Structural properties and surface chemistry of nano structured electroactive materials

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Nanostructured transition metal oxide systems such as metal spinel oxides have received renewed attention due to their demonstrated usefulness for a wide range of electrochemical reactions and recent applications as electrode materials in batteries and as oxygen reduction catalysts in fuel cells, but also as interesting magnetic materials, sensors, and capacitors. In this research program, we will use our expertise in electrochemistry, surface science and materials characterization to identify, quantify and understand the role of active sites at the surface of transition metal oxides (such as AxB3-xO4, AxByCzOq) and study the role that the redox properties of these metal cations have in electrochemical reactions to establish trends and guidelines that can be employed to predict their performance. The short terms objectives of our program are to identify, quantify and understand the role of active sites in transition metal (M)-cobalt oxide spinel (MxCo3-xO4) thin films with M = Cu, Ni and Fe and x values ranging from 0 to 1, as well as the effects of the preparation method, annealing and electrode history on the material's structure, surface chemistry and relevant properties. These materials will be used to perform our first in situ X-ray absorption spectroscopy (XAS) studies, more specifically in situ X-ray absorption near-edge structure (XANES). Using these materials, we will identify their bulk structures including types of cations and their chemical environments, as well as possible phase segregation at the surface of the materials, identifying how they form and affect electrochemical reactions. Once, a clear understanding is obtained the role of additional dopants in these materials will be investigated using our methodology to form (M)(M')CoO4 spinels with, for example, M, M' = Cu, Ni, Mn, Fe, in a systematic way. Based on their composition and structure, these oxide materials find applications in areas such as heterogeneous catalysis, electrode, gas and glucose sensors, fuel cells and photo driven electrolysis of water relevant to the production of H2 fuel.**