Tunable Biogenic Manganese Oxides. Issue 54 (28th August 2017)

• Record Type: Journal Article
• Authors: Simonov, Alexandr N.; Hocking, Rosalie K.; Tao, Lizhi; Gengenbach, Thomas; Williams, Timothy; Fang, Xi‐Ya; King, Hannah J.; Bonke, Shannon A.; Hoogeveen, Dijon A.; Romano, Christine A.; Tebo, Bradley M.; Martin, Lisandra L.; Casey, William H.; Spiccia, Leone
• Is Part Of: Chemistry. Volume 23:Issue 54(2017)
• Page Start: 13482
• Page End: 13492
• Publication Date: 2017-08-28
• Subjects: biogenic materials -- manganese -- MnxEFG protein complex -- structural disorder -- structure elucidation -- tunable morphology; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201702579
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Influence of the conditions for aerobic oxidation of Mn 2 + ( aq ) catalysed by the MnxEFG protein complex on the morphology, structure and reactivity of the resulting biogenic manganese oxides (MnO x ) is explored. Physical characterisation of MnO x includes scanning and transmission electron microscopy, and X‐ray photoelectron and K‐edge Mn, Fe X‐ray absorption spectroscopy. This characterisation reveals that the MnO x materials share the structural features of birnessite, yet differ in the degree of structural disorder. Importantly, these biogenic products exhibit strikingly different morphologies that can be easily controlled. Changing the substrate‐to‐protein ratio produces MnO x either as nm‐thin sheets, or rods with diameters below 20 nm, or a combination of the two. Mineralisation in solutions that contain Fe 2 + ( aq ) makes solids with significant disorder in the structure, while the presence of Ca 2 + ( aq ) facilitates formation of more ordered materials. The (photo)oxidation and (photo)electrocatalytic capacity of the MnO x minerals is examined and correlated with their structural properties. Abstract : Tune in ! The MnxEFG protein complex is a natural catalyst for the generation of manganese oxides. Structural properties and morphology of these biogenic MnO x can be easily tuned by adjusting the synthesis conditions, in particular by variations in the substrate‐to‐protein ratio or introduction of other metal cations. The tunability and robustness of biogenic MnO x make these materials attractive for various applications.