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Vertically Aligned Carbon Nanosheets As Immobilization Supports for Enzyme Bio-Electrocatalysis
Tuesday, May 13, 2014: 12:00
Floridian Ballroom G, Lobby Level (Hilton Orlando Bonnet Creek)
Y. Umasankar (The University of Georgia), D. B. Brooks, B. Brown, Z. Zhou (Luna Innovations Inc., Luna nanoWorks Division, Danville, VA 24541, USA), and R. P. Ramasamy (The University of Georgia)
High performance laccase-based biofuel cell cathode has been developed using carbon nanosheet (CNS) with buckypaper (BP) as the substrate electrode. Compared to multi-walled carbon nanotubes (MWNT) based electrode, CNS based electrode exhibited better electrochemical activity for oxygen reduction reaction (ORR) at biologically relevant conditions. The scanning electron microscopy and Raman spectroscopy studies show that CNS was coated on the nano-tubule bundles within the BP. The attenuated total resonance Fourier transform infrared spectroscopy results show that laccase was intimately attached on to the CNS-BP. Electrochemical characterization including cyclic voltammetry and Tafel region sweep were performed to derive the kinetic parameters of ORR at the laccase-CNS-BP cathode. The onset potential obtained from the cyclic voltammogram for laccase ORR at CNS-BP is 20 mV higher than the MWNT based electrodes. The laccase-CNS-BP also exhibited steep ORR cathodic wave in the voltammograms with a Tafel slope of 19 mV decade
-1. Steady state cathode polarization curves also reveal that laccase-CNS-BP cathode yielded higher current density than MWNT electrodes.
Fig. 1: Schematic representation of four electron transfer ORR at laccase-CNS interface.
Acknowledgements:
This work was partially supported by the United States Army under Contract No W911NF-13-C-0014.
References:
1. Ramasamy, R. P.; Luckarift, H. R.; Ivnitski, D. M.; Atanassov, P. B.; Johnson, G. R. (2010) High electrocatalytic activity of tethered multicopper oxidase-carbon nanotube conjugates. Chemical Communications., 46, 6045-6047.
2. Parimi, N. S.; Umasankar, Y.; Atanassov, P.; Ramasamy, R. P. (2012) Kinetic and mechanistic parameters of laccase catalyzed direct electrochemical oxygen reduction reaction. ACS Catal., 2, 38-44.
3. Umasankar, Y.; Brooks, D. B.; Brown, B.; Zhou, Z.; Ramasamy, R. P. (2013) Three dimensional carbon nanosheets as novel catalyst support for enzymatic bioelectrodes. Advanced Energy Materials, (accepted paper).
