Anodization, Precursor Route to Flowerlike Patterns Composed of Nanoporous Tin Oxide Nanostrips on Tin Substrate

In the present work, we report for the first time an investigation on anodic oxidation of tin in an electrolyte of dimethyl sulfoxide (DMSO)/water mixtures containing citric acid in the trans-passive region. The anodization leads to the formation of flowerlike patterns composed of tin citrate complex nanostrips on tin substrates. The products were characterized using XRD, SEM, TEM, FTIR, and XPS measurements. The formation mechanism of the tin citrate complex microstructures is discussed and the influences of the voltage, citric acid concentration, and electrolyte composition on the morphology of the microstructures were investigated. The nanostrips with a smooth surface can be transformed to polycrystalline SnO 2 nanostrips with a porous structure by a thermal annealing process. This work developed a simple, clean, and effective route for fabrication of large area SnO 2 nanostructured films.