Preparation Of Ceria Modified Platinum-based And Cobalt-based Catalysts And Their Applications In Microbial Fuel Cells

With the increase of population,the demand for energy is inevitably increased,and a series of environmental problems such as air pollution and water pollution are brought along.Therefore,it is urgent for people to develop a green and environmentally friendly new energy technology.The rise of Microbial fuel cell?MFC?provides an effective solution for the development of renewable energy.It can directly convert the chemical energy contained in organic matter in sewage into electric energy by using the metabolism of microorganisms,which has the functions of wastewater treatment and electricity generation.At present,the most efficient cathode catalyst is precious metal platinum.However,platinum has limited the large-scale application of microbial fuel cells due to its low natural reserves and low tolerance to toxicity.Therefore,how to develop a cheap and efficient cathode catalyst has become our research focus.The research and development of high performance low-platinum or non-noble metal oxygen reduction catalysts to replace the traditional platinum-carbon catalysts is a key topic and research hotspot in the field of fuel cells,and related research has great significance for promoting the commercialization of fuel cells.In this paper,two different series of catalysts were synthesized based on the development of new cheap and efficient cathode catalysts.Two kinds of carbon materials,carbon powder and ordered mesoporous carbon?OMC?,were selected as supports.On the basis of this,two series of catalysts,low platinum?Pt-CeO₂/C?and platinum-free?Bi-CoPc/x%CeO₂/OMC?,were obtained by doping other materials.Various catalyst characterization methods were used to analyze the materials,to obtain the morphology,composition,content and structural characteristics of the materials.At the same time,some electrochemical and hydrochemical analysis methods were also used to analyze the oxygen reduction activity,electrical properties and sewage treatment ability of the catalyst.To further investigate the actual performance of the catalyst in single chamber microbial fuel cells?SCMFCs?and the feasibility of application.Some substantive research results have been obtained as follows:?1?In order to reduce the platinum content in the catalyst,Pt-CeO₂/C series catalysts with low platinum content were synthesized by adding cheap and oxygen-storing ceria particles to the Pt/C catalyst.The performance of the catalyst was studied by changing the morphology?rod-like,sphere-like and flower-like?of ceria.The electrochemical characterization results showed that the catalyst loaded with Sphere-like ceria compared to other doping morphology has a higher electrochemical activity.The output voltage data obtained after the catalyst was assembled into the SCMFC showed that the catalyst supported on the Sphere-like ceria had the highest output voltage of 432 mV and higher power density of 406 mW/m².However,considering other characterization results,the morphology of the ceria nanoparticles has no significant effect on the improvement of the catalyst performance.?2?Based on the research results of Pt-CeO₂/C series catalysts,we do not consider the influence of the morphology of ceria.Instead,a relatively simple method was adopted to prepare a non-platinum Bi-CoPc/x%CeO₂/OMC catalyst by using ordered mesoporous carbon?OMC?as a carrier to carry ceria and binuclear cobalt phthalocyanine.The doping amount x of ceria was 3,6 and 12.Electrochemical characterization showed that Bi-CoPc/6%CeO₂/OMC had the highest power density?487±6 mW/m²?and maximum output voltage?427±3 mV?.Moreover,the output voltage of Bi-CoPc/6%CeO₂/OMC drops only 3.7%after the MFC runs for nearly 1300h,shows extremely high stability.The results of the rotating disk electrode test show that the Bi-CoPc/6%CeO₂/OMC catalyst has excellent electrocatalytic activity.Combined with the results of XPS,Bi-CoPc/6%CeO₂/OMC has the highest content of Ce³⁺,which can form more defects on the surface of the catalyst to facilitate the adsorption of oxygen,thereby increasing the oxygen reduction activity.Therefore,this catalyst is expected to be a cheap and efficient cathode catalyst for microbial fuel cells to replace precious metal platinum.