Preparation Of Conductive Polymer And MnO₂ Modified Anode And Its Application In Benthic Microbial Fuel Cells

The problem of energy has been attracting much attention.In order to solve the problem of energy shortage and resource waste,microbial fuel cell（MFC）as a new green energy comes into being.Benthic microbial fuel cells（BMFC）is a new type of battery developed on the basis of microbial fuel cell.However,the relatively low power output density limits the application of BMFC.In order to improve the output power density of BMFC,the surface of carbon felt and graphite plate anode were modified,and the anode BMFC was constructed.The microorganisms were acclimated and cultured to study their electrical performance.Polyaniline/carbon felt（PANI/CF）electrode and polyaniline/graphite plate（PANI/GP）electrode were prepared by modifying carbon felt and graphite plate substrates respectively by electrodeposition of polyaniline.FT-IR and SEM showed that the material was prepared successfully.The three-dimensional network linear structure of PANI was conducive to the colonization of electrogenic microorganisms in the anode.The specific capacitance of PANI/CF electrode and PANI/GP electrode is 40.70 and 38.91 times higher than that of carbon felt and graphite plate.The BMFC was constructed with PANI composite electrode and blank electrode as anode respectively to study the electrical performance.The results show that the theoretical capacitance of PANI is large,which can stabilize the anode performance and facilitate the power output.Compared with carbon felt and graphite plate electrodes,the maximum power density of PANI/CF and PANI/GP electrodes was increased by 0.24 W/m²and 0.35 W/m².Polyaniline/carbon felt（PPy/CF）electrode and polypyrrole/graphite plate（PPy/GP）electrode were prepared by direct current electrodeposition.The successful deposition of PPy on CF and GP surfaces was demonstrated by SEM and FT-IR,and the spherical accumulation structure of PPy was observed,which was more conducive to the adhesion of electrogenic bacteria.The electrochemical performance test showed that the electrochemical performance of PPy modified electrode was significantly improved compared with blank CF and GP.BMFC system was constructed for electricity generation test.RCTS of PPy/CF anode and PPy/GP anode decreased by 5.35Ωand 4.31Ωcompared with CF and GP respectively,effectively reducing electron transfer resistance.The maximum power density of BMFC with PPy/GP as anode was 1.36W/m²,which was 3.2 times that of the unmodified electrode.Based on the previous research,with graphite plate as matrix,MnO₂,PPy and MnO₂composite modification,MnO₂/GP electrode,PPy@MnO₂/GP electrode,PPy/MnO₂/PPy/GP electrode.The composite electrode was successfully prepared by FT-IR,SEM,XRD and XPS.The power density of MnO₂/GP anode battery is higher than that of carbon material.The electron transfer rate of PPy@MnO₂/GP anode modified with MnO₂and PPy is higher than that of MnO₂/GP,and the exchange current density can reach 1.39 m A/cm².And for the"sandwich"structure of PPy/MnO₂/PPy/GP electrode in electrochemical performance and biocatalytic performance compared to MnO₂/GP,PPy/GP has significantly improved,when charging 20 min,discharge 10 min,The charge storage capacity of PPy/MnO₂/PPy/GP electrode is 1130.83C/m².In addition,the maximum output power density of BMFC using it as anode can reach 1.90 W/m²,150.00%and 39.71%higher than that of MnO₂/GP and PPy/GP anodes,respectively.By high-throughput analysis,the composite anode successfully domesticated microorganisms in seafloor sediment,and the electrode surface biodiversity decreased,which was attributed to the specific selection and enrichment of electrogenic bacteria（Halomonas（23.37%）and Marinobacter（9.64%））by PPy/MnO₂/PPy/GP（1）.The synergistic action between different bacteria was used to improve the performance of BMFC.