Synthesis And Characterization Of Intermetallic Compounds And Transition Metal Nitrides As High-Performance Proton Exchange Membrane Fuel Cell Materials

One of the major challenges in fuel cell technologies, particularly for Proton Exchange Membrane Fuel Cells (PEMFCs), is developing effective catalysts for use in both the anode and cathode. Ordered intermetallic compounds have shown considerable potential for fuel cell applications due to their enhanced catalytic activity, better durability and lower cost. In this work, Pd-Sn intermetallic compounds were investigated. PdSn and Pd3Sn nanoparticles were synthesized under air-free conditions and were tested for their electrochemical properties. Both materials showed poor activities in acidic environment for formic acid and methanol oxidation, but enhanced activities under basic conditions. Various electrochemical tests and structural characterization including high-resolution TEM/STEM and EDX were performed to investigate the changes in these materials that might have resulted in such performance. In this thesis, we also focus on developing stable catalyst supports for fuel cell electrodes, another topic in fuel cell research. Motivated by recent studies which revealed the potential of transition metal nitrides as high performance catalyst supports, we developed a facile synthesis of single-phase, nanocrystalline macroporous chromium nitride and chromium titanium (oxy)nitride with an inverse opal morphology. Characterization using XRD, SEM, HR-TEM/STEM, TGA and XPS is reported. Interconversion of macroporous CrN to Cr2O3 and back to CrN while retaining the inverse opal morphology was also demonstrated. ii