Cobalt particles dispersed on an oxide support form the basis of many important heterogeneous catalysts. Strong interactions between cobalt and the support may lead to irreducible cobalt oxide formation, which is detrimental for the catalytic performance. Therefore, several strategies have been proposed to enhance cobalt reducibility, such as alloying with Pt or utilization of nonoxide supports. In this work, we fabricate bimetallic PtCo supported on graphene-coated ZnO with enhanced cobalt reducibility. By employing a model/planar catalyst formulation, we show that the surface reduction of cobalt oxide is substantially enhanced by the presence of the graphene support as compared to bare ZnO. Stimulated by these findings, we synthesized a realistic powder catalyst consisting of PtCo particles grafted on graphene-coated ZnO support. We found that the addition of graphene coating enhances the surface reducibility of cobalt, fully supporting the results obtained on the model system. Our study demonstrates that realistic catalysts with designed properties can be developed on the basis of insights gained from model catalytic formulation.

中文翻译：

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石墨烯包覆ZnO负载高还原度PtCo颗粒的设计与制备

分散在氧化物载体上的钴颗粒构成许多重要的非均相催化剂的基础。钴与载体之间的强相互作用可能导致不可还原的氧化钴形成，这不利于催化性能。因此，已经提出了几种提高钴还原性的策略，例如与Pt合金化或利用非氧化物载体。在这项工作中，我们制备了负载在石墨烯涂层的ZnO上的钴还原性增强的双金属PtCo。通过使用模型/平面催化剂配方，我们显示出与裸露的ZnO相比，石墨烯载体的存在大大提高了氧化钴的表面还原率。受这些发现的启发，我们合成了一种现实的粉末催化剂，该催化剂由接枝在石墨烯涂层的ZnO载体上的PtCo颗粒组成。我们发现，石墨烯涂层的添加增强了钴的表面还原性，完全支持了在模型系统上获得的结果。我们的研究表明，可以根据从模型催化配方中获得的见识来开发具有设计性能的现实催化剂。