Cobalt phosphide nanoparticles embedded in 3D N-doped porous carbon for efficient hydrogen and oxygen evolution reactions

An electrocatalyst based on a unique three-dimensional (3D) N-doped porous carbon sheet networks embedded with CoP2 nanoparticles (CoP2@3D-NPC) was synthesized by a facile pyrolysis process as well as an in-situ phosphatization method. The improved CoP2@3D-NPC hybrid materials show excellent electrocatalytic activity toward HER and OER. This material provides a low overpotential of 126 mV at 10 mA cm(-2) in 0.5 M H2SO4 and 167 mV at 20 mA cm(-2) in 1.0 M KOH for HER with a small Tafel slope value of 59 mV dec(-1), respectively. Besides, it is also active for the OER under alkaline conditions. Such a prominent property of the CoP2@3D-NPC electrocatalyst could be attributed to its excellent electrical conductivity of 3D carbon substrate, strong synergistic effect between CoP2 nanoparticles and carbon nanosheet as well as extra active sites created by the N-doped structure. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.