Thermal analysis of the improved Hummers’ synthesis of graphene oxide

Abstract

The improved Hummers' synthesis of graphene oxide (GO) from graphite is investigated to monitor how the functional groups form during the synthesis steps. To achieve these, samples are taken after every preparation step, and analyzed with TG-DTA/MS, FTIR, XRD and SEM-EDX techniques. It was found that the main characteristic mass loss step of GO was around 200 °C, where at first the carboxyl and lactone groups were released, and the evolution of sulphonyl groups followed them right away in a partially overlapping step. It became clear that in the as-prepared acidic GO sample the presence of H 2 SO 4 originating from the reaction solution was still dominant. The functional groups were formed only after washing the as-prepared GO with HCl. The consecutive washing step with distilled water did not alter the functional groups or the thermal properties significantly; however, it made the GO structure more ordered. The reduction of the GO structure back to reduced GO (rGO) resulted in the loss of the functional groups and a graphitic material was obtained back.

High performance composites of spinel LiMn2O4/3DG for lithium ion batteries

“…Graphite oxide (GO) gel was synthesized from natural graphite using the modied Hummers method. 40,41 The concentration was controlled at 4 mg mL À1 . 10% mass content of NiCl 2 $6H 2 O was added into 50 mL graphite oxide solution.…”

Thermal properties of electrospun polyvinylpyrrolidone/titanium tetraisopropoxide composite nanofibers

“…The thermal properties of the composite were investigated in air and nitrogen atmospheres by simultaneous thermogravimetry/ differential thermal analysis (TG/DTA). The evolved gases were analyzed by on-line coupled mass spectrometry (TG/ DTA-MS) [24][25][26], which was previously not done in the literature when these precursors were used for the preparation of TiO 2 nanofibers [27].…”

Preparation of graphene oxide/semiconductor oxide composites by using atomic layer deposition

“…After the final washing and centrifugation step a light brown suspension with a GO nanoparticle content of 1 w/w% was obtained. [66]…”