TiO2/Ni–NC Hybrid Derived from Ti3C2TX/NiMOF for Highly Sensitive Electrochemical Sensing of Mercury Ions

Mercury ions (Hg 2+ ) pose serious threats to ecological environment and human health, which lead to the increasing demand for rapid and sensitive detection methods. Herein, an electrochemical sensor based on titanium dioxide/nickel nanoparticles-nitrogen doped carbon (TiO 2 /Ni–NC) modified glassy carbon electrode (GCE) was developed for the detection of Hg 2+ . A Ti 3 C 2 T X /NiMOF composite was synthesized by in situ growing NiMOF on the multilayered structure of Ti 3 C 2 T X . Through a facile pyrolysis treatment, TiO 2 /Ni–NC was derived from Ti 3 C 2 T X /NiMOF. N element doped carbon with a porous structure provided electron transfer channels for the electrochemical reaction and an ideal matrix for immobilizing catalytic sites. The TiO 2 and Ni nanoparticles were homogeneously distributed on the carbon matrix, and they exhibited good catalytic activity toward the electrochemical reaction of Hg 2+ . The accumulation of Hg 2+ was promoted due to the chelation with the doped N element. The differential pulse anodic stripping voltammetry (DPASV) method coupled with the TiO 2 /Ni–NC/GCE sensor was used to determine the concentration of Hg 2+ . Under the optimal conditions, our proposed method presented a wide detection range (1 nM to 10 μ M) and a low detection limit (0.79 nM). The sensor provided a satisfactory recovery in real water sample analysis, demonstrating the feasibility for environmental monitoring applications.