A self-supporting electrode with in-situ partial transformation of Fe-MOF into amorphous NiFe-LDH for efficient oxygen evolution reaction

Metal-organic frameworks (MOFs) have been extensively researched in recent years benefiting from the large surface area, abundant active centers, and adjustable structure. However, low conductivity and inaccessible active sites severely hinder its application in water electrolysis. Herein, a self-supporting electrocatalyst by developing MOF derivative on the surface of iron foam (IF) was synthesized through a self-templated partial transformation strategy. In addition, a series of catalysts with different morphologies were synthesized by adjusting the amount of Ni and the reaction time. Profiting from the unique hierarchical structure with large active area and abundant active sites, strong combination of highly active amorphous NiFe-LDH and Fe-MOF, and high conductivity and stability of the MOFs array in situ growth on IF, the resulting NiFe-LDH@Fe-MOF/ IF-2 shows excellent oxygen evolution reaction (OER) activity in alkaline electrolyte with required overpotentials of 183, 237 and 257 mV to achieve current densities of 10, 100, and 200 mA cm-2, respectively, and long-term stability for at least 20 h. This work provides new insights for the design and development of selfsupporting MOFs derived high performance electrocatalysts.