Electrodeposition?�?Assisted Synthesis of Fe-doped NiCo Layered Double Hydroxide Nanosheets for Efficient Oxygen Evolution Reaction

Abstract

Hydrogen, as a sustainable and green energy carrier, is an ideal alternative to traditional fossil fuels to solve the aggravating energy crisis and environmental pollution. However, industrial production of hydrogen from water splitting is mainly hindered by sluggish kinetics of oxygen evolution reactions (OER) at the anode in alkaline solution due to the difficulty in forming binding protons. Thus, the development of robust, highly active, and cost-efficient catalyst is critical to enhance reaction efficiency and decreasing required overpotential. Layered double hydroxides (LDHs) containing first-row transition metals (e.g., iron (Fe), cobalt (Co), and nickel (Ni)) have attracted significant interest for electrocatalytic applications owing to their earth abundance and excellent performance for OER in alkaline media. Herein, Fe-doped NiCo LDH (Fe-NiCo LDH) nanosheets (NSs) with a hierarchical nanostructure were successfully fabricated on nickel foam (NF) via a facile electrochemical deposition method. The optimum Fe-NiCo-LDH NS sample shows a low overpotential of 189 mV at a current density of 10 mA cm−2 and a low Tafel slope of 98.7 mV dec−1 . The enhanced OER activity of the Fe-NiCo LDH catalyst is attributed to (i) the high specific surface area of the nanosheets, which is beneficial for increasing the number of active sites and (ii) the improved kinetics and enhanced ion transport arising from iron doping and synergistic effects. This study provides an effective avenue to fabricate efficient cation-doped multimetallic LDH electrocatalysts for efficient water splitting.