▎ 摘　　要

The synthesis of graphene by chemical vapor deposition (CVD) is a promising approach for producing graphene for novel applications. Especially graphene synthesis on Copper substrates has resulted in high quality, large area graphene growth. This method, however, exhibit limitations in achievable graphene quality due to the low catalytic activity of the growth substrate and occurring catalyst deactivation at high graphene coverage. We here study the effect of adding a material to promote graphene growth on Cu. Catalytic materials such as Nickel and Molybdenum were found to affect the graphene quality and growth rate positively. The origin for this enhancement is a decrease of the energy barrier of catalytic methane decomposition through a process of distributed catalysis. This process can also help overcome the issue of catalyst deactivation and increase film continuity. These findings not only provide aroute for improving the CVD synthesis of graphene but also answer fundamental questions about graphene growth. (C) 2013 Elsevier Ltd. All rights reserved.