Optimizing oxygen reduction efficiency with a robust nickel nitrogen-doped carbon nanotube catalyst for polymer electrolyte membrane fuel cells

The Polymer Electrolyte Membrane Fuel Cells (PEMFCs) require highly efficient and durable catalysts for the Oxygen Reduction Reaction (ORR) at the cathode. While platinum (Pt) remains the benchmark ORR catalyst, its high cost and limited availability significantly hinder large-scale commercialization. To address this challenge, a non‑platinum group catalyst based on nickel-decorated and nitrogen-doped carbon nanotubes (Ni-NCNTs) was synthesized via a hydrothermal method. The morphology and structural characteristics of the Ni-NCNTs were examined using X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy coupled with Energy Dispersive Spectroscopy (SEM-EDS). The electrocatalytic activity of the Ni-NCNTs was evaluated and compared with pristine nickel oxide and commercial Pt/C catalysts through Linear Sweep Voltammetry (LSV) using a Rotating Disk Electrode (RDE) in an acidic medium. The Ni-NCNT catalyst exhibited a high current density of −2.7 mA cm −2 and an overpotential of −0.27 V versus the Saturated Calomel Electrode (SCE), outperforming bare nickel, which achieved −1.8 mA cm −2 . Furthermore, full-cell testing revealed an open circuit voltage of 1.0 V and a peak power density of 18 mA cm −2 . These results demonstrate that Ni-NCNTs possess excellent ORR activity, durability, and cost-effectiveness, highlighting their strong potential as a promising alternative to Pt-based catalysts for PEM fuel cell applications.