Low-cost, active and stable catalysts, with a bifunctional capability if possible, are required to achieve the chemical transformations between saturated and unsaturated N-heterocycles. In this work, [email protected] graphene shells ([email protected]) was used as a bifunctional catalyst with high activity and stability for the oxidative dehydrogenation (ODH) and hydrogenation (HYD) of quinolines. The excellent performance can be attributed to the synergetic effect of N-doped graphene, underlying Co nanoparticles, and the encapsulation structure in which carbon shells protect Co from leaching and aggregation. Poisoning tests with KSCN and spectroscopic analysis clearly unveil that the active sites for ODH and HYD are quite different: N-doped graphene shells modified by Co NPs via electron transfer serve as active sites for the O₂ activation in ODH, while the underlying Co NPs promoted by N dopants favor the H₂ activation in HYD. This finding challenges the previous concept of N-doped carbon sites as active sites for both ODH and HYD. The bifunctional property is due to the access of both N-doped graphene and Co sites to small molecules in our one-pot pyrolyzed [email protected] catalysts.

需要低成本，活性和稳定的催化剂，如果可能的话，具有双功能能力，以实现饱和和不饱和N-杂环之间的化学转化。在这项工作中，[电子邮件保护的]石墨烯壳（[电子邮件保护的]）被用作对喹啉的氧化脱氢（ODH）和氢化（HYD）具有高活性和稳定性的双功能催化剂。优异的性能归因于N掺杂石墨烯，下面的Co纳米颗粒的协同作用，以及其中碳壳保护Co免受浸出和聚集的封装结构。KSCN中毒测试和光谱分析清楚地表明，ODH和HYD的活性位点非常不同：Co NPs通过电子转移修饰的N掺杂石墨烯壳充当O的活性位点。ODH中的₂活化，而N掺杂剂促进的潜在Co NPs促进HYD中的H ₂活化。这一发现对以前的氮掺杂碳位点作为ODH和HYD活性位点的概念提出了挑战。双功能性质是由于在我们的一锅热解[受电子邮件保护]催化剂中，N掺杂的石墨烯和Co位点都可以进入小分子。