212 results about "Electron transfer rate" patented technology

Provided is a method for preparing a g-C3N4 / carbon quantum dot composite electrode. The method comprises: adding carbon quantum dots into ethanol in order to prepare carbon quantum dot ethanol solution; mixing urea with the carbon quantum dot ethanol solution, performing ultrasonic dispersion on the mixed solution and then transferring the mixed solution to a crucible; warming the mixed solution to 350 to 700 degree centigrade with a muffle furnace step by step, maintaining the temperature for one to three hours and then decreasing the temperature of the mixed solution to room temperature; and grinding the obtained substance with ethanol and filtering the same so as to obtain g-C3N4 / carbon quantum dot composite material. The method has advantages of simpleness, no by-products, raw material easy to obtain, and low price. The obtained composite material is stable in performance, uneasy to decompose, and nontoxic. The method may increase the electron transfer rate of the g-C3N4 material, has good conductive performance, enhances electrode specific area, improves the electron adsorption capability of an electrode surface, and effectively increases the specific capacitance of a capacitor.

A molecular memory cell includes first and second electrodes. First and second charge storage molecules have respective first and second oxidation potentials and are disposed between the first and second electrodes. A molecular linkage couples the first and second charge storage molecules to the first electrode and provides respective first and second electron transfer rates for the first and second charge storage molecules. The first and second different oxidation potentials are different and / or the first and second electron transfer rates are different. In particular, the second oxidation potential may be greater than the first oxidation potential and the first electron transfer rate may be greater than the second electron transfer rate, such that the first charge storage molecule may be used as fast, volatile primary memory and the second charge storage molecule can be used as slower, less volatile secondary memory. In various embodiments, memory cells can be constructed from an admixture of charge storage molecules or by using a bipartite charge storage molecule. Memory cells can include a molecular transistor incorporating such molecular structures.

The invention provides an oxygen-doped nitrogen carbide-precious metal composite catalyst, and a preparation method and an application thereof. Hydrogen peroxide is used to prepare oxygen-doped nitrogen carbide, and precious metal nano-particles are uniformly dispersed on the surface of the oxygen-doped nitrogen carbide, so very good contact surface and very good loading effect are realized; and the prepared catalyst has a good catalysis effect on nitro aromatic compounds. The visible light responding composite catalyst is formed through compounding the oxygen-doped nitrogen carbide with precious metals. The above compound can improve the absorption range of visible lights, accelerate the electron transfer rate and inhibit photoproduced electron and hole compounding, greatly improves the photocatalytic activity of the oxygen-doped nitrogen carbide, and makes the practical application of the composite catalyst to organic catalysis, and degradation and industrialization of organic pollutants in environment be possible.

The invention belongs to the field of gas sensors, and particularly relates to a NASICON-based mixed-potential type H2S sensor with a novel composite metallic oxide sensitive electrode. The NASICON-based mixed-potential type H2S sensor can be used for detecting poisoned gas in the atmospheric environment and consists of a nickel-cadmium alloy heater, an Al3O3 ceramic tube used as an insulating layer, an NASICON ion conductive layer, an Au reference electrode and the sensitive electrode consisting of Au and metallic oxide electrodes. Cobalt chromate doped with manganese is used as the sensitive electrode for the first time, the catalytic activity of the cobalt chromate in electrochemical reaction is increased owning to the manganese, the efficiency of electrode reaction at a three-phase boundary is improved, electron transfer rate is effectively increased, electrochemical reaction rate is greatly increased, and the purpose of increasing sensitivity is achieved. The sensitivity of the sensor using CoCr1.2Mn0.8O4 as the sensitive electrode is far higher than that of a sensor using CoCr2O4 without manganese as a sensitive electrode.

