Study On Construction And Performances Of Anode Based On Nanometer Carbon Materials For Biofuel Cells

Enzymatic biofuel cells (EBFCs), which can convert directly chemical energy into electrical energy using enzymes as catalytst, receive much concern due to many advantages such as environmental friendly, low cost, simple operation and renewable fuel. Nowadays, low output power and short lifetime are the main barriers which restrict the development and application of EBFCs. With the purpose of enhancing the performances of EBFCs, the support materials and methods for immobilization of enzyme and/or mediator on the electrode are the key issues. In this article, several methods for immobilizating of enzyme or mediator on the surface of carbon nanomaterial have been investigated to construct enzyme anode, and the performances of the enzyme electrodes and the resulted EBFCs have been studied in detail. The main research content is as follows:(1) GOD was functionalized with 1-pyrenylboronic acid and used to modify surface of carbon nanotubes (CNTs) through ?-? stockpiling interaction to obtain GOD-PBA/CNTs. Then, an enzyme electrode was produced with GOD-PBA/CNTs modified GC electrode. The electrochemical results showed that the GOD-PBA/CNTs/GC electrode improved the loading amount of GOD and stability compared to the GOD/CNTs/GC electrode. The resulted glucose/O2 EBFC with the GOD-PBA/CNTs/GC electrode as anode and E-ETK Pt/C as the cathode had an open circuit potential (Voc) and short circuit current density (isc) of 0.44 V and 0.43 mA cm-2,respectively, and the obtained maximum power density is 28?W cm-2 at 0.12 V.(2) Graphene decorated with gold nanoparticles (GNs-Au) has been synthesized by in situ thermal reduction of graphene oxide (GO) and HAuCl4 with ?-CD under alkaline condition. Then, mediator Fc was modified to the surface of GNs-Au taking Cysteine as the "bridge", and the resulted GNs-Au-Fc was mixed with the GOD to obtain GNs-Au-Fc/GOD-GA through GA crosslinking. Under the same conditions, the GNs-Au-Fc/GOD-GA electrode shows much higher activity for glucose oxidation than the GNs/Fc/GOD-GA/GC electrode and the GNs-Au/GOD-GA/GC electrode. The resulted glucose/O2 EBFC with the GNs-Au-Fc/GOD-GA/GC electrode as anode and E-ETK Pt/C as the cathode had an open circuit potential (Voc) and short circuit current density (isc) of 0.68 V and 12.4 mA cm-2, respectively, and the obtained maximum power density is 12.7?W cm-2 at 0.3 V.(3) Ferrocenecarboxaldehyde (Fc) was used as the mediator and covalently immobilized on the ethylenediamine (EDA)-functionalized CNTs (CNTs-EDA). Glucose oxidase (GOD) was conveniently incorporated into the composite gel by simply grinding GOD with the CNTs-Fc/IL gel. The resulted electrode (GOD@CNTs-Fc/IL gel modified glassy carbon (GC) electrode) exhibited good catalytic activity and stability towards glucose oxidation. For the assembled glucose/O2 BFC with the GOD@CNTs-Fc/IL gel modified GC electrode as the bioanode and a commercial E-TEK Pt/C modified GC electrode as the cathode, the open circuit potential is 0.66 V and the maximum power density of 60?W cm-2 can be achieved at 0.23 V.