Electrochemical Catalysis And Biosensing Of Functionalized MOFs

The metal organic framework?MOFs?is a class of functional porous materials.Due to its controllable morphology,abundant pores,high specific surface area and versatility,it has been widely used in various fields such as catalysis,separation and biomedical engineering.In recent years,it has become a hot topic in research on electrocatalysts and electrochemical sensors.However,due to the poor conductivity of single-phase MOFs,its inherent weaker electron conductivity and electrochemical stability hinder its development,and effective strategies to solve these problems depend on the functionalization of MOFs.The methods for functionalizing MOFs mainly include dopant modification,in-situ capture of functional molecules or nanoparticles in the framework,and post-modification methods.By modifying the specific surface area,pore volume and functionality of the frame structure by post-modification,it can improve its application in electrochemistry.MOFs functionalized composites have high electron conductivity and catalytic activity.In this thesis,MOFs functionalized composites are used as electrochemical catalytic materials for electrocatalytic oxygen evolution and biosensing.The main contents are as follows:1)The CeMOF nanomaterial was synthesized by a simple water bath method and then functionalized with gold nanoparticles.The Au@CeMOF composite was obtained,and the telomerase activity was detected by Au@CeMOF based on excellent electrocatalysis of hydroquinone oxidation and conformational transformation of hairpin DNA.A ratio electrochemical biosensor was constructed.The biosensor showed an ideal dynamic range from 2 x 10² to 2 x 10⁶ HeLa cells mL^-1 with a detection limit of 27 HeLa cells mL^-1 and was used to assess single cell telomerase activity.The ratiometric signal output mode is used for the electrochemical detection of telomerase activity,which overcomes the shortcomings of enzyme-containing,high cost,difficult operation,and low sensitivity compared with the conventional method for electrochemical detection of telomerase activity.Also,this proposed method has excellent selectivity and stability,and has broad application prospects for the detection of telomerase activity.2)We prepared 2D Ni-MOF@Co-MOF nanosheets,2D Ni-MOF nanosheets and Co-MOF nanosheets by simple ultrasonic method.Meanwhile,3D Ni-MOF micron flowers and 3D Ni-MOF@Co-MOF micron flowers were synthesized by hydrothermal method.The obtained product showed high electrocatalytic activity for OER,especially for 2D Ni-MOF@Co-MOF nanosheet.In 1.0 M KOH electrolyte,the overpotential at 20mA cm^-2 was 259 mV,and the Tafel slope was 149 mV dec^-1.Also,20 hours of electrochemical stability can be maintained.It has more excellent electrocatalytic performance because of the ultra-thin thickness of the nanosheet and the high accessibility of the active sites exposed on the surface,making the metal sites more accessible to electrons to promote catalytic activity and stability.It also has excellent electron transfer and fast mass transfer.This work will facilitate the extensive research on MOFs nanostructures with abundant active sites and excellent potential electrocatalytic properties.