Abstract

Graphite oxide (GrO), the precursor of graphene oxide (GO) has been prepared by pre-treating graphite in a mixture of nitric and sulfuric acid, followed by chemical oxidation by a modified Hummers approach. The effect of pretreatment, KMnO₄, and sulfuric acid on the chemical oxidation reaction was observed by characterizing GrO specimens on the bulk scale. KMnO₄ oxidizes the carbon atoms by withdrawing electrons, instead of penetrating between the stacked carbon layers and directly interacting with the carbon atoms. Sulfuric acid and water molecules penetrate the interlayers of carbon planes and form the functionalities by nucleophilic attack on the charged carbon atoms. The pretreatment of graphite induces a small number of moieties, distributed evenly across the entire domain, serving as the primary reaction site of chemical oxidation. The inclusion of a small amount of functionalities marginally increases the lattice spacing and mildly intercalates the stacked carbon layers, facilitating the diffusion of acid and water molecules in the later step. The prepared GrO possesses only 24% graphitic carbon atoms and 11-layer of carbon stacking, confirming significant oxidation and intercalation.

摘要

氧化石墨 (GrO) 是氧化石墨烯 (GO) 的前体，通过在硝酸和硫酸的混合物中预处理石墨，然后通过改进的 Hummers 方法进行化学氧化来制备。预处理、KMnO ₄和硫酸对化学氧化反应的影响通过在大块尺度上表征 GroO 样品来观察。KMnO ₄通过吸收电子来氧化碳原子，而不是穿透堆叠的碳层之间并直接与碳原子相互作用。硫酸和水分子穿透碳平面的夹层并通过对带电碳原子的亲核攻击形成官能团。石墨的预处理诱导了少量的部分，均匀分布在整个域中，作为化学氧化的主要反应位点。包含少量功能会略微增加晶格间距并温和地插入堆叠的碳层，从而促进酸和水分子在后续步骤中的扩散。制备的GrO只有24%的石墨碳原子和11层碳堆积，证实了显着的氧化和插层。