Carbon atomic layers with encapsulated transition metal nanoparticles exhibit high catalytic activity for the oxygen reduction reaction (ORR), and good tolerance for poisoning species and acid leaching. However, the active sites and catalytic mechanism are not yet clear, mainly due to the highly heterogeneous structure of encapsulated types of catalysts. In this study, we developed a new model catalyst to mimic encapsulated types of catalysts by covering the well-defined active sites of iron phthalocyanine (FePc) with a monolayer of graphene. It was found that the FePc can activate the surface carbon layer to catalyze the ORR. Unlike exposed FePc on graphene, the embedded catalyst is insensitive to poisoning by SCN^- ions. The designed model catalyst demonstrates that molecular type active sites, as well as metal nanoparticles, can form encapsulated catalysts for ORR. The simple and well-defined structure of this model catalyst is helpful for investigating the active sites and the catalytic mechanism at the atomic scale.

具有封装的过渡金属纳米粒子的碳原子层对氧还原反应（ORR）表现出高催化活性，并且对中毒物质和酸浸具有良好的耐受性。然而，活性位点和催化机理尚不清楚，这主要归因于封装类型的催化剂的高度异质结构。在这项研究中，我们开发了一种新型模型催化剂，通过用石墨烯单层覆盖铁酞菁（FePc）的明确定义的活性位来模拟封装的催化剂。已经发现FePc可以活化表面碳层以催化ORR。与石墨烯上暴露的FePc不同，嵌入式催化剂对SCN中毒不敏感^-离子。设计的模型催化剂表明，分子类型的活性位以及金属纳米颗粒可以形成ORR的封装催化剂。该模型催化剂的简单且定义明确的结构有助于研究原子级的活性位和催化机理。