3D interlayer nanohybrids composed of reduced graphenescheme oxide/SnO2/PPy grown from expanded graphite for the detection of ultra-trace Cd2+, Cu2+, Hg2+ and Pb2+ ions

The three dimensional (3D) interlayer rGO/SnO2/PPy nanohybrids, based on reduced graphene oxide (rGO) obtained from expanded graphene (EG), SnO2 nanoparticles (NPs) and polypyrrole (PPy) were obtained by facile method. The rGO/SnO2/PPy nanohybrid electrodes were composed of a thin conducting film of PPy on the surface of rGO/SnO2 (EG: Sn molar ratio of 1.2:1), used for the determination of ultra-trace ions (Cd2+, Cu2+, Hg2+ and Pb2+) with the square wave anodic stripping voltammetry (SWASV) technique. Among the rGO/SnO2/PPy, rGO/SnO2 (rGS), rGO/PPy (rGP) and pure polypyrrole (PPy) samples, the sensitivity and current density of rGO/SnO2/PPy-4 (rGS: PPy mass ratio of 1:4), have shown excellent performance for the recognition of above ultra-trace heavy metal ions (HMIs). The limit of detection (3σ method) of the rGO/SnO2/PPy-4 nanohybrids modified electrode toward Cd2+, Cu2+, Hg2+ and Pb2+ ions was 7.5 × 10−13, 8.3 × 10−13, 8.1 × 10−13 and 8.8 × 10−13 mol L-1 (M), respectively. The 3D interlayer rGO/SnO2/PPy nanohybrid is a favorable material constructed for multiple functionalities having the advantages of conducting material PPy, active site SnO2 NPs and outstanding electrical substrate graphene nanosheet (obtained from EG) in electrochemical detection of HMIs.