Study On The Electrical Performance Of NbC Anode Of Microbial Fuel Cells

Microbial Fuel Cells(MFCs)is a new technology in the electricity generation and wastewater treatment.The mechanism of microbial fuel cell is to oxidize organic matter in sewage by using exoelectrogens.The chemical energy stored in the organic matters is directly converted into electricity without any polluted byproducts.There are many limitations for the practical application of MFCs,among which the performance of the anode material is an important factor affecting the overall performance of MFCs.Transition metal carbide has platinum-like properties,so it has high conductivity but low price.Meanwhile,it has high melting point,low resistance and large specific surface area,as well as good biological compatibility and chemical stability.In this project,Nb C is selected as the material and coated on the commercial carbon cloth as the anode of MFC.By using this electrode,a better battery discharge time is obtained,the maximum output voltage and power density of the battery are improved,and the high cost,complex fabrication and large internal resistance of the existing electrode materials are solved.In this thesis,Nb C/CC electrode was prepared by pasting carbon cloth electrode with Nb C nanoparticles.It was found that the Nb C/CC electrode had a larger area for microbial adhesion and more electrochemical catalytic activity sites than the CC electrode.Through a variety of electrochemical characterization methods,the charge transfer resistance of Nb C/CC(30.2 ?)is far lower than that of CC electrode(185.9 ?),certificating that Nb C/CC electrode has higher electron transfer rate than CC electrode.The start-up time for Nb C/CC is 23.8h,and the output voltage reaches 603.35 m V in the first cycle while the start-up time for CC is319.2h,and the peak output voltage is only 464.47 m V.The average output voltage of Nb C/CC electrode(580.35 ± 21.23 m V)is 1.41 times that of CC electrode(419.67 ± 18.53 m V).The maximum output power density of Nb C/CC electrode(3.9 W/m2)is 1.95 times that of CC electrode(2.0 W/m2).The COD removal of Nb C-MFC is 87.5%,1.23 times that of CC-MFC under the same conditions(71.4%),indicating that Nb C-MFC has better ability for degradation of organic matters.Nb C-MFC shows the coulomb efficiency(81.5%),1.49 times that of CF-MFC(54.6%),which further indicates that NBC-MFC has a higher ability for electronics recycling.Sequencing analysis shows that the excellent performance of the above battery is attributed to more types of electrogenic bacteria attached on the surface ofniobium carbide(Nb C/CC)electrode,indicating that the anode modified with niobium carbide is efficient for improving the electrical performance of microbial fuel cells,and the material is expected to be applied in the industrialization of MFCs in the future.