Construction And Performance Of Transition Metal Catalytic System For Glucose Fuel Cell

History shows that the innovation and breakthrough of energy technology have promoted social prosperity and economic development.With the continuous development of society,people’s demand for energy is increasing day by day.At present,we are facing with energy crisis,environmental pollution and so on,the traditional way of energy utilization is facing the depletion of raw materials,low conversion rate,environmental pollution and other problems.Fuel cell has the advantages of high energy conversion efficiency,not limited by the Carnot cycle,small environmental pollution,easy to prepare and store,fast load response and so on.It is a new form of energy production and being the fourth type of power generation technology after hydropower,thermal and nuclear power generation.Glucose,cellulose and other biomass exist widely in nature,and their molecules contain abundant energy,oxidating them to produce electricity is an effective way to obtain energy.At present,precious metal catalyzed glucose fuel cells still have some problems,such as low output power,short service life,high construction cost and unstable output current.At present,there are few studies on cellulosic fuel cells,cellulosic fuel cells catalyzed by cellulase,cellulose-digesting microorganisms or noble metals platinum and palladium electrodes are not only costly,but also being environmentally demanding,with low output power and unstable output current.Therefore,the research on new biomass fuel cell for the utilization of biomass energy and alleviating the problem of human energy demand has very important value.In this paper,a new type of bimetallic oxide catalyst was successfully prepared and loaded on a porous and thin carbon felt to form a porous multi-layer MoO2/β-MnO2 composite cathode(MLC),the heterogeneous catalysis system of MLC was combined with a homogeneous catalysis system of Fe2+/Fe3+/H3PO4/glucose anode to produce a sustainably breathing glucose fuel cell without noble metals.The experiment also investigated the performance changes of the GFC in self-heating and series-parallel process.The specific research content is divided into the following three parts:(1)The polyacrylamide gel structure is loose and porous,it can conduct electricity after carbonization.MnO2 is an active catalyst for cathodic oxygen reduction reaction of fuel cell,combining these two kinds of material and preparing polyacrylamide gel-dispersed α-MnO2 and β-MnO2 cathode catalyst,through their microscopic structure and electrochemical performance,choosing the better active β-MnO2,polyacrylamide gel-dispersed β-MnO2 cathode catalyst was successfully prepared by cyclic voltammetry(CV)to explore the best proportion of catalytic materials.A system of active chloride oxygen reduction was also constructed,using the reaction between ClO2/Cl2O and O2 to improve cathodic oxygen reduction reaction rate.The cocatalytic effect of the system on cathodic oxygen reduction was analyzed by verification device and electrochemical testing.In order to prevent the gas from escaping,liquid paraffin oil was used to seal the gas in the electrolyte to reduce gas volatilization.(2)An efficient and inexpensive double transition metal oxide catalyst,MoO2/β-MnO2 composite is developed for oxygen reduction reaction(ORR)and showing better performance than either MoO2 or β-MnO2.The multi-layered cathode(MLC)for GFC was prepared by loading the composite catalyst onto a porous and thin carbon felt,the MLC is consisted of a graphite flake and several porous catalyst layers attached to both sides,allowing more adsorption and reaction sites for O2.The better cathode performance of MLC over single metal oxide catalysts or single layer electrodes is confirmed by cyclic voltammetry(CV)and Tafel analysis.By coupling the MLC with a glucose oxidation system catalyzed by Fe(Ⅲ)/H3PO4,a double-chambered GFC device has been built with an open-circuit potential of 0.68 V and a stable current density of 24 mA·cm-2.Therefore,the utilization of bimetallic multi-layer porous cathodes is a good method to improve the efficiency of ORR for fuel cells.(3)On the basis of the previous two chapters,a new cathode electrolyte(VO2)2SO4 was prepared.The conversion between VO2+and VO2+ was used to improve the cathodic oxygen reduction activity.The influence of temperature on the performance of GFC is also explored,and the fuel cell does thermal work when it discharges,so by realizing self-heating to provide temperature for GFC,the power density and cell life of the GFC were measured under the condition of self-heating.We also connected the cells in series(parallel),it is found that the voltage and current density of the GFC stack increased multiples with the number of cells in the stack,and the performance of the GFC did not decrease during the test.At the end of the experiment,the discharge efficiency of GFC in short time is calculated.