Alkaline intercalation of Ti3C2 MXene for simultaneous electrochemical detection of Cd(II), Pb(II), Cu(II) and Hg(II)

Two-dimensional accordion-like alk-Ti3C2 was prepared by acid etching and alkaline intercalation treatment, and demonstrated as a new platform for the simultaneous electrochemical detection toward multiple heavy metal ions using square wave anodic stripping voltammetry. The alk-Ti3C2 modified electrode exhibited significantly improved electrochemical response in comparison with the Ti3C2 modified electrode due to the unique morphology and surface chemistry characteristics. Key operational parameters including pH, deposition potential and deposition time were optimized for the determination of trace heavy metal ions. Under the optimum conditions, it exhibited a high sensitivity superior to most of reported values and good linear correlations, with a detection limit of 0.098 μM, 0.041 μM, 0.032 μM and 0.130 μM for Cd(II), Pb(II), Cu(II) and Hg(II), respectively. Furthermore, mutual interference among the four target metal ions was explored, and the preferential deposition of Pb(II) in the presence of other three metal ions together with an enhanced Hg(II) sensitivity in the presence of Cd(II) were discovered. This method offers a new strategy for heavy metal detection using MXenes materials.