Construction of hierarchical FeP/Ni2P hollow nanospindles for efficient oxygen evolution

In this work, we demonstrate the design and construction of hierarchical FeP/Ni2P hybrid hollow nanospindles (HNSs) as an active and stable electrocatalyst for the oxygen evolution reaction (OER). Employing solid FeOOH NSs coated with a thin layer of SiO2 as the template and Ni(NO3)(2)center dot 6H(2)O as the reagent, 2D nickel silicate (Ni3Si4O10(OH)(2)center dot 5H(2)O) nanosheets were grown on the surface of the FeOOH spindles through a facile solvothermal method to produce hierarchical FeOOH@Ni3Si4O10(OH)(2)center dot 5H(2)O hybrid NSs. Following a subsequent phosphorization treatment, the as-prepared solid composite NSs were successfully converted into FeP/Ni2P HNSs. The SiO2 nanocoating was found to play a crucial role in this synthesis, and served not only as a reagent for the solvothermal reaction, but also as a nanoreactor for preserving the template morphology after the phosphorization treatment. Benefiting from the unique hollow and hierarchical nanoscaled hybrid structure, the FeP/Ni2P HNS electrocatalyst displays superior electrocatalytic activity for the OER to FexP, Ni2P and the physical mixture of FexP and Ni2P samples, achieving an overpotential of 234 mV at a current density of 10 mA cm(-2) in 1 M KOH and a relatively low Tafel slope of 56 mV dec(-1).