Study On The Influence Mechanism Of Interfacial Electron Transfer In Microbial Fuel Cells Based On Electrospinning Porous Nanowire

Microbial Fuel Cell（MFC）as a new type of green energy with great development potential,due to its non-pollution,renewable,mild reaction conditions,a wide range of substrate sources,organic waste or pollutants can be degraded into electricity and other advantages received widespread attention.However,the performance of MFC is far below the ideal state,and the low output power density is the main factor limiting the development of MFC,the electron transfer rate at the interface between anode electrogenic microorganisms and anode is of great importance.In recent years,the application of porous materials has improved the electron transfer rate at the interface of MFC anode,but how porous nanostructured anodes enhance electron transfer efficiency and the electrochemical behavior of electrogenic microorganisms on porous nanostructured anodes are not clear,this provides some development ideas for MFC and higher requirements for the design of porous anode materials.In this paper,three kinds of multilayer porous nanowires were prepared by loading different templates in the precursor of electrospinning,the effects on the electrocatalytic mechanism of S.putrefaciens CN32.The main contents and results are as follows:（1）Using polymer polyacrylonitrile（PAN）as precursor,dissolved in N,N-dimethylformamide（DMF）,five kinds of porous carbon nanowires were prepared by electrostatic spinning,two-step high temperature treatment and acid etching by controlling the content of pore forming agent Si O₂,and used as anodic materials of S.putrefaciens CN32.By controlling the content of Si O₂,the porous structure（micro,medium and macroporous）of porous nanowire can be controlled.The experimental results show that among the five materials prepared with Si O₂as pore-making agent,when Si O₂content is 6%（HP-CNFsⅣ）,the best bioelectrocatalytic performance is higher than that of HP-CNFsⅣwith large volume and large specific surface area.The reason is that HP-CNFsⅣhas reasonable microporous,mesoporous and macroporous contents,and the connectivity between various pores helps to promote the electron transfer at the interface of the electronic medium of flavonoids,thus showing better bioelectrocatalysis and better biofilm formation,so that it can obtain the best power output performance in S.putrefaciens CN32.（2）Using metal-organic framework（MOF）ZIF-8 as template,polymer polyacrylonitrile as precursor,dissolved in N,N-Dimethylformamide,by controlling the content of ZIF-8,five kinds of porous carbon nanowires were prepared by vacuum overnight stabilization,two-step carbonization and acid etching,and they were used as anode materials of S.putrefaciens CN32 MFC.The porous structure of porous nanowires can be controlled by controlling the content of ZIF-8.The results show that PAN/ZIF-8（40%）nanomaterials have the largest specific surface area and the largest pore volume,and the contents of micropores,mesoporous pores and macropores are higher than those of other materials.The maximum output power density of PAN/ZIF-8 as an MFC anode is 2051.83 m W m^-2.Significantly higher than smooth nanowires and conventional carbon cloth anodes.The main reason is that PAN/ZIF-8（40%）nano-materials have abundant pore structure,in which mesopore is the main one,micropore and macropore are the secondary one,and many porous nanowires are intersected to form a network structure,it is very beneficial to the formation of biofilm,promotes the electron transfer at the interface of xanthophylls,and obtains the best power output performance in MFC of S.putrefaciens CN32.（3）Polytetrafluoroethylene emulsion（PTFE）was used as soft template and polymer polyvinyl alcohol was used as precursor,which was dissolved in secondary water.The porous nanowires were formed by pyrolysis and gasification of PTFE with5%（wt.%）boric acid as cross-linking agent after high temperature vacuum treatment and high temperature carbonization treatment.The specific surface area and porous structure of porous nanowires can be adjusted by controlling the content of PTFE.The experimental results show that the five materials prepared in this chapter,HP-CNFs（3-7）,have the best pore structure and the largest specific surface area,and promote the electron transfer rate of the xanthin-type electron medium at the interface.Meanwhile,this way obtains the maximum output power as MFC anode.In conclusion,abundant porous nanostructured anodes not only benefit the interfacial electron transfer of flavin electronic mediators,but also shorten the electron transfer pathway and further accelerate the electron transfer.Therefore,the optimal porous nanostructured anodes achieve both biocatalysis and electrocatalysis.