Oxygen evolution on Fe-doped NiO electrocatalysts deposited via microplasma

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• The oxygen evolution reaction (OER) is critical for renewable energy technologies but requires efficient electrocatalysts.
• Nanostructured metal oxides offer promising catalytic properties but their synthesis and stability remain challenges.
• Iron-doped nickel oxide (Ni1-xFexO) presents potential for improved OER performance in alkaline environments.

Purpose of the Study:

• To investigate the OER activity of nanostructured Fe2O3, NiO, and Ni1-xFexO electrocatalysts.
• To understand the influence of iron doping on the morphology, structure, and catalytic performance of NiO.
• To evaluate the stability and efficiency of microplasma-deposited Ni1-xFexO for OER in alkaline media.

Main Methods:

• Microplasma deposition of electrocatalysts onto indium tin oxide substrates.
• Characterization using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and X-ray Photoelectron Spectroscopy (XPS).
• Electrochemical assessment via cyclic voltammetry and chronopotentiometry.

Main Results:

• Iron was fully incorporated into the NiO lattice, forming Ni1-xFexO nanostructures.
• Overpotentials for OER decreased from 360 mV for NiO to 310 mV for Ni1-xFexO at 10 mA cm-2, with optimal doping levels observed.
• Ni1-xFexO catalysts exhibited low Tafel slopes (20-30 mV dec-1) and significantly increased turnover frequencies (0.07 to 0.48 s-1) with increasing Fe content.
• The Ni1-xFexO catalysts demonstrated excellent mechanical and chemical stability under alkaline OER conditions.

Conclusions:

• Microplasma deposition is an effective method for creating conformal coatings of nanostructured, doped oxides.
• Fe-doped NiO (Ni1-xFexO) exhibits enhanced electrocatalytic activity and stability for OER in alkaline media.
• This approach offers a versatile route to high-performance electrocatalysts for energy conversion applications.