Selective oxidation of aromatic alkanes by C–H activation is one of the key reactions in organic synthesis and the chemical industry. Activation of C–H bonds to obtain high-value added products under mild conditions by using sustainable carbocatalysts is of particular interest. Herein, we report a sustainable, green and template-free strategy towards the fabrication of N-doped and N/S codoped carbon nanosheets by metal-free carbonization of bioprecursors guanine and guanine sulfate. The formation of thin and N/S codoped carbon nanosheets was induced by multiple interactions of the nucleobases. Benefiting from the unique textural structure of the as-synthesized carbons, including ultrathin thickness, optimal porosity, and rich structural defects, and the synergistic coupling effect of multiple dopants, the carbon nanosheets show a high catalytic performance with 85% ethylbenzene conversion and 98% selectivity to acetophenone at 80 °C after 4 h reaction, which outperforms other equivalent benchmarks (e.g. 8.5 times higher conversion and 3.2 times higher selectivity than those of oxidized carbon nanotubes). Density functional theory simulations indicate that the oxidation of ethylbenzene is catalyzed by the synergistic effect of p-N/S and g-N/S catalysts via an OH radical mechanism. This N/S codoped strategy provides guidance for the design of carbon-based catalysts for the selective oxidation of other alkanes.

中文翻译：

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无模板合成类石墨烯碳作为有效的碳催化剂，用于烷烃的选择性氧化

C–H活化对芳香族烷烃的选择性氧化是有机合成和化学工业中的关键反应之一。通过使用可持续的碳催化剂，在温和条件下激活C–H键以获得高附加值产品尤为重要。在这里，我们报告了一种通过无生物碳化鸟嘌呤和鸟嘌呤硫酸盐来制备N掺杂和N / S共掺杂的碳纳米片的可持续，绿色和无模板的策略。核碱基的多次相互作用诱导了薄的和N / S共掺杂的碳纳米片的形成。受益于合成后碳的独特结构，包括超薄厚度，最佳孔隙率和丰富的结构缺陷，以及多种掺杂剂的协同偶联作用，例如，转化率比氧化碳纳米管高8.5倍，选择性高3.2倍。密度泛函理论模拟表明，乙苯的氧化是通过OH自由基机理由pN / S和gN / S催化剂的协同作用催化的。这种N / S共掺杂策略为设计用于选择性氧化其他烷烃的碳基催化剂提供了指导。