136 results about "Potassium ferricyanide" patented technology

The invention relates to the technical field of nano-enzyme preparation and electrochemical and colorimetric dual-mode sensing, and particularly discloses a Mn3Fe2.7-atC nano-enzyme, a preparation method thereof and application of the Mn3Fe2.7-atC nano-enzyme in determination of amoxicillin content. The preparation method of the Mn3Fe2.7 at C nano-enzyme is characterized by comprising the following steps: dissolving manganese chloride and trisodium citrate in water to prepare a solution A; dissolving potassium ferricyanide in water to prepare a solution B; adding the solution B into the solution A under a stirring condition, continuously stirring for 16-32 hours after the solution B is added, carrying out suction filtration, and drying the obtained precipitate to obtain a ferromanganese prussian blue analogue precursor; and placing the ferromanganese prussian blue analogue precursor in a tubular furnace, carrying out pyrolysis, and after the pyrolysis is finished, carrying out acid soaking, washing and drying to obtain the Mn3Fe2.7 at C nano-enzyme. When the Mn3Fe2.7 (at) C nano-enzyme is used for measuring the content of amoxicillin, the accuracy is good, and meanwhile, the Mn3Fe2.7 (at) C nano-enzyme has the advantages of interference resistance, stability, good recovery rate and the like.

The invention provides a low-cyanide gold leaching agent system and a dump leaching process thereof, and belongs to the technical field of hydrometallurgy. According to the method, a synergistic process of'interface activation, cyanide etching and iron precipitation inhibition 'is constructed by designing a low-cyanide gold leaching agent system. The amino acid auxiliary leaching agent adsorbs the gold surface to weaken lattice energy, so that the etching efficiency of trace cyanide ions is improved; mercapto-containing malic acid is used as a chelating agent, specific mercapto in molecules of the mercapto-containing malic acid and iron ions form an ultrahigh-stability water-soluble complex, generation of ferric hydroxide precipitates is thoroughly blocked, ferrous ions stabilized by the chelating agent are subjected to in-situ oxidation through dissolved oxygen and efficiently regenerated into potassium ferricyanide, and accumulation of free cyanogens in a solution system is eliminated; meanwhile, a chelating agent-iron complex forms a self-buffering pair, the pH of the dump leaching solution is accurately controlled, and secondary precipitation caused by local alkalization is prevented. According to the process, under the synergistic effect that the core chelating agent guarantees permeation stability and the leaching aid accelerates gold dissolution, the heap leaching period is compressed to 45 days.

The invention belongs to the technical field of thermoelectric materials and functional polymer materials, and particularly relates to thermoelectric hydrogel based on synergistic enhancement of zwitterions and a polar solvent as well as a method and application of the thermoelectric hydrogel. The thermoelectric hydrogel is obtained through the steps that a precursor solution is subjected to a polymerization reaction to form a gel matrix, then the gel matrix is soaked in a soaking solution, potassium ferricyanide / potassium ferrocyanide redox couple is introduced, and the thermoelectric hydrogel is obtained, and the precursor solution is prepared from acrylamide, N-isopropylacrylamide, dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylformamide, N, N-dimethylformamide, N, N-dimethylformamide, N, N-dimethylformamide and N, N-dimethylformamide. The photoinitiator is prepared by mixing N, N-dimethylformamide, 1-ethyl-3-methylimidazolium tetrafluoroborate, a zwitterionic monomer [2-(methylacryloyloxy) ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide, a cross-linking agent N, N '-methylene bisacrylamide, a photoinitiator and deionized water. The thermoelectric hydrogel prepared by the invention has high mechanical strength, high ductility and high Seebeck coefficient, and has better temperature resistance.

The invention provides a sulphide ore alkaline desulfurization and cyanidation gold leaching agent system and a method for extracting gold through the sulphide ore alkaline desulfurization and cyanidation gold leaching agent system, and belongs to the technical field of hydrometallurgy. According to the method, a ternary agent system consisting of potassium ferricyanide, low-concentration sodium cyanide and thioguanosine is constructed. An efficient'oxidation-inhibition 'synergistic system is formed between the auxiliary desulfurization agent potassium ferricyanide and the thioguanosine. The rapid and selective oxidation of potassium ferricyanide is smoothly carried out under the synergistic effect of thioguanosine, minerals are thoroughly decomposed, and the surface keeps high activity; meanwhile, due to the existence of the thioguanosine, the local microcell passivation risk and catalytic electron transfer can be eliminated more directionally. The sodium cyanide and the sodium cyanide complement each other, it is jointly guaranteed that the exposed gold can be smoothly and efficiently leached through follow-up low-concentration sodium cyanide, finally, the total consumption of reagents is reduced, environmental pollution is reduced, and meanwhile high-recovery-rate extraction of the gold in the sulfide ore difficult to treat is achieved.

