Preparation Of Indium-based Sulfide Sensing Material For Photoelectrochemical Detection Of 17?-estradiol

17?-estradiol?E₂?,a kind of environmental estrogen,has strong hormone activity,relates to a host of environmental issues and health problems.Hence,it is of great significance to explore sensitive and efficient analytical methods for E₂ detection.Photoelectrochemical?PEC?sensor is an innovative analytical testing tool that integrates the nanomaterials and target recognition technology.Furthermore,finding materials with high conversion efficiency and reliability is an essensial requirement for constructing an efficient PEC sensor.Recently,indium-based sulfide materials have gained attention due to the advantages of low toxicity and strong light absorption capacity.In this paper,the performance of indium-based sulfides,when it was applied to construct PEC aptasensors for the detection of E₂,was improved by multi-level sensitization,anodic regulation,and electron donor or acceptor furnishing.The specific research contents are as follows:?1?A PEC aptasensor for the detection of E₂ based on an In₂S₃ and CdS co-sensitized cerium doped TiO₂?Ce:TiO₂?electrode was constructed successfully.In₂S₃ nanoparticles were prepared through one-step hydrothermal method and applied as sensing material and sensitizing layer.According to the characterization,In₂S₃appeared to be irregular sheet morphology.The absorption edge was at 580 nm,which made it very efficient at absorbing light.According to the electrochemical characterizations,compared with Ce:TiO₂ and In₂S₃,a more negative conduction band of CdS created a potential difference which facilitated electron transfer.Based on the results of photoelectrochemical characterizations,after modifying with In₂S₃ and CdS,the photocurrent increased sharply.When the concentration of E₂ rised from 10 fg/m L to 100 ng/m L,the photocurrent kept falling and the value of photocurrent has a significant linear correlation with the logarithm of E₂ concentration.The detection limit was 4.0 fg/mL.The fabricated aptasensor exhibit good selectivity,stability and repeatability,which is expected to applied in real water sample.?2?Flower-like Fe OOH and In₂S₃ nanoparticles were modified on the electrode and used as a substitute for common Pt counter electrode.ITO/CuInS₂ was employed as working electrode.The light radiated at both electrodes,the interfaces of different phases between FeOOH and In₂S₃ in favour of drving more electrons to the working electrode and combining with the holes in the valence band of CuInS₂,which decreased the recombination rate of photo-induced electrons and holes,therefore enhanced the cathodic photocurrent.The electrons in the conduction band of Cu InS₂transferred to the electrolyte and combined with dissolved oxygen.The results indicated when p-type semiconductor CuInS₂ modified on working electrode,the cathodic photocurrent response can be lifted indirectly when the electrode modified with photoelectric active materials was employed as Pt counter electrode.The constructed cathodic aptasensor of E₂ presented linear scope in the range of 10fg/mL-1.0?g/m L with detection limit of 3.7 fg/mL.?3?The ITO/Fe₂O₃ electrode rooted from calcination of ITO/FeOOH electrode,the calcination combined the material more tightly.Besides,Fe₂O₃ has large specific surface area and multiple active sites which could be used as substrate material to in-situ form AgInS₂ nanoparticles.ITO/Fe₂O₃/AgInS₂ was obtained by successive ionic layer adsorption and reaction method.After the modification of AgInS₂,the cathodic photocurrent increased.ITO/BiOI was applied as working electrode,In order to get rid of the restrict of dissolved oxygen,K₃Fe?CN?₆ was employed as electron acceptor.Under light irradiation,photoinduced electron transfer effect accelerated the movement of photo-generated electrons towards K₃Fe?CN?₆.The transmission process was blocked with the emergence of E₂ and finally achieved the detection.The linearity range of the proposed the PEC cathodic aptasensor was 1.0 pg/mL-50 ng/m L,and the detection limit was 0.30 pg/mL.