Fe-Doped Ni/Co-Based Selenide Hierarchical Nanosheet Arrays as Self-Supporting Bifunctional Electrocatalysts for Overall Water Splitting
Xiaoyu Fan, Hui Ding, Tingting Huang, Xia Liu, Juan Xiao, Mengyuan Xie, Guan‐Cheng Xu, Li Zhang
Abstract
It is necessary to optimize the electrocatalytic activity of an electrocatalyst by means of morphology and composition regulation. Herein, Fe-doped bimetallic selenide hierarchical nanosheet arrays grown on nickel foam (Fe-NiCoSe/NiCoSe/NF) are obtained for overall water splitting. The Fe-NiCoSe/NiCoSe/NF is fabricated by selenizing the NiCoFe Prussian blue analogue (NiCoFe-PBA) growing on a NiCo-layered double hydroxide (NiCo-LDH). Benefiting from the hierarchical nanosheet arrays, the synergistic effect of the bimetallic selenides, as well as the electronic structure rearrangement caused by Fe-doping, the Fe-NiCoSe/NiCoSe/NF catalyst exhibits low overpotentials of 120 mV for hydrogen evolution reaction (HER) and 199 mV for oxygen evolution reaction (OER) at 10 mA·cm –2 in 1.0 M KOH. In addition, when used as a bifunctional electrocatalyst for overall water splitting, the Fe-NiCoSe/NiCoSe/NF requires a cell voltage of 1.93 V (1.82 V) to reach 100 mA·cm –2 (50 mA·cm –2 ). Additionally, Fe-NiCoSe/NiCoSe/NF exhibits prolonged durability lasting for 150 h at 10 mA·cm –2 . This work provides a reasonable idea for designing a hierarchical nanostructured bifunctional electrocatalyst toward overall water splitting by regulating the structure and composition.