• 한국신재생에너지학회:학술대회논문집
• /
• 2011.05a
• /
• pp.159.2-159.2
• /
• 2011

In this study, we prepared the activated graphite nanofibers (A-GNFs) via chemical activation with KOH reagent. The effect of A-GNFs on the surface and textural properties of Ni-loaded graphite nanofibers (Ni/GNFs) was investigated by X-ray diffraction (XRD), transmission electron microscope (TEM), and Brunauer-Emmett-Teller (BET). The textural properties of samples were investigated by $N_2$/77K adsorption isotherms. The electrochemical performances were investigated by cyclic voltammetry. As a results, the electrochemical performances of Ni/GNFs were improved with usage of A-GNFs. This could be interpreted by the high specific surface area and large total pore volume of the A-GNFs.

• Carbon letters
• /
• v.19
• /
• pp.99-103
• /
• 2016

Porous carbons have attracted much attention for their novel application in gas storage. In this study, porous graphite nano-fiber (PGNFs)-based graphite nano fibers (GNFs) were prepared by KOH activation to act as adsorbents. The GNFs were activated with KOH by changing the GNF/KOH weight ratio from 0 through 5 at 900℃. The effects of the GNF/KOH weight ratios on the pore structures were also addressed with scanning electron microscope and N₂ adsorption/desorption measurements. We found that the activated GNFs exhibited a gradual increase of CO₂ adsorption capacity at CK-3 and then decreased to CK-5, as determined by CO₂ adsorption isotherms. CK-3 had the narrowest micropore size distribution (0.6–0.78 nm) among the treated GNFs. Therefore, KOH activation was not only a significant method for developing a suitable pore-size distribution for gas adsorption, but also increased CO₂ adsorption capacity as well. The study indicated that the sample prepared with a weight ratio of ‘3’ showed the best CO₂ adsorption capacity (70.8 mg/g) as determined by CO₂ adsorption isotherms at 298 K and 1 bar.

• Korean Chemical Engineering Research
• /
• v.48 no.6
• /
• pp.673-678
• /
• 2010

In the present study, mixed carbon-supported platinum(Pt) nanoparticles were prepared by a chemical reduction method of Pt precursor solution on two types of carbon materials such as activated carbons(ACs) and graphite nanofibers(GNFs). Average crystalline sizes and loading levels of Pt metal particles could be controlled by changing a content of GNFs. The highest electroactivity for methanol oxidation was obtained by preparing the carbon supports having 15 wt% GNFs. Furthermore, with an increase of GNFs content from 0% to 15%, an electrical conductivity was changed from $10^{-4}S/cm$ to $10^{-1}S/cm$. By an introduction of 10 wt% GNFs additive, the electroactivity of platinum particles was enhanced, but was saturated in the case of 15 wt% GNFs contents. This was related with the fact that the electroactivity change was dependent on the electrical conductivity of mixed carbon supports and Pt particle deposition content or deposition morphology.

• Polymer(Korea)
• /
• v.36 no.3
• /
• pp.321-325
• /
• 2012

In this work, we prepared the activated graphite nanofibers (A-GNFs) via chemical activation with KOH/GNFs ratios in a range of 0 to 5. The effect of KOH activation was studied in the surface and pore properties of the samples for electrochemical performance. The surface properties of A-GNFs were characterized by XRD and SEM measurements. The textural properties of the A-GNFs were investigated by $N_2$/77 K adsorption isotherms using Brunauer-Emmett-Teller (BET) equation. Their electrochemical behaviors were investigated by cyclic voltammetry and galvanostatic charge-discharge performance. From the results, electrochemical performances of the A-GNFs were improved with increasing the ratio of KOH reagent. It was found that specific surface area and total pore volume of the A-GNFs were increased by KOH activation.

• 한국신재생에너지학회:학술대회논문집
• /
• 2011.05a
• /
• pp.93.2-93.2
• /
• 2011

In this work, graphite nanofibers (GNFs) were prepared for using catalyst supports in fuel cells. The GNFs were chemically activated to obtain high surface area and small pore diameter with different potassium hydroxide (KOH) amounts, i.e., 0, 1, 3, 4, and 5 g as an activating agent. And then Pt-Ru was deposited onto activated GNFs (A-GNFs) by chemical reduction method. The characteristics of Pt-Ru catalysts deposited onto A-GNFs were determined by specific surface area and pore size analyzer, X-ray diffraction (XRD), transmission electron microscopy (TEM), and inductive coupled plasma-mass spectrometer (ICP-MS). The electrochemical properties of Pt-Ru/A-GNFs catalysts were also analyzed by cyclic voltammetry (CV) experiments. From the results, the A-GNFs carbon supports activated with 4 g of KOH (A4g-GNFs) showed that the highest specific surface areas. In addition, the A4g-GNFs led to uniform dispersion of Pt-Ru onto A4g-GNFs, resulting in the enhancement of electrochemical activity of Pt-Ru catalysts.