| Microbial fuel cells(MFCs)is an electricity output device which can ultilize bacteria as a catalyst to oxidize organic compounds and convert chemical energy into electricity energy.During electricity generation in MFC,anode material is the most important part.Therefore,it is very important to enhance electricity generation through manipulation of good anode material with high bio-electrochemical performance.In this study,PEDOT(Poly(3,4-ethylenedioxythiophene))as a modifier is electrochemically polymerized to modify traditional carbon material,namely PEDOT-modified graphite(PEDOT/G),PEDOT-modified carbon paper(PEDOT/CP).The properties of modified electrodes are characterized by Scanning Electron Microscopy(SEM),Energy Dispersive Spectrometer(EDS),Electrochemical Impedance Spectroscopy(EIS)and Cyclic Voltammetry(CV)and so on.The modified electrodes are used in anode material in MFCs.The main results are listed as follow:Comparing with G and CP electrodes,PEDOT/G and PEDOT/CP electrodes have a layer which is simlar to particulate matter and more rugged so that they can absorb much more bacteria cells.EDS analysis showed that O and S elements are both fromed on the PEDOT layer.XPS analysis demonstrated that electrodes modified by PEDOT have valence states of element O and S.EIS analysis indicates that PEDOT/G and PEDOT/CP electrodes have a relatively lower charge transfer resistance.Experiment of substrate conversion reveals that sodium lactate and lactate can be both electron donor for PEDOT layer.Experiment of Exoelectrogens attached on electrodes indicates that PEDOT is more biocompatible.Here are electrical characteristics of different anode material of MFC devices:maximum electricity density,PEDOT/G electrode is 187 mA/m2,G electrode 83 mA/m2;maximum power density,PEDOT/G electrode is 40 mW/m2,G electrode 26 mW/m2;apparent specific resistance,PEDOT/G electrode is 390 ?,G electrode 471?;columbial efficiency,PEDOT/G electrode is 34%,G electrode 12%.For PEDOT/CP and CP electrodes,maximum electricity density,PEDOT/CP electrode is 230 mA/m2,CP electrode 149 mA/m2;maximum power density,PEDOT/CP electrode is 94 mW/m2,CP electrode 53 mW/m2;apparent specific resistance,PEDOT/CP electrode is 149?,CP electrode 123 ?;columbial efficiency,PEDOT/CP electrode is 35.2%,CP electrode 16%.During MFCs,potassium ferricyanide can transmit proton exchange membrane.Bacteria counting of anode chamber and anode liquid reveals that the number of PEDOT-modified electrodes is larger than that of raw electrodes.PEDOT/G and G electrodes,concentration of anode liquid(OD600),after MFC,G electrode is from 0.3-0.4 to 0.55,PEDOT/G from 0.3-0.4 to 1.22;counting with blood cell counting chamber,PEDOT/G electrode of anode liquid is 5.55×1010,anode chamber 2.89×108;G electrode of anode liquid 4.31×1010,anode chamber 2.78×108.For PEDOT/CP and CP electrodes,concentration of anode liquid(OD600),after MFC,CP electrode is from 0.3-0.4 to 0.769,PEDOT/CP from 0.3-0.4 to 0.896;counting with blood cell counting chamber,PEDOT/CP electrode of anode liquid is 5.1×109,anode chamber 6.96×107;CP electrode of anode liquid 4.2×109,anode chamber 5.14×107.Anode resistance and capacitance analysis show that anode resistance could be lower and anode capacitance could be more with high performance electrical characteristics.graphite material,for anode resistance,PEDOT/G electrode could be from 8100 ? to 135 ?,G electrode from 19000 ? to 2300 ?;for anode capacitance,PEDOT/G electrode is from 28 mF to 71.5 mF,G electrode from 7.7 mF to 16.4 mF.Carbon paper material,for anode resistance,PEDOT/CP electrode could be from 827? to 255 ?,CP electrode from 12240 ? to 470 ?;for anode capacitance,PEDOT/CP electrode is from 53.4 mF to 112.8 mF,CP electrode from 0.18 mF to 14,5 mF,Therefore,anode resistance of PEDOT/G and PEDOT/CP electrodes are both lower than those of G and CP electrodes,anode capacitance larger than those of G and CP eletrodes.Electrical characteristics of both modified electrodes are superior to unmodified electrodes. |
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