Abstract
M.Sc. (Chemistry)
The investigation of the effect of the platform (electrode) for electrocatalyst in the electro-oxidation of methanol for application in alcohol fuel cells (AFCs) was conducted. The three electrodes that were studied are exfoliated graphite (EG), glassy carbon (GC) and basal plane pyrolytic graphite (BPPG) electrode. The new and cheap electrode material named exfoliated graphite (EG) was prepared by intercalating natural graphite flakes with H2SO4 and HNO3 mixture in the ratio of 3:1 (v/v). The intercalated material was then subjected to thermal shock to obtain EG. In the case of GC and BPPG electrodes, the commercial electrodes were used.
This study reports the preparation of platinum monometallic (Pt) and platinum based bimetallic electrocatalysts (Pt-Au, Pt-Ru and Pt-Pd) supported on acid treated multi walled carbon nanotubes using polyol method. The physical properties of the prepared electrocatalysts were investigated using several techniques such as TEM, EDX coupled with TEM, XRD and FTIR spectroscopy. The electrochemical behaviour of Pt/fMWCNTs catalyst on three different electrodes namely EG, GC and BPPG were investigated. The BPPG electrode platform gave a better electrocatalytic performance compared to the EG and GC electrodes. Detailed electrochemical studies (involving cyclic voltammetry and chronoamperometry) proved that the electrocatalytic oxidation of methanol at Pt/fMWCNTs electrocatalyst on BPPG electrode platform is more stable and occurs at lower potential.
The results further revealed that Pt-Pd/fMWCNTs catalyst on BPPG platform showed better electrocatalytic behaviour for methanol oxidation in acidic medium, with high current response of 18.2 mAcm-2. However, Pt-Au/fMWCNTs electrocatalyst is more tolerant to CO poisoning than Pt-Ru/fMWCNTs and Pt-Pd/fMWCNTs during methanol oxidation in acidic medium...