Research On The Application Performance Of Activated Carbon In Microbial Fuel Cells And H₂O₂ Fuel Cells

Fuel cells as a type of electricity generation device could convert the chemical energy in reactant directly into electrical energy,and their energy conversion efficiency is high and have low emissions during the process of electricity generation.Therefore,they are considered as the most promising new clean energy which can replace fossil fuels.In the current research of fuel cells,microbial fuel cells(MFCs)are a new type of device that use microbes as an anode catalyst to generate electricity by oxidizing organic substrates.Their greatest feature are can use some complex organic matter or even pollutants in wastewater to work,so they can realize both power generation and wastewater treatment at the same time and have a very broad application prospect.And hydrogen peroxide fuel cells are another kind of new fuel cells which are very friendly to environment.This type of cells use hydrogen peroxide as a fuel,don't generate harmful emissions during operation,and don't need extra oxidants,so they can be applied in many fields.Now the biggest obstacle affects the practical application of these two types of cells is the choice of catalysts.It has been found that some cheap and readily available carbon materials have good catalytic performance,lay a good foundation for their practical application.In this paper,we study the reason why the performance of MFC with activated carbon as cathode catalyst will gradually decrease during long-term operation,and found that the performance of the cathode can be restored in a simple way.And investigate the effect of activated carbon's properties on MFC performance.We additionally found that activated carbon has good catalytic performance for hydrogen peroxide electro-oxidation and electro-reduction,and base on it,we successfully built activated carbon electrode hydrogen peroxide fuel cells.1.Influence of the properties of activated carbon on MFC performanceThe single-chamber air cathode MFC was constructed using four different types of activated carbon,and the performance was tested after their stable operation.It was found that the performance of air cathodes made with different activated carbons has a very big difference.In subsequent experiments,the physical and chemical properties of the four types of activated carbon were tested to analyze the relationship between their structure and performance by using specific surface area tests,X-ray photoelectron spectroscopy,Raman spectroscopy,and acid-base titration.We found that all the specific surface area,surface groups,and conductivity can affect the catalytic performance of activated carbon.2.The change of activated carbon air-cathode's performance in long-term operation MFCThe single-chamber air cathode MFC was constructed and the performance change in a process over one year was recorded,and found that some biomass and inorganic salts secreted by microorganisms will deposit on activated carbon air-cathode in MFC make its performance gradually become worse and worse,caused a decrease in MFC output power.In the subsequent experiments,the performance of the cathode was restored by the wash-dry-repress methods.It has been found that the destruction of the three-phase interface required for the cathodic reaction is the main reason leading to its performance degradation,the catalytic performance of activated carbon is basically not affected.After the activated carbon was recollected and repressed with new gas diffusion layer and new current collector,the activated carbon still have very good catalytic performance.This suggests that activated carbon can be reused in MFC.3.Application of activated carbon in hydrogen peroxide fuel cellThe activated carbon has a good catalytic performance for hydrogen peroxide electro-oxidation and electro-reduction over a wide pH range was found.Then some activated carbon electrodes suitable for hydrogen peroxide fuel cells were prepared by pressing and spraying methods,and single-chamber and double-chamber hydrogen peroxide fuel cells also have been successfully constructed.Next,we found that the single-chamber hydrogen peroxide fuel cells constructed by nickel anode and activated carbon cathode can obtain a large output power,but nickel will participate in electrode reaction and restrict its application.And double-chamber hydrogen peroxide fuel cells can be successfully constructed using activated carbon as both cathode and anode catalyst.Finally,the effects of fuel concentration,catalyst amount,and electrolyte concentration on hydrogen peroxide fuel cells were studied.