Interfacial Effects of NiFe-Based Bifunctional Electrocatalysts for Highly Efficient Overall Water Splitting

The reasonable design of highly efficient NiFe-based bifunctional electrocatalysts is imperative for water splitting and alleviation of the energy crisis. Herein, the NiFe-based bifunctional electrocatalysts are designed and grown in situ on Ni foam by a simple hydrothermal method. The interfacial effect among NiFe-LDH, Fe₅O₇(OH), and NiFe₂O₄ exposes more catalytic active sites, modulated electronic structure, and optimization of the electrocatalytic performances. The overpotentials of NiFe-LDH/Fe₅O₇(OH)/NiFe₂O₄/NF-15h (NFN/NF-15h) for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are 78 and 208 mV at 10 mA cm^–2, respectively. Overall water splitting can drive 10 mA cm^–2 with a cell voltage of only 1.538 V. This work contributes a feasible idea for the design and synthesis of NiFe-based bifunctional electrocatalysts with outstanding water splitting performance.