Home About us Contact
|
Home About us Contact | ||
|
|
||
Aluminum Oxide Templates (aluminum + oxide_templates)
Selected AbstractsTuning the Composition and Nanostructure of Pt/Ir Films via Anodized Aluminum Oxide Templated Atomic Layer DepositionADVANCED FUNCTIONAL MATERIALS, Issue 18 2010David J. Comstock Abstract Nanostructured metal films have been widely studied for their roles in sensing, catalysis, and energy storage. In this work, the synthesis of compositionally controlled and nanostructured Pt/Ir films by atomic layer deposition (ALD) into porous anodized aluminum oxide templates is demonstrated. Templated ALD provides advantages over alternative synthesis techniques, including improved film uniformity and conformality as well as atomic-scale control over morphology and composition. Nanostructured Pt ALD films are demonstrated with morphological control provided by the Pt precursor exposure time and the number of ALD cycles. With these approaches, Pt films with enhanced surface areas, as characterized by roughness factors as large as 310, are reproducibly synthesized. Additionally, nanostructured PtIr alloy films of controlled composition and morphology are demonstrated by templated ALD, with compositions varying systematically from pure Pt to pure Ir. Lastly, the application of nanostructured Pt films to electrochemical sensing applications is demonstrated by the non-enzymatic sensing of glucose. [source] Tuning the Composition and Nanostructure of Pt/Ir Films via Anodized Aluminum Oxide Templated Atomic Layer DepositionADVANCED FUNCTIONAL MATERIALS, Issue 18 2010David J. Comstock Abstract Nanostructured metal films have been widely studied for their roles in sensing, catalysis, and energy storage. In this work, the synthesis of compositionally controlled and nanostructured Pt/Ir films by atomic layer deposition (ALD) into porous anodized aluminum oxide templates is demonstrated. Templated ALD provides advantages over alternative synthesis techniques, including improved film uniformity and conformality as well as atomic-scale control over morphology and composition. Nanostructured Pt ALD films are demonstrated with morphological control provided by the Pt precursor exposure time and the number of ALD cycles. With these approaches, Pt films with enhanced surface areas, as characterized by roughness factors as large as 310, are reproducibly synthesized. Additionally, nanostructured PtIr alloy films of controlled composition and morphology are demonstrated by templated ALD, with compositions varying systematically from pure Pt to pure Ir. Lastly, the application of nanostructured Pt films to electrochemical sensing applications is demonstrated by the non-enzymatic sensing of glucose. [source] Template Synthesis of Aligned Carbon Nanotube Arrays using Glucose as a Carbon Source: Pt Decoration of Inner and Outer Nanotube Surfaces for Fuel-Cell Catalysts,ADVANCED FUNCTIONAL MATERIALS, Issue 6 2008Zhenhai Wen A facile method is developed to synthesize aligned arrays of open-ended carbon nanotubes (CNTs) via in situ glucose polymerization in the inner pores of anodic aluminum oxide templates under hydrothermal conditions, followed by carbonization at high temperature. Pt nanoparticles are decorated on the surfaces of the as-prepared CNTs using the incipient wet method based on the use of NaBH4 as a reductant. Characterization of the resulting structures by transmission electron microscopy and field-emission scanning electron microscopy demonstrates that the Pt nanoparticles are anchored on both the inner and outer walls of CNTs, thus giving rise to a shell,core,shell-like nanotube composite. The electrocatalytic properties of the Pt,CNT,Pt electrodes are investigated for methanol oxidation by cyclic voltammetry and chronoamperometric measurements. It is found that the hybrid electrodes show superior catalytic performance compared to commercial carbon-black-supported Pt. The increased catalytic efficiency of Pt might be a result of the unique morphology of these structures. [source] Structural and Magnetic Properties of Various Ferromagnetic NanotubesADVANCED MATERIALS, Issue 45 2009Xiu-Feng Han Abstract The structural and magnetic properties of ferromagnetic nanotubes fabricated by a low cost electrodeposition method are investigated. The fabrication of various elemental ferromagnetic materials are described, such as Fe, Co, and Ni, and ferromagnetic alloys, such as NiFe, CoPt, CoFeB, and CoCrPt nanotube arrays, in aluminum oxide templates and polycarbonate membranes with different diameters, wall thicknesses, and lengths. The structural, magnetic, and magnetization reversal properties of these nanotubes are investigated as a function of the geometrical parameters. The angular dependence of the coercivity indicates a transition from the curling to the coherent mode for the ferromagnetic nanotubes. The results show that nanotube fabrication allows the outer and inner diameter, length, and thickness of the nanotubes to be tuned systematically. The magnetization processes of ferromagnetic nanotubes are influenced by the wall thickness. [source] Orientation of Syndiotactic Polystyrene Crystallized in Cylindrical NanoporesMACROMOLECULAR RAPID COMMUNICATIONS, Issue 3 2009Hui Wu Abstract Syndiotactic polystyrene (sPS) nanorods with different diameters have been prepared by using anodic aluminum oxide templates, and the orientation of the sPS crystals in the nanorods has been investigated by FT-IR spectroscopy. It is found that the c axis of the ,, crystals preferentially oriented perpendicular to the axis of the nanorod, and the degree of orientation is lower as the diameter of the nanorod decreases. This unexpected result is attributed to nuclei formed at the surface of the nanopores and their subsequent growth, in addition to the preferential growth compatible with the pore direction by the nuclei formed in the bulk film and in the nanorods. [source] | ||||||||||