The effect of graphite nature on the properties of exfoliated graphite doped with nickel oxide

Graphite flake (200-300 mu m), expandable graphite and exfoliated graphite with specific area 40 m(2)/g were used as graphite material. Doping of exfoliated graphite with NiO was carried out by anodic oxidation of graphite material in aqueous nickel nitrate solutions (C = 0.5%, 5%, 25% and 50%) followed by exfoliation at 250 and 900 degrees C. Exfoliation of the synthesized samples shows that bulk density of exfoliated graphite is provided by nature of initial material and synthesis conditions. Bulk density for the best samples is about 2-3 g/l at 250 degrees C. Anodic oxidation of exfoliated graphite leads pounding of the sample and allows obtaining exfoliated graphite with bulk density as high as 40-100 g/l. The specific surface area of EG-NiO was determined by nitrogen desorption measurements. The exfoliated graphite with a bulk density of 1-3 g/l have specific area 100-160 m(2)/g. The microstructure of exfoliated graphite was studied. The homogeneous distribution of nickel oxide particle 10-20 mu m in size was shown. The applied technique allows obtaining exfoliated graphite with bulk density as low as 2-10 g/l, high specific surface area of 50-160 m(2)/g and contains 1-60% NiO. (C) 2007 Elsevier Ltd. All rights reserved.