The invention discloses a preparation method and application of an aqueous iron ion battery positive electrode material. The preparation method comprises the following steps: (1) respectively mixing a single type of ferric salt and potassium ferricyanide with water to obtain a solution A and a solution B; (2) mixing the solution A and the solution B, stirring in a water bath kettle, and carrying out a co-precipitation reaction to obtain a solid precipitate; and (3) centrifuging, washing and drying the solid precipitate to obtain the nano-particles with the particle size of 150-200nm. The obtained nanoparticles can be used as an aqueous iron ion battery positive electrode material, the positive electrode can realize Fe < 2 + > and NH4 < + > ion co-de-intercalation electrochemical reaction in the charging and discharging process, and the reversible specific capacity of the battery is remarkably improved; the embedded NH < 4 + > and N in the positive electrode material can form a stable hydrogen bond structure, so that the cycling stability of the battery is effectively improved. The preparation process is easy to operate, the product yield is high, the consistency is excellent, and the method is suitable for large-scale preparation and application.

The invention discloses an electrochemical microscopic imaging analysis method based on a fluorescence signal, which comprises the following steps of: constructing a fluorescence response electrochemical signal instrument by combining electrochemistry with a fluorescence microscope, and observing the redox potential of K3 [Fe (CN) 6] by taking a terpyridyl ruthenium (Ru (bpy) 32 +) / potassium ferricyanide (K3 [Fe (CN) 6]) fluorescence system as a research object. Influences of electrochemical behaviors on fluorescence signals are deeply explored, and the relationship between fluorescence signal changes and electric signal changes is revealed. According to the present invention, the combination of the electrochemical technology and the fluorescence signal is achieved, the disadvantage of the poor spatial-temporal resolution of the electrochemiluminescence is made up, the new dimension capable of being regulated and controlled by the electrical parameter is provided for the fluorescence imaging, and the Faraday current and the non-Faraday current can be completely reflected by the fluorescence signal. Therefore, the method has wide application value in the aspects of exploring the conductivity of the nano material and the like.

The invention relates to the technical field of detection and identification of fentanyl substances, and discloses a selective quantitative detection method of fentanyl. According to the method, a differential pulse voltammetry (DPV) is used for making a linear relation diagram of a potassium ferricyanide peak current and fentanyl solutions with different concentrations to obtain a standard working curve, a linear equation is obtained through the standard curve, and the detection limit is 1.0 * 10 <-12 > mol.L <-1 >; the molecularly imprinted membrane modified electrode prepared by the invention is used for measuring the peak current of a potassium ferricyanide solution, so that fentanyl molecules can be indirectly and quantitatively analyzed and measured. The method is characterized in that a fentanyl molecularly imprinted membrane is electrically polymerized on the surface of a glassy carbon electrode, m-phenylenediamine is used as a functional monomer, and the selectivity and sensitivity of an electrochemical method for detecting fentanyl are improved. Meanwhile, by taking an adsorption pulse stripping voltammetry (DPASV) as a detection technology, a method capable of rapidly detecting fentanyl molecules in the presence of various drugs is established. The molecularly imprinted membrane electrode disclosed by the invention is simple to prepare, quick in response and good in selectivity and reproducibility, and can be repeatedly used for more than five times.

This invention belongs to the field of biochemical detection and discloses a portable hepatitis biomarker detection kit. The kit contains a hydrogel; the hydrogel is obtained by dispersing hollow manganese dioxide in water to obtain an H-MnO2 dispersion, mixing the H-MnO2 dispersion with sodium alginate solution to obtain a mixed solution, and then adding a calcium salt solution to obtain the hydrogel. The hollow manganese dioxide is obtained by etching manganese Prussian blue analog nanoparticles with sodium hydroxide. The manganese Prussian blue analog nanoparticles are prepared from potassium ferricyanide, polyvinylpyrrolidone, and manganese salts. This invention utilizes the color change of hollow manganese dioxide in relation to TMB to construct a method for detecting hepatitis biomarkers using a smartphone to capture signals. This kit reduces the detection cost of hepatitis biomarkers, does not require large instruments, and is highly portable and widely applicable, possessing great potential as a novel point-of-care testing device.

