A Unique 3D Nitrogen-Doped Carbon Composite as High-Performance Oxygen Reduction Catalyst.

Ramesh Karunagaran,Tran Tung,Cameron Shearer,Diana Tran,Christian Doonan,Campbell Coghlan,Dusan Losic

doi:10.3390/ma10080921

Abstract

The synthesis and properties of an oxygen reduction catalyst based on a unique 3-dimensional (3D) nitrogen doped (N-doped) carbon composite are described. The composite material is synthesised via a two-step hydrothermal and pyrolysis method using bio-source low-cost materials of galactose and melamine. Firstly, the use of iron salts and galactose to hydrothermally produceiron oxide (Fe2O3) magnetic nanoparticle clusters embedded carbon spheres. Secondly, magnetic nanoparticles diffused out of the carbon sphere when pyrolysed in the presence of melamine as nitrogen precursor. Interestingly, many of these nanoparticles, as catalyst-grown carbon nanotubes (CNTs), resulted in the formation of N-doped CNTs and N-doped carbon spheres under the decomposition of carbon and a nitrogen environment. The composite material consists of integrated N-doped carbon microspheres and CNTs show high ORR activity through a predominantly four-electron pathway.

Highlights

Rising energy demands and the depletion of non-renewable fossil fuels have generated significant interest in renewable energy sources such as solar, wind, and geothermal [1]
The presence of FeMNPs encapsulated within the sphere was confirmed by transition electron microscopy (TEM) (Figure 1B)
The FeMNPCs are encapsulated within the carbon sphere through coulombic interactions formed between surface functional groups (i.e., OH, C=O) of galactose and

Summary

Introduction

Rising energy demands and the depletion of non-renewable fossil fuels have generated significant interest in renewable energy sources such as solar, wind, and geothermal [1]. Among alternate energy devices currently being considered, for mobile applications, fuel cells have been widely investigated due to their theoretically high efficiencies and low carbon footprint [2]. In a hydrogen fuel cell O2 and H2 are converted into electricity and water. This process involves reducing O2 at the cathode, a reaction typically carried out by expensive platinum-based catalysts. The commercial viability of hydrogen fuel cells requires the development of low-cost and efficient oxygen reduction reaction (ORR) catalysts [3]. Recent research efforts have focused on the development of alternative catalysts that can be synthesised from readily available starting materials while overcoming the drawbacks of the

Methods

Discussion

Conclusion