Design And Detection Applications Of MXene Quantum Dot-Based Nanoenzymes

MXene quantum dots（MQDs）have tunable catalytic performance and physicochemical properties,making them widely applicable in the field of sensors.The structure of MQDs has high conductivity,biocompatibility,high specific surface area,and a rich variety of surface functional groups,which can be applied to design nanoenzymes with excellent catalytic activity.Compared to natural enzymes,nanoenzymes have the advantages of low cost and good stability.However,currently reported nanoenzymes still have many shortcomings.To obtain MQDs-based nanoenzymes with unique physicochemical properties and high stability,the development of an efficient surface engineering strategy to improve catalytic activity is still an important aspect of nanoenzyme research.Therefore,this paper developed a novel,efficient,and highly selective nanoenzyme using MQDs as the carrier material,and studied its morphology and microstructure through a series of characterization methods,as well as studying its catalytic mechanism through experiments and density functional theory（DFT）calculations.The specific research contents are as follows:（1）Preparation of Ag@MQDs nanozyme and its application in colorimetric detection of hydroquinoneThis study successfully prepared Ag@MQDs hybrid materials using a chemical reduction method and systematically studied their morphology and microstructure.The catalytic performance of Ag@MQDs was experimentally studied,and the results showed that Ag@MQDs hybrid materials have catalytic activity similar to that of peroxidase,and their catalytic activity is affected by temperature,p H,and H₂O₂ concentration.Ag@MQDs can catalyze the oxidation of colorless TMB to produce blue ox TMB,but hydroquinone（HQ）can reduce ox TMB to fade the blue color,establishing a colorimetric method for detecting HQ,with a detection limit as low as 0.95μM.These results indicate that Ag@MQDs can be used as an excellent nanoenzyme material for environmental monitoring.（2）Preparation of CuNi_1:1@MQDs nanobiocatalyst and its colorimetric detection application of glyphosateFirstly,CuNi bimetallic materials were synthesized by hydrothermal method,and then CuNi bimetallic materials were combined with MQDs through the same preparation method,and their structure and morphology were studied.The catalytic experiment results showed that CuNi_1:1@MQDs had the highest catalytic activity.In addition,the DFT theoretical calculation results showed that the excellent catalytic activity of CuNi_1:1@MQDs comes from the interaction between CuNi bimetallic materials and MQDs,which can greatly promote the activation and decomposition of H₂O₂,making it easier to combine with the hydrogen at the end of TMB.Due to the significant nanobiocatalytic activity of CuNi_1:1@MQDs,an efficient and simple Glyp colorimetric detection system was established.Based on the above conclusions,CuNi_1:1@MQDs hybrid materials have broad application prospects as nanobiocatalysts in the field of pesticide detection.The above study indicates that through the interaction between MQDs and metal-based nanomaterials,more active sites can be exposed to improve the catalytic activity of the nanoenzyme.