B, N-co-Doped Graphene-Supported Ir and Pt Clusters for Methane Activation and C-C coupling: A Density Functional Theory Study

摘要

Methane conversion by using transition metal catalysts plays in an important role in various usages of the industrial process. The mechanism of methane conversion on B, N-co-doped graphene supported Ir and Pt clusters, BNG-Ir4 and BNG-Pt4, have been investigated using density functional theory calculations. Methane was found to adsorb on BNG-Ir4 and BNG-Pt4 clusters via strong agostic interactions. The first step of methane dehydrogenation on BNG-Ir4 has a lower energy barrier, indicating a facile methane dissociation on BNG-Ir4. In addition, it shows that hydrogen molecule can form on the BNG-Ir4 and hydrogen can desorb from the surface. Besides, the C-C coupling reaction of CH3 to form ethane is a more thermodynamically favorable process than CH3 dehydrogenation on BNG-Ir4. Further, ethane is easier to desorb from the surface due to its low desorption energy. Therefore, the BNG-Ir4 cluster is a potential catalyst for activating methane to form ethane and to produce hydrogen. (C) 2019 Wiley Periodicals, Inc.