Fabrication And Their Application Of Electrochemical Sensors Based On Noble Metal Nanoparticles

Noble metal nanoparticles have become one of the hot topics in the field of electrochemical sensors because of their excellent electrocatalytic performance,good electrical conductivity and other advantages.In this thesis,five kinds of nanocomposites were prepared and five kinds of nonenzymatic electrochemical sensors were fabricated.Therefore,new methods for the detection of glucose,N2H4,hydroquinone and catechol,nitrite,dopamine were established.This study provided a reference for the preparation of PtNPs or AuNPs based electrocatalysts with good morphology and good dispersibility.Moreover,it also promoted the development of high-performance electrochemical sensor to a certain extent.This thesis was divided into three chapters,the main contributions of the author were summarized as follows:1.PtNPs were modified onto the surface of Ni(OH)2/CS by chemical reduction method.A glucose electrochemical sensor based on Ni(OH)2/CS/PtNPs was fabricated and a new method for the detection of glucose was established.SEM,TEM and EDS were used to study the structure,surface morphology and elemental composition of Ni(OH)2/CS/PtNPs.The results showed that PtNPs were successfully deposited onto the surface of Ni(OH)2/CS.Electrochemical investigation results showed that the linear range of the sensor for the determination of glucose was 3-11000 ?mol L-1,detection limit was 0.56±0.03 ?mol L-1(S/N= 3)and sensitivity was 64.83±0.12?A(mmol L-1)-1 cm-2;PtNPs were deposited onto the surface of GO by chemical reduction method using CS as a protective agent and coupling agent.A N2H4 electrochemical sensor based on GO/CS/PtNPs was fabricated and a new method for the detection of N2H4 was established.TEM,XRD and EDS were used to study the structure,surface morphology and elemental composition of GO/CS/PtNPs.The results showed that flower-like and well-dispersed PtNPs were successfully modified onto the surface of GO.This synthetic strategy can overcome the disadvantage of PtNPs agglomeration.Electrochemical investigation results showed that the linear range of the sensor for the determination of glucose was 20.0-10000 ?mol L-1,the detection limit was 3.6?mol L-1(S/N= 3)and the sensitivity was 104.6?A(mmol L-1)-1 cm-2.2.AuNPs were modified onto the surface of carboxyl-functionalized MWCNTs by chemical reduction method.A hydroquinone and catechol electrochemical sensor based on MWCNT/CS/AuNPs was fabricated and a method for simultaneous quantitative detection of hydroquinone and catechol was established.TEM,XRD and EDS were used to study the structure,surface morphology and elemental composition of MWCNT/CS/AuNPs.The results showed that well-dispersed spherical AuNPs were successfully deposited onto the surface of MWCNTs.Electrochemical investigation results showed that the linear range of the sensor was 0.5-1500?mol L-1 for hydroquinone and 5-900?mol L-1 for catechol.The detection limit was calculated to be 0.17?M for hydroquinone and 0.89?M for catechol(S/N =3).The sensitivity was calculated to be 45.53?A(mmol L-1)-1 for hydroquinone and 54.47?A(mmol L-1)?1 for catechol(S/N= 3).By comparison with the references cited in the thesis,the linear range of the sensor for detection of hydroquinone was widened by two orders of magnitude and the sensitivity of this sensor was doubled;GO-MWCNT/1-pyrenemethylamine/AuNPs was prepared by self-assembly method.A nitrite electrochemical sensor based on this nanocomposites was fabricated and a method for detection of nitrite was established.Electrochemical investigation results showed that the linear range of the sensor for the determination of glucose was 2-10000?mol L-1 and the sensitivity was 483.5?A(mmol L-1)-1 cm-2;AuNPs were deposited onto the surface of multilayer structure of GO-MWCNT/MnO2 by self-assembly method using PDDA as a protective agent and coupling agent.A dopamine electrochemical sensor based on GO-MWCNT/MnO2/AuNPs was fabricated and a method for the detection of dopamine was established.TEM,EDS and Raman spectra were used to study the structure,surface morphology and elemental composition of GO-MWCNT/MnO2/AuNPs.The results showed that homogeneous AuNPs were successfully loaded onto the surface of GO-MWCNT/MnO2.Electrochemical investigation results showed that the linear range of the sensor for the determination of glucose was 0.5-2500 ?mol L-1 and the detection limit was 0.17 ?mol L-1(S/N= 3).The sensitivity of this sensor was 233.4 ?A(mmol L-1)-1 cm-2.By comparison with the references cited in the thesis,the linear range of the sensor was widened by two orders of magnitude and detection limit was the lowest.