The invention provides a high-entropy nano enzyme. The chemical formula of the high-entropy nano enzyme is Mn < 0.4 > Co < 0.4 > Ni < 0.4 > Cu < 0.4 > Zn < 0.4 > Fe < 2.0 >) O. The invention also provides a preparation method of the high-entropy nano-enzyme, which comprises the following steps: dissolving manganese nitrate tetrahydrate, cobalt nitrate hexahydrate, nickel nitrate hexahydrate, copper nitrate trihydrate, zinc nitrate hexahydrate and sodium citrate in deionized water to prepare a clear solution A; dissolving potassium ferricyanide in deionized water to prepare a clear solution B; directly pouring the solution B into the solution A, stirring, standing and aging the obtained mixed solution at room temperature, and centrifugally collecting a product; and calcining the sample powder in a muffle furnace to obtain the high-entropy nano-enzyme. The invention further provides a catalyst which is composed of the high-entropy nano enzyme, 3, 3 ', 5, 5'-tetramethyl benzidine and H2O2. The invention also provides a method for detecting reduced glutathione by using the microfluidic paper chip analysis device. The invention provides a new normal form for constructing a multifunctional biosensing and environment monitoring platform.

The invention relates to the technical field of oxygen free radical detection, in particular to a manufacturing process of a portable and reliable oxygen free radical detector. Comprising the following steps: mixing superoxide dismutase, potassium ferricyanide, an isothiazolinone preservative, hexammine ruthenium chloride, polyethylene glycol octylphenol ether, trehalose and bovine serum albumin, and uniformly stirring to prepare an enzyme preparation; mixing an enzyme preparation with the high polymer material solution to form reagent layer slurry with viscosity; uniformly coating the reagent layer slurry on a substrate material, and drying; printing an electrode material on the substrate material to form a working electrode and a counter electrode; the silver electrode is placed in an electrolyte containing chloride ions, potential is applied, the silver surface is subjected to a chlorination reaction, and a silver / silver chloride electrode is formed; covering the reagent layer above the electrode, tightly combining the reagent layer with the electrode in a sticking or hot pressing manner, and cutting to obtain the test paper; the prepared portable oxygen free radical detector can be used for conveniently and efficiently detecting oxygen free radicals of a human body at low cost.

The invention provides a method for reducing the diameter of a tungsten filament of tungsten filament screen cloth, which reduces the risk of injury to operators and is good in environmental friendliness. The size precision control of the tungsten filament reducing process is high; the corrosion degree of equipment is reduced, and the maintenance cost is reduced. The method is characterized in that a mixed solution containing potassium ferricyanide, potassium hydroxide and deionized water is adopted as an etching solution for reducing the tungsten filament, the mass percent of potassium ferricyanide in the etching solution is 5%-20%, and the mass percent of potassium hydroxide in the etching solution is 3%-10%.

The present application relates to wastewater treatment technical field, provide a kind of physicochemical method for treating acid etching waste liquid and potassium ferricyanide waste liquid simultaneously, comprising the following steps: S1.diluted after adding water in part etching waste liquid, add iron oxide, react for a period of time;Then add iron powder, after a period of time, add hydrochloric acid, after filtration separation, obtain metal copper and filtrate;S2.mixture of remaining etching waste liquid and biomass material is treated after using equal volume impregnation method, at 300-500 DEG C, under mixed protective atmosphere, calcine for a period of time;Then again at 600-1100 DEG C, under nitrogen atmosphere, calcine for a period of time;Iron-based carbon material is prepared;S3.iron-based carbon material, filtrate is directly mixed with potassium ferricyanide wastewater, react for a period of time, after filtration, evaporation, crystallization treatment can enter biochemical treatment system;It can realize the efficient recovery of metal copper, while the removal efficiency of ferricyanate in potassium ferricyanide wastewater is high, realizes waste treatment with waste, and the degree of resource utilization is high.

The application relates to the technical field of sodium ion battery negative electrode materials, and discloses a preparation method and application of a copper-iron sulfide / nitrogen-doped porous carbon composite material, which comprises the following steps: (1) mixing copper salt, potassium ferricyanide, a nitrogen source and polyethylene glycol, and obtaining a copper-iron Prussian blue precursor after ball milling; (2) pyrolyzing the copper-iron Prussian blue precursor under an inert atmosphere, washing and removing impurities, and drying to obtain an intermediate product; and (3) heat-treating the intermediate product and a sulfur source under an inert atmosphere to obtain a copper-iron sulfide / nitrogen-doped porous carbon composite material. Through the synergistic effect of the double-metal sulfide and the nitrogen-doped porous carbon composite, sodium ions with a larger ion radius can be more easily embedded and de-embedded in the interlayer spacing, meanwhile, abundant active sites are provided to enhance ion storage, so that the sodium ion battery has outstanding rate performance and stable cycle performance.

