Abstract The scarcity and weak durability of metal, especially precious metal catalysts are big obstacles for their large-scale application in many reactions. The state-of-the-art of the catalytic science prefers such type of catalysts, which can replace metal-based catalysts to alleviate energy and environmental crises and exhibit catalytic performance comparable to or even exceeding these metal catalysts. Herein, we report that N-doped porous carbon (NKC) derived from cheap and abundant radish can be employed as versatile and efficient bifunctional catalysts in both the catalytic reduction of 4-nitrophenol (NRR) and oxidation of styrene (SOR). The series of NKC catalysts were prepared with a simple and facile one-pot strategy by coupling the N-doping, carbonization and KOH activation processes. These catalysts show hierarchical porosity, with the specific surface area, total pore volume and N-doping content ranging from 918.9–3062.7 m2 g−1, 1.01–2.04 cm3 g−1 and 1.29–15.3 at%, respectively. Interestingly, our finding suggests that the catalytic performance is not directly related to these parameters but correlates positively with the content of graphitic N dopants, which is the dominant contributor for impelling both the NRR and SOR. Another intriguing finding is that for both reactions, the optimal catalyst was found to be the NKC-3-800 which possesses the highest graphitic N content of 3.13 at%. In addition, to gain insight into the catalytic behavior, analyses of kinetics and thermodynamics were performed, and the catalytic mechanisms were postulated. This work paves the way for the construction of biomass-derived N-doped carbon catalysts for bi- or even multi-functional applications in various organic reactions.

中文翻译：

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生物质衍生的多功能双功能掺氮多孔碳催化还原 4-硝基苯酚和氧化苯乙烯

摘要 金属尤其是贵金属催化剂的稀缺性和耐久性是其在许多反应中大规模应用的一大障碍。最先进的催化科学更喜欢这种类型的催化剂，它可以替代金属基催化剂来缓解能源和环境危机，并表现出与这些金属催化剂相当甚至超过这些催化剂的催化性能。在此，我们报道了从廉价且丰富的萝卜中提取的 N 掺杂多孔碳（NKC）可用作多功能且高效的双功能催化剂，用于催化还原 4-硝基苯酚（NRR）和氧化苯乙烯（SOR）。该系列 NKC 催化剂是通过将 N 掺杂、碳化和 KOH 活化过程结合起来，采用简单易行的一锅法制备的。这些催化剂显示出分级孔隙率，比表面积、总孔体积和 N 掺杂含量范围分别为 918.9-3062.7 m2 g-1、1.01-2.04 cm3 g-1 和 1.29-15.3 at%。有趣的是，我们的发现表明催化性能与这些参数没有直接关系，但与石墨 N 掺杂剂的含量呈正相关，这是推动 NRR 和 SOR 的主要贡献者。另一个有趣的发现是，对于这两个反应，发现最佳催化剂是 NKC-3-800，其石墨 N 含量最高，为 3.13 at%。此外，为了深入了解催化行为，进行了动力学和热力学分析，并假设了催化机制。