Graphene thin film electrodes synthesized by thermally treating co-sputtered nickel–carbon mixed layers for detection of trace lead, cadmium and copper ions in acetate buffer solutions

Abstract

Graphene thin films were synthesized using a solid-state carbon diffusion method by thermally treating (heating at 1000°C for 3min 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.