The development of active and robust electrocatalysts for water splitting, especially the non-precious-metal electrocatalysts with well-defined nanostructures, has attracted much attention. Herein, we report a nitrogen-doped carbon nanofiber embedded with ultrafine graphene layers-wrapped FeNiP nanoparticle (denoted as FeNiP@N-CFs) by direct pyrolysis reduction of electrospun Fe3+/Ni2+/poly-acrylonitrile precursor fibers followed by in situ phosphorization. Benefiting from the high electro-chemical activity of in situ formed FeNiP/FeNiOOH core-shell nanoparticles during test, strong coupling with few layers graphene shell, and synergistically enhanced electronic conductivity of N-doped carbon nanofiber matrix, the as obtained FeNiP@N-CFs exhibits outstanding electrocatalytic activity, in terms of a low overpotential (300mV at 10mA cm(-2)), small Tafel slope of 47 mV dec(-1) and remarkable long-term stability in 1.0 M KOH for oxygen evolution reaction (OER). This work provides a general approach for fabrication of double-metal phosphide-graphitized carbon nanofiber hybrid electrodes with enhanced conductivity and catalytic activity for electrochemical water oxidation. (C) 2018 Elsevier Ltd. All rights reserved.