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Graphite oxide, formerly called graphitic oxide or graphitic acid, is a compound of carbon, oxygen, and hydrogen in variable ratios, obtained by treating graphite with strong oxidizers. The maximally oxidized bulk product is a yellow solid with C:O ratio between 2.1 and 2.9, that retains the layer structure of graphite but with a much larger and irregular spacing.〔 The bulk material disperses in basic solutions to yield monomolecular sheets, known as graphene oxide by analogy to graphene, the single-layer form of graphite. Graphene oxide sheets have been used to prepare a strong paper-like material, and have recently attracted substantial interest as a possible intermediate for the manufacture of graphene. This goal remained elusive until 2012 since graphene obtained by this route still has many chemical and structural defects. ==History and preparation== Graphite oxide was first prepared by Oxford chemist Benjamin C. Brodie in 1859, by treating graphite with a mixture of potassium chlorate and fuming nitric acid. He reported synthesis of "paper-like foils" with 0.05 mm thickness. In 1957 Hummers and Offeman developed a safer, quicker, and more efficient process called The Hummers' Method, using a mixture of sulfuric acid H2SO4, sodium nitrate NaNO3, and potassium permanganate KMnO4, which is still widely used, often with some modifications. Graphite oxides demonstrate considerable variations of properties depending on degree of oxidation and synthesis method. For example, temperature point of explosive exfoliation is generally higher for graphite oxide prepared by Brodie method compared to Hummers graphite oxide, the difference is up to 100 degrees with the same heating rates. Hydration and solvation properties of Brodie and Hummers graphite oxides are also remarkably different. Recently a mixture of H2SO4 and KMnO4 has been used to cut open carbon nanotubes lengthwise, resulting in microscopic flat ribbons of graphene, a few atoms wide, with the edges "capped" by oxygen atoms (=O) or hydroxyl groups (-OH). Graphite (Graphene) oxide (GO) has also been prepared by using a "bottom-up" synthesis method (Tang-Lau method) in which the sole source is glucose, the process is safer, simpler, and more environmentally friendly compared to traditionally “top-down” method, in which strong oxidizers are involved. Another important advantage of Tang-Lau method is control of thickness, ranging from monolayer to multilayers by adjusting growth parameters. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Graphite oxide」の詳細全文を読む スポンサード リンク
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