Ni-dosed CoP with multi-level hollow structure as efficient electrocatalyst for overall water splitting

High-efficiency noble metal-free electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are of great significance for clean and renewable energy technologies. In this work, we construct novel hollow Ni-doped CoP nanoparticles embedded in hollow carbon polyhedron (denoted as H-Ni-CoP@HC) by using Ni-ZIF-67 as precursor through a developed pyrolysis-phosphidation strategy. The hollow structures of both cages and nanoparticles (NPs) endow the materials with abundant exposed active sites and significantly decreased mass transport resistance. Moreover, the material possesses strong electronic coupling between CoP and NiCoP. Consequently, low overpotentials of 170 and 150 mV are able to drive oxygen and hydrogen evolution at current densities of 10 mA cm(-2) in 1.0 M KOH solution over H-Ni-0.04-CoP@HC, respectively. Furthermore, the H-Ni-0.04-CoP@HC as a bifunctional catalyst for overall water splitting yields current densities of 10 mA cm(-2) at 1.47 V vs. RHE.