Preparation Of MXene Composite And Its Application In Electrochemical Detection

Electrochemical sensors have attracted a lot of attention for their advantages of simple operation,low cost,high sensitivity and low detection limit.Transition metal carbide or nitride（MXene）is a new kind of two-dimensional materials newly discovered in recent years,which have great application potential in the field of electrochemical detection due to their good electrical conductivity,abundant active sites,large specific surface area and good hydrophilicity.However,the etched MXene layers are prone to self-stacking due to van der Waals forces and hydrogen bonds,which causes the degradation of their electrochemical performance,further affecting the application of MXene in the electrochemical field.To address this problem,titanium carbide（Ti₃C₂）as the substrate material,by introducing the intercalation agent to prevent its self-stacking,and improve its electrochemical performance.Above all,three kinds of electrochemical sensors based on MXene nanocomposites were constructed to detect phenolic pollutants,such as catechol,hydroquinone,p-aminophenol and acetaminophen.The research contents are as follows:1.An electrochemical sensor based on titanium carbide（Ti₃C₂）and carbon black（CB）was prepared by ultrasonic self-assembly method,which was used for simultaneous determination of catechol and hydroquinone.A number of-O、-F、-OH functional groups on the surface of Ti₃C₂,which has good recognition and capture ability of catechol and hydroquinone.Due to the introduction of CB,the stacking of Ti₃C₂ was effectively avoided,and its large specific surface area was fully utilized,which further enhanced its electrochemical performance.Under the optimum experimental conditions,the detection linear range of catechol and hydroquinone was 0.5-120μM and the detection limits（S/N=3）were 0.016μM and 0.011μM,respectively.In addition,the Ti₃C₂/CB sensor was studied for the determination of catechol and hydroquinone in industrial wastewater.Satisfactory recoveries were obtained.Therefore,the sensor with excellent electrochemical performance is a reliable choice for the detection of organic pollutants in the environment.2.A novel MXene/MOF derivative N-Ti₃C₂/PC composite was successfully synthesized through in-situ nucleation and conversion of ZIF-8 on 2D hierarchical Ti₃C₂ nanosheets.Due to in-situ growth,N-doped Ti₃C₂（N-Ti₃C₂）and porous carbon（N-PC）were obtained from high temperature pyrolysis of Ti₃C₂/ZIF-8,which effectively avoided the accumulation of Ti₃C₂ nanosheets and significantly improved their electrochemical properties.The obtained N-Ti₃C₂/PC composite was constructed for the detection of p-aminophenol and paracetamol simultaneously.The results showed that the as-fabricated electrochemical sensor owned excellent electrocatalytic activity for p-aminophenol and acetaminophen,which was attributed to the synergistic effect of N-Ti₃C₂and PC that accelerating the electron transfer on the electrode surface.Under optimum experimental conditions,the linear detection range was1-150μM for p-aminophenol and acetaminophen,and the detection limits（S/N=3）for p-aminophenol and paracetamol were evaluated to be 0.059μM and 0.050μM respectively.Furthermore,the N-Ti₃C₂/PC electrochemical sensor was employed to determine p-aminophenol and acetaminophen in industrial wastewater and paracetamol tablets,and satisfying recoveries were obtained.Consequently,the N-Ti₃C₂/PC composite is expected to have a wide range of applications in electrochemical for detecting of environmental pollutants.3.Ti₃C₂/Co@N-C electrochemical sensor was constructed by a simple ultrasonic self-assembly method for the detection of p-aminophenol and acetaminophen with high sensitivity and selectivity.After carbonization of ZIF-67,Co and N co-doped carbon nanomaterial（Co@N-C）was obtained,which was introduced into Ti₃C₂ nanosheets as an intercalators,which played a synergistic role and showed good electrocatalytic and conductive properties for the target molecule.Under the optimal experimental conditions,Ti₃C₂/Co@N-C/GCE showed good detection performance for p-aminophenol and acetaminophen,with the linear ranges of 1-120μM and 0.5-120μM,respectively,and the detection limits（S/N=3）of 0.044μM and 0.042μM,respectively.The results show that the method could be used for the determination of p-aminophenol and acetaminophen in industrial wastewater and commercial tablets.And satisfied recovery was obtained.In addition,the sensor shows good anti-interference ability,high sensitivity,stability and reproducibility.