Nitrogen self-doped carbon nanoparticles derived from spiral seaweeds for oxygen reduction reaction

Abstract

In this work, nitrogen self-doped porous nanoparticles were synthesized through a low cost and simple method with spiral seaweed as a source of nitrogen and carbon. Transmission electron microscopy (TEM), nitrogen adsorption–desorption, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analysis showed that nitrogen was successfully doped into the framework of porous nanostructures. The nitrogen self-doped porous nanomaterial featured a high surface area and micro/mesoporous structures. The fabricated nanomaterial was then used as a metal-free catalyst for oxygen reduction reaction (ORR). This catalyst exhibited improved electrocatalytic activity, long-term operation stability, and high CH₃OH tolerance for ORR in alkaline fuel cells compared with commercial Pt/C catalysts. The influence of different nitrogen species formed in different atmospheres on ORR activity was further investigated. This study shows that spirulina is a suitable nitrogen and carbon source for various carbon-based materials for the development of metal-free efficient catalysts for applications beyond fuel cells.