Simultaneous Detection of Cd2+ and Pb2+ with a Bismuth Film/Sulfur and Nitrogen Co-Doped Porous Graphene Electrode

In this work, a novel electrochemical sensor based on sulfur and nitrogen co-doped porous graphene (SNPG) is developed for the simultaneous detection of Cd 2+ and Pb 2+ by in situ plating bismuth film. The large effective surface area and doped sulfur and nitrogen in porous graphene supply active sites with high affinity toward Cd 2+ and Pb 2+ by electrostatic interaction to improve the sensor performance, and the bismuth film improves the stripping voltammetric performance by forming bismuth-metal (Cd, Pb) alloys. Under optimized conditions, this sensor exhibits linearity in the range of 0.05-2 μM for Cd 2+ and Pb 2+ with a low detection limit of 0.02 μM for Cd 2+ and 0.008 μM for Pb 2+ . Moreover, the proposed sensor was applied for the simultaneous detection of Cd 2+ and Pb 2+ in tap water with satisfactory results, suggesting that SNPG is a promising electrode material for detecting heavy metal ions.