The invention relates to an enzyme electrode, an enzyme biosensor as well as preparation methods and application of the enzyme electrode and the enzyme biosensor. The enzyme electrode comprises a base electrode, wherein a carbonized eggshell membrane is attached on the surface of the base electrode; nano-metal particles and enzyme are cured on the carbonized eggshell membrane. According to the enzyme electrode, a composite material of the eggshell membrane and the nano-metal particles is used as a carrier, enzyme molecules are effectively fixed and direct electron transfer between enzyme and the electrode is realized, thereby improving the catalytic activity of the enzyme molecules and the sensitivity of the sensor. Compared with the prior art, the enzyme electrode has the advantages that the eggshell membrane is used as a material so that reutilization of wastes is realized, and the preparation method is simple and low in cost, and electron transfer rate of the electrode and the enzyme is high; the enzyme biosensor is fast and accurate and high in detection sensitivity, stability and repeatability.

The invention relates to a preparation method and application of a sandwich type immunosensor for detecting a stomach cancer tumor marker, and belongs to the field of novel nano functional materials,immunoassay and biological sensors. Three-dimensional porous molybdenum disulfide loading gold nano particle h-MoS2 / Au NPs is prepared to serve as a substrate material to modify a bare glassy carbon electrode, the solid supporting amount of the tumor marker to capture antibody is improved, and the electron transferring rate of electrode surface is effectively accelerated; an octahedral cuprous oxide / titanium dioxide core-shell structure loading mesoporous platinoid nano particle Cu2O@TiO2 / PtCu composite nano material is prepared to immobilize and detect the antibody, and the simple, rapid andsensitive sandwich type electrochemical immunosensor is prepared by utilizing the excellent electrochemical catalytic property of the composite nano material to hydrogen peroxide H2O2, and the immunosensor is used for detecting related tumor markers of stomach cancer.

The invention discloses a nitrogen and phosphor-doped biomass carbon material synthetic method and an application of the biomass carbon material in a microbiological fuel cell cathode. The method comprises the following steps: taking cellular biomass as a substrate, after pretreatment, respectively sintering the cellular biomass to a carbon material under inert atmosphere at the temperatures of 600 DEG C, 700 DEG C and 800 DEG C, taking cellular as a carbon source, respectively taking melamine and 1,2-vinyl diphosphate as a nitrogen source and a phosphorus source, mixing the raw materials according to a certain proportion for doping, performing a hydrothermal reaction for 5 h in a reaction vessel at the temperature of 100 DEG C, and successfully preparing a nitrogen and phosphor-doped carbon N / P-C semispherical porous microbe cathode material. The method has the advantages that the microbe cathode oxygen reduction catalytic activity is increased, the biomass carbon material has more excellent cycle stability, catalysis electrode charge transfer impedance is reduced, the electron transfer rate is accelerated, a cathode oxygen reduction reaction is promoted, and the provided electric energy can supplies the requirements of other fields.

Disclosed herein is a method for modifying the surface of a counter electrode. According to the method, the surface modification is achieved by treating the surface of a counter electrode with a polyethylene glycol derivative having a pendant group at one end. Also disclosed is a counter electrode whose surface is modified by the method. The electron transfer rate at the interface between the counter electrode and an electrolyte layer of a photovoltaic device is increased and the affinity of the counter electrode for the electrolyte layer is improved, resulting in an improvement in the power conversion efficiency of the photovoltaic device.

The invention discloses a graphene (GR)-exfoliation hydrotalcite-like compound (ELDH) composite material immobilized protein modified electrode, a production method and an application thereof. The method comprises the following steps: compounding ELDH with negatively-charged exfoliation graphene oxide (GO) nanosheets through electrostatic attraction by using the characteristics of positive charges and large specific surface area of the ELDH, and reducing by using hydrazine hydrate to prepare a GR-ELDH hybrid; and sequentially immobilizing the GR-ELDH, ferrohemoglobin and chitosan on an ionic liquid modified carbon paste electrode through adopting a dispensing technology to produce the graphene-exfoliation hydrotalcite-like compound composite material immobilized protein modified electrode. The obtained modified electrode has monolayer GR nanosheet and ELDH synergistic effects, and the GR nanosheets increase the conductivity of the ELDH and inhibits the aggregation and accumulation of the ELDH; and the ELDH effectively inhibits the afresh stacking of the GR nanosheets, reduces the interlamellar contact resistance and improves the electron transfer rate of the above composite material, and a constructed CTS / GR-ELDH-Hb composite film-based third-generation trichloroacetic acid sensor has the advantages of low detection limit, wide detection range and small Michaelis constant.

