Preparation Of The ORR Catalysts And Their Electricity Generation Performance In Microbial Fuel Cells

Microbial fuel cells(MFCs)are a device that use microbes to degrade organic matter in sewage as a catalyst and convert chemical energy into electrical energy.As the clean and environmentally friendly new energy technology,more and more attention has been paid on MFCs in recent years.Oxygen reduction reaction(ORR)is one of the most important reactions in MFCs and is one of the major factors that affect the power generation efficiency of MFCs.Because ORR itself weak kinetics and high overpotential lower the its efficiency,therefore,the search for low cost,good stability and high catalytic activity of ORR catalyst has become the focus of research to improve MFCs performance.The research content of this dissertation is divided into two parts:(1)The results of PANI/?-MnO2 composite catalysts prepared in this dissertation showed that ?-MnO2 in the composite catalyst had a rod-like structure with a length of about 8-12 ?m and a width of about 200-300 nm.PANI particles grown onto the ?-MnO2 surface.The results of electrochemical analysis showed that PANI/?-MnO2 catalyst possessed obvious redox peaks,and the peak current and exchange current density(i0)increased with the increase of PANI/?-MnO2 content.Compared with the three different materials(?-MnO2,PANI+?-MnO2 and PANI/?-MnO2),when the MFC was equipped with PANI/?-MnO2 as cathode catalyst,the power and electricity producing performance of the cell were the highest.The maximum power density and open circuit voltage were 248 mW m-2 and 0.77 V,respectively,and as the PANI/?-MnO2 cathode catalyst content increased,the MFC performance also increased.Therefore,the prepared PANI/?-MnO2 can be used as a potential microbial fuel cell ORR catalyst.(2)The results of the CoMn2O4/rGO composite catalysts prepared in this dissertation showed that CoMn2O4 particles were dispersed on the rGO sheets.The valence states of Co and Mn in the catalyst were not single,but the redox couples of Co3+/Co2+ and Mn4+/Mn3+ existed.Electrochemical analysis showed that CoMn2O4/rGO had obvious redox peaks,and the reduction peak current and exchange current density(i0)increased with the increase of CoMn2O4/rGO content.Using CoMn2O4 and CoMn2O4/rGO as the cathode catalysts in MFCs,the MFC with CoMn2O4/rGO cathode catalyst was found to have higher electricity yield.The maximum power density of MFC reached 361 mW m-2 and the open circuit voltage was 0.822V.Therefore,CoMn2O4/rGO can be applied to MFCs as a cheap and efficient ORR catalyst.