▎ 摘　　要

As a promising new-star electrocatalyst, transition metal phosphide (TMP) has been widely applied in electrocatalytic hydrogen and oxygen evolution reactions (HER and OER). However, the current catalytic activity and stability are unsatisfactory. Herein, we started from optimizing the geometric and electronic structure of the catalyst, choosing FeCo Prussian blue analogues (PBAs) with rich pores as precursors and epitaxially grown Ni(OH)(2) and then connecting them though graphene oxide (GO) by electrostatic interaction, and finally transformed them into ternary TMPs and graphene composites (Fe2P/CoP/Ni5P4/RGO). Due to the porous structure of phosphides and the large surface area and excellent conductivity of reduced graphene oxide (RGO), the Fe2P/CoP/Ni5P4/RGO exposed more active sites, promoted electrolyte diffusion and gas release, and accelerated the charge transport. The synergistic effect among ternary TMPs and between them and RGO made Fe2P/CoP/Ni5P4/RGO a highly efficient electrocatalyst for water splitting with only 57 mV, 232 mV overpotential, and 1.56 V cell voltage for obtaining 10 mA/cm(2) current density in HER, OER, and overall water splitting. Benefiting from the protection of RGO, the Fe2P/CoP/Ni5P4/RGO remained the original structure and showed good stability during long-term testing. This work proposed a design thought to improve the activity and stability of metal phosphides that may be extended to other metal organic framework-derived compounds and carbon-based materials composites.