The Photoelectrochemical Sensor Constructed Based On TiO₂ Composite For Determination Of BPA

Since the beginning of the 21st century,people's living standards have undergone a qualitative leap with the advancement of science and technology.However,the ensuing environmental problems have become the most prominent issue that restricts social development and harms human health.In all kinds of environmental pollution problems,the influence of environmental estrogen is a problem that cannot be ignored.As a typical representative of environmental estrogen,bisphenol A?BPA?is a serious threat to the health of human beings and organisms.At present,the numerous methods were used to detect BPA.Among them,photoelectrochemical?PEC?sensor is considered to be a more sensitive method owing to the efficient separation of excitation source?light?and detection signal?current?.In addition,it has the advantages of low cost,miniaturization,simple operation,and environmental friendliness.Based on the above understanding,this paper focuses on PEC detection of BPA.Chapter 1:The harmfulness and detection methods of BPA were summarized.On this basic PEC method was introduced.And then we clarified the PEC detection mechanism.In particular,the application of TiO₂in PEC sensors was introduced in detail.Chapter 2:A facile and sensitive PEC sensing platform based on zinc phthalocyanine?ZnPc?sensitized TiO₂ nanorodarrays?NRAs?was successfully fabricated for detection of BPA.The vertically aligned TiO₂NRAs with one-dimensional?1D?nanostructure was synthesized in-situ on fluorine-doped tin oxide-coated glass?FTO?substrate by simple one-step hydrothermal method,and then ZnPc was deposited on TiO₂ NRAs/FTO surface.With the addition of BPA,the photocurrent of the PEC sensing platform increased,ascribing to the oxidation of BPA by the consumption of photogenerated holes during PEC reaction.BPA could be quantified by measuring the change of the photocurrent.The developed PEC sensor exhibited outstanding analytical performance with high sensitivity,excellent stability and good reproducibility.A wide linear work range from 0.047 to52.1?mol L^-1 was obtained with a low detection limit of 8.6 nmol L^-1.This PEC sensor further supplied a new technology for detection of BPA.Chapter 3:Iodine oxygen bismuth/TiO₂ nanorod arrays?BiOI/TiO₂NRAs?composite was synthesized in-situ on FTO substrate by simple two-step hydrothermal method.The combination of BiOI with TiO₂ NRAs extended effectively the adsorption of TiO₂ to visible region,and such p-n heterojunction formed could contribute to the spatial charge separation as well as the enhanced photocatalytic activity.The PEC sensing platform fabricated by using this composite was applied for detection of BPA via the oxidation of BPA by the consumption of photogenerated holes during PEC reaction.Under 420 nm irradiation,I-t technique was used for sensitive detection of BPA at applied potential of 0.0 V,a wide linear work range from0.0047 to 14.7?mol L^-1 was obtained with a low detection limit of 0.93nmol L^-1.Compared with the second chapter,the sensitivity of BPA detection was further enhanced.Thus,a new analytical technique was provided for the detection of BPA in the environment.Chapter 4:On the basis of the synthesized materials in the third chapter,the molecular imprinting materials were added,and the selective detection of BPA can be achieved while ensuring high sensitivity.Molecularly imprinted mesoporous organosilica?MIMO?using a semicovalent imprinting technique was synthesized.BPA as the imprint template,ICPTES as functional monomer,a precursor substance with a thermally reversible covalent bond was formed under certain conditions.This precursor was incorporated into a cross-linked mesoporous silica matrix via a typical acid-catalyzed,triblock copolymer-templated,sol-gel synthesis.After thermal treatment,the imprinted template molecule was removed,named MIMO-ir.The BiOI/TiO₂ NRAs/FTO was used as the substrate electrode to loading MIMO-ir.The results showed that the linear range was 0.0075¹.47 pmol L^-1 under 420 nm visible light,and the detection limit was 0.0036 pmol L^-1.The linear range of BPA detection was wider by using the molecular imprinting PEC sensor,and the sensitivity of detection was improved,as well as the selective detection of BPA was obtained in complicated environment.