Confinement synthesis of few-layer MXene-cobalt@N-doped carbon and its application for electrochemical sensing

Herein, the few-layer Ti₃C₂T_x nanosheets loaded zeolitic imidazolate framework-67 nanoplates (Ti₃C₂T_x-ZIF-67) with a unique structure has been synthesized by surfactant control method, and then is employed as the core of precursor. A thin layer of polydopamine as the shell of precursor covered Ti₃C₂T_x-ZIF-67 forms a micro-nano reactor, leading to the confinement carbonization process. Consequently, a novel sensing material that few-layer Ti₃C₂T_x nanosheets loaded Co nanoparticles coated N-doped carbon (Ti₃C₂T_x-Co@NC) is obtained for the non-enzymatic determination of glucose. Owing to the impressive structure, the established glucose sensor based on Ti₃C₂T_x-Co@NC/glassy carbon electrode exhibits 0.5-100.0 μM of linear detection range and 66.8 nM of detection limit, which tends to detect low concentration of glucose. The synergistic few-layer Ti₃C₂T_x nanosheets, Co nanoparticles and NC are considered through a series of control experiments. First, few-layer Ti₃C₂T_x nanosheets provide a good transport channel for electron transfer, resulting in the lower steric hindrance. Second, Co nanoparticles provide active centers for the electrochemical detection. Third, N-doped carbon with conductivity and hydrophilia plays the role of stabilizing material structure to prevent the fragmentation of Ti₃C₂T_x and the agglomeration of Co nanoparticles. Such work proposes a confined strategy to develop MXene-ZIF-67-derived nanocomposite with high-performance structure.