Preparation Of Ti₃C₂-MXene Based Composite Electrochemical Sensors And Their Application For Flavonoids Detection

Electrochemical sensors have attracted extensive attention due to their high sensitivity,low detection limit,low cost and portability.Two-dimensional transition metal carbides or nitrides(MXene)are a new kind of graphene materials,which not only have high conductivity,large specific surface area,many active sites and controllable atomic layer thickness,but also have good hydrophilicity.It is expected to be a new generation of high-performance electrochemical sensing materials.However,MXene is prone to self stacking between layers,which leads to the decrease of its conductivity and specific surface area,and further affects the application of MXene in the field of electrochemical sensors.In order to solve this problem,MXene is compounded with other materials or builded to be three-dimensional structure is to prevent its self stacking in this paper.The prepared composite materials were used as electrode modification materials for the fabrication of electrochemical sensors for flavonoids detection.The content includes the following parts:(1)MXene/ZIF-67/CNT(ZIF-67: zeolitic imidazolate framework-67,CNT: carbon nanotube)was synthesized via an in-situ growth of ZIF-67/CNT,followed by the ultrasound with MXene.MXene/ZIF-67/CNT composite was used as electrode material for the fabrication of electrochemical sensor for luteolin(LUT)detection.The MXene/ZIF-67/CNT electrode combines the high adsorption property of MXene/ZIF-67 and the high electrocatalytic activity of CNT,displaying wide linear relationship ranging from 0.1 to 1000 nM,and a low detection limit of 0.03 nM.Meanwhile,the electrochemical sensor shows good stability,high sensitivity and reproducibility,and can be applied to detect LUT in grape juice drink sample.(2)M-NTO-CNT(M-NTO: MXene-derived sodium titanate)was prepared by treating MXene-CNT with a simultaneous oxidation and alkalization method.The MNTO-CNT composite was used as electrode material for the fabrication of electrochemical sensor for LUT detection.The M-NTO-CNT electrode combines the large specific surface area of M-NTO and high electrocatalytic activity of CNT,displaying wide linear range from 0.01 to 100 nM and a low detection limit of 0.003 nM.In addition,the electrochemical sensor shows good stability,high sensitivity,and reproducibility,which can be applied to detect LUT in tea sample.(3)β-CD /M-NTO-CNT was obtained by treating MXene-Pt via a simultaneously oxidized and alkalized process,followed by the self-assembly with β-CD.The M-NTOPt/β-CD composite was used as electrode material for the fabrication of electrochemical sensor for quercetin(QUE)detection.Due to the large specific surface area of M-NTO and the specific recognition performance of β-CD,the constructed electrochemical sensor displays wide linear range from 0.1 to 1000 nM and a low detection limit of 0.03 nM.In addition,the electrochemical sensor also shows good selectivity,high sensitivity and reproducibility,and can be applied to detect QUE in tea sample.