Background: Fuel cells have a very low emission of greenhouse gases such as CO2, SOx
etc with high efficiencies and are non-polluting energy sources. One of the current challenges is to
develop inexpensive and efficient oxygen reduction reaction (ORR) materials. Extensive research
has been conducted to develop platinum (Pt) loaded carbon nanomaterials for ORR applications.
However, the literature is rife with inconsistencies owing to varying synthesis conditions of Pt
nanoparticles, variation of carbon supports materials and indeed the ORR experiments.
Method: A comparative electrochemical analysis of various carbon supports, including commercial
PtCB, pristine and Pt loaded carbon nanotubes (MWCNTs), graphene oxide (GO) and graphene nano
platelets (GNP) has been conducted, to ascertain their electrochemical response towards oxygen
reduction reactions under identical experimental conditions.
Results: The reduction potential (least negative) and the peak current densities for the materials follow
the order of MWCNTs>GNP>GO, with the performance of pristine MWCNTs (3 mA/cm2)
comparable to that of N- and B-doped MWCNTs. Furthermore, low-loading of platinum nanoparticles
on the carbon supports, carried out via microwave-assisted polyol synthesis, lead to an increase
in the peak reduction current density significantly at lower reduction potentials. Although the same
synthesis process is used; the MWCNTs, GO and GNP support samples have different metallic Pt
loadings. A comparison of ORR current densities mass normalized to Pt loading shows that
Pt/MWCNTs have the highest linear sweep voltammetry (LSV) reduction current density of 900 A/g,
much higher than 510 A/g of the commercial Pt-carbon black supports, and is followed by Pt/GNP
and Pt/GO which have the LSV value of 500 A/g and 200 A/g LSV, respectively.
Conclusion: The results showed that the Pt/MWCNTs should be given a favourable consideration in
ORR for the future development of fuel cell technologies.