Graphene materials with different structures prepared from the same graphite by the Hummers and Brodie methods

Abstract

Graphene materials containing different functional groups were prepared from a natural graphite, by means of two different oxidation methods (Hummers and Brodie). It was observed that the differences in the structure of the resultant graphite oxides (GOs) greatly affect the structure of the graphenes resulting from their thermal exfoliation/reduction. Although the oxidation of the graphite was more effective with the modified Hummers method than with Brodie´s method (C/O of 1.8 vs 2.9, as determined by XPS), the former generated a lower residual oxygen content after thermal exfoliation/reduction and a better reconstruction of the 2D graphene structure (with fewer defects). This is explained by the presence of conjugated epoxy and hydroxyl groups in the GO obtained by Brodie´s method, which upon thermal treatment, lead to the incorporation of oxygen into the carbon lattice preventing its complete restoration. Additionally, graphene materials obtained with Brodie´s method exhibit, in general, a smaller sheet size and larger surface area.

A hydrogel biosensor for high selective and sensitive detection of amyloid-beta oligomers

“…24,25 GO hydrogel was prepared based on our previous work except that no fish sperm DNA was added. 23 A total of 0.5 mL of 4.05 mg/mL GO was dropped into a 2 mL conicalbottom centrifuge tube, which was heated at 95°C for 1 h in a thermomixer and cooled down to room temperature to form GO hydrogel.…”

Nitrogen-Doped Reduced Graphite Oxide as a Support for CoSe Electrocatalyst for Oxygen Reduction Reaction in Alkaline Media

“…After oxidation, the distance of layers is 0.602 nm (2θ = 14.70) which is attributed to the incorporation of oxygen-groups, and water. 44 Additionally, the number of layers associated to GO was reduced to ca. 19.…”

“…• C. 44 Nitrogen doping occurs when the vacancies left by the reduction of oxygen functional groups are substituted by nitrogen from the polymer structure, Figure 1.…”

“…Graphite oxide (GO).-GO was obtained by a modified Brodie 43 method reported by Botas et al 44 In short, 10 g of powdered graphite (Alfa Aesar, ≥99.9%, Mesh 300) were mixed very slowly with 200 mL of fuming nitric acid (Sigma Aldrich, ≥99.5%) at 0…”

Nanolif Yapılı Poli (Akrilonitril-Vinil Asetat)/ Grafen Oksit Yapıların Karakterizasyonu

“…Grafenin aksine, yapısında çeşitli oranlarda karbon, oksijen ve hidrojen bulunduran [3,5,6] grafen oksidin (GO), çözeltilerde kolaylıkla disperse olması, dielektrik özelliği, şeffaflığı, elektronik özelliklerinin ayarlanabilir olması ve üstün mekanik özellik-leri sebebiyle kullanım alanları gün geçtikçe genişlemektedir. Diğer yandan hidrofilik özellikli olan GO sp 2 bağlarının bozulması sebebiyle elektriksel iletkenlik açısından yalıtkan sınıfına girmektedir [7,8].…”