NiSe and Fe-Based Layerd Double Hydroxide Nanosheet/Ni Foam Bifunctional Catalyst for Water Splitting

The efficiency of overall water splitting (OWS) can be enhanced by developing active and stable bifunctional catalysts to accelerate the kinetics of oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). In this work, a class of hierarchical NiSe@MFe-LDH (M = Ni, Co, Mn, or Zn) heterostructure nanosheet arrays on nickel foam was constructed through hybridizing NiSe and Fe-based layered double hydroxide (LDH). Benefiting from the unique sheet-on-sheet structure and synergistic effect of heterostructure by combining the merits of NiSe and MFe-LDH, NiSe@MFe-LDH/NF exhibited excellent catalytic performances for OER, HER, and OWS. The resultant NiSe@NiFe-LDH/NF requires low overpotentials for OER (244 mV) and HER (193 mV) to achieve a current density of 100 mA cm–2, respectively. For OWS, at the potentials of 1.512 and 1.705 V, the respective current densities were 10 and 100 mA cm–2, which are superior to the RuO2/NF||Pt/C/NF (1.552 and 1.722 V) and many reported state-of-the-art catalysts. This electrode remained active and stable for 100 h in 1.0 M KOH media. This work suggests that the sheet-on-sheet structure, binder-free electrode, and heterostructure nanocomposite can synergistically boost catalytic performances and hence provides a promising strategy for developing efficient and robust catalysts for OWS.