Abstract
The objective of this thesis is to develop corrosion resistant catalyst support materials that can potentially replace carbon in Polymer electrolyte fuel cells. Therefore, Nb doped TiO 2 and SnO 2 nanofibres and nanotubes were prepared by electrospinning and characterised by X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, N 2 adsorption/desorption analysis and electronic conductivity measurements. The obtained Nb doped TiO 2 and SnO 2 one dimensional structures demonstrated higher conductivity and surface area than non-doped oxides. Pt nanoparticles were prepared using a modified microwave-assisted polyol method and deposited on the electrospun supports. Electrochemical characterisation of the obtained electrocatalysts was performed ex situ using a rotating disc electrode, and compared with a commercial carbon support (Vulcan XC-72R). Pt supported on Nb doped SnO 2 provided higher electrochemical stability in comparison to Pt on carbon. Thus, a cathode of Pt/Nb-SnO 2 prepared by spray-coating was integrated into Membrane Electrode Assembly (MEA) and characterised in situ in a single polymer electrolyte fuel cell. The MEA exhibited higher durability though lower power density compared to MEA with Pt/C based cathode. Sb doped SnO 2 nanotubes have higher conductivity than Nb doped material and when integrated into a cathode, provided enhanced power density in comparison to Nb-SnO 2 based cathode.