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In this work, silicon single crystal nanofibers were prepared first via self-catalyzed chemical etching. Then, Bi–Te nanoparticles were electrochemically deposited onto the nanofibers. Thermoelectric behavior of the Bi–Te capped nanofibers was characterized by Seebeck coefficient measurement. It is found that the Seebeck coefficient of the Si nanofiber capped with Bi–Te is 180 µV/K. It is two times higher than that of the single Si crystal nanofiber (70 µV/K) and four times higher than that of the single Si crystal wafer (40 µV/K).

Nanoscale Bi–Te particles with thermoelectric properties on copper substrate were investigated. The substrate was prepared by electroplating copper layer on a copper zinc alloy plate in a copper sulfate solution. Electrodeposition of the Bi–Te alloy particles was then performed in a nitrate bath. The electrolyte is composed of 0.05 M bismuth nitrate and 0.01 M tellurium dioxide dissolved in 2.0 M HNO 3 . Cyclic voltammetry and quartz microbalance tests associated with the electrodeposition process were conducted to show the mechanism and kinetics of the deposition. The morphology and compositional analysis of Bi–Te was obtained using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) respectively. The morphology analysis suggested that nanoscale Bi–Te particles were obtained and the EDS results indicated that the surface of the copper substrate contained Cu 2 O. The atomic ratio 1:1 for Bi:Te in the alloy, which is equivalent to the weight percentage of Bi:Te = 62%:38% was confirmed from the data obtained.

Iron as a catalyst has wide applications for hydrogen generation from ammonia, photodecomposition of organics, and carbon nanotube growth. Tuning the size and shape of iron is meaningful for improving the catalysis efficiency. It is the objective of this work to prepare nanostructured iron with high surface area via electrochemical deposition. Iron nanoneedles were successfully electrodeposited on Ti supported TiO 2 nanotube arrays in a chlorine-based electrolyte containing 0.15 M FeCl 2 ·4H 2 O and 2.0 M HCl. Transmission electron microscopic analysis reveals that the average length of the nanoneedles is about 200 nm and the thickness is about 10 nm. It has been found that a high overpotential at the cathode made of Ti/TiO 2 nanotube arrays is necessary for the formation of the nanoneedles. Cyclic voltammetry test indicates that the electrodeposition of iron nanoneedles is a concentration-limited process.