-temperature treatment, however, leads to significant loss of active sites. To address this, Fe-MOFs, FeCo-MOFs, and FeCo-MOFs/graphene oxide (GO) composites using a one-pot hydrothermal method are synthesized and annealed at a low temperature of 300 °C. Characterization reveals that FeCo-MOFs/GO composites possess unique nanowire structures mixed with a small amount of nanoflakes. It is believed that introducing graphene oxide plays a critical role in forming this structure, because the defects in GO provide numerous nucleation sites for nanowire growth. With high specific surface area and good stability, these nanostructures show a low overpotential of 261.5 mV at a current density of 10 mA cm⁻² and a Tafel slope of 20.47 mV dec⁻¹ in 1 mol L⁻¹ KOH alkaline water electrolysis. Density functional theory calculations further indicate that the synergistic effect of Fe and Co atoms enhances the catalytic activity.