A novel free-standing electrode consisting of nickel phosphide (Ni2P) nanoparticles on nitrogen and phosphorus co-doped porous carbon (NPC) are synthesized on carbon cloth (CC). Polyaniline (PANI) and nickel (Ni) are sequentially electro-deposited on the surface of CC, which are then transformed into NPC and Ni2P by an in-situ carbonization-phosphorization combined process. The electrode surface is distributed with large amounts of uniform macropores, which could expose more active sites and enhance the interfacial exchange with the electrolyte. The Ni2P@NPC@CC electrode delivers early overpotentials of 92 and 280 mV vs. Reversible Hydrogen Electrode (RHE) at 10 mA cm(-2) for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline condition, respectively. The electrolytic cell with Ni2P@NPC@CC electrode both as anode and cathode can achieve 10 mA cm(-2) at a small bias of 1.54 V for the overall water splitting. Density functional theory (DFT) calculation indicates that combination with Ni2P and NPC can decrease Gibbs free energy for H* adsorption (Delta G(H).) and increase charge density on the interface, thus could lead to the enhanced activity for water splitting. The free-standing and noblemetal free Ni2P@NPC@CC electrode is stable, highly active and cost effective, thus have great potential for the hydrogen production. (C) 2020 Elsevier Inc. All rights reserved.