Graphene Oxide-Silver Nanowire Nanocomposites for Enhanced Sensing of Hg²⁺

We demonstrate a highly sensitive and selective sensing platform for the electrochemical detection of Hg²⁺ in aqueous media. A graphene oxide (GO) and silver nanowire (AgNW) nanocomposites modified platinum (Pt) electrode has been applied to determine Hg²⁺ by using square-wave anodic stripping voltammetry (SWASV). The synergistic effect of graphene oxide and conductive AgNW greatly facilitates faster electron transport and sensing behavior for Hg²⁺. Under the optimum conditions, the sensor shows a high sensitivity of ∼0.29 μA/nM and a linear response in the range 1-70 nM toward Hg²⁺. The detection limit of the GO-AgNW nanocomposites modified electrode toward Hg²⁺ is ∼0.1 nM, which is significantly less than the safety limit defined by the World Health Organization. The sensor has an excellent selective response to Hg²⁺ against other interfering heavy metal ions such as Pb²⁺, Cd²⁺, Cu²⁺, Na⁺, and Ag⁺. In addition, the sensor exhibits a high repeatability and reproducibility. The sensor is employed for the detection of Hg²⁺ in tap water samples with an outstanding performance, suggesting it is a very promising platform for on-site monitoring of Hg²⁺ in water.