Search

Porous anodic metal oxides have been widely used for the development of various functional nanostructures. So far, these self‐organized pore structures were prepared as hexagonal arrangements of nanopores, which have become a popular template system for the fabrication of functional nanostructures. Here we report a new oxalic acid‐based anodization process for long‐range ordered arrays of submicrometer tin dioxide plates at low applied voltages in buffered solution, which prevents the precipitation of SnC2O4 on the Sn anode surface. The chemical composition of the surface SnO2 was established by Mössbauer spectroscopy and X‐ray photoemission spectroscopy (XPS). The growth direction of the SnO2 nanoplates was shown to be related to the orientation of the domains of the underlying polycrystalline yet oriented β‐Sn foil. The structured SnO2 surface is highly photoactive and generates superoxide radicals (O2·–) upon UV exposure resulting in a strong degradation of organic contaminants and a strong antimicrobial activity. Upon illumination the SnO2 coating exhibits a switchable amphiphilic behavior, which – in combination with its photoactivity – creates a self‐cleaning surface. [ABSTRACT FROM AUTHOR]

Nanoporous metal oxides are widely used for the development of various functional nanostructures. We report on the synthesis of sponge-like tin oxide films on copper foil by anodization of electrochemically deposited tin films. The thin films are functionalized using a surface-anchoring carbon precursor-polymer (poly(acrylonitrile-b-dopamine acrylamide)) followed by annealing at elevated temperature to convert the polymer coating into a carbonaceous coating. The as prepared and the carbon coated films are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and Raman spectroscopy. Subsequently, both SnOx films are employed as anode materials in lithium ion batteries. Carbon coating has a beneficial effect on the battery performance with respect to the rate capability, increasing the capacity by 200 mA h g−1 for all applied current densities. After 20 cycles, coated samples show a reversible specific charge capacity of 497 mA h g−1. Ex situ scanning electron microscopy reveals the retention of the sponge-like morphology even after cycling. [ABSTRACT FROM AUTHOR]