The invention discloses a graphene (GR)-hydrotalcite-like compound (LDH)-graphite phase carbon nitride (g-C3N4) composite material immobilized protein modified electrode, a production method and an application thereof. The method comprises the following steps: compounding an exfoliation hydrotalcite-like compound with negatively charged exfoliation graphene oxide nanosheets, mixing the obtained material with melamine, roasting, and adding water to recover in order to prepare a GR-LDH-g-C3N4 hybrid; and adding a GR-LDH-g-C3N4 and Hb mixed solution to an ionic liquid modified carbon paste electrode in a dropwise manner in order to produce the GR-LDH-g-C3N4 composite material immobilized protein modified electrode. The graphene-hydrotalcite-like compound-graphite phase carbon nitride composite material immobilized protein modified electrode fully displays advantages of a gel method and an integrating, merging and layering method, increases the specific surface area, the conductivity and the biocompatibility of the hybrid material, and inhibits the afresh stacking of GR sheets; and a roasting method allows g-C3N4 to grow on the surface of a GR sheet layer, increases the specific surface area of the hybrid material, and improves the electron transfer rate of an electrochemical reaction process. A constructed CTS / GR-LDH-g-C3N4-Hb composite film-based third-generation trichloroacetic acid sensor has the advantages of low detection limit, wide detection range and small Michaelis constant.

The invention discloses an undone nitrogen doped carbon nanotubes derivative with good electrochemical performance and a preparation method thereof. Undoing bamboo-like nitrogen doped multi-walled carbon nanotubes along the longitudinal direction is conducted through a solution chemical oxidation method, and the nitrogen doped carbon nanotubes derivative is obtained; through controlling the degree of undoing, caterpillar-shaped nitrogen doped graphene / carbon tube composite materials with heterojunction structures are obtained when undoing is conducted half and nitrogen doped graphene nanobelts are obtained when undoing is completed. The undone carbon nano tube is used for modifying a glassy carbon electrode. It is indicated by the test of electrochemical performance that the materials obtained from the undone nitrogen doped carbon nanotubes derivative with good electrochemical performance have the advantages that the specific surface area is high, more reaction active sites are achieved, and the electron transfer rate is higher, so that the wide application prospects in the field of electrochemistry, such as capacitors, lithium batteries, electro-catalysis, and electrochemical sensors are achieved.

The present invention provides a catalyst electrode for oxygen evolution comprising an electrode current collector comprising a carbon fiber fabric, a nanowire layer comprising a metal oxide-based porous nanowire grown radially from the surface of the carbon fiber, and a porous carbon coating layer disposed around the outer surface of the nanowire, thereby maximizing the specific surface area and increasing the electron transfer rate, and thus exhibiting an excellent catalytic activity for oxygen evolution reaction, and a preparation method thereof.

The invention provides a preparation method of a gold-graphene composite nanomaterial, and an application of the gold-graphene composite nanomaterial in glucose detection. The preparation method has the advantages of simplicity, fastness and good repeatability; the above obtained gold-graphene nanocatalyst can be firmly adhered to the surface of an electrode; gold nanoparticles are uniformly dispersed in a graphene flake, and the highly dispersed gold particles provide a large surface area for an electric cataltyic reaction, so the detection sensitivity is improved; and graphene can promote the electron transfer rate due to high electric conductivity, and can effectively prevent the agglomeration phenomenon in the detection process due to stable layered structure in order to improve the catalysis property and the stability. The gold-graphene composite nanomaterial has the advantages of high sensitivity and wide detection limit in the glucose detection, and allows the response time to glucose to be shorter than 3s and the lowest detection limit to be 25[mu]moL / L during electrochemical test.

