Tongtao Wang

Pt Nanoclusters Electrodeposited on Single-Walled Carbon Nanotubes for Electrochemical Catalysis

Single-walled carbon nanotube supported Pt (Pt-SWNT) catalysts with uniform Pt nanoclusters were successfully synthesized on the carbon electrode by a pulse electrodeposition technique. The morphology of the catalysts was characterized by scanning electron microscopy analysis. The electrocatalytic activities of the catalysts toward the methanol oxidation reaction and the oxygen reduction reaction were investigated by cyclic voltammetry measurements. In comparison with Pt-XC-72 catalysts prepared by the same method, the Pt-SWNT catalysts exhibited higher electrocatalytic activity for methanol oxidation and oxygen reduction. Electrochemical active surface area and chronoamperometry results indicated that Pt-SWNT catalysts had larger active surfaces. This may be attributed to the high dispersion of Pt catalysts and the unique properties of single-walled carbon nanotube support. The substructure of Pt particles also contributed to the enhanced active surfaces. Furthermore, the electron transition mechanism in the oxygen reduction reaction at the Pt-SWNT electrode is preliminarily discussed using the rotating disk electrode analysis.

Suppression of methanol cross-over in novel composite membranes for direct methanol fuel cells

A series of novel composite membranes was prepared by using poly(vinyl alcohol) (PVA) with polyimide (PI) as base material and 8-trimethoxysilylpropyl glycerine ether-1,3,6-pyrenetrisulfonic acid (TSGEPS) as proton conductor for direct methanol fuel cells (DMFCs). The parameters of membranes, including water sorption, hydrolysis stability, dimensional stability, proton conductivity, and methanol permeability were studied. The proton conductivity of the membranes is in the order of 10–2 S/cm, and the membranes show better resistance to methanol permeability (1.51 × 10–7 cm2 s–1) and better selectivity (20.6 × 104 S cm–3 s) than those of Nafion115 under the same measurement conditions.

Fabrication of highly oriented ZnO nanorod arrays by galvanostatic deposition

Abstract Highly oriented ZnO nanorod arrays were successfully prepared on the indium tin oxide (ITO) substrate using a galvanostatic electrodeposition method. The ITO substrate was pretreated with ZnO nanoparticles via simple low-temperature solution route. The crystallinity, micro- structure of surface, and optical properties of the obtained ZnO were characterized by X-ray diffraction, scanning electron microscope, and transmittance spectrum. The results indicate that the average diameter of ZnO nanorod arrays is about 30 nm, and the narrow size distribution ranges from 20 to 50 nm. The nanorod arrays are growing along [001] direction with an orientation perpendicular to the substrate. When the wavelength of incident is over 380 nm, the ZnO nanorod arrays show a high optical transmission of above 95%. Furthermore, the possible growth mechanism of the nanorod arrays was discussed.