Boosting oxygen evolution reaction of hierarchical spongy NiFe-PBA/Ni3C(B) electrocatalyst: Interfacial engineering with matchable structure

[Display omitted] •Hierarchical spongy structure is constructed by borate-assisted.•Matchable interface structure between NiFe-PBA and Ni3C boosts the OER activity.•The interfacial synergy and electron redistribution are achieved. Rational interfacial structure with excellent charge transfer and exposure of numerous active sites plays vital roles in heterogeneous catalysis. Herein, a hierarchical spongy electrocatalyst with active NiFe Prussian blue analogues and nickel carbides interface (NiFe-PBA/Ni3C(B)) is proposed and fabricated by a borate-assisted strategy. The unique structure and matchable interface benefit from the desorption of borate ligands in-situ during the pyrolysis and carbonization process. The optimal electrocatalyst composing of metal–organic framework (NiFe prussian blue analogues) in conjunction with a metallic transition carbide phase (nickel carbide) exhibits an ultra-low overpotential of only 196 mV at 10 mA cm−2 and a small Tafel slope of 30.1 mV dec-1 for OER in KOH. The robust water oxidation performance can be ascribed to the abundant adsorption sites and effective interfacial interaction. In addition, computational simulations further confirm that NiFe-PBA/Ni3C(B) is favorable for OER since the optimized electronic distribution and metal-3d orbitals interact around Fermi level at the interface. This research provides a new insight into rationally designing efficient electrocatalysts via morphology engineering and integrating different functional phase with complementary advantages for catalysis application.