Hierarchical FeOxHy@Ni3B hybrid for efficient alkaline oxygen evolution at high current density

Electrocatalysts with high activity and long-term durability are vital toward large-scale hydrogen production from electrocatalytic water splitting. Here, the self-supported electrode (FeO x H y @Ni 3 B/NF) with hierarchical heterostructure was simply prepared by using Ni 3 B chunks grown on nickel foam as substrate to in situ form vertical FeO x H y nanosheets. Such hybrid shows efficient oxygen evolution reaction activity with overpotentials as low as 267 and 249 mV at 100 mA cm −2 in 1 M KOH solution and 30 wt% KOH solution, respectively. Meanwhile, it also exhibits excellent catalytic stability, sustaining catalysis at 500 mA cm −2 in 1 M KOH solution for 200 h, and even for 200 h at 1000 mA cm −2 in 30 wt% KOH solution. Further experimental results reveal that the FeO x H y @Ni 3 B/NF is endowed with superhydrophilic and superaerophobic surface properties, which not only provide more mass transport channels, as well as facilitated the diffusion of reaction intermediates and gas bubbles. Also, it holds faster reaction kinetics, more accessible active sites and accelerated electron transfer rates due to strong synergistic interactions at the heterogeneous interface.