Research On Electricity Generation Of Nano Silver / Carbon Composite Cathode Microbial Fuel Cell

With increasing energy and environmental issues, the development and utilizationof new energy technologies received widespread attention. Microbial fuel cellstechnology is a new method of power generation, which could be able to producebio-energy in the form of electricity and hydrogen exist through the use of microbialbiomass from the wastewater instead of consuming energy. However, its low poweroutput and electricity recovery rate (coulombic efficiency CE), besides the higher costof catalytic material (commercial Pt/C) were still the main constraint to limit itslarge-scale application. The tiny cube air cathode single chamber reactor was designedto enhance the power output by reducing the distance between the electrodes (4cm) todecrease the internal resistance of the battery. Unfortunately, organiccross-contamination from the anode to the cathode in the single chamber formed a layerof heterotrophic microbial on the surface of the cathode, which would lead to theoxygen consumption and the loss of substrate during the cathodic oxygen reductionwith the results of gradually decreasing of power delivery and so were the decline ofcoulombic efficiency and oxygen concentration.In this study, we did research according to the above-mentioned problemsencountered in the single-chamber reactor. We synthesized nano silver/carboncomposite material as the cathode catalysts to improve the capacity of the electricalgeneration of MFCs by using the oxygen reduction reaction (ORR) activity and theinhibition of microorganisms of the silver nanoparticles. We had prepared two types ofcathode materials to further enhance oxygen reduction ability of the compounds byusing the waste biomass (pomelo peel) as the carbon precursor and introducing Fe3+andWC as graphite catalyst and cocatalyst, respectively. Meanwhile, we made acomparative study on electricity production performance of MFCs system in terms ofmaterial properties, power output, as well as the operation conditions of the reactor, andthen analyzed and optimized the influencing factors affecting the battery productionperformance in MFCs.The composites were characterized and evaluated by XRD、Raman、XPS、TG-IR、 BET、SEM、TEM、BAS100electrochemical analysis system and other physical andchemical characterization of the test used to study a variety kind of crystalline phase,morphology, phase transformation and its application in microbial fuel cells (MFCs). Experimental results show that the introduction of Fe3+effectively promote the extent ofgraphite composites, and silver nanoparticles can be uniformly dispersed and closelyintegrated with carbon by using one-step thermal reduction method. The resultingcomposite material could be used as the cathode catalyst and successfully applied inMFCs with a superior stabilizing effect, which also had potential applications formicrobial fuel cells commercialization. This in-situ reduction method is simple, easy tooperate and provide a cheap and efficient avenue for the novel functional carbon-basednano-composites for further application of MFCs.