Catalysts And Supports In Enzymatic Biofuel Cell

In recent years, with less and less fossil fuel on the earth day after day, the new energy's the exploit and utilization has been paid much more attention by governments around the world. Now, developing new energy is very important the urgent mission of our scientific research worker.The enzymatic biofuel cell is special fuel cell; the organic compounds are used as fuel and enzyme are directly or indirectly used as catalyst in it. It can directly convert chemical energy which is stored in animals and plants to electrical energy. it has many the merit such as high energy conversion efficiency,good biocompatibility,wide source of raw materials and is a really and ideally green environmental-protecting power sources. In the future, the enzymatic biofuel cell has wide application prospect and huge potential market. But, the enzymatic biofuel cell also has many disadvantages such as enzyme is deactivated in Vitro,poor stability,low electron transfer efficiency,short life etc. These disadvantages become bottleneck which hinders the development of the enzymatic biofuel cell. So, prolonging Life of enzyme and improving electron transfer efficiency between enzyme and electrode are critical problem to increase enzymatic biofuel cell performance.In order to increase enzymatic biofuel cell performance and solve the problem such as enzyme catalyst is deactivated in Vitro,low electron transfer rate,poor stability. This paper researches the direct electrochemistry behavior and the electrocatalysis action of GOD which is anode catalyst and MP-11 which is cathode catalyst in enzymatic biofuel cell on different matrix, selects suitable matrix material of electrode of enzymatic biofuel cell, the basic work for construction enzymatic biofuel cell is done in the future. The main research contents in this paper are as follows:(1)Mesopore Molecular Sieve SBA-15 is used as matrix of GOD which is anode catalyst of enzymatic biofuel cell in this paper; the Nafion/GOD-SBA-15/GC work electrode is prepared by physical adsorption method. The direct electrochemistry behaviors of Nafion/GOD-SBA-15/GC electrode were characterized by cyclic voltammogram (CV). The result indicates that the GOD immobilized on Nafion/GOD-SBA-15/GC electrode can display direct, nearly reversible and surface-controlled redox reaction which contains two electrons and two protons exchange. Secondly, the GOD immobilized on Nafion/GOD-SBA-15/GC electrode has linear response to glucose both in positive potential range and in negative potential range, which proves that the GOD on modified electrode can keep its own biocatalytic activity.On the other hand, the spectra of UV–vis and FTIR shown spatial structure of the adsorbed GOD on the mesopore molecular sieve SBA-15 surface has been changed which is beneficial to direct electron transfer between the GOD molecular and electrode, and which greatly improves electron-transfer rate constant of the GOD molecular immobilized on modified electrode. Therefore, the mesopore molecular sieve SBA-15 is an efficient matrix of GOD, which is hopeful to be applied in enzymatic biofuel cell in the future.(2)In this paper, mesoporous carbon FDU-15 (MC-FDU-15) used as matrix of GOD which is anode catalyst of enzymatic biofuel cell, the Nafion/GOD-MC-FDU-15/GC work electrode is prepared by physical adsorption method. The electrochemistry behaviors of the Nafion/GOD-MC-FDU-15/GC electrode were characterized by cyclic voltammogram (CV). The result indicates that the GOD immobilized on MC-FDU-15/Nafion composite membrane has displayed direct, reversible electrochemical reaction which contains two electrons and two protons transfer. Moreover, the formal potential of electrochemical reaction is close to that of the native GOD. While the acidity and basicity of phosphate buffer solution is nearly neutral, the direct electrochemistry of the GOD on MC-FDU-15/Nafion composite membrane is optimal.In addition, under ferrocenecarboxylic acid condition (FCA), the GOD on MC-FDU-15/Nafion composite membrane has linear response to glucose in positive potential range, so MC-FDU-15 will be used as matrix of the second generation's glucose biosensor. Under O2-saturated conditions, the GOD immobilized on MC-FDU-15/Nafion composite membrane can catalyze the reduction of O2 in negative potential range, thus, MC-FDU-15 may be used as matrix of cathode catalyst of enzymatic biofuel cell in the near future. In short, MC-FDU-15 is suitable for matrix of GOD, which can promote direct electron transfer between the GOD molecular and electrode. Last, MC-FDU-15 is hopeful to be intensively applied in enzymatic biofuel cell and biosensor.(3)MP-11 which is cathode catalyst of enzymatic biofuel cell is immobilized on chitosan(CHI)matrix which has good biocompatibility. In this article, the MP-11/CHI/GC work electrode is prepared by physical adsorption method, and the MP-11/CHI/GC electrode is analyzed by cyclic voltammogram. The result shows that the MP-11 on work electrode has displayed quasi-reversible coupled with proton transfer electrochemical reaction, besides that, the MP-11 on work electrode has the catalysis behaviour to O2 and H2O2. All this indicates that the MP-11on CHI matrix keep its own biocatalytic activity, and natural polymer matrix material CHI which has good biocompatibility can supply suitable microenvironment for MP-11.Thus, the matrix material CHI which has many merit such as abundant yield,high Stability,low market value is worthy of attention. In the future, the matrix material CHI can meet with great production of enzymatic biofuel cell, and it is adapted to practical application requirement of enzymatic biofuel cell.