Abstract
M.Tech. (Chemistry)
Direct alcohol fuel cells are potential future energy sources for mobile and stationary appliances. They are fascinating more than the hydrogen fuel cells because they utilise a liquid fuel that is easy to store and transport. However, several drawbacks such as the high cost of pure platinum and the instability of carbon electrodes in the fuel cell environment are hindering the commercialisation of the DAFC technology. The platinum electrocatalyst is easily poisoned by the intermediates that are produced during alcohol electro-oxidation reactions, this result in low energy output. This study was devoted in synthesising a carbon support material with high surface area and to prepare platinum-based electrocatalysts with anti-poisoning and anti-corrosion properties.
Carbon nanodots (CNDs) with sizes below 10 nm were synthesised by pyrolysing oats grains. The BET surface area of the CNDs was found to be 312.5 m2 g-1. XPS and FTIR results jointly revealed that the CNDs contain oxygen-containing functional groups which facilitate the attachment of metal nanoparticles. The Pt/CNDs electrocatalyst was synthesised using water as a solvent without adding any reducing agent.
The Pt/CNDs electrocatalyst was tested against the commercial Pt/C standard to evaluate the performance of the CNDs (support material). Cyclic voltammetry results showed that the Pt/CNDs electrocatalyst prepared by this method exhibit superior performance for methanol and ethanol electro-oxidation at room temperature.
The Pt-Sn/CNDs electrocatalyst was synthesised by the alcohol reduction method with the aim to reduce platinum loading and improve electroactivity. XPS results showed that the nanoparticles were present in the form of Pt-Sn metallic alloy with a significant amount of SnO- species. The lattice parameter of Pt in Pt-Sn/CNDs electrocatalyst was calculated to be 0.3926 nm; this value is higher than 0.3921 nm, the lattice parameter of Pt in Pt/CNDs electrocatalyst. XRD results proved that...