Electricity Production And Anode Capacitive Characteristics Of Microbial Fuel Cell With CeO₂ And Mn₃O₄ Modified Anode

Microbial fuel cell is a device which can convert organic or inorganic substrate into electricity by using bacteria as electro catalyst.Anode modification can improve the electricity production of MFC.In this paper,CeO2 and Mn3O4 were prepared by sol-gel method,and they were used to modificate the graphite electrode as the anode of MFC.The paper studied the electricity production and anode capactive characteristics of the modificated MFC.Besides,the modification methods of carbon felt anode were compared for Mn3O4.The main results were as follows:Anode modification with CeO2 shortened the start-up period,raised the output voltage,prolonged the electricity production cycle,and improved the columbic efficiency of MFC.Anode modificated MFC had a maxmum power density of 986mW/m2,higher than the control MFC(539mW/m2).Anode modification reduced the charge transfer resistance of biofilm and electode interface,as a result,reduced the apparent internal resistance.Since Ce02 had good pseudo capacitance characteristics,the modified anode had larger specific capacitance,and stored more energy in batch mode MFC.Graphite anode modified with 1.5mg/cm2 or 2.0mg/cm2 Mn3O4 improved the output voltage,and increased the maxmum power density by about 25%,and reached about 250 mW/m2.The results of electrochemical impedance spectroscopy(EIS)showed that the modified anode reduced the charge transfer resistance of biofilm and electrode interface,and improved the electricity production.However,excess load of Mn304 would increase the apparent internal resistance and decrease the electricity production.Besides,Mn3O4 had good pseudo capacitance characteristics,and increased the anode specific capacitance.Mn3O4 modified carbon felt anode prepared by sol dipping method had a uniform Mn3O4 film on the surface.Anode modification shortened the start-up period,reduced anode charge transfer resistance,and increased the output voltage of MFC.The maxmum power density was 431mW/m2.Mn3O4 modified carbon felt anode prepared by ultrasonic dispersion method had larger charge transfer resistance.Its output voltage and maxmum power density was lower than those of the control MFC.