Study On Preparation Of Transition Metal-based Composite Electrodes And Their Application In Electrochemical Detection

In recent years,with the improvement of social development levels and people’s awareness on health,the safeties of grain,medicine and public sanitation and the personal health issues have received growing attention.Therefore,it has strongly promoted the development of related fields such as biomedicine and food industry,and it is particularly important to detect the content of pharmaceutical ingredients quickly and accurately in the process of actual clinical medical treatment,the research and production of food and medicine.At the same time,the vigorous development of nanomaterials has greatly enhanced the progress in the field of electrochemistry,including electrochemical sensors.Transition metal-based nanomaterials have the advantages of abundant material sources,diverse chemical compositions and morphology,good redox capacity and excellent electrochemical performance,so they have been widely used in the field of electrochemical sensors.Herein,we made cobalt-doped cerium dioxide nanosheets/graphite felt composite electrode（Co-Ce O₂ NSs/GF）by solvothermal method and high temperature pyrolysis treatment firstly,and applied it to detect the antipyretic and analgesic drug Acetaminophen（ACOP）.Then,we prepared nickel foam-supported tungsten-doped cobalt-nickel selenides nanosheets arrays composite electrode(W-Co_0.5Ni_0.5Se₂ NSAs/NF)by a multi-step hydrothermal method and used it to detect Gallic acid（GA）,natural medicinal active ingredients.Finally,we derivatized the precursor cerium-doped MIL-88A@graphene oxide into cerium-doped nickel-iron sulfides@reduced graphene oxide by aging treatment and hydrothermal method,and loaded it onto a graphite felt substrate to form the composite electrode（Ce-Ni Fe S₂@r GO/GF）as Luteolin,the natural medicinal active ingredient,electrochemical sensor.The main contents are as follows:1.Firstly,we used the solvothermal method to in situ synthesize the leaf-like cobalt-doped cerium precursor on the carbon fiber of graphite felt,and then acquired the Co-Ce O₂ NSs/GF composite electrode by high-temperature pyrolysis treatment in the air atmosphere.And then,the chemical composition and morphology of the material were characterized by means of Infrared Spectra（FT-IR）,X-ray Diffraction Spectra（XRD）,Raman Spectra,Scanning Electron Microscope（SEM）,Transmission Electron Microscope（TEM）,X-ray Photoelectron Spectra（XPS）,etc.After that,the Co-Ce O₂NSs/GF composite electrode was applied as an ACOP electrochemical sensor.The results show that the sensor exhibits low detection limit,high sensitivity,wide linear range,excellent anti-interference stability,long-time assay stability and long-term stability.And the satisfactory practical detection results are acquired in commercial tablets and human urine samples.2.Secondly,we synthesized the nickel-cobalt flaky bimetallic hydroxides arrays precursor on a nickel foam substrate by hydrothermal method,and used the hydrothermal tungsten doping treatment and hydrothermal selenization to obtain the W-Co_0.5Ni_0.5Se₂ NSAs/NF composite electrode.Then,the techniques like FT-IR,Raman Spectra,XRD,SEM,TEM,XPS,etc were carried out to characterize the chemical composition and morphology of the material.Afterwards,we used the W-Co_0.5Ni_0.5Se₂NSAs/NF composite electrode in the GA electrochemical detection,and the sensor indicates the excellent electrochemical performance such as wide linear range,low detection limit,high sensitivity,good anti-interference stability,long-term stability,and reproducibility.It also gets great actual detection results in black tea and green tea samples.3.Finally,we prepared spindle-shaped Ce-doped MIL-88A precursor on GO by solution synthesis method,and gained Ce-Ni Fe S₂@r GO composites by aging process and hydrothermal sulfurize reaction.Subsequently,the chemical composition and morphology of the material were characterized via techniques like FT-IR,Raman Spectra,XRD,SEM,TEM,XPS,etc.And we further loaded the composite material on GF to obtain the Ce-Ni Fe S₂@r GO/GF composite electrode and used it for the Luteolin electrochemical detection.The sensor shows high sensitivity,low detection limit,wide linear range,good anti-interference stability and long-term stability.Besides,it obtains excellent realistic detection results in honeysuckle and chrysanthemum samples.