Preparation And Characterization Of Cathode Catalysts For Microbial Fuel Cell

Microbial fuel cell (MFC), using microorganism as catalyst, combines traditionalbiodegradation and electrochemical technology converts chemical energy stored inbiodegradable organic/inorganic matters directly into electrical energy. Anaerobicfluidized bed microbial fuel cell (AFBMFC) can strengthen mass transfer of anodechamber to improve the electricity generation performance of MFC. Low cathodicORR activity and expensive price of cathode MFC are some of the critical factors tolimit the MFC’s commercial application. Based on this, cathode catalyst and masstransfer of anode chamber were researched. The main research contents and results aregiven as follows:(1) M-N-C (M=Fe, Co) catalysts were synthesized by heat treatment methodusing polyaniline and nitrate as precursors. The performance of the prepared M-N-Ccatalysts applied for AFBMFC cathode catalysts was examined. The resultsdemonstrate that, the maximum power of AFBMFC operated with Fe-N-C cathodecatalyst was166.82mW·m-2, which was10%higher than that of Pt/C catalyst. Theopen circuit voltage was up to636.0mV.(2) LaxSr1-xCoO3(La: Sr: Co=x:1-x:1, x=0.5,0.7,0.8) perovskite catalysts onthe performance of the air cathode oxygen reduction was systematically investigated.Based on this, in order to improve the conduction of catalyst and reduce the potentialof cathode, La0.7Sr0.3CoO3/PANI composites used as cathode catalysts of AFBMFCwere synthesized by polymerization method. The experiment results show that, theopen circuit voltage of AFBMFC with La0.7Sr0.3CoO3/PANI catalyst containing PANImass fraction of6%shows the best performance. The different mass fraction ofpolyaniline (PANI) leads to great difference in activity of the prepared catalysts. Inphosphate buffer solution, the composite La0.7Sr0.3CoO3/PANI catalyst containingPANI mass fraction of6%showed fine electrocatalytical activity. Using it as thecathode catalyst, the maximum output power density and open circuit voltage of MFCwere up to258.91mW·m-2and642.7mV, respectively. And the total cost of La0.7Sr0.3CoO3/PANI catalyst was lower than that of Pt/C catalyst.(3) The numerical simulation of the internal flow channel for anode chamber offluidized bed microbial fuel cell has been completed by fluent software. Underdifferent flow velocity of wastewater, the concentration of the particle presentsobviously inhomogeneity. Central area of the fluidized bed presents highconcentration, and the wall area presents small concentration. Fluidization conditionof particles in fluidized bed microbial fuel cell is coupling with electricity generationperformance of it.