The application discloses an anti-caking salt product and a preparation method thereof. The anti-caking salt product comprises raw salt and an anti-caking agent, the anti-caking agent is food-grade ferric tartrate, and the addition amount of the anti-caking agent is 0.05-0.106 g / kg of the salt. The core of the anti-caking method of the salt lies in that the food-grade ferric tartrate is used as the main anti-caking agent, the addition amount is 0.05-0.106 g / kg of the salt, the salt is dried at 100 DEG C for 4 hours, then the anti-caking agent is added, and the water vapor transmission rate is less than or equal to 0.5 g / m 2 24h of high-barrier material packaging, while 6 g of quicklime or 2 g of calcium chloride desiccant is added in every 200 g of the salt. The application also controls the Mg 2+ content in the salt to be less than or equal to 0.02%, the KCl content to be less than or equal to 10%, and the particle size to be in the range of 0.45-0.6 mm, so that the salt caking is synergistically inhibited from multiple dimensions. The method has extremely significant anti-caking effect (the caking rate is only 8.7% after 15 days of open storage), is safe and economical, and has a simple process, and can effectively replace or reduce the use of potassium ferrocyanide, and is suitable for large-scale industrial production.

The invention relates to the technical field of photocatalysis, in particular to a strontium bismuth vanadium oxide photocatalyst and a preparation method and application thereof.The chemical formula of the photocatalyst is Sr3. 59Bi19.41 V4O42, the crystal structure of the photocatalyst belongs to an orthorhombic system, the space group of the photocatalyst is Immm, and the photocatalyst is of a unique layered structure composed of cation triple plate layers; the photocatalyst is synthesized by a molten salt method, and shows the activity of photocatalytic decomposition of water to produce oxygen under visible light. The preparation method comprises the following steps: mixing and grinding SrO, Bi2O3 and VO precursors with a molten salt medium, and then carrying out temperature programming calcination to synthesize a target product; the catalyst prepared by the method has the characteristics of high crystallinity, few defects and regular morphology, the photocatalytic oxygen production performance of the catalyst is remarkably superior to that of a same-component sample synthesized by a traditional solid-phase method, and photocatalytic water decomposition and oxygen production can be realized by taking a silver nitrate, ferric nitrate, ferric chloride or potassium ferricyanide aqueous solution as a sacrificial agent system under the irradiation of visible light with the wavelength of more than or equal to 420 nm.

The application discloses a synthesis method of a foamed nickel loaded iron-nickel-phosphorus C3N4 electrocatalytic material, and specifically comprises the following steps: S1, potassium ferricyanide, citric acid and C3N4 are weighed respectively and added into deionized water, and magnetic stirring is performed through a magnetic stirrer until complete dissolution; S2, 2cm*2cm foamed nickel is cut, surface impurities are washed away, and the treated foamed nickel is dried in a vacuum oven at 70 DEG C for 6h, and the dried foamed nickel is placed in the solution prepared in S1, and the reactor is sealed; S3, the foamed nickel in S2 is dried in a vacuum oven at 70 DEG C for 12h, is placed in the upstream of a porcelain boat, 450mg-550mg sodium hypophosphite is weighed and placed in the downstream of the porcelain boat, the porcelain boat is placed in the middle position of a tube furnace, and the foamed nickel is subjected to phosphating reaction in an argon atmosphere, the reaction temperature is controlled to be 345-355 DEG C, the reaction time is controlled to be 115-125min, and the foamed nickel loaded iron-nickel-phosphorus / C3N4 electrocatalytic material is obtained after the reaction is completed. The foamed nickel surface participates in the formation of a metal organic compound, so that the performance of the material is improved, and the service life of the material is prolonged.

This invention relates to a metal-organic framework-derived copper ferrite-based hydrogen sulfide gas-sensitive element and its preparation method, belonging to the field of gas-sensitive element preparation technology. The invention first involves reacting polyvinylpyrrolidone with hydrochloric acid solution and potassium ferricyanide. After the reaction, the mixture is washed and dried. The resulting blue precipitate is then reacted with copper acetate in an organic solvent. The resulting powder is then subjected to a heat treatment to obtain the metal-organic framework-derived copper ferrite material. The gas-sensitive element prepared from the copper ferrite material of this invention exhibits excellent adsorption and reactivity for hydrogen sulfide gas, which helps to solve the problem of hydrogen sulfide poisoning and improves the sensitivity and selectivity of the element. Furthermore, it features a simple preparation process.

