| The photoelectrochemical sensing（PEC）technology has advantages such as high sensitivity and fast detection speed,and has a wide range of applications in early disease diagnosis,environmental monitoring,and food safety.Developing new photoelectric sensing materials is an important guarantee for enhancing photoelectric sensing activity and developing new detection technologies.In this dissertation,two imidazole-based metal-organic frameworks（ZIF-8&ZIF-90）were in situ compounded with electrostatically spun Ti O2 nanofibers to construct novel photoelectric sensing materials and systematically explored their multifunctional sensing activities.The main research contents are as follows:1.Ti O2 nanofibers and ZIF-8 metal-organic framework composites（Ti O2@ZIF-8）were prepared using electrospinning and hot pressing techniques.Subsequently,the ZIF-8nanocrystals were thermally decomposed to obtain Ti O2@Zn O heterostructure with a pearl-necklace morphology by controlling the ZIF-8 to Ti O2 molar ratio and calcination temperature.The Ti O2@Zn O heterostructure was used as a photoelectroactive material to construct a PEC sensor for selective detection of lactic acid.Compared to individual Zn O and Ti O2,the pearl-necklace Ti O2@Zn O heterostructure exhibited significantly enhanced charge transfer activity,photocurrent density,and the lowest overpotential,thereby demonstrating higher PEC detection activity.The photocurrent of the sensor showed a linear relationship with lactic acid concentration in the range of 0-1 m M,with a detection limit of 0.031μM and significant selectivity,sensitivity and reproducibility.2.Based on the aforementioned research,the influence of metal oxide doping on PEC activity was further explored.In situ doping through the hot-pressing of ZIF-8 was used to introduce transition metal ions such as Ni（II）,Mn（II）,Fe（II）,and Co（II）,and a Ti O2@Zn O composite photoelectrochemical sensing material with metal doping was constructed.Using erythromycin as the detection target,the PEC sensing activity of different metal-doped composite materials was systematically evaluated.The results showed that Ti O2@Ni O-Zn O with Ni doping exhibited the best PEC activity,with a two-stage linear relationship between photocurrent and ROX concentration in the range of 0-60 and 60-140μM,and a detection limit of 0.081μM.3.A chiral PEC sensor was constructed using electrospinning and hot-pressing techniques to produce Ti O2@ZIF-90.Firstly,Ti O2@ZIF-90 composite material was fabricated using hot-pressing,and then the aldehyde groups on the ZIF-90 framework structure were used as modification sites.L-Threoninol was introduced through Schiff base condensation for post-modification to create Ti O2@ZIF-90-Thr chiral PEC sensing material.CD spectroscopy indicated successful chiral factor post-modification grafting,and tests demonstrated excellent selective recognition activity towards levamisole,with higher photocurrent recognition response activity towards L-Valinol and a detection limit as low as0.077μM.This article systematically investigates a novel approach for constructing multifunctional heterojunction materials on electrospun Ti O2 nanofibers using hot-pressed MOFs technology.The regulating mechanisms of techniques such as metal doping and chiral post-modification on PEC sensing activity are thoroughly studied,achieving efficient PEC detection and recognition of functional molecules such as lactate,roxithromycin,and L-ascorbic acid.The reported material synthesis method and regulation strategy provide valuable insights for the construction and regulation of MOFs heterojunctions,which is of great significance for the development of novel and efficient PEC sensing technologies in the future. |
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