(329v) Sorption Properties Of N2 And H2 On Multi-Walled Carbon Nanotube-Graphite Mixture Modified By Alkaline Hydroxides

Carbon has been known as one of the best adsorbents for gases. Since the discovery of carbon nanotubes numerous studies have been conducted on their synthesis, treatment and sorption properties [1]. The physical and chemical activation are well known methods to obtain microporous carbon with high surface area from different precursors [2,3]. Among all the chemical activation agents, alkaline hydroxides as KOH or NaOH are reported to be highly interesting from the performance point of view, allowing activated carbons to be prepared from many kinds of carbonaceous precursors [4]. Hydrogen sorption studies in carbon materials have been of great concern in recent years as hydrogen is regarded as an ideal energy source causing no pollutants or greenhouse gases during combution unlike the fossil fuels [5,6]. In this study, the multiwalled carbon nanotubes-graphite mixture produced as a cathode deposit during the Kratschmer-Huffman arc process modified by alkaline hydroxides (KOH, NaOH) at different temperatures was used to enhance the surface area and the capability of hydrogen sorption. The surface area of the MWCNT-graphite mixture was increased by physical activation in the temperature range of 300-800°C and the highest value of the surface area was obtained at 800°C. KOH and NaOH activations were applied for the sample mixture in a temperature range of 500-800°C. The surface area and the micropore volume of MWCNT-graphite sample mixture was increased by alkaline hydroxides activation. The samples produced by physical and the alkaline hydroxides activations were compared according to their hydrogen sorption characteristics.

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