Date of Award

Fall 2007

Document Type

Thesis

Degree Name

Master of Science in Chemistry - (M.S.)

Department

Chemistry and Environmental Science

First Advisor

Zafar Iqbal

Second Advisor

S. Mitra

Third Advisor

Carol A. Venanzi

Abstract

The work presented in this thesis has focused on designing and characterizing biofuel cell electrodes using porous silicon (p-Si) as the substrate or current collecting platform on which carbon nanotubes (CNTs), both single-walled carbon nanotubes (SWNTs) and multi-walled carbon nanotubes (MiWNTs), were synthesized directly, followed by enzyme catalyst immobilization on the CNTs. Laccase and glucose oxidase (GOx) were used as enzymatic biocatalysts, which were immobilized on the CNT walls and tips using an electrochemical technique. Cyclic voltammetry showed well-defined redox peaks which indicated that the enzyme (GOx and laccase) were successfully immobilized on the CNTs. The amperometric responses of the laccase electrode upon additions of bubbled air and potentiometric responses of GOx electrode to additions of glucose demonstrated that the immobilized enzymes retained their bioelectrocatalytic activity after electrochemical deposition. Working biofuel cells with p-Si/SWNTs and p-Si/MWNTs based electrodes with immobilized enzymes were studied at room temperature in a 0. iM phosphate buffer solution of pH 7.0, containing 4 mM glucose. The peak power output of the biofuel cell with p-SiISWNTs based electrodes was 3.32 μW at 357 mV vs. SCE (Saturated Calomel Electrode). It provided much better performance than the biofuel cell with p-Si/MWNTs electrodes, which yielded a peak power of 1.23 nW at 5.6 mV. The combination of p-Si/CNTs with redox enzymes provided a convenient prototype for a direct electron transfer, membrane-less biofuel cell.

Included in

Chemistry Commons

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