Fabrication of Nanomodified Anodes for Power Density Enhancement of Microbial Fuel Cells
- PDF / 244,145 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 23 Downloads / 220 Views
1170-R05-13
Fabrication of Nanomodified Anodes for Power Density Enhancement of Microbial Fuel Cells Rebecca Schaller1, Yanzhen Fan2, Shoutao Xu2, Alan Fern3, Frank Chaplen2, Hong Liu2, and Jun Jiao1 1 Department of Physics, Portland State University, Portland, OR 97207, USA 2 Department of Biological and Ecological Engineering, Oregon State University, Corvallis, OR 97331, USA 3 Department of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR 97331, USA ABSTRACT Microbial fuel cells (MFCs) use microorganisms to simultaneously break down organic materials and generate electricity. One of the greatest challenges in the practical application of MFCs is to sufficiently increase their power generation. Nanomodified graphite carbon anodes were prepared for use in MFCs to enhance the electron transport from the microbes to the electrode. Nanomodification to the anodes included growth of nanoparticles and multi-walled carbon nanotubes (MWCNTs). Nanoparticles of various metals, including Au, Ni, Pd, and Fe, were synthesized through thermal annealing and Fe catalyzed MWCNTs were synthesized through chemical vapor deposition. Power density was measured in MFCs for each type of nanomodified electrodes. Significant increase in power density was observed for the MFC with anodes decorated with MWCNTs (with 50-100nm diameters). INTRODUCTION Alternative and renewable energy is becoming increasingly important, and the effect on the environment is a pressing concern. Greater output of energy with less environmental impact is key to advancing technologies in this field. One sustainable approach to power generation is the microbial fuel cell (MFC). This fuel cell employs bacteria, found in typical sewage wastewater, to generate electricity. Not only can the cell produce power, but it can simultaneously clean wastewater1 and other hazardous sites such as nuclear waste sites2. If the power output on these fuel cells can be optimized for commercial use, they could become a viable option for alternative energy sources. MFCs use a catalytic reaction to convert chemical energy to electricity. Microbes in these cells are used as a catalyst to oxidize the fuel (organic material) into electrons and protons. The bacteria convert fuel into CO2, water, and energy. The protons recombine at the cathode with the electrons from the circuit and oxygen to form water. The MFC harvests some of this energy to produce a current.
FIG 1. Schematic of a single chamber MFC with a single bacteria and air cathode. Presently, in MFCs (basic schematic in FIG 1 above), the power output density is very low. One cause of the low power density is the inefficient transfer of electrons from the microbes to the anode surface. Current research is exploring ways of enhancing and increasing this output. Possible solutions include using different strains of microbes, genetically modifying these bacteria, and physically modifying the surface of the anode. Structures grown on the surface of the anode, such as nanotubes or nanowires, may act a
Data Loading...
