Activating and optimizing the activity of NiCoP nanosheets for electrocatalytic alkaline water splitting through the V doping effect enhanced by P vacancies

Abstract

Vacancy engineering or element doping has been extensively developed to tune the electrocatalytic activity of electrocatalysts. However, it is challenging to simultaneously generate doping and defects, and insights into the structure–property relationship in vacancy-rich and doped catalysts are lacking. Herein, a V-doped NiCoP electrocatalyst is developed through utilizing the V-doping effect enhanced by P vacancies via plasma treatment. The P vacancies can enhance the V doping effect to increase the electroactive sites and regulate the electron density of the active site center. Thus, an enlarged electrochemical active area, accelerated electron transportation and promoted electronic coupling effects can be achieved. As a result, the overpotentials at a current density of 10 mA cm⁻² are 58 and 246 mV for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in 1 M KOH, respectively. When serving as a bifunctional electrode for overall water splitting, V-doped NiCoP with P vacancies can achieve a low voltage of 1.55 V at 10 mA cm⁻². This work highlights a feasible strategy to explore efficient electrocatalysts via the heterogeneous atom doping effect enhanced by vacancies.