Double-walled Nanotube Arrays Research Articles

Design of Polymer Composite Double-Walled Nanotube Arrays for Electrochemical Energy Storage

not Available.

Carbon/MnO2Double-Walled Nanotube Arrays with Fast Ion and Electron Transmission for High-Performance Supercapacitors

The novel carbon (C)/MnO2 double-walled nanotube arrays (DNTAs) are designed and fabricated via template-assisted electrodeposition. The unique DNTA architectures of C/MnO2 composites with high weight fraction of MnO2 allow high electrode utilization ratio and facilitate electron and ion transmission. In the half-cell test, the hybrid C/MnO2 DNTAs as electrodes show a large specific capacitance (Csp) of 793 F/g at the scan rate of 5 mV/s, high energy/power densities, and much enhanced long-term cycle stability. After 5,000 cycles, the Csp retention of C/MnO2 DNTAs keeps ∼97%, which is much larger than 69% of the MnO2 nanotube arrays (NTAs). The symmetrical supercapacitors (SSCs) composed of C/MnO2 DNTAs also show the predominant performance, such as large Csp of 161 F/g and high energy density of ∼35 Wh/kg, indicating that the C/MnO2 DNTAs is a potential electrode for supercapacitors. The high order pore passages, double-walled structures, hollow structures, and high conductivity are responsible for the superior performance of C/MnO2 DNTAs. Such hybrid C/MnO2 DNTAs may bring new opportunities for the development of supercapacitors with superior performance.

Design of Polypyrrole/Polyaniline Double-Walled Nanotube Arrays for Electrochemical Energy Storage

The novel hybrid polypyrrole (PPy)/polyaniline (PANI) double-walled nanotube arrays (DNTAs) were designed to exploit the synergistic effects and shape effects for supercapacitive energy storage. The PPy/PANI DNTAs showed large specific capacitance (Csp) of 693 F/g at a scan rate of 5 mV/s. The PPy/PANI DNTAs also exhibited good rate capability and high long-term cycle stability (less 8% loss of the maximum specific capacitance after 1000 cycles). The synergistic effects between PPy and PANI, the shape effects of nanotube arrays and double-walled nanostructures, and high utilization rate of electrode are crucial for the outstanding performance of PPy/PANI DNTAs. The large Csp, good rate capability, and high long-term cycle stability offered by the PPy/PANI DNTAs, make them promising candidate electrodes for high-performance supercapacitors.

Synthesis and Photocatalytic Activity of Cu<SUB>2</SUB>O/TiO<SUB>2</SUB> Double Wall Nanotube Arrays

Synthesis and Photocatalytic Activity of Cu<SUB>2</SUB>O/TiO<SUB>2</SUB> Double Wall Nanotube Arrays

Double-Wall Anodic Titania Nanotube Arrays for Water Photooxidation

Vertically oriented double-wall titania nanotube (external diameters of 82 and 206 nm) arrays are synthesized by a sonoelectrochemical anodization technique in combination with a unique room-temperature ionic liquid and organic electrolyte. Compared to similar single-wall nanotubes (0.638 mA/cm(2)) and commercial nanoparticles (0.365 mA/cm(2)), these double-wall nanotube arrays show 2-4 times more photoactivity to split water under solar light illumination to generate hydrogen and oxygen. Partial doping of B and C into the TiO(2) matrix gives rise to these double-wall nanotubes which absorb visible solar light more efficiently than the intrinsic TiO(2). The structural properties of these novel structures have been studied extensively using various spectroscopic, analytical, and electrochemical techniques.