【摘要】 与小片氧化石墨烯相比，大片氧化石墨烯在多种应用场景中具有显著优势。然而，通过Hummers法氧化大片天然石墨来制备大片氧化石墨烯比较困难。研究者普遍认为：大片石墨难以被完全氧化，且在反应过程中易碎裂成小片。通过对石墨氧化过程进行原位监测，发现若给予足够时间，大片石墨能够被完全氧化，同时宏观上保持基本完整。石墨的氧化过程受制于氧化剂在层间的扩散，该过程遵循菲克定律，较高的氧化剂浓度梯度可提高扩散速率。因此，本研究提出，通过减少浓H₂SO₄用量以提高氧化剂浓度，探索最小H₂SO₄使用量，实现了半固态条件下克级大片石墨的完全氧化。此外，本研究还指出，优化反应温度可平衡石墨氧化反应与Mn（VII）自分解反应。基于此，在较低的H₂SO₄与KMnO₄用量下，成功实现了克级200目、100目及50目天然石墨的完全氧化。在剥离过程中石墨片破碎，最终获得平均径向尺寸分别为27.3、58.7、116.2μm的大片氧化石墨烯。本研究不仅为大片氧化石墨烯的制备提供了可规模化且经济高效的策略，也深化了对Hummers类反应机制的理解。更多还原

【Abstract】 Large graphene oxide（LGO） sheets have significant advantages over smaller ones in various applications. However,producing them by the Hummers-type oxidation of large natural graphite flakes is challenging. The inherent limiting factors are generally believed to be that large graphite flakes are both difficult to oxidize fully and prone to fragmentation during the process. By in-situ monitoring the graphite oxidation, we observed that, given sufficient time, large graphite flakes may be fully oxidized while still remaining largely intact. Graphite oxidation is governed by diffusion of the oxidizer between the layers, and is described by Fick’s law, where a high oxidizer concentration gradient increases the diffusion rate. We therefore increased the oxidizer concentration by minimizing the amount of solvent（concentrated H₂SO₄）, achieving full oxidation of gram-scale large graphite flakes in a semi-solid state with significantly reduced reagent consumption. In addition, the reaction temperature was adjusted to balance graphite oxidation and Mn（VII） self-decomposition. Using this approach, gram-scale 200-, 100-, and 50-mesh natural graphite were all fully oxidized with a significantly reduced consumption of both H₂SO₄ and KMnO₄. A reduction in size occurs during exfoliation, yielding LGO with average sizes of 27.3, 58.7, 116.2 μm, respectively. This study not only provides a scalable and cost-effective strategy for LGO production but also advances the understanding of Hummers-type methods.更多还原