Study On Preparation And Performance Of MXene-based Enzyme-free Hydrogen Peroxide Sensor

MXenes（MXs）are a new type of two-dimensional transition metal carbides or/and nitrides.Due to its unique characteristics,such as a layered structure with a large specific surface area,hydrophilic and negatively charged surface active groups,excellent metal conductivity,etc..They have always attracted people’s attention and have been used in catalysis,storage and other fields.In particular,their excellent electrical conductivity and catalytic performance have shown great application potential in the fields of catalysis and energy storage.Although MXenes have done a lot of work on sensors,including gas sensors,pressure sensors and impedance sensors,there are few reports on MXs-based control potential current sensors.Therefore,this research is dedicated to expanding the application of MXenes in the field of electrochemical sensing.In this study,MXene（Ti₃C₂T_x,MX for short）was used to construct a hydrogen peroxide（H₂O₂）enzyme-free electrochemical sensor to study its application in constructing a sensing interface.Hydrogen peroxide（H₂O₂）is a simple but very important compound in nature.It is well known because it is often used for environmental disinfection,wound sterilization,and food preservation.In fact,its strong redox properties make it widely used as antibacterial agent,bleaching agent,oxidizing agent and reducing agent in the fields of pharmacy,environment,textile,papermaking,food manufacturing and chemical industry.Therefore,hydrogen peroxide has also become an important medium for food,medicine,clinical and environmental analysis.In addition,hydrogen peroxide is also the most important type of reactive oxygen species（ROS）,and it is involved in various physiological and pathological processes of cell proliferation,differentiation and migration.Because hydrogen peroxide acts as a precursor in the formation of highly reactive and potentially harmful hydroxyl radicals（·OH）,it is also considered to be one of the most important signals of oxidative stress.Therefore,the accurate,rapid,and sensitive detection of hydrogen peroxide is of great significance in analysis and diagnosis.This paper is based on MXene（Ti₃C₂T_x）modified glass carbon electrode（GCE）to construct an enzyme-free hydrogen peroxide electrochemical sensor with high selectivity and high stability.The specific contents are as follows:（1）MXene-chitosan/GCE（MX-CS/GCE）electrochemical sensor was constructed by drip coating method.Amperometric i-t was used to detect hydrogen peroxide.The experimental results show that compared with bare electrodes,MX-CS/GCE has a more obvious catalytic effect on hydrogen peroxide,the initial oxidation potential shifts negatively by about 200 m V.And the response current has a good linear relationship with the detection concentration,and the linear range is 0.05-21.85 m M,and the limit of detection is 1.91μM（S/N=3）.The electrode also has good stability and reproducibility,and the recovery rate in actual samples is satisfactory.（2）In view of the oxidation potential of MX-CS/GCE is still high,“artificial peroxidase”Prussian Blue（PB）is selected as the selective electrocatalyst of H₂O₂ in this part to reduce the potential.Variety of electrochemical characterization methods were used to detect hydrogen peroxide.The test results show that compared with bare GCE,CS/GCE,MX/GCE,PB/GCE and CS/PB/GCE,MX/CS/PB/GCE has better electrical conductivity.In particular,compared with CS/PB/GCE,MX/CS/PB/GCE shows more rapid catalysis and higher sensitivity.Finally,the response current has an excellent linear relationship with the detection concentration,and the linear range is 0.05-667μM.Through calculation,the limit of detection（LOD）is 4 n M（S/N=3）,comparable to most of the reported electrodes based on graphene,gold nanoparticles and other materials.The recovery rate of hydrogen peroxide was measured in different food and biological samples,and the results were satisfactory.The experimental results show that MX/CS/PB/GCE has good selectivity to hydrogen peroxide in complex environments.In general,the electrode exhibits high sensitivity,high selectivity,and high anti-interference,and can be used for the detection of actual samples.