A Study of Hydrogen Adsorption in Pretreated Nanocarbon
- PDF / 541,945 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 80 Downloads / 172 Views
I12.3.1
A Study of Hydrogen Adsorption in Pretreated Nanocarbon Sang Moon Lee*, Satoshi Ohshima, Kunio Uchida and Motoo Yumura * Japan Fine Ceramics Center, AIST Tsukuba Central 5, Tsukuba, Ibaraki 305–8565, Japan Nanostructured Materials Team, Research Center for Advanced Carbon Materials, AIST Tsukuba Central 5, Tsukuba, Ibaraki 305–8565, Japan ABSTRACT A thermal treatment was applied with CO2 and air for the development of a porous structure. Adsorption isotherms of nitrogen were measured on well-characterized Ni-C nanoparticles. The thermal treatment with CO2 increased the total surface area and micropore volume. In addition, the thermal treatment with CO2 increased the hydrogen adsorption. INTRODUCTION In recent years, the preparation of new materials, such as carbon nanotubes[1], carbon nanoparticles[2], and nanofibers[3] has been receiving much attention. These carbon nanomaterials are of interest from scientific and technological points of view, and they are expected to hold a great potential for application in various fields. In particular, the reversible storage of hydrogen on carbon nanotubes and nanofiber has been studied extensively[4-6]. Moreover, for adsorption utilization, opening of the potential adsorption space of nanotubes has been studied[7-8]. However, there has not been a study of gas adsorption on nanoparticles. Therefore, we investigated the pore structure, which plays an essential role in gas adsorption, as well as the properties of hydrogen adsorption and the surface properties of Ni-C nanoparticles. Ni-C nanoparticles with a diameter of 5-20nm were synthesized by the arc-discharge method. The particles were stable under the atmosphere because they were surrounded with a graphite sheet and amorphous carbon. Because Ni-C nanoparticles are nearly nonporous, the thermal treatment was applied with CO2 and air in order to develop a porous structure. After that, the pore structure parameters of Ni-C nanoparticles before and after thermal treatment were investigated by high-resolution N2 adsorption measurement at 77K. In addition, the surface properties of Ni-C nanoparticles were investigated by X-ray Photoelectron Spectroscopy (XPS). Hydrogen adsorption studies were performed using a gravimetric method in which weight changes in samples with gas adsorption were measured using a balance.
I12.3.2
EXPERIMENTAL Ni-C particles were synthesized by the arc-discharge method. Ni-C nanoparticles have a diameter of 5-20nm. Thermal treatment was respectively performed by CO2 and air for development of a porous structure. Ni-C nanoparticles were heated in a CO2 flow of 200mL/min at 1173K for 15min using a tubular furnace and in air atmosphere at 623K for 15min using a box furnace. Prior to the thermal treatment, TGA analysis of Ni-C nanoparticles was carried out to determine the temperature of thermal treatment in CO2 and air, respectively. The micropore structures were determined by adsorption of N2 at 77K using volumetric equipment (Quantachrome AS-1-MP) after preevacuation at 573K and 10-4 Pa for 24hr
Data Loading...
