Convenient Synthesis of NiCo Alloy Nanoparticles Encapsulated by N‑Doped Porous Carbon for the Oxygen Evolution Reaction

Abstract

Extremely important for water electrolysis are the rational design and investigation of oxygen evolution reaction (OER) electrocatalysts with excellent performance and long-term durability and that are precious metal-free. Herein, we demonstrate the convenient synthesis of a nitrogen-doped carbon-wrapped nickel cobalt alloy (NiCo2@NC) by pyrolysis of the metal complex. The results indicate that the ideal Ni/Co ratio and NC wrapping can provide high Cdl, low charge transfer resistance, and long-term durability for electrocatalysts, which are all reasons for significant OER performance. The optimal NiCo2@NC composite exhibits rapid OER reaction kinetics, which require a comparatively low overpotential of 288 mV at 10 mA cm–2 and a relatively small Tafel slope of 66 mV dec–1 in the alkaline electrolyte. Furthermore, I–t experiments were performed to demonstrate its better long-term catalytic endurance. In short, this study may provide guidance for the rational construction and design of carbon-coated bimetallic alloy materials