(4)In this article, the widespread research idea which constructs compound membrane modified electrode by multi-wall carbon nanometer tube (MWCN) combined with other material has been changed, only MWCN is used as matrix material for immobilized MP-11, and the MP-11 is immobilized on glassy carbon electrode by simply physical adsorption method, and the electrochemical characteristics of MP-11 immobilized on MWCN modified electrode are researched. The testing results by cyclic voltammogram(CV) show that the MP-11 on MWCN modified electrode has displayed direct,quasi-reversible coupled with one proton and two electron transfer redox reaction. Secondly, the reduction reaction of the MP-11 immobilized on modified electrode to O2 is diffusion-controlled process. The MP-11 immobilized on modified electrode has linear response to H2O2 concentration, and the apparent Michaelis–Menten constant of the reaction is very small, and indicating strong the appetency between immobilized MP-11 and H2O2. So, the single use of MWCN as matrix of cathode catalyst is possible, this work is helpful for practical preparation of enzymatic biofuel cell.(5) At present, the study of gold nano-particles as matrix of enzyme catalyst is very general, but because of high price for gold nano-particles, it has some limitation as matrix material of enzymatic biofuel cell in the practical production. Thus, it is necessary to find appropriate nano-particles instead of gold nano-particles as matrix of enzyme catalyst in enzymatic biofuel cell, which is an effective approach to reduce the cost of enzymatic biofuel cell. In this paper, silicon dioxide (SiO2) nanoparticles which has many advantages such as low price,high specific surface area,excellent electric-thermal stability,non-toxic and good biocompatibility becomes ideal substitute of gold nano-particles. The cathode catalyst MP-11 of enzymatic biofuel cell is modified on the surface of silicon dioxide nanoparticles by simple method, and the MP-11/SiO2/GC work electrode is successfully prepared. The modified MP-11on glassy carbon electrode has also undergone a direct and reversible coupled with two electron and one proton transfer electrochemical reaction. The electrical catalytic reaction of MP-11 on modified electrode to O2 is controlled by diffusion of O2. In addition, MP-11/SiO2/GC electrode shows sensor's functions to substrate H2O2, and the detection limit of MP-11/SiO2/GC electrode is 0.22mmol/L at a signal-to-noise ratio of 3 in the linear range. Therefore, the MP-11on silicon dioxide nanoparticles matrix completely realizes self-electrochemistry behaviors. It is feasible to adopt silicon dioxide nanoparticles instead of gold nano-particles as matrix of enzyme catalyst in enzymatic biofuel cell; the ideality of reducing the cost of enzymatic biofuel cell by the method has come true in the next several years.(6) Both GOD and Cytc are together immobilized on surface of glassy carbon modified with CHI matrix by physical adsorption method, these two enzymes both keep their own activities and each direct electrochemistry characteristics is also realize on modified electrode. The direct quasi-reversible and surface-controlled electrochemical reaction coupled with two protons and two electrons transfer of GOD on modified has displayed. The direct quasi-reversible and surface-controlled electrochemical reaction coupled with one proton and two electron transfer of Cytc on modified has also displayed. While O2 and glucose coexist, the catalytic reduction of the GOD and Cytc bienzyme electrode to O2 occurs at -0.623V, and there was a good linear relationship between reduction current and glucose concentration, thus, the bienzyme electrode hold promise as glucose sensor to be used in the future. In addition, the catalytic reduction current of Cytc on bienzyme electrode to H2O2 has linear response to H2O2 concentration, so, the bienzyme may be prepared hydrogen peroxide sensor. While glucose is examined by the GOD and Cytc bienzyme electrode, the detection potential of glucose is relatively low which can completely prevent from interference of the matter is easily oxidized, which provide a new idea for construction glucose biosensor. The simultaneous response of the GOD and Cytc bienzyme electrode to glucose and hydrogen peroxide is realized, which can also provide a novel idea for development multifunctional sensor.The innovative points of the paper:(1) Mesoporous carbon FDU-15(MC- FDU-15) is used as matrix of anode catalyst of enzymatic biofuel cell for the first time, and the anode of enzymatic biofuel cell is prepared successfully, MC- FDU-15 adsorption makes the space conformation for at the direction of electron transfer, which shortens the distance between electrode and catalyst and electron-transfer rate of GOD is increased greatly, and develops a new research field of catalysts matrix of enzymatic biofuel cell. (2) Mesopore Molecular Sieve SBA-15 is used alone as matrix of anode catalyst of enzymatic biofuel cell, at the same time, anode of enzymatic biofuel cell is also made, direct electrochemistry characteristics of the GOD is completely displayed on the matrix, the high load of GOD on SBA-15 surface accelerate electron-transfer GOD and electrode, thus, matrix SBA-15 with high stability is used, which may extend the enzymatic biofuel cell using life.(3) The natural polymer matrix material CHI which has good biocompatibility can supply suitable microenvironment for cathode catalyst MP-11, which promotes the electrochemistry response of cathode catalyst MP-11of enzymatic biofuel cell.(4) The design idea of the GOD and Cytc bienzyme electrode provide a new idea for exploiting multifunctional biosensor.The research results of this article provide a simple and convenient analysis method for understanding of electrochemical characteristics of redox proteins, and provide an effective direction for studying catalyst matrix of enzymatic biofuel cell, and also provide a significant reference for exploiting multifunctional biosensor.