HEA-NiFeCuCoCe/NF through ultra-fast electrochemical self-reconstruction with high catalytic activity and corrosion resistance for seawater electrolysis

Abstract

The development of an electrocatalyst with excellent corrosion resistance and catalytic performance in seawater electrolysis is of great significance for advancing and utilizing sustainable hydrogen energy in the future. Additionally, the exploration of actual active sites to enhance the performance of OER (oxygen evolution reaction) is highly valuable in improving the overall efficiency of water electrolysis. To achieve these objectives, we synthesized a Ni-Fe-Cu-Co-Ce high entropy alloy (HEA-NCFCC) on a nickel foam (NF) substrate through electrodeposition. Subsequently, by employing an effective electrochemical self-reconstruction method, we successfully introduced M−OOH on the surface of the HEA-NCFCC/NF, resulting in a catalyst that exhibits both high OER activity and exceptional corrosion resistance (HEA-NCFCC/NF@EA). The catalyst's exceptional OER performance was clearly demonstrated by the experimental results, as evidenced by the achieved overpotentials of 219 mV, 220 mV, and 236 mV at current densities of 10 mA·cm−2 in alkaline solution, alkaline simulated seawater, and alkaline seawater, respectively. Furthermore, the HEA-NCFCC/NF@EA exhibited remarkable stability during continuous OER operation in alkaline simulated seawater and alkaline seawater, with a minimum operating time of 100 h. The outstanding corrosion resistance and catalytic performance of the HEA-NCFCC/NF@EA resulted from the distinctive synergistic effect intrinsic to the high entropy alloy itself and the incorporation of a stable lattice oxygen mechanism through electrochemical self-restructuring. This ensured that the catalyst remained highly resistant to significant erosion and reconstruction caused by chloride ions during continuous seawater electrolysis.