Electronic modulation of FeOOH coupled NiFe-LDH for highly efficient alkaline water oxidation at high current density

Developing an inexpensive and efficient electrocatalyst can significantly decrease the electric power consumption during electrochemical water decomposition. However, oxygen evolution reaction (OER) contains complicated four electron transport and slow transport kinetics, which limits the process of water decomposition. The wet-chemical etching method provides a more cost-effective and energy-efficient alternative compared to other techniques. Herein, a self-supported NiFe layered double hydroxide (NiFe-LDH) nanosheets are constructed using an easy wet-chemical method where nickel foam (NF) as matrix and nickel source, and then coupled with iron oxyhydroxide (FeOOH) to obtain NiFe-LDH@FeOOH heterostructures catalyst for OER process. Owing to its superhydrophilic self-supported lamellar structure and the electronic interactions between Ni and Fe caused by strong interface interactions between NiFe-LDH and FeOOH, the NiFe-LDH@FeOOH hybrid electrocatalyst reveals excellent OER catalytic performance. It requires 245 and 259 mV to achieve large current densities of 100 and 300 mA cm-2, respectively. Moreover, a home-made electrolyzer consisting of NiFe-LDH@FeOOH (anodic) and commercial Pt/C (cathodic) displays superior overall water electrolysis performance, requiring 1.565 V to attain 100 mA cm-2 and stable operation for 120 h, demonstrating the potential for industrial applications.