Sr@FeNi-S Nanoparticle/Carbon Nanotube Nanocomposite with Superior Electrocatalytic Activity for Electrochemical Detection of Toxic Mercury(II)

In this work, we developed a Sr-doped FeNi-S nanoparticle by a simple one-step pyrolysis process and successfully integrated it with single-walled carbon nanotubes (Sr@FeNi-S/SWCNTs) using an ultrasonication method. The Sr@FeNi-S/SWCNTs nanocomposite consisted of Sr, Fe, Ni, and S atoms inside the nanosized particle of Sr@FeNi-S firmly anchored on the surface of the SWCNTs. Electrochemical impedance analysis of the Sr@FeNi-S/SWCNTs electrode shows favorable kinetic charges for transport compared to those of Sr@FeNi-S and SWCNTs. A glassy carbon electrode modified with Sr@FeNi-S/SWCNTs is constructed and used for the selective and sensitive electrochemical determination of trace amounts of mercury (Hg-(II)). The electrochemical behavior of the modified electrode and the mechanism of the Hg-(II) were investigated by cyclic voltammetry. By differential pulse voltammetry at optimum parameters such as a wide linear range (WLR: 0.05-279 mu M), an ultralow level detection limit (LOD: 0.52 nM) of Hg-(II) is observed with a sensitivity of 1.838 mu A mu M-1 cm(-2). The practical feasibility of the electrode was assessed in lake water and river water samples with satisfactory recovery results of H-(II) added. Moreover, this work not only demonstrates the tremendous potential of electrochemical detection of Hg-(II) but also highlights a simple and robust methodology to develop material discovery and design for improved electrochemical performance.