The rapid growth of environment pressures and fast depletion of fossil fuels compel public to pay more attention on developing affordable and efficient catalysts for renewable energy production. Metal (Co, Fe, Ni, etc.) phosphide nanoparticles uniformly encapsulated in porous N,P-codoped nanofibrous carbon coated on carbon paper (MeP@NPC/CP) are prepared through one-pot carbonization-phosphorization strategy, which are potential for effective electrocatalytic water reduction/oxidation reactions. The well-designed self-supported structure and the abundant accessible active centers together contribute to the high electrocatalytic performance for hydrogen and oxygen evolution. Remarkably, an alkaline electrolyzer assembled from CoP@NPC/CP as cathode and anode can afford the current density of 10 mA cm(-2) at the voltage of 1.67 V for overall water splitting in alkaline media with excellent stability. The easily prepared route with suitable structural and textural properties endows this self-supported materials with versatile function as abundant metal catalysts for realistic energy conversion and storage systems. (c) 2017 Elsevier Ltd. All rights reserved.