TiO₂/Ni–NC Hybrid Derived from Ti₃C₂T_X/NiMOF for Highly Sensitive Electrochemical Sensing of Mercury Ions

Abstract

Mercury ions (Hg2+) 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 (TiO2/Ni-NC) modified glassy carbon electrode (GCE) was developed for the detection of Hg2+. A Ti3C2TX/NiMOF composite was synthesized by in-situ growing NiMOF on the multilayered structure of Ti3C2TX. Through a facile pyrolysis treatment, TiO2/Ni-NC was derived from Ti3C2TX/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 TiO2 and Ni nanoparticles were homogeneously distributed on the carbon matrix, and they exhibited good catalytic activity toward the electrochemical reaction of Hg2+. The accumulation of Hg2+ was promoted due to the chelation with the doped N element. The differential pulse anodic stripping voltammetry method coupled with the TiO2/Ni-NC/GCE sensor was used to determine the concentration of Hg2+. Under optimal conditions, our proposed method presented a wide detection range (1 nM to 10 μM) 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.