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Design and Fabrication of Advanced Electrode Materials Based on Metal-organic Frameworks and Double Layered Hydroxides Using Hollow Copper Hydroxide Nanotubes Scaffold; Application to Nonenzymatic Glucose Sensor

Khaki Sanati, Elnaz | 2019

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 52013 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Shahrokhian, Saeed
  7. Abstract:
  8. One of the remarkable subject in advanced electrochemistry is, design and architecting new advanced materials with new electrochemical capabilities. One of the notable capabilities is electrocatalysis. Extensive researches are carrying out into the design and preparation of electrocatalyst materials to take advantage of these materials in fabrication of electrochemical sensors and storage/conversion devices. In this field nonoporous materials attracted a lot of attentions due to their unique features. In order to make use of the nanoporous materials as the electrocatalysts, these materials must be fabricated into continuous supported thin films on the electrode surface, which is the challenge in synthesis of these materials. One of the most desirable preparation method with ability of saving time, energy and materials, is direct fabrication. The purpose of this research is to introduce the new electrocatalyst materials and fabricate the thin films of these electroactive nanoporous materials onto the carbonous electrodes with efficient, fast, facile, inexpensive and highly controllable method, to take advantages of their electrocatalytic properties.In the first work, Cu-based metal-organic frameworks with high electroactive surface area was prepared to electrocatalytic sensing of glucose. The direct growth of self-supported metal-organic frameworks (MOFs) thin film can be considered as an effective strategy for fabrication of the advanced modified electrodes in sensors and biosensor applications. However, most of the fabricated MOFs-based sensors suffer from some drawbacks such as time consuming for synthesis of MOF and electrode making, need of a binder or an additive layer, need of expensive equipment and use of hazardous solvents. Here, a novel free-standing MOFs-based modified electrode was fabricated by the rapid direct growth of MOFs on the surface of the glassy carbon electrode (GCE). In this method, direct growth of MOFs was occurred by the formation of vertically aligned arrays of Cu clusters and Cu(OH)2 nanotubes, which can act as both mediator and positioning fixing factor for the rapid formation of self-supported MOFs on GCE surface. The effect of both chemically and electrochemically formed Cu(OH)2 nanotubes on the morphological and electrochemical performance of the prepared MOFs were investigated. Due to the unique properties of the prepared MOFs thin film electrode such as uniform and vertically aligned structure, excellent stability, high electroactive surface area, and good availability to analyte and electrolyte diffusion, it was directly used as the electrode material for non-enzymatic electrocatalytic oxidation of glucose. Moreover, the potential utility of this sensing platform for the analytical determination of glucose concentration was evaluated by the amperometry technique. The results proved that the self-supported MOFs thin film on GCE is a promising electrode material for fabricating and designing non-enzymatic glucose sensors.In the second work, nanosheets of cobalt nickel layered double hydroxides (CoNi-LDHs) were directly grown on Cu(OH)2 nanotubes (as-prepared on GCE) in order to design hierarchical core-shell nanostructure with using efficient, inexpensive and fast method. Here, Cu(OH)2 nanotubes not only served as backbone, but also steer the CoNi-LDH to attach on nanotubes surface preferentially. Vertical growth of CoNi-LDHs nanosheets on the naturally porous and conductive Cu(OH)2 nanotubes make the efficient use of electroactive materials possible due to not only, highly porous 3D configuration, but also, the synergistic effect between the core and the shell structurers. This direct growth of hierarchical core-shell CoNi-LDH@Cu(OH)2 nanostructures on the GCE surface without requirement of any binder or additive layer make efficient use of electrocatalyst materials. Due to the unique properties of the prepared CoNi-LDH@Cu(OH)2 thin film electrode such as uniform and vertically aligned structure, excellent stability, high electroactive surface area, and good availability to analyte and electrolyte diffusion, it was directly used as the electrode material for non-enzymatic electrocatalytic oxidation of glucose. Moreover, the potential utility of this sensing platform for the analytical determination of glucose concentration was evaluated by the amperometry technique. Furthermore in order to miniaturizing the sensor and making the modified electrode more applicable, these hierarchical core-shell CoNi-LDH@Cu(OH)2 nanostructures were directly grow on GSPEs surface with the analogous direct method. The potential utility of this sensor for the analytical determination of glucose concentration was evaluated by the chronoamperometry technique. Investigation results, revealed the use of CoNi-LDH@Cu(OH)2/GSCE as nonenzymatic, in-situ and efficient sensor for accurate measurement of glucose
  9. Keywords:
  10. Glassy Carbon Electrode ; Screen Printed Electrode ; Surface Modification ; Electrocatalysts ; Direct Growth ; Graphite Electrode ; Metal-Organic Framework ; Double Layered Hydroxides ; Nonenzymatic Sensor

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