| Enzyme biofuel cell(EBFC)is a special type of fuel cell that uses organic matter as a fuel and uses enzymes as catalysts.It can convert chemical energy or biochemical energy in biological fluids or metabolites into electrical energy,so it has attracted much attention.Compared with traditional fuel cells,EBFC has the advantages of high energy conversion efficiency,good biocompatibility,wide fuel sources,and mild reaction conditions.Carbon nanomaterials with low cost,good electrical conductivity,large specific surface area,easy surface modification,and good biocompatibility show advantage in the research and development of EBFC.They would influence enzyme loading and the electron transfer rate and thus influence the performance of EBFC.Therefore,the main work of this thesis is to search for different kinds of carbon materials with good performance to improve the performance of EBFC.The main contents are as follows:1.Using commercially available lotus root powder as a carbon source and template,a new kind of carbon nanosphere was prepared by a simple hydrothermal reaction,and characterized by scanning electron microscopy and transmission electron microscopy.It was found that the as prepared carbon nanospheres are of uniform particle size and good dispersion It was used as a matrix for glucose oxidase(GOX)and bilirubin oxidase(BOD)immobilization.A membrane-free biofuel cell was constructed by using Nafion/C/GOX/MB/GCE and Nafion/C/BOD/MB/GCE as bioanode and biocathode,respectively.Methylene blue(MB)was used as an electron mediator in this biofuel cell to transfer electrons from glucose to the electrode surface.The catalytic mechanism of this biofuel cell was analyzed and studied.This membrane-free glucose/O2 enzyme biofuel cell(EBFC)showed an open circuit voltage of 0.65 V and a maximum power density of 6.5μW·cm-2 at 0.35 V.2.In view of the small specific surface area and low conductivity of carbon spheres we obtained in the first section,we explored a hollow carbon sphere with a larger specific surface area for the adsorption of enzymes and construction EBFC.The hollow carbon sphere was obtained by using silicon dioxide as a template,through simple stirring,high-temperature carbonization and sodium hydroxide etching.Then,the hollow carbon spheres were doped with gold nanoparticles to obtain a new material,gold nanoparticles doped hollow carbon spheres(AuNPs-HCSs),which improved the conductivity of the material.A membrane-free biofuel cell was constructed by using Nafion/AuNPs-HCSs/GOX/MB/GCE and Nafion/AuNPs-HCSs/BOD/MB/GCE as bioanode and biocathode,respectively.AuNPs-HCSs was used as an effective substrate to construct glucose/O2 enzyme biofuel cell.The EBFC based on this composite materials showed an open circuit potential of 0.63 V,a maximum power density of 22.1 μW·cm-2,and improved power output and stability.It was proved that AuNPs-HCSs can effectively improve the performance of EBFC.3.Three-dimensional(3D)graphene,especially free-standing porous graphene with tunable pore size,void space,high surface area and good conductivity have attracted increasing attention in different application areas.In this work,a simple hydrothermal method was applied for the preparation of 3D porous reduced graphene oxide(rGO)in the presence of thiourea and sodium citrate which were acted as stabilizers and reducing agents.The sample was freeze-dried for use.The scanning electron microscopy and transmission electron microscopy characterizations showed the porous and flake structure of the obtained rGO.This material was used as the substrate for the immobilization of enzymes and construction of a glucose/O2 enzyme biofuel cell.The constructed EBFC,based on 3D graphene,has improved power output and stability.It showed an open circuit potential of 0.55 V and a maximum power density of 33.0 μW·cm-2 at 0.45 V.This proves that the porous graphene we prepared can effectively improve the performance of EBFC. |
