Constructing Mo-Co2P/Ni12P5 heterostructures as highly efficient electrocatalysts for overall water splitting

Abstract

Green hydrogen production through electrocatalytic water splitting represents an important approach to utilizing renewable energy sources, and the development of efficient bifunctional noble-metal-free electrocatalysts is the key to wide industrial applications. In this work, a nanoflower-like Mo-doped cobalt phosphide/nickel phosphide heterostructure array (Mo-Co₂P/Ni₁₂P₅) has been constructed by using CoMo-layered double hydroxide (LDH) as precursor, followed by transforming into metal-organic framework (MOF) and phosphorization. The introduction of MOF improves the porosity and active areas of the electrocatalyst. The presence of multiple interfaces of heterostructure and the synergistic effect between transition metals accelerates the charge transfer. Consequently, the as-prepared Mo-Co₂P/Ni₁₂P₅ demonstrates to be a promising bifunctional electrocatalyst for hydrogen evolution reaction (η₁₀₀ = 209 mV) and oxygen evolution reaction (η₁₀₀ = 333 mV). The assembled electrolytic cell using Mo-Co₂P/Ni₁₂P₅ as anode and cathode can drive 100 mA cm⁻² at 1.81 V with good operation durability. This study provides a practical synthesis strategy for heterostructured multimetallic phosphides, which shows great promise for electrochemical energy storage and conversion.