Designing Dispersible Phosphorene With Stability In Water-and Oxygen-rich Environments For Electrochemical Sensors

Black phosphorus is one of the allotropic forms of phosphorus.Black phosphorus with atomic thickness is called black phosphene?BP?.The in-depth study of BP began with its successful application in field-effect transistors,and quickly expanded to the fields of photoelectric conversion devices,energy storage devices,sensors,biological diagnosis and treatment.However,the unmodified thin layer of BP will react with water and oxygen to rapidly degrade when exposed to the air,which severely limits its further application.How to prepare a thin layer of BP with high stability in the environment is a key problem that needs to be solved in the current research on BP.In this paper,several solvents with different surface tensions are used as media.Ultrasonic liquid phase exfoliation method is used to prepare a thin layer of BP from black phosphorus crystals.By combining with common materials,BP is modified to improve its stability.These several BP-based composite materials construct electrochemical sensors to detect several common biological molecules.The main research contents are as follows:?1?In this study,the PEDOT:PSS with high electrical conductivity,excellent film-forming ability,excellent environmental stability and satisfactory solution processability was introduced to improve the environmental stability of BP.The BP-PEDOT:PSS hybrid dispersions with different weight ratios were successfully prepared in isopropanol by ultrasonic assisted liquid exfoliation in anhydrous and nitrogen atmosphere.The semiconductive hybrid membranes of BP-PEDOT:PSS was obtained by drying the corresponding BP-PEDOT:PSS in vacuum.These membranes were exposed to ambient for several days and then characterized for their morphology,structure,and other properties.The BP-PEDOT:PSS thin film electrodes were prepared by dropping the corresponding BP-PEDOT:PSS isopropanol dispersion system,and the environmental stability was certificated by comparing the electrochemical stability in different oxygen-containing water systems.The introduction of PEDOT:PSS not only enhances the film-forming ability and electrical conductivity of the composite film,but also improves its environmental stability in oxygen-containing water.?2?In-situ reduction and deposition of silver nanoparticles on the BP surface was designed and controlled preparation with aminoized multiwalled carbon nanotube(N_H2-MWCNT)composites.BP-based nanocomposites were prepared by ultrasonic-assisted liquid exfoliation by adding N_H2-MWCNT and A^g+.The morphology,microstructure and electrochemical properties of the obtained nanocomposites were characterized.The resulting N_H2-MWCNT-BP-Ag NPs exhibit high environmental stability,good water processability,high electrocatalytic capacity and enzyme-like kinetic properties.The resulting nanocomposite was further applied in electrochemical sensors,which can be used to detect uric acid?UA?,xanthine?XT?,and hypoxanthine?HX?individually or simultaneously.Under the optimal experimental conditions,the sensor can be used to determine UA in a linear range of0.1 to 800?M,with a detection limit?LOD?of 0.052?M,a LOD of 0.021?M for XT and a linear range of 0.5 to 680?M,a linear range of 0.7 to 320?M for HX and a LOD of 0.025?M.In addition,the developed nano-enzymatic sensors were used for simultaneous voltammetric analysis of UA,XT and HX in real samples with satisfactory recovery rate.?3?The BP-IL-SWCNH composite was obtained by using1-ethyl-3-methylimidazoliumtetrafluoroborate?[EMIm]BF₄?as solvent.Black phosphorene was obtained by ultrasonic treatment in[EMIm]BF₄,and complex with high performance single wall carbon nanohorns?SWCNH?.Because the liquid phase exfoliation of BP is usually carried out in the organic solvent system,the boiling point of the organic solvent is high,which is difficult to remove in the subsequent application,and the organic solvent is harmful to the environment and human body.Ionic liquids as a green solvent with excellent properties such as nonvolatile,high thermal stability,high viscosity,high ionic conductivity,non-toxic,recyclable,etc.By using ionic liquid as solvent,BP was obtained through ultrasonic treatment.The obtained BP-IL-SWCNH was characterized with detailed morphology and performance measurements,which could be successfully applied to the construction of 5-hydroxytryptamine?5-HT?electrochemical sensors with a linear range of 0.3-50?m under optimal condition.