One-pot Synthesis Of Mxoy/pedot/rgo Nanocomposite For Electrochemical Detection Of Caffeine

Graphene has drawn considerable attention and research in material,chemical and physical research field due to its excellent chemical and physical properties.However,graphene tends to easily form irreversible agglomerates and it is difficult to be processed,because graphene has a special conjugation system,which seriously limit its applications in all fields.Therefore,Preparation of graphene-based composites can further improve its dispersion and processing performance,improve its electrocatalytic activity,electrochemical selective and stability.At present,the research of graphene based composites is mainly focused on binary graphene nanocomposites,however,the preparation and research of ternary nanocomposites and more than ternary are less relatively.The traditional methods of preparing ternary nanocomposites are step by step chemical way and electrochemical method.They have some unavoidable shortcomings in the preparation of materials.But“one-pot method”is a clear,cost-effective,simple and high-efficiency synthetic technique.It provides new ideas for fabricating novel nanocomposite with complicated structures and outstanding properties simply and rapidly.Electrochemical sensor is a fast,simple and efficient detection tool,and it is one of the main directions for researchers to search for suitable electrode modifiers to improve the performance of electrochemical sensors.In the present work,we prepared three different M_xO_y/PEDOT/rGO nanocomposites by one-pot method in consideration of the large surface area of graphene,excellent conductivity of PEDOT,and electrocatalytic properties of metallic oxide.And then we modified it on the glassy carbon electrode for caffeine electrochemical detection.Specific content is as follows:?1?SnO₂/PEDOT/rGO ternary nanocomposites with a three-dimensional hierarchical structure were prepared by one-pot method.The SnO₂/PEDOT/rGO modified glassy carbon electrode?GCE?showed significantly improved charge transfer efficiency and high electrocatalytic activity toward caffeine oxidation as compared to bare GCE and SnO₂/rGO modified electrode.This is mainly due to the great increase of the conductivity and specific surface area of the material by the introduction of PEDOT.Under optimized conditions,the SnO₂/PEDOT/rGO constructed sensors exhibited a wide linear range of 1-500?M and a detection limit of 0.33?M for the detection of caffeine.Furthermore,the sensor has a good detection effect of caffeine in cola samples,and has good anti-interference ability to other substances in cola.?2?Fe₂O₃/PEDOT/rGO ternary nanocomposites were facilely prepared in a same one-pot method.And we confirmed that Fe₂O₃ nanoparticles were formed by?-Fe₂O₃,we also optimized the amount of iron,the final obtained Fe₂O₃/PEDOT/rGO nanocomposites have much better electrocatalytic performance to caffeine than obtained Fe₂O₃/rGO.Under optimized conditions,the Fe₂O₃/PEDOT/rGO modified glassy carbon electrode showed a wider linear range of 1-800?M and a low detection limit of 0.33?M for caffeine detection.In addition,the electrochemical sensor is also used to detect caffeine in energy drink samples,and the recovery rate is satisfactory.?3?TiO₂/PEDOT/rGO ternary nanocomposites were prepared by a same one-pot method.Through characterization data,it is found that the morphology of metal oxide is spherical,the composite material has many micropores and a large specific surface area,which is useful to the adsorption of the detected substances.Under the optimal conditions,the TiO₂/PEDOT/rGO/GCE constructed sensors exhibited a linear range of 0.2-500?M and a low detection limit of 0.066?M for the detection of caffeine.Finally,we have successfully applied the modified electrode to the analysis and determination of the content of caffeine in instant coffee,and the result is very close to the actual content.