Study On Biofuel Cell And Biosensor Applying MWCNTs Nanocomposites Mimic Enzymes As Catalysts

Today,facing the challenge of global environmental degradation and the energy crisis,people are constantly searching and utilizing the renewable energy,biomass energy and clean energy technology.Among them,the biofuel cell(BFC)is considered as a new generation potential power device that has potential for development.Normally,the BFC is using natural enzymes or microorganisms as catalyst to convert the chemical energy that in biomass fuels to electrical energy under the condition of environment friendly.Although the natural enzymes have high specificity and high catalytic efficiency,the enzyme electrodes are easily affected by environmental conditions,which limit the development of BFC.In order to overcome the intrinsic defects of enzyme electrodes,the mimic enzyme BFC based on inorganic nanomaterials as catalyst get off the ground.Compared with the natural enzymes,the mimic enzyme has more prominent advantages,such as the preparation of low cost,easy storage,as well as the controlled structure,etc.So it's significant to develop mimic enzyme with low cost,good biocompatibility and high catalytic activity.H202 is a kind of important cell signal molecule,and in the food industry food-grade H2O2 has been applied for many years,so it has important value to detect H2O2 by a fast and simple way.multi-walled carbon nanotube(MWCNTs)with cavity structure has large specific surface area and special electrical properties,was considered as the ideal load phase to load or complete other materials to form nano composite materials which has special properties.In this regard,we use the oil amine reduction precipitation method,hydrothermal method,water precipitation respectively to synthesize Au nanowires,CuS/MWCNTs nano composite,CeO2/MWCNTs nano composite,and apply in building the mimic enzyme BEC and biosensor.Concrete research contents are as follows:One-dimensional Au nanowires were prepared successfully using Oleylamine as reducing agent,and combined with carboxylic MWCNTs through electrostatic adsorption to form a layer-by-layer assembled Au nanowires-MWCNTs composites.The nano-composite was modified on the glassy carbon electrode(GCE)as the electrochemistry catalyst for the anodic oxidation of glucose in new type of nonenzymic biofuel cell.Electrochemical research results showed that the Au nanowires-MWCNTs/GCE electrode displays higher catalytic properties than the simple Au nanowires or MWCNTs modified electrode towards the oxidation of glucose.Therefore,a nonenzymatic glucose biofuel cell was elaborately assembled using Au nanowires-MWCNTs/GCE as the anodic catalyst and electrodeposition of platinum membrane as the cathodic catalyst,which showed an open circuit-potential of 0.57 V,a maximum power density of 0.28 mW ·cm-2 at 0.44 V.Beaded-like CuS/MWCNTs nanocomposites with mimic enzyme properties was synthesized successfully by hydrothermal method.In the process of synthesis,CuCl2 as copper source,L-cysteine as sulfur source and reducing agent,and mixed acid treated MWCNTs as raw material respectively.The nano-composite was modified on the glassy carbon electrode(GCE)as the electrochemistry catalyst for the anodic oxidation of glucose in nonenzymic biofuel cell.Electrochemical research results showed that the CuS/MWCNTs/GCE electrode displays higher catalytic properties than the simple CuS or MWCNTs modified electrode towards the oxidation of glucose.Therefore,a nonenzymatic glucose BFC was assembled using CuS/MWCNTs/GCE as the anodic catalyst and electrodeposition of platinum membrane as the cathodic catalyst,which showed an open circuit-potential(OCP)of 0.87 V,a maximum power density of 0.22 mW·cm-2 at 0.77 V.Water precipitation approach was used to synthesis CeO2/MWCNTs nanocomposite.Due to the CeO2 nano particles(CeO2 NPs)with hydrogen peroxide Enzyme properties in the simulation,so the CeO2/MWCNTs nanometer complex was used for reduction of hydrogen peroxide catalyst to build up mimic enzyme electrochemical biosensors.Results show that because of the MWCNTs has the unique nature to promote CeO2NPs coated on the surface of MWCNTs.Synergies between the two kind of materials makes the sensor of H2O2 has good electrochemical catalytic properties,repeatability and stability.Using square wave voltammetry(SWV)method to measure the concentration of H2O2.In a concentration range of 1.0×10-6?10×10-3 mol·L-1,the reduction peak of H2O2 had good linear relationship between peak current and its concentration,the corresponding linear equation for ?I(?A)=0.82 + 0.10 I log c(mol·L-1),the linear correlation coefficient R = 0.994,detection limit of 2.7× 10-8 mo1·L-1.