Preparation And Photoelectrochemical Properities Of Au Doping Bismuth Oxyhalide Composites

With the further understanding of severity and harmfulness of antibiotics,photoelectrochemical?PEC?aptasensor is a novel antibiotics detection method with many characteristics as sensitivity,selectivity,and miniaturization,attracting widespread attention.The detection performance of PEC aptasensor is closely related to the PEC performance of active materials.Therefore,it is necessary to choose active materials with favourable PEC property for constructing high-performance PEC aptasensor.Bismuth oxyhalide?BiOX,X=Cl,Br,I?based PEC active materials have become a research hotspot in PEC fields attributed to their unique electronic structure and proper physical or chemical properties.Exploring appropriate strateges is critical to promote the effective separation of photogenerated electron-hole pairs in BiOX materials for obtaining favourable PEC performance.Consequently,Au doping BiOX?Au/BiOX?composites with good PEC performance were prepared by doping Au nanoparticles on the surface of BiOX materials to enhance light response capability and photogenerated electron separation efficiency.The enhancement mechanism of PEC performance for Au/BiOX composites was investigate by material characterization and PEC measurement.PEC aptasensor was constructed for detecting trace antibiotics based on Au/BiOX composites as PEC active materials.The research contents as follows:?1?Au/BiOBr composites were successfully synthesized by a solvothermal in-situ reduction of Au³⁺.The enhancement mechanism of PEC performance was studied by the PEC measurements under monochromatic light.Under different wavelengths irradiation,Au nanoparticles could trap electrons and feed hot electrons in the electron transfer process for enhancing the photogenerated electron migratition of Au/BiOBr composites.Consequently,a PEC aptasensor was established to detect tetracycline based on Au/BiOBr composites with enhanced PEC performance.The PEC aptasensor monitoring tetracycline possessed a wide line range(1 ng L^–1-10000 ng L^–1)and a satisfactory dection limit(0.35 ng L^–1,S/N=3).?2?The influence of Au doping strategy was further studied on the PEC performance of BiOI with high visible light absorption capacity.After the introduction of Au nanoparticles,the PEC performance of Au/BiOI composites can be significantly enhanced owing to the promoted electrons transfer efficiency.Therefore,a PEC aptasensor with high detection performance for tetracycline was established based on Au/BiOI composites.The PEC aptasensor possessed a wider linear range(0.4-14370ng L^–1)and a lower detection limit(0.2 ng L^–1,S/N=3)for detecting tetracycline.?3?Owing to the enhancement of the PEC performance for BiOBr materials by the bismuth-rich strategy,non-stoichiometric BiOBr materials were paid great attention on the PEC field.To verify the universality of Au doping strategy,Au/Bi₂₄O₃₁Br₁₀composites were prepared by photoreduction method and the enhancement mechanism of PEC performance for Au/Bi₂₄O₃₁Br₁₀ composites was studied.Au nanoparticles doping can enhance the light absorption and photogenerated electron transfer efficiency of Bi₂₄O₃₁Br₁₀,bringing out the better PEC performance of Au/Bi₂₄O₃₁Br₁₀ composites than Bi₂₄O₃₁Br₁₀.Consequently,a PEC aptasensor detecting enrofloxacin based on Au/Bi₂₄O₃₁Br₁₀ composites possessed a wide linear range(0.72-36000 ng L^–1),a low detection limit(0.3 ng L^–1,S/N=3).The universality and feasibility of Au doping strategy was further affirmed,providing a new way for non-stoichiometric-BiOX-based materials in PEC field and antibiotic detection field.