Vol.:(0123456789) Reaction Kinetics, Mechanisms and Catalysis https://doi.org/10.1007/s11144-019-01587-9 1 3 Comparative study of CO oxidation on biogenic lepidocrocite layered on anodic alumina samples Maya Shopska 1  · Daniela Paneva 1  · Hristo Kolev 1  · Georgi Kadinov 1  · Jaroslav Briančin 2  · Martin Fabián 2  · Daniela Kovacheva 3  · Zara Cherkezova‑Zheleva 1  · Ivan Mitov 1 Received: 4 April 2019 / Accepted: 17 May 2019 © Akadémiai Kiadó, Budapest, Hungary 2019 Abstract Leptothrix genus bacteria were cultivated in Lieske medium in presence of anodic Al 2 O 3 /Al to synthesize γ-FeOOH as a biogenic precursor for catalyst preparation. Diferent amounts of biogenic iron (0.6, 0.9, 9.2% Fe) were deposited. γ-FeOOH deposition on the support was identifed the process being determined by the anodic Al 2 O 3 surface structure. The catalytic activity in the CO oxidation reaction was examined by in situ difuse-refectance infrared spectroscopy up to 250 °C. A max- imum conversion of 42% was achieved with 9.2% Fe sample. However, the low- est amount of reaction product CO 2 was determined. Lepidocrocite conversion into maghemite occurred during catalytic experiments. Static adsorption study showed presence of carbonate (bidentate, monodentate) species and formates on the sam- ples surface indicating that oxidation occurred at room temperature by CO interac- tion with (sub)surface oxygen. Bidentate carbonate species were not registered with 9.2% Fe sample. Additionally, inhibited formate species formation was registered on the same sample. In this case the biogenic iron coverage could be considered thicker and denser determining CO 2 adsorption–desorption to/from the surface of iron-containing compound and anodic alumina. So, the higher CO conversion with 9.2% Fe sample was at the expense not only for transformation to CO 2 but some part remained on the surface as strongly adsorbed species. Keywords Biogenic lepidocrocite · Leptothrix sp. · (In situ) infrared spectroscopy · CO oxidation Electronic supplementary material The online version of this article (https://doi.org/10.1007/s1114 4-019-01587-9) contains supplementary material, which is available to authorized users. * Maya Shopska shopska@ic.bas.bg; maya11may@abv.bg Extended author information available on the last page of the article