In-situ growth of Fe doped NiCo-MOF electrocatalyst from layered double hydroxide effectively enhances electrocatalytic oxygen evolution performance

Two-dimensional (2D) metal-organic frameworks (MOFs) with high exposure of electro-active surface are regarded as promising oxygen evolution reaction (OER) electrocatalysts. This work demonstrates the in-situ conversion of a NiCo-LDH (LDH: double-layer hydroxide) into Fe doped NiCo-MOF on a conductive substrate (Fe-NiCo-MOF/NF) by a two-step hydrothermal method. The hierarchical book-like structure of Fe-NiCo-MOF/NF electrode provides large electro-active surface and improved electron transport capability, leading to enhanced oxygen evolution performance in alkaline environment. Specifically, Fe-NiCo-MOF/NF needs an overpotential of 290 mV to drive the current density of 50 mA cm-2, which is 136 mV lower than the precursor NiCo-LDH. Additionally, its activity can be maintained at least 20 h at a high current density of 200 mA cm-2. Moreover, the real active centers of the catalyst were discovered to be the metal oxides converted during the OER cycles. This work used a simple hydrothermal method to enhance the OER performance, convenient for direct application of MOF materials in electrocatalysis fields.