Thesis
Introduction and characterization of an innovative biofuel cell platform with improved stability through novel enzyme immobilization techniques
Washington State University
Master of Science (MS), Washington State University
2006
Handle:
https://hdl.handle.net/2376/103496
Abstract
Enzyme-based biofuel cells (BFCs) are a promising technology as a small-scale power source, but their practical uses are hampered by their short lifetime and poor power density. In this work, we have developed a miniature BFC consisting of an airbreathing cathode and an enzymatic anode. The miniaturization of BFC was done by adopting the design of stackable proton exchange membrane (PEM) fuel cells, and the smallest dimension of BFC was 12 x 12 x 9 mm. The enzymatic anodes were constituted with stabilized glucose oxidase (GOx) in a form of crosslinked enzyme clusters (CEC) on the surface of carbon nanotubes (CNTs). When these enzyme clusters on CNTs were applied to carbon supports, a high surface area multilayered complex with internal pore structures was formed within the enzymatic anode. We have compared these enzymatic CEC anodes to anode electrodes fabricated by more conventional methods, such as enzyme coating (EC) and covalent attachment (CA), and demonstrated that our novel CEC electrodes far outperform these electrodes both based upon power density output and stability. We have also demonstrated that the buffer solution plays an important role in determining the performance and stability of BFCs. It was found that when the cell was buffered, the initial performance was very high but its performance quickly dropped due solely to a deactivation of the PEM. On the other hand, when the cell was unbuffered, the initial performance was lower than that of the buffered runs due to the low pH condition but its performance was very stable for a very long operation time. For example, under continuous operation, a potentiostatic measurement of the BFC in an unbuffered solution showed no significant current density drop for more than 16 hours. This unprecedentedly high operational stability of the BFC using the enzyme-CNT hybrid materials opens up a new potential for many BFC applications. Finally, we have explored the effect of glucose and mediator concentrations in the feed solution of the BFC and have shown that maximum power output occurs at concentrations around 100 mM and 10mM, respectively.
Metrics
7 File views/ downloads
11 Record Views
Details
- Title
- Introduction and characterization of an innovative biofuel cell platform with improved stability through novel enzyme immobilization techniques
- Creators
- Michael Bryant Fischback
- Contributors
- Su Ha (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Chemical Engineering and Bioengineering, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525074701842
- Language
- English
- Resource Type
- Thesis