1D@2D Hierarchical NiCo₂O₄@MIL-53(Fe) Nanostructures Synergistically Enhance Oxygen Evolution Reaction

Hierarchical nanostructures with unique synergistic electronic effects and abundant active sites play an essential role in the field of electrocatalysis. In this work, 1D@2D hierarchical NiCo2O4@MIL-53(Fe) nanostructures are constructed via introducing MIL-53(Fe) over NiCo2O4 nanoneedles grown on nickel foam [NiCo2O4@MIL-53(Fe)]. NiCo2O4@MIL-53(Fe) exhibits high catalytic activity of the oxygen evolution reaction due to the strong electronic interaction between NiCo2O4 and MIL-53(Fe), as well as the hierarchical nanostructures that provide numerous active sites. In 1.0 M KOH, the NiCo2O4@MIL-53(Fe) can achieve the current densities of 10 and 100 mA cm–2 with overpotentials of only 231 and 260 mV, respectively; the hierarchical catalysts show good electrochemical and structural stability, operating for more than 100 h at a current density of 10 mA cm–2 without obvious decay.