▎ 摘　　要

Graphene thin films were synthesized using a solid-state carbon diffusion method by thermally treating (heating at 1000 degrees C for 3 min and then cooling) nickel-carbon (Ni-C) mixed layers co-sputtered on silicon (Si) substrates with or without a silicon dioxide layer. Field-emission scanning electron microscopy, high resolution transmission electron microscopy and Raman spectroscopy were used to characterize the structure and composition of both the as-deposited and thermally treated Ni-C coated samples with respect to the C concentration of the Ni-C thin films. The graphene thin films were used as working electrodes in the simultaneous detection of trace heavy metal ions (Pb2+, Cd2+ and Cu2+) in acetate buffer solutions modified with bismuth ions (Bi3+). The enhancing effect of Bi3+ on the electroanalytical performance of the graphene electrodes was studied. (C) 2013 Elsevier B.V. All rights reserved.