The invention relates to a preparation method of a graphene-based composite solid base catalyst with a 3D structure. The method comprises the following steps: vertically growing magnesium aluminum hydrotalcite hexagonal crystal sheets on graphene oxide through adopting a one-step in situ growth technology, and carrying out high temperature calcination and hydration recovery to obtain the highly-active magnesium aluminum hydrotalcite / reduced graphene oxide solid base catalyst with a 3D array structure. The graphene oxide carrier with a high specific surface area facilitates the dispersion of the active sites of the marginal portion of the sheet structure of hydrotalcite to realize full exposure, and high interaction between a substrate and the sheet structure effectively improves the structural stability of the catalyst and improves the electron transfer rate in the catalytic reaction process. The graphene-based magnesium aluminum hydrotalcite solid base catalyst with a 3D composite structure has a good catalysis effect on the self-condensation reaction of acetone.

The invention relates to a three-dimensional composite material of the titanium carbide, and a preparation method thereof, and an application in constructing a thrombin aptasensor. A substrate of thethree-dimensional composite material TiO2 / Ti3C2TX is formed by the self-growth of TiO2 nanorods on the surface of Ti3C2TX by one-step hydrothermal method; meanwhile, the three-dimensional composite material M NPs / TiO2 / Ti3C2TX is obtained by reducing noble metal nanoparticles (M NPs) on the surface of the three-dimensional material. The material has a highest current intensity, due to the fact thata variety of enhancements are achieved in one step. The three-dimensional structure of the composite material may provide a particularly large accessible surface area, which facilitates the anchoringof the M NPs. The introductions of transition metal carbonitrides (MXenes) and metal nanoparticles can improve the efficiency of the charge separation, and accelerate the electron transfer rate. A sensitive unlabeled aptamer is successfully established through the combination of M NPs and aptamer chains, and is used for determining the enzyme protein. According to the three-dimensional compositematerial of the titanium carbide, and the preparation method thereof, and the application in constructing thrombin aptasensor, the aptasensor has a good electrochemical performance, a wide linear range, and a relatively low detection limit, thereby indicating that the M NPs / TiO2 / Ti3C2TX will be promising for the use as electrode materials in electrochemical biosensors.

The invention relates to a lithium-rich material / conductive organic polymer composite positive material and an electrode preparation method. A one-step oxalate coprecipitation- solvothermal method isadopted to obtain the lithium-rich positive material of a nano / micron rodlike hierarchical structure; an in-situ polymerization method is performed on a conductive organic polymer to coat the lithium-rich positive material, and the lithium-rich material / conductive organic polymer composite positive material is obtained. The prepared lithium-rich material / conductive organic polymer composite positive material can be used for preparing a positive electrode. According to the preparation method, by synthesizing the lithium-rich layered oxide positive material of the nano / micron rodlike hierarchical structure, the positive material has dual advantages of nano and micron structures, the diffusion path of lithium ions is short, the material structure has good stability, the positive material is coated with the conductive organic polymer, the electron transfer rate of the lithium-rich material is improved, the charge transfer resistance is reduced, the cycling stability is improved, and the rate capability of the material is greatly improved.

The invention discloses a detection apparatus and a detection method of photosynthesis of phytoplankton on the basis of chlorophyll fluorescence. The detection apparatus includes an excitation-emission optical structure, an excitation light source driving module, a main control module, and a fluorescent detection module and a light source reference photo-detection module, wherein the structure of the fluorescent detection module and the light source reference light detection module are same. According to the invention, an optical pulse-varying light source is employed with combination of a double-channel signal detection module, quick and accurate measurement of three optical-induced fluorescent dynamic process comprising single-turnover, multi-turnover and relaxation is achieved. By means of analysis on a fluorescent dynamic curve, a plurality detail parameters representing the photosynthesis situation, comprising functional absorption cross section, maximum photochemical quantum efficiency, electron transfer rate and the like of photosynthesis, can be obtained.

