Scalable room-temperature synthesis of NiFe LDH/FeOOH with Cr vacancies for enhanced oxygen evolution reaction

It is of great significance to develop energy-saving and scalable synthetic methods for high-performance electrodes in green hydrogen production. Here we report a green room-temperature synthesis to produce integrated electrode with Cr-doped NiFe LDH/FeOOH nanosheets grown on iron foam. This simple one-step corrosion strategy can fabricate the electrode with an area up to 600 cm 2 . Through in situ self-activation process, the obtained Cr v -NiFeOOH/FeOOH@IF electrode exhibits excellent OER activity and durability, offering ultralow overpotentials of 279.3 and 308.4 mV to drive high current densities of 500 and 1000 mA cm −2 and operating steadily at industrial-level current density of 1000 mA cm −2 over 200 hrs with a high potential retention of 98.2 %. In situ electrochemical tests and theoretical calculations reveal the synergistic kinetics modulation. Both Cr vacancies and NiFeOOH/FeOOH heterostructure can accelerate water oxidation process by optimizing the adsorption energy of the intermediates. DFT calculations confirm Cr vacancies can further reduce the rate-determining step (RDS) energy barrier of the heterostructure. This work offers an economical and scalable corrosion strategy to produce high-efficient OER electrocatalysts toward industrial water splitting.