Noble-metal-free hydrogen/oxygen evolution reaction (HER/OER) electrocatalysts,especially bifunctional electrocatalysts,are essential for overall water splitting,but their performance is impeded by many factors like poor electrical conductivity.Herein,we fabricated cobalt phosphide (CoP) nanoparticles embedded in P and N co-doped carbon (PNC) matrix (CoP@PNC) to fully realize the high activity of CoP by maximizing its conductivity.Simply a carbonization coupled phosphidation approach was utilized where Co ions and organic ligands of Co-MOF were transferred into CoP and P and N co-doped carbon.The synthesized material shows an ideal electrical conductivity,excellent HER (overpotential of -84mV and-120 mV@10 mAcm-2 in acidic and alkaline medias,respectively) and OER (overpotential of 330 mV@10 mA cm-2 in alkaline media) performances.Further,CoP@PNC acts as a superior catalyst for both anode and cathode to catalyze overall water splitting and only requires an voltage of 1.52 V to deliver a current density of 10mAcm-2,superior to the noble-metal catalysts system (Pt/C∥lrO2) and the reported noble-metal-free bifunctional electrocatalysts.