Novel methods for preparing nanocrystalline SnO2 and Sn/SnO2 composite by electrodeposition

Tin oxide is one of the most widely studied oxide semiconductors. A novel process to prepare Sn/SnO2 nanocomposite and nanocrystalline Snot coating from nitrate solution by chronoamperometry and pulse technique, respectively, has been established in the present study. For the chronoamperometric technique, the percentage of Sn, ranging from 12.3 to 49.1 mol.%, can be controlled by the applied voltage (-0.2 to -0.6 V). The co-deposited metallic Sn can be oxidized into nanocrystalline Sn02 at -0.1 V versus Ag/AgC1 by using a pulse technique composed of alternatively a higher voltage stage (-0.2 to -0.6 V) and a low voltage stage (-0.1 V), and then a pure nanocrystalline SnO2 coating can thus be synthesized. The grain size of Sn02, ranging from 28.9 to 16.6 nm, could also be controlled by the applied voltage. The phase compositions and morphologies of the coatings were characterized by X-ray diffraction and SEM observation, respectively, and the percentage of Sn was determined by XPS analysis.