Study On The Photoelectrochemical Biosensor And Photocatalytic Performance Based On Doped Mesoporous Titanium Dioxide

Photoelectrochemical biosensors have attracted great interest due to the advantages of high sensitivity,low background and easy operation,etc.Photoactive materials play a crucial role in analytical performances of the PEC biosensor.Currently,semiconductor nanomaterials,as a kind of significant materials with high stability and strong photocatalytic activity,have gained much attention in photoelectrochemical sensors in recent years.TiO₂,n-type semiconductor material,has been extensively investigated in many research fields,such as solar cell,drug delivery and photoelectrochemical analysis due to the excellent photoelectric effect,good biocompatibility.In comparison with commercial TiO₂,mesoporous TiO₂ provide a higher specific surface area and uniform pore channels with more active sites for loading dyes or pollutants.These features are very beneficial for photoelectrochemical biosensor,photovoltaic cells,photocatalysis and other fields.To improve the photocurrent response efficiency of TiO₂,various methods have been investigated,for example,doping with rare earth element,combining TiO₂ with gold nanomaterial or quantum dot.In this paper,the following four aspects of doping mesoporous TiO₂materials are studied:1.In this work,Eu doped mesoporous TiO₂ nanomaterials were prepared by soft template method,which were spin-coated on the indium tin oxide?ITO?electrode.Cadmium sulfide quantum dots?CdS QDs?was then modified on ITO electrodes through electrodeposition.The label-free PEC immunosensor based on CdS/Eu-TiO₂was constructed.The PEC activematerials were characterized by transmission electron microscopy?TEM?,scanning electron microscopy?SEM?,X-ray photoelectron spectroscopy?XPS?and X-ray diffraction diffraction?XRD?.The AFP antibody was immobilized on the modified ITO electrode using glutaradehyde as a linker.The immosensor was constructed based on the specific immuoreaction between AFP antibody and antigen.The immunosensor displayed a linear response to AFP in the ranges of 0.001-100 ng·mL^-1with a detection limit of 0.5 pg·mL^-1.2.In this study,the PEC aptasensor based on Au/Eu-TiO₂ for quantitative detection of tetracycline?TET?was constructed.Au/Eu-TiO₂ showed enhanced intensity of photocurrent in visible region,which is beneficial to the quantitative detection of TET.The immosensor was constructed based on aptamer-specific interaction of TET with TET aptamers on Au/Eu-TiO₂/ITO surfaces.The aptasensor showed the linear range for TET concentration from 0.5 nM to 1000 nM,and the detection limit of 0.2 nM was obtained.3.In this study,the PEC aptasensor based on GO/Eu-TiO₂ for quantitative detection of carcinoembryonic antigen?CEA?was constructed.GO/Eu-TiO₂ showed enhanced intensity of photocurrent in visible region,which is beneficial to the quantitative detection of CEA.The immosensor was constructed based on aptamer-specific interaction of CEA with CEA aptamers on GO/Eu-TiO₂/ITO surfaces.The aptasensor showed the linear range for CEA concentration from 0.01 ng·mL^-11 to20 ng·mL^-1,and the detection limit of 0.005 ng·mL^-1was obtained.4.In this study,the silver iodide?AgI?doped nano-mesoporous TiO₂ was prepared through soft template method by using tetrabutyl titanate?TBOT?as the titanium source and P123 as the template.The prepared materials were characterized by the N₂ adsorption-desorption,UV-vis spectroscopy,XRD and XPS.The photocatalytic properties of the doped TiO₂ nanomaterial were studied using methyl orange as degradation compound for the model pollutant.The results showed that the AgI-TiO₂ exhibit good photocatalytic activity,the sample has achieved the purpose of material modification.