Preparation Of Metal Nanocomposites And Their Application In Electrochemical Sensing

Nanomaterials and nano-polymer have received great interest and exhibit excellent performance in electrochemical sensing due to their special physical and chemical properties. In this sensor, six tiypes of metal nanocomposites and composites formed with the conductive polymer were prepared, and further six types of non-enzymatic electrochemical sensors were successfully fabricated. Investigation on the electrochemical and electrocatalytic behavior of these sensors, the new method to detect hydrogen peroxide (H2O2), glucose, nitrite (NO2-) and dopamine (DA) was established. The investigation was benificial to research new electrochemical sensor with high sensitivity, high selectivity and low detection limit and played a certain positive role in extending the application of metal nanomaterials and nano-polymer. In this thesis, there were a total of four chapters, the contribution of the author mainly includes the following four aspects.1. Core-shell types of Au@Ag NPs were prepared by a seed-mediated growth procedure in an aqueous solution. Based on the Au@Ag NPs, non-enzymatic H2O2 sensor was fabricated. Investigation on the relationship between response behavior of the sensor and size of sensing interface material, dispersion and electrocatalytic properties was carried out. Thus, the new method to detect H2O2 was established. The as-prepared Au@Ag NPs were characterized by transmission electron microscope (TEM) and dynamic light scattering (DLS). TEM and DLS analysis indicates that the obtained 31.5 nm Au@Ag NPs are highly dispersed and possess narrow size distributions without any aggregation; The sensor exhibits excellent electrochemical performance toward H2O2 reduction and a linear range from 5.0 ?M to 8.0 mM, a limit of 1.3 ?M and a high sensitivity of 116.7 ?A mM-1 cm-2; Compared with other H2O2 sensor based on Ag, this sensor show slow 3 times more sensitivity, lower detection limit and wider linear range.The F-Au@PtNPs and U-Au@PtNPs were prepared by a seed-mediated growth procedure in an aqueous solution. Based on the two types of nanoparticles, non-enzymatic H2O2 sensor was fabricated. Investigation on the relationship between response behavior of the sensor and size, morphology and structure of sensing interface material and electrocatalytic properties was carried out. Thus, the new method to detect H2O2 was established. The two types of nanoparticles were characterized by TEM, which indicates that the obtained nanoparticles are highly dispersed and possess narrow size distributions with regular morphology; The sensor exhibits excellent electrochemical performance toward H2O2 reduction and with a linear range from 0.5 ?M to 500 ?M, a limit of 0.15 ?M and a high sensitivity of 457.1 ?A mM-1 cm-2; Compared with other H2O2 sensor based on Pt, this sensor shows good stability, one order of magnitude lower detection limit and 1.5 times more sensitivity.2. Au@Ag NPs were prepared by a seed-mediated growth procedure at a gas/liquid interface. Based on the nanoparticles, non-enzymatic H2O2 sensor was fabricated. Investigation on the relationship between response behavior and electrocatalytic properties was carried out. Thus, the new method to detect H2O2 was established.The nanoparticles were characterized by TEM and DLS, which indicates that the obtained nanoparticlesare highly dispersed and possess narrow size distributions without any aggregation; The sensor exhibits excellent electrochemical performance toward H2O2 reduction and a linear range from 5 ?M to 15 mM, a limit of 0.9 ?M and a high sensitivity of 251.9 ?A mM-1 cm-2; Compared with other H2O2 sensor based on Ag,this sensor show five times more sensitivity, low potential and one orders of magnitude wider linear range.Conductive PANINF was prepared at a liquid/liquid interface. Based on the PANINF, a DA sensor was fabricated. Investigation on the relationship between response behavior of the sensor and size and morphology of sensing interface material was carried out. Thus, the new method to detect DA was established. The PANINF was characterized by TEM, SEM and EDS, which indicates that the synthetic fibrous PANINF possesses a curved shape, uniform diameter and uniform fiber distribution. Co nanoparticles uniformly also attached to surface of PANINF; The sensor exhibits excellent electrochemical performance toward DA oxidation and a linear range from 0.1 ?M to 200 ?M, a limit of 0.03 ?M and a high sensitivity of 807.1 ?A mM-1 cm-2; Compared with other DA sensor based on Co, this sensor shows resistance toward interfering substances, four times more sensitivity and one order of magnitude lower detection limit.3. The three-dimensional (3D) hierarchical nanostructured conducting polymer hydrogel with a mesh-like hydrogel network were prepared. Then CuNPs were loaded onto as-parepared 3D-HPANI by electrodeposition. Based on the 3D-HPANI-CuNPs, a NO2-sensor was fabricated. Investigation on the relationship between response behavior of the sensor and size and morphology of sensing interface material was carried out.Thus, the new method to detect NO2 was established.The 3D-HPANI were characterized by SEM and EDS, which indicates that the synthetic fibrous 3D-HPANI possesses hydrogel network and Co nanoparticles uniformly also attached to network of 3D-HPANI; The sensor exhibits excellent electrochemical performance toward NO2 oxidation and a linear range from 0.2 ?M to 4.3 mM, a limit of 0.07 ?M and a high sensitivity of 139.3 ?A mM-1 cm-2; Compared with other NO2- sensor based on Co,this sensor shows fast response, one orders of magnitude wider linear range and one orders of magnitude lower detection limit.The 3D-HPANI was prepared. Then Pd was loaded onto as-parepared 3D-HPANI by electrodeposition. Based on the 3D-HPANI-PdNW and 3D-HPANI-PdNF, a glucose sensor was fabricated. Investigation on the relationship between response behavior of the sensor and size and morphology and structure of sensing interface material was carried out. Thus, the new method to detect glucose was established. The 3D-HPANI were characterized by SEM and EDS, which indicates that the synthetic fibrous 3D-HPANI possess hydrogel network and Pd nanowires uniformly also attached to surface of 3D-HPANI; The sensor exhibits excellent electrochemical performance toward glucose oxidation and a linear range from 5 ?M to 8 mM, a limit of 0.8 ?M and a high sensitivity of 187.3 ?A mM-1 cm-2; Compared with other glucose sensor based on Pd, this sensor shows wider linear range, two orders of magnitude lower detection limit and three times more sensitivity.