The invention discloses a spherical-cavity microelectrode array biosensor, and the protein-modified spherical-cavity microelectrode array biosensor is obtained by dropwisely coating a phosphate buffer with dissolved protein on a surface of a spherical-cavity microelectrode array and vaporizing the buffer to dryness to form a membrane; the protein comprises various oxidases, various dehydrogenases, and all iron-containing protein. The signal to noise ratio of the detection signal of the biosensor is high; the protein load capacity is high, which greatly increases the sensitivity; and problems of redox protein load capacity, activity, direct electron transfer rate between the protein and the electrode, signal to noise ratio, and the like are solved.

The invention discloses a DNA sensor for detecting staphylococcus aureus as well as preparation method and application thereof, belonging to the technical field of rapid pathogenic bacteria detection. A electrochemical carbon nano tube / gold nano particle composite membrane DNA sensor is prepared by utilizing the biological fixation effect and electrochemical electron transfer rate enhancing function of the gold nano particle, and is capable of effectively improving the detection sensitivity. According to the invention, a detection method, having high universality, high sensitivity and high accuracy, and detection conditions for staphylococcus aureus are preliminarily established through a detection technology in which specific staphylococcus aureus gene sequence is synthesized to be used as probe ssDNA so as to form a hybridization system with a complementation target ssNDA segment and methylene blue is used as a hybridization indicator.

This invention discloses a new fluorine functional order mesoporous carbon and its composition method. Synthesize fluorine functional resol of low molecular weight, of which molecular weight is 200-500. Lead-in surface acting agent self-assembly system, induce self-assembly by solvent volatilizing; carbonize to prepare fluorine functional mesoporous carbon. Prepared fluorine functional mesoporous carbon is of high order, high specific surface (600-1000sq m / g), large bore (0.3-0.7cu cm / g), uniform pore diameter (2.3-5.0nm). In cyclic voltammetry research of three potential system, it indicates that potential difference of oxidoreduction peak-to-peak of cyclic vohammogram modified by this material is small (DeltaE=87mV), electron transfer rate of electrode surface is fast.

The invention provides a novel carbon paste electrode, which can greatly improve the performances of the carbon paste electrode such as electrical conductivity, electrochemical activity, stability and the like. A carbon paste of the novel carbon paste electrode is made of carbon material powder which is agglutinated by triphenylamine. The carbon paste can greatly improve the electrical conductivity and the electron transfer rate of the electrode, and simultaneously can improve the stability of the electrode. The invention also provides a method for preparing the novel electrode, which comprises the following steps of: mixing a conducting carbon material with the triphenylamine, and then sufficiently grinding and mixing the mixture; stuffing the even mixture into a clean electrode sleeve, compacting the mixture, and inserting a conducting wire in the rear part of the mixture to prepared a semi-finished product of the electrode; and heating the prepared semi-finished product in a baking oven, and when the conducting carbon material is combined with the triphenylamine, cooling the mixture at the normal temperature. The electrode prepared by the method enhances the responses to potassium ferricyanide and dopamine. The mechanical properties and the long-term stability of the electrode are also greatly improved. The electrode has the advantages of simple manufacturing, simple and convenient operation, good repeatability and low cost.

The invention discloses an oxygen evolution catalyst with a low noble metal loading amount for a water electrolysis unit. According to the oxygen evolution catalyst with the low noble metal loading amount for the water electrolysis unit, the catalyst is an iridium and titanium composite catalyst and is composed of powder titanium and iridium oxide loaded on the surface of the powder iridium; and the mass percent of the iridium oxide is 5 to 30 percent. According to the catalyst provided by the invention, on one hand, metal titanium powder with high metal conductivity is used as a carrier of the catalyst and the electron conductivity of the catalyst is strengthened; on the other and, the iridium and the carrier titanium are tightly combined, a bonding force between the iridium oxide and thecarrier is improved and the electron transfer rate between an active center and the carrier is improved, so that the activity of the catalyst reaches 3 times or more 3 times of that of commercial iridium oxide; and meanwhile, the dosage of the noble metal iridium can be greatly reduced and the mass ratio of the iridium can be reduced to 5 to 30 percent.

