Zhizhong Dong

Combined Flame and Electrodeposition Synthesis of Energetic Coaxial Tungsten-Oxide/Aluminum Nanowire Arrays

A nanostructured thermite composite comprising an array of tungsten-oxide (WO2.9) nanowires (diameters of 20-50 nm and lengths of >10 μm) coated with single-crystal aluminum (thickness of ~16 nm) has been fabricated. The method involves combined flame synthesis of tungsten-oxide nanowires and ionic-liquid electrodeposition of aluminum. The geometry not only presents an avenue to tailor heat-release characteristics due to anisotropic arrangement of fuel and oxidizer but also eliminates or minimizes the presence of an interfacial Al2O3 passivation layer. Upon ignition, the energetic nanocomposite exhibits strong exothermicity, thereby being useful for fundamental study of aluminothermic reactions as well as enhancing combustion characteristics.

On the Morphologies and Photocatalytic Properties of TiO2 Nanoparticles Synthesized by Pulsed-Laser Decomposition of Titanium Tetraisopropoxide

Titanium dioxide belongs to the transition-metal oxide family and forms several polymorphs, including anatase (tetragonal), brookite (orthorhombic) and rutile (tetragonal). In comparison with other polymorphs, anatase-TiO2 is preferable for solar cell applications because of its high electron mobility, low dielectric constant, and low density [1,2]. In this investigation, a novel method is used to synthesize amorphous TiO2 nanoparticles, which upon subsequent post-annealing transform into unique nanostructures of anatase-TiO2. The resulting nanostructures display photocatalytic activity, which is enhanced when the anatase-TiO2 is doped with W using this new synthesis method.

Synthesis of Silver Doped TiO 2 Nanostructured Composites for Photocatalytic Applications

Titanium dioxide nanomaterials have received great attention in the past few years due to their unique properties such as high chemical stability, photocatalytic activity and high specific surface area [1,2]. Recently, TiO2 has been utilized as a photocatalyst in dye sensitized solar cells (DCCSs) [2] due to its electronic properties and low cost. Performance of TiO2-based DCCSs depends mainly on their band gap energy. Many efforts have been directed to dope TiO2 with various elements in order to shift its absorbance edge and hence to improve its efficiency in the visible region. Our previous work has shown ~23% improvement in efficiency when anatase-TiO2 is doped with ~7% wt. carbon [3]. In our research, we continue the effort in tuning the electronic properties of TiO2-based nanocomposites via doping different elements. In this paper, we describe the doping and characterization of nanostructured TiO2 with silver nanoparticles. Advanced characterizations techniques have been utilized to analyze the Ag-doped TiO2 nanocomposite and correlate structure with properties of the produced powder. This method will also be compared to novel laser-based doping technique developed recently in our laboratory.