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An improved Hummers method for eco-friendly synthesis of graphene oxide

On the correlation between surface chemistry and performance of graphite negative electrodes for Li ion batteries

There has been an intense surge in interest in graphene during recent years. However, graphene-like materials derived from graphite oxide were reported in 1962, and related chemical modifications of graphite were described as early as 1840. In this detailed account of the fascinating development of the synthesis and characterization of graphene, we hope to demonstrate that the rich history of graphene chemistry laid the foundation for the exciting research that continues to this day. Important challenges remain, however; many with great technological relevance.

From Conception to Realization: An Historial Account of Graphene and Some Perspectives for Its Future

As an important precursor and derivate of graphene, graphene oxide (GO) has received wide attention in recent years. However, the synthesis of GO in an economical and efficient way remains a great challenge. Here we reported an improved NaNO3-free Hummers method by partly replacing KMnO4 with K2FeO4 and controlling the amount of concentrated sulfuric acid. As compared to the existing NaNO3-free Hummers methods, this improved routine greatly reduces the reactant consumption while keeps a high yield. The obtained GO was characterized by various techniques, and its derived graphene aerogel was demonstrated as high-performance supercapacitor electrodes. This improved synthesis shows good prospects for scalable production and applications of GO and its derivatives.

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High-efficient Synthesis of Graphene Oxide Based on Improved Hummers Method

Electrochemical approaches to the production of graphene flakes and their potential applications

The reaction of graphite with sulfuric acid in the presence of KMnO4 (oxidant : graphite ratio 0.027–0.55) involves consecutive and concurrent reactions: graphite intercalation and direct oxidation of the carbon matrix. The properties of graphite bisulfate and its reaction products are determined by the stage number of the intercalation compound; the decomposition enthalpies of the stage I–IV graphite bisulfate correlate with the enthalpies of graphite intercalation with sulfuric acid.

Reaction of Graphite with Sulfuric Acid in the Presence of KMnO4

Intercalation reactions and carbide formation in graphite-lithium system

The problems of synthesis and study of the physicochemical properties of graphite intercalation compounds (GIC) formed upon insertion of various molecules into the interplanar space of graphite are considered. Binary and ternary intercalation compounds with protonic acids (HNO3, CH3COOH, H3PO4, H2SO4, etc.) are described. The results of systematic research into graphite intercalation by potentiometry, calorimetry, powder X-ray diffraction, conductivity measurements, DTA, chemical analysis, and other methods are given. These results underlie elucidation of the characteristic and peculiar features of acid insertion into graphite. The physicochemical properties and practical applications of GIC and low-density carbon materials are analyzed.

Acceptor-type graphite intercalation compounds and new carbon materials based on them

The choice of oxidizers for graphite hydrogenosulfate chemical synthesis

The anodic oxidation of highly oriented pyrolytic graphite in 50 to 98% HNO3 was studied in a galvanostatic mode at a current of 1.5 mA. At HNO3 concentrations from 55 to 98%, the potential-vs.-charge curves showed steplike behavior, and the number of steps increased with decreasing acid concentration, reflecting the successive formation of stage III, II, and I graphite nitrate. Electrochemical synthesis of stage I graphite nitrate was shown to be possible in 75 to 98% HNO3. The anodic oxidation in 60 to 70% HNO3 resulted in a stage I + II mixture, and that in 55% HNO3 yielded a mixture of stage II and a defect graphite phase. In 50% HNO3, no intercalation compounds were formed. The specific charge required for the formation of stage I graphite nitrate was determined as a function of HNO3 concentration. The assumption is made that, in dilute HNO3 solution containing significant amounts of water, rapid electrochemical oxidation leads to the formation of graphite oxides

I. V. Nikol'skaya

Papers

Reaction of Graphite with Sulfuric Acid in the Presence of KMnO4

Intercalation reactions and carbide formation in graphite-lithium system

Acceptor-type graphite intercalation compounds and new carbon materials based on them

The choice of oxidizers for graphite hydrogenosulfate chemical synthesis

Electrochemical study of the graphite—HNO3 system