Beam intensity of N2 plasma controlled surface engineering on WO3 for enhanced hydrogen evolution and oxygen evolution

Tungsten oxide is a promising electrocatalyst for water splitting reactions, due to its flexible chemical state, strong structural malleability and good corrosion resistance. Herein, the surface engineering on WO 3 was conducted by a controllable N 2 plasma for enhancing the performance of water splitting reactions. Under the specific N 2 plasma treatment, the surface crystalline phase and the surface morphology of the tungsten oxide can be changed, as well as the creation of oxygen vacancies. These changes lead to a greatly increased electrochemical surface area, a narrowed bandgap, and a distorted crystal lattice. For oxygen evolution reaction (OER) in 1.0 M KOH, the activity of the modified tungsten oxide electrodes presents a positive correlation with the input plasma, and an optimal overpotential of 269 mV @ 10 mA cm −2 is achieved with a Tafel slope of 122 mV dec -1 . With a high N 2 plasma flux, the W-N bond can be formed on the tungsten oxide surface, which contributes to the promotion of the hydrogen evolution reaction (HER) activity, and an overpotential of 93 mV @ 10 mA cm −2 in 1.0 M KOH is exhibited, and the Tafel slope largely reduced to 76 mV dec -1 . Such a facile strategy provides an engineering route of preparing efficient electrodes for water splitting reactions.