A study of the key parameters, including the crucial role of H2 for uniform graphene growth on Ni foil

In this work we present a low-cost, scalable technique to fabricate few-layer graphene films via ambient pressure chemical vapor deposition (CVD) on a low-cost commercial polycrystalline Ni foil. Critical parameters including Ni thickness, cooling rate, and polycrystalline crystallographic orientation have been explored to understand the graphene formation mechanism and to obtain controlled carbon growth. We have studied the effect of operating conditions such as the synthesis time and feed composition, as well as the key role played by H-2. The effect of the foil position in the reactor with respect to the feed flow was reported: the back Ni surface, not exposed to the feed flow, shows an increased carbon deposition with respect to the front one. An increase of the segregation and precipitation phenomena, as a function of the cooling rate and under Ni thickness increase was observed. By decreasing the synthesis time, it is possible to obtain 1 L on areas showing an increased Ni(1 1 1) diffraction peak intensity. By varying the hydrogen concentration it is possible to control the final graphene formation on the nickel surface, obtaining quite uniform 2-3-layer graphene. (c) 2012 Elsevier B.V. All rights reserved.