Core-shell structured NiCo@NiCoP nanorod array as an enhanced electrocatalyst for water electrolysis

초록

Water electrolysis, consisting of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) has recently attracted attention as an effective way for hydrogen (H2) production, which is regarded as an eco-friendly and sustainable energy to address the depletion of fossil fuels and environmental pollution problems. Recently, to replace high-cost ruthenium and platinum-based materials and improve thermodynamically sluggish kinetics of OER and HER, transition metal-based materials i.e., oxides, sulfides and phosphides have been researched.[1] In this study, the core-shell structured NiCo@NiCoP nanorod on nickel foam was synthesized and investigated electrocatalytic performance for overall water electrolysis. As illustrated in below scheme, NiCo alloy core was fabricated by two step method, which were hydrothermal method and H2 heat treatment, while NiCoP shell was synthesized by in situ anodic oxidation of core surface and annealing. The core-shell structured NiCo@NiCoP/NF showed the excellent electrochemical performance with low overpotentials and high stability for both OER and HER compared with commercial RuO2 and Pt/C. These results derived from structure properties that NiCo alloy core provides the efficient electron transport pathway and NiCoP shell serves as rich active sites due to the strong capillary force of hierarchical 1D structured NiCo@NiCoP.[2,3]