In situ electrochemical deposition of a bismuth/cerium dioxide/reduced graphene oxide nanofilm for enhanced Pb2+ sensing performance

Abstract

A novel bismuth/cerium oxide/reduced graphene oxide (Bi/CeO₂/rGO) platform was prepared on an FTO electrode via an in situ electrochemical deposition method, which was employed for the detection of Pb²⁺. The differential pulse anodic stripping voltammetry (DPASV) results demonstrated that the Bi/CeO₂/rGO/FTO sensing platform exhibited good electroanalytical performance. The linear calibration curve for Pb²⁺ ranged from 0.001 to 2 μM with a detection limit of 0.00045 μM (S/N = 3). The resulting data were compared with some other reported sensors. The present electrochemical sensor possessed high sensitivity, anti-interference ability, stability and reproducibility for the detection of Pb²⁺. The improved Pb²⁺ sensing performance was attributed to the synergetic effect, where rGO was employed as a supporter to improve electron transport and CeO₂ was used to increase the stability of rGO and prevent the re-stacking of rGO. Calculations based on density functional theory (DFT) revealed that the Bi/CeO₂/rGO/FTO possessed lower Gibbs free energy for the detection of Pb²⁺ in comparison with the rGO/FTO and CeO₂/rGO/FTO, which might further explain the improved sensitivity of the Bi/CeO₂/rGO/FTO electrode. The proposed Bi/CeO₂/rGO/FTO sensing platform was relatively facile, nontoxic and low-cost. Consequently, it was successfully applied for the analysis of Pb²⁺ in actual water samples.