PDF Publication Title:
Text from PDF Page: 011
OG to 274 nm for ROG.[17] The spectrum for a dispersion of graphene oxide (GO) which shows an absorption peak at 230 nm is included in Figure 4 as a reference. As in the case of OG, the addition of drops of NaCl solution to the ROG dispersion instantaneously causes it to coagulate (see inset in Figure 4). This shows that the stabilization of the colloidal suspension of ROG is caused by electrostatic repulsion forces between the graphene sheets. Like the dispersed graphene sheets produced by the reduction of graphene oxide,[3] the stability of the ROG colloidal suspension is due to the negatively charged oxygen groups (i.e. carboxylic groups attached to the graphene layers) that remain after the reduction reaction. The presence of carboxylic groups in the ROG sample is evidenced by the XPS and ATR-IR spectra in Figures 3a and 3b respectively. Thus, the data in Figure 3a (inset) reveal that, although the reduction of OG involves a notable drop in the number of C-O groups (hydroxyl and epoxy, peak at ∼ 286.6 eV) and C=O carbonyl groups (peak at ∼ 288.5 eV), the amount of carboxylic O-C=O groups (290.6 eV) hardly varies. This result is corroborated by the ATR-IR spectrum corresponding to the ROG sample, which shows a sharp peak at 1730 cm-1 that can be attributed to C=O stretching vibrations from carbonyl and carboxylic groups (Figure 3b). It should also be pointed out that when the ROG dispersion was centrifuged at 9000×g for 10 min, < 20 wt.% of the graphene sheets precipitated, confirming the stability of the colloidal suspension. The SEM images of the ROG sample (precipitated from the dispersion with the aid of NaCl) show that like the OG sample, it consists of randomly interconnected graphene sheets (Figures 5a-c). Also as in the case of the OG sample, the graphene ROG sheets are flat and have a lateral size of around 1 11PDF Image | Graphene from Electrochemically Exfoliated Graphite
PDF Search Title:
Graphene from Electrochemically Exfoliated GraphiteOriginal File Name Searched:
80863368.pdfDIY PDF Search: Google It | Yahoo | Bing
Salgenx Redox Flow Battery Technology: Power up your energy storage game with Salgenx Salt Water Battery. With its advanced technology, the flow battery provides reliable, scalable, and sustainable energy storage for utility-scale projects. Upgrade to a Salgenx flow battery today and take control of your energy future.
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)