Investigation of the Effect of Amine Functionalized Multiwall Carbon Nanotubes as promising support for Pt Nanoparticles on Oxygen Reduction Reaction

In this study, multi-wall carbon nanotubes were chemically oxidized (OMWCNTs) and functionalized with ethylenediamine (EDAMWCNTs) as an amine precursor. The electrocatalysis were prepared through deposition of platinum nano particles on the functionalized carbon nanotubes by polyol method with the ratio of 10 wt% Pt. The formation of functional groups, the average size of Pt particles and the structural changes were characterized by FTIR, XRD and TEM. The average size of Pt nano particles was found to be between 4 and 5 nm. An appropriate dispersion of nanoparticles was observed especially in the presence of nitrogen atoms which can enhance the electro catalytic activity of the electro catalysis for oxygen reduction reaction. Cyclic voltammetry (CV) and rotating disk electrode (RDE) were employed to evaluate the electrochemical properties of the electro catalysis. Electrochemical active surface area (EAS), number of electron transferred (n), and onset potential were increased in the case of Pt-EDAMWCNTs which were found to be 32.2 (m2/g Pt), 0.987 (V vs RHE), and 4.03 electron per oxygen molecule, respectively. However, in the case of Pt-OMWCNTs the above mentioned electrochemical characteristics were calculated to be 27.8 (m2/g Pt), 0.824 (V vs RHE), and 3.34 electron, respectively. Thus, the reduction of oxygen molecules improves in the presence of amine functional groups owing to better nucleation and growth of Pt nano particles. The results indicate that, the presence of nitrogen atoms at amine functional groups improves the electro catalytic activity due to its high electron conductivity.

Keywords:

Oxygen Reduction Reaction , MWCNTs , Ethylenediamine , Platinum , Koutecky-Levich equation