Preparation Of PSS/LDH Nanocomposite And Its Application In Air Cathode Microbial Fuel Cell

Microbial fuel cells(MFC),as a sustainable green technology,can realize biological power generation while realizing sewage treatment,which helps to alleviate energy demand and improve wastewater pollution.Among them,the structure of the air cathode MFC is simple,and directly uses oxygen as an electron acceptor,which has low cost and the most potential for large-scale application.However,if the air cathode MFC is to be commercialized,it needs to maximize its electrical output.The use of a catalyst to promote the oxygen reduction reaction of the cathode is the most commonly used method to increase the power output of the air cathode MFC.At present,Pt is the most commonly used and effective catalyst for oxygen reduction reaction.However,because Pt catalysts are expensive,it is difficult to make large-scale commercial applications.Therefore,the development of high-efficiency and cheap cathode catalysts has become a scientific and technological task urgently needed to be tackled in current research.In this paper,on the basis of summarizing the research on oxygen cathode catalysts for air cathode MFC at home and abroad,the nickel-iron-based layered double hydroxide(Ni Fe-LDH)nano-catalyst material was designed and synthesized using the method derived from the metal organic framework compound(MOF).After obtaining Ni Fe-LDH,further through the intercalation technology of polystyrene sodium sulfonate(PSS),a nickel-iron-based layered double hydroxide(Ni Fe-LDH-PSS)was obtained.Using physical and chemical characterization techniques,the physical and chemical properties of the two materials obtained were characterized and applied to the MFC,and finally the MFC cathode function was enhanced.The details are as follows:Using Fe-MOF material as a template and Ni SO4 to provide Ni ions,Ni Fe-LDH nanomaterials with hollow structure were prepared by cation exchange.Thermogravimetric and scanning electron microscopy analysis results indicate that Ni Fe-LDH nanomaterials have been successfully synthesized and have good dispersibility.At the same time,Ni Fe-LDH nanomaterials were used as air cathode catalysts in air cathode MFCs to test their electrical performance.By comparing with the previous nickel-iron layered double hydroxide material prepared by co-precipitation method,it was found that the Fe-MOF-derived Ni Fe-LDH materialcan more effectively promote the generation of MFC electrical energy.On the basis of the above experiment,through the intercalation technique,the PSS intercalated nickel-iron-based layered double hydroxide(Ni Fe-LDH-PSS)was obtained.After a series of physical and chemical characterization,it was found that PSS was successfully inserted into the material.Scanning electron microscope observation revealed that Ni Fe-LDH-PSS has better dispersibility than Ni Fe-LDH materials.Through the application of Ni Fe-LDH-PSS material in air cathode MFC,it was found that Ni Fe-LDH-PSS material can greatly improve the power generation performance of air cathode MFC,which exceeds the power generation performance of Ni Fe-LDH material as a cathode catalyst.This is due to the excellent dispersion performance of Ni Fe-LDH-PSS material on the cathode substrate,which fully exposes the active sites and accelerates the rate of cathode oxygen reduction.Through the analysis of the anode surface flora,it is found that the use of the cathode catalyst is also conducive to the enrichment of the anode surface flora,which can further improve the power generation performance of the MFC.