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Cathode performance as a factor in electricity generation in microbial fuel cells.
Environ Sci Technol. 2004 Sep 15; 38(18):4900-4.ES

Abstract

Although microbial fuel cells (MFCs) generate much lower power densities than hydrogen fuel cells, the characteristics of the cathode can also substantially affect electricity generation. Cathodes used for MFCs are often either Pt-coated carbon electrodes immersed in water that use dissolved oxygen as the electron acceptor or they are plain carbon electrodes in a ferricyanide solution. The characteristics and performance of these two cathodes were compared using a two-chambered MFC. Power generation using the Pt-carbon cathode and dissolved oxygen (saturated) reached a maximum of 0.097 mW within 120 h after inoculation (wastewater sludge and 20 mM acetate) when the cathode was equal size to the anode (2.5 x 4.5 cm). Once stable power was generated after replacing the MFC with fresh medium (no sludge), the Coulombic efficiency ranged from 63 to 78%. Power was proportional to the dissolved oxygen concentration in a manner consistent with Monod-type kinetics, with a half saturation constant of K(DO) = 1.74 mg of O2/L. Power increased by 24% when the cathode surface areas were increased from 22.5 to 67.5 cm2 and decreased by 56% when the cathode surface area was reduced to 5.8 cm2. Power was also substantially reduced (by 78% to 0.02 mW) if Pt was not used on the cathode. By using ferricyanide instead of dissolved oxygen, the maximum power increased by 50-80% versus that obtained with dissolved oxygen. This result was primarily due to increased mass transfer efficiencies and the larger cathode potential (332 mV) of ferricyanide than that obtained with dissolved oxygen (268 mV). A cathode potential of 804 mV (NHE basis) is theoretically possible using dissolved oxygen, indicating that further improvements in cathode performance with oxygen as the electron acceptor are possible that could lead to increased power densities in this type of MFC.

Authors+Show Affiliations

Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

15487802

Citation

Oh, SangEun, et al. "Cathode Performance as a Factor in Electricity Generation in Microbial Fuel Cells." Environmental Science & Technology, vol. 38, no. 18, 2004, pp. 4900-4.
Oh S, Min B, Logan BE. Cathode performance as a factor in electricity generation in microbial fuel cells. Environ Sci Technol. 2004;38(18):4900-4.
Oh, S., Min, B., & Logan, B. E. (2004). Cathode performance as a factor in electricity generation in microbial fuel cells. Environmental Science & Technology, 38(18), 4900-4.
Oh S, Min B, Logan BE. Cathode Performance as a Factor in Electricity Generation in Microbial Fuel Cells. Environ Sci Technol. 2004 Sep 15;38(18):4900-4. PubMed PMID: 15487802.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Cathode performance as a factor in electricity generation in microbial fuel cells. AU - Oh,SangEun, AU - Min,Booki, AU - Logan,Bruce E, PY - 2004/10/19/pubmed PY - 2005/2/11/medline PY - 2004/10/19/entrez SP - 4900 EP - 4 JF - Environmental science & technology JO - Environ Sci Technol VL - 38 IS - 18 N2 - Although microbial fuel cells (MFCs) generate much lower power densities than hydrogen fuel cells, the characteristics of the cathode can also substantially affect electricity generation. Cathodes used for MFCs are often either Pt-coated carbon electrodes immersed in water that use dissolved oxygen as the electron acceptor or they are plain carbon electrodes in a ferricyanide solution. The characteristics and performance of these two cathodes were compared using a two-chambered MFC. Power generation using the Pt-carbon cathode and dissolved oxygen (saturated) reached a maximum of 0.097 mW within 120 h after inoculation (wastewater sludge and 20 mM acetate) when the cathode was equal size to the anode (2.5 x 4.5 cm). Once stable power was generated after replacing the MFC with fresh medium (no sludge), the Coulombic efficiency ranged from 63 to 78%. Power was proportional to the dissolved oxygen concentration in a manner consistent with Monod-type kinetics, with a half saturation constant of K(DO) = 1.74 mg of O2/L. Power increased by 24% when the cathode surface areas were increased from 22.5 to 67.5 cm2 and decreased by 56% when the cathode surface area was reduced to 5.8 cm2. Power was also substantially reduced (by 78% to 0.02 mW) if Pt was not used on the cathode. By using ferricyanide instead of dissolved oxygen, the maximum power increased by 50-80% versus that obtained with dissolved oxygen. This result was primarily due to increased mass transfer efficiencies and the larger cathode potential (332 mV) of ferricyanide than that obtained with dissolved oxygen (268 mV). A cathode potential of 804 mV (NHE basis) is theoretically possible using dissolved oxygen, indicating that further improvements in cathode performance with oxygen as the electron acceptor are possible that could lead to increased power densities in this type of MFC. SN - 0013-936X UR - https://www.unboundmedicine.com/medline/citation/15487802/Cathode_performance_as_a_factor_in_electricity_generation_in_microbial_fuel_cells_ L2 - https://doi.org/10.1021/es049422p DB - PRIME DP - Unbound Medicine ER -