Formation and characterisation of CeO2 and Gd:CeO2 nanowires/rods for fuel cell applications

Ceria and gadolinium (Gd) doped ceria nanowires have been synthesised by hydrothermal technique with mild reaction conditions. The structure and morphology of as-prepared nanowires were studied by X-ray diffraction and field emission scanning electron microscopy (FE-SEM) techniques. The FE-SEM analysis revealed the formation of nanowires with an average diameter of 10-15nm. Atomic force microscopy (AFM) analysis for the annealed samples confirms the existence of well defined nanorods of 120-150 nm diameter and 1-1.3 mu m length. Fluorescence and diffuse reflectance spectroscopy techniques have been used to study the optical properties of the prepared nanowires. The observed red shift in the ultraviolet-visible absorption spectra confirmed the promoted electron-phonon interaction in CeO2 and Gd:CeO2 nanowires compared to bulk structures. The prepared nanowires/rods were thermally stable at up to 350 degrees C, as revealed by thermogravimetric analysis. The electrical properties were studied by cyclic voltammetry (CV) and impedance spectroscopy. The CV results demonstrated that Gd:CeO2 exhibited a higher electro-oxidation than CeO2 nanowires.