Preparation Of Fe,N-codoped Porous Carbon-based MFC Cathode And Its Catalytic Performance

Microbial fuel cell(MFC)is a green energy,which can convert the chemical energy into electricity by utilizing the microorganisms in the anode as catalyst to oxidize organic matters.However,the energy production efficiency is low,while the cathode performance is one of the major factors that affecting the power generation of MFC.Platinum(Pt)is the well-known ORR catalyst for its high electrocatalytic activity,but the high price and low reserve limit its widespread application.Thus,the development of low-cost and high-efficiency cathode catalyst is crucial for the industrialization of MFC.In view of the main problems existing in MFC,we use inexpensive transition metal iron(Fe)and zinc(Zn)as metal ion centers to synthesize metal organic frameworks(MOFs)materials.After carbonization,the porous carbon material co-doped with iron and nitrogen was prepared.Then they were applied as MFC cathode and the performace was evaluated.In this dissertation,the effects of different carbonization temperatures on the properties of the as-synthesized catalysts were studied.The prepared MOFs materials were carbonized at different temperature,named as Fe-Zn-X(X = 700,800,900).As a control,a sole Fe-based MOFs material was prepared and named as Fe-800 after thermal treatment at 800℃.These materials were evaluated by a series of physical characterization and electrochemical tests,then the conductivity and electrochemical activity of the obtained porous carbon materials were investigated.The results showed that Fe-Zn-800 had the highest conductivity and the largest specific surface area(544.83 m2/g).The content of pyridine N and graphite N is also the maximum among all of the four prepared porous carbon materials.Meanwhile,Fe-Zn-800 showed the best electrochemical performance.It has a relatively positive reduction potential and the maximum closed curve area,and also through a 4 electron transfer pathway during the ORR.Finally,these porous carbon materials were coated on the surface of a carbon cloth as the cathode of microbial fuel cells,the carbon brush was used as anode,then its electricity production performance was studied.The experimental results show that Fe-Zn-800 had the highest power density and output voltage,the power density reached 0.76 W/m2,and the voltage reached 0.53 V.Its power density is 1.3 times that of commercial Pt/C catalyst,and it is also significantly superior to Fe-800 catalyst,the power density is 0.21 W/m2.The electrocatalytic performance of Fe-N co-doped porous carbon materials is better than that of commercial Pt/C catalysts in MFC,which indicated that it maybe become a substitute for traditional Pt/C catalysts.