부산대학교 도서관

• Biogenic lepidocrocite was deposited on anodic Al 2 O 3 /Al plate support. • Biogenic FeOOH/anodic Al 2 O 3 catalysts demonstrated activity in CO oxidation. • Change of lepidocrocite to maghemite accompanied catalytic activity increase. • CO/CO 2 species on surface indicated interaction with surface or subsurface oxygen. • Synergism of iron-containing compound and support surface in CO 2 evolution. Bacteria from Leptothrix genus were cultivated in Lieske's medium in presence of metallic lamellae (Al foil one-sided covered by anodic Al 2 O 3) in order to obtain supported γ-FeOOH as a biogenic precursor of catalytically active γ-Fe 2 O 3. Samples were studied by the methods of infrared, Moessbauer, and X-ray photoelectron spectroscopy and scanning electron microscopy (with energy dispersive X-ray analysis). Among possible FeOOH modifications, only the deposition of γ-FeOOH on the lamellae was attributed to the γ-AlOOH ingredient in the used support because of crystal structure similarity. Different amounts of biogenic iron (0.6 and 0.9%) were deposited. The catalytic activity in the reaction of CO oxidation was examined by in situ diffuse-reflectance infrared spectroscopy. Changes of lepidocrocite to maghemite occurred during the catalytic experiments. Static CO adsorption measurements showed formation of carbonate (bidentate, monodentate) and formate species on the surface indicating that the oxidation occurs at room temperature by reaction of CO with surface or subsurface oxygen. [ABSTRACT FROM AUTHOR]