The invention relates to a method for producing methane by enhancing anaerobic digestion of municipal sludge based on electron transfer, which comprises the following steps: adding an iron-carbon composite conductive material with zero-valence iron as a core and a carbon material as a coating layer into an anaerobic digestion system, and enhancing the electron transfer rate of the anaerobic system, thereby promoting the hydrolysis acidification process and methane production process of sludge, and increasing the methane production. Compared with the prior art, the method has the advantages that the electron transfer rate among electro-active microorganisms in the sludge anaerobic system is increased through compounding of iron and carbon; the carbon layer can provide a good attachment point for microorganisms, meanwhile, the carbon layer is used as a protective layer of zero-valence iron to effectively control the dissolution amount of iron and reduce the loss amount of iron, and ironreduction type hydrolysis acidification bacteria can be enriched to promote degradation of organic matters while the zero-valence iron core provides electrons and improves the conductivity of the composite material. The method has the advantages of being low in cost, high in yield and stable in effect, the electron transfer rate in the anaerobic digestion process is increased, and the methane yield is increased.

The invention relates to a preparation method of an iron oxide-mesoporous carbon lithium ion battery anode material. Hexagonal stacked micelles are formed by self-assembly of resorcinol and a surfactant, ferrous gluconate is complexed to the micelles under the action of charges and is calcined in an inert gas atmosphere, and the iron oxide-mesoporous carbon lithium ion battery anode material is generated. The stable mesoporous carbon structure of the anode material can not only increase the lithium ion diffusion and electron transfer rate, but also mitigate the structural failure caused by the volume change and agglomeration, thereby significantly improving the reversible capacitance and cycle stability of the anode material.

The invention discloses an aza-phenanthro-fluorene derivative and a preparation method thereof as well as an electrically-induced fluorescence luminescent device. The structural general formula of the aza-phenanthro-fluorene derivative is as shown in the specification, wherein Ar1 and Ar2 in the structural general formula are carbazole groups. The aza-phenanthro-fluorene derivative disclosed by the invention has the advantages that the aza-phenanthro-fluorene derivative has a relatively good non-planar rigid structure, due to the introduction of heteroatom, the electron transfer rate of the fluorene compound is increased, the device efficiency is improved, meanwhile the fluorene compound is connected to other carbazole groups with high fluorescence quantum efficiency and hole transfer rate through 9-site of the aza-phenanthro-fluorene, the molecular rigidity of the whole compound can be enhanced very well, the glass transition temperature of the compound is increased, the luminescent layer hole and the electron transfer rate of the device are promoted, the exciton recombination probability is increased, the stability of the luminescent device is further improved, meanwhile the pi-pi stacking between molecules of the compound is inhibited, the red shift degree of electroluminescent spectra is reduced, and the efficiency of the fluorescence luminescent device is improved.

The invention provides a catalytic ozonation water treatment and impurity removal technology based on enhanced electron transfer efficiency, and belongs to the field of water treatment technology andenvironmental functional materials. A catalyst prepared by the preparation method disclosed by the invention realizes organic combination of a perovskite-type oxide and graphite-phase carbon nitride,so that the active sites of the catalyst can be increased, the decomposition of ozone can be accelerated, the structural defect degree in the catalyst can be improved, the catalytic activity of the nano catalyst is improved, the electron transfer rate is increased, the pollutant degradation time is shortened, and the mineralization and detoxification capability of the pollution removal system is further improved. The catalytic ozonation water treatment and impurity removal technology aims at solving the problem that the existing conventional drinking water treatment has poor removal effect onnovel pollutant benzotriazole, the novel perovskite type oxide / graphite phase carbon nitride is used as the catalyst, the catalyst can be successfully applied to the catalytic ozonation system, the degradation capability of the benzotriazole can be improved, and the catalyst can be used for synchronously inhibiting generation of toxic and side product bromate, and has a wide application prospect.

The invention discloses a carbon nano tube immobilized laccase, which is prepared by the following steps of carrying out grafting of succinimido and grafting of a nitrilotriacetic acid functional group on a carbon nano tube; carrying out surface functionalization treatment through copper ion chelating and modifying, and carrying out immobilized reaction with the laccase with copper ion removal. The laccase active center is directly connected with the copper ions of the carbon nano tube surface functional group, so that the real meaning direct electron transfer can be realized, and the shielding effect produced by a laccase protein shell on the direct electron transfer process from the active center to the carbon nano tube is overcome. The carbon nano tube immobilized laccase provided by the invention solves the problem of limitation of the electron transfer rate during the carbon nano tube immobilized laccase catalytic process, the sensitivity of the immobilized laccase in biological detection can be improved, the lowest detection limit during phenol determination is reduced by 85 percent to 96 percent, and the current density in biological fuel cell application is improved by 80 percent to 120 percent.

The invention relates to the technical field of biological energy, and discloses a recombinant plasmid, recombinant shewanella and an electricity generation method of a microbial fuel cell (MFC). A promoter suitable for the shewanella is selected to be connected with an exogenous electron carrier flavins gene, so that the shewanella is enabled to generate more flavis, and the electrochemical performance of the MFC is improved; furthermore, a mutant strain is combined with a porin oprF gene, so that the formation of a biofilm is further improved, the going in and out of the flavins in the shewanella can be promoted, the electron transfer rate is increased, and electrons are better transmitted. Furthermore, biocompatible graphene oxide (GO) is used and can be self-assembled into the three-dimensional multilayer biofilm together with the shewanella, so that the thickness of the biofilm and the anode biocapacity are further greatly improved; the operation is simple and fast, and the electrochemical performance of the MFC is effectively improved.

The invention discloses a preparation method of a non-noble metal doped molybdenum carbide hydrogen evolution electrode. The method includes the steps: (1) dissolving ammonium molybdate and non-noblemetal salt in water, and adding benzylamine to stir mixture; (2) adjusting pH (potential of hydrogen) of a system acquired in the step (1) to reach 4-6, stirring the mixture for 3-6h at the temperature of 40-80DEG C, filtering the mixture, and cleaning and drying acquired sedimentation; (3) calcining a dried sample in inert gas atmosphere, and cleaning and drying the calcined sample to obtain a non-noble metal doped molybdenum carbide catalyst; (4) preparing catalyst solution from the non-noble metal doped molybdenum carbide catalyst, immerging a pretreated electrode into the catalyst solution, stirring mixture, and drying the mixture to obtain the hydrogen evolution electrode. Under the non-noble metal doped molybdenum carbide hydrogen evolution electrode, electrons can be more effectively and indirectly from hydrogen by autotrophic microorganisms, and the shortcoming of low bio-film electron transfer rate is avoided, so that acetic acid production efficiency is improved when carbon dioxide is reduced by a bioelectric synthesis system.

A preparation method and application of a graphene-polypyrrole electrochemical sensor for trace lead ion detection belong to the field of environmental analysis. The invention utilizes the complexation of the nitrogen atom on the amine group in the polypyrrole and the lead ion to obtain high selectivity and the high conductivity of the graphene nanosheet to amplify the signal and realize the detection of trace lead ions. The presence of graphene can also increase the steric binding sites of the composite material and the interfacial electron transfer rate, thereby improving the detection effect of the sensor. Due to the synergistic effect of graphene nanosheets and polyaniline, the graphene-polypyrrole electrochemical sensing method has the characteristics of high sensitivity and high selectivity. ‑The preparation method of the polypyrrole electrochemical sensor is simple and controllable, without secondary pollution. The invention has wide application prospects in in-situ monitoring of trace lead ions in water bodies.