This invention discloses a copper hexacyanoferrate-potassium heptacopper sulfide composite electrode material, its preparation method, and its application, belonging to the field of electroanalytical sensing material preparation technology. This invention uses a hydrothermal synthesis method to prepare potassium heptacopper sulfide. Subsequently, the potassium heptacopper sulfide-modified electrode is placed in an electrolyte solution containing potassium ferricyanide, and in-situ electrosynthesis is performed using cyclic voltammetry. This allows the hexacyanoferrate ions and copper ions present in the electrolyte to react and generate water-insoluble copper hexacyanoferrate, which grows in situ on the electrode surface, resulting in the copper hexacyanoferrate-potassium heptacopper sulfide composite electrode material. In this material, potassium heptacopper sulfide serves as a conductive substrate, and copper hexacyanoferrate serves as a redox probe. This composite electrode material can be used to construct an electrochemical sensor containing a molecularly imprinted layer, which exhibits high sensitivity, high specificity, a wide detection range, and good stability.

This invention belongs to the field of high-entropy transition metal coordination polymer technology, specifically relating to a high-entropy Prussian blue material, its preparation method, and its applications. The invention involves dissolving various hydrated inorganic metal salts and sodium citrate complexing agent in water, slowly adding potassium ferricyanide solution dropwise to this solution, and then stirring for 30 min. The resulting solution is allowed to settle at room temperature for 24 h, washed three times by centrifugation with deionized water, and then washed three times by centrifugation with ethanol to obtain the high-entropy Prussian blue material Cu. 0.2 Ni 0.2 Co 0.2 Mn 0.2 Zn 0.2 (Fe(CN)6) 0.667 This invention yields a high-entropy Prussian blue electrocatalyst that is simple to synthesize, structurally stable, and uses readily available raw materials. This electrocatalyst can be applied to the electrocatalytic reduction of nitrate, laying the foundation for developing other high-entropy transition metal coordination compounds with framework structures as electrocatalysts for the electrocatalytic synthesis of value-added chemicals from nitrate.

The invention discloses a copper-iron prussian blue / graphene oxide composite electro-catalysis cathode and a preparation method thereof. The method comprises the following steps: dissolving copper chloride, single-layer graphene oxide powder, citric acid and sodium citrate in water by adopting a one-step coprecipitation method, heating in a water bath, carrying out a heat preservation reaction to form a copper source precursor solution, mixing the copper source precursor solution with a potassium ferricyanide solution, carrying out heat preservation aging, taking the precipitate, carrying out centrifugal washing, drying and grinding to obtain catalyst powder, and drying the catalyst powder to obtain the single-layer graphene oxide / potassium ferricyanide composite catalyst. Finally, the powder and PVDF are mixed and dissolved in NMP, hydrophilic carbon cloth is coated with the mixture, and the copper-iron prussian blue / graphene oxide composite electro-catalysis cathode is prepared. The preparation process is simple, mass production can be achieved, the prepared composite electro-catalysis cathode has efficient hydrogen peroxide production capacity and in-situ Fenton catalysis capacity, active oxygen species can be effectively generated for organic pollutant degradation, and the application potential of a Prussian blue analogue material in the field of water treatment is greatly improved.

The present invention relates to a method for improving the detection performance of an electrochemical biosensor and its application in a ratiometric electrochemical biosensor. Methylene blue and cholesterol-modified double-stranded DNA probes are immobilized on a gold electrode modified with a 1-hexanethiol assembly layer via hydrophobic interaction, thereby improving the stability of the methylene blue at the gold electrode interface and the immobilization efficiency of the double-stranded DNA probe at the gold electrode interface. In a potassium ferricyanide-mediated electrocatalytic system, the methylene blue on the gold electrode serves as a signal unit, and ferrocene is introduced as another signal unit. The 1-hexanethiol assembly layer on the gold electrode can shield [Fe(CN)6] 3‒ Electron transfer between the electrode interface and methylene blue enables simultaneous signal amplification of both methylene blue and ferrocene. Methylene blue, acting as an electron mediator, enhances the signal response of ferrocene, achieving secondary signal amplification of ferrocene, thereby improving sensor detection sensitivity. The ratiometric electrochemical biosensor constructed using this method exhibits excellent sensitivity, accuracy, and selectivity.

The application discloses a sweat detection device based on one-way liquid discharge composite paper-based fiber membrane and a preparation method, and relates to the technical field of sweat detection. The preparation method is as follows: SEBS is dissolved and then added into LiCl aqueous solution to prepare an electrospinning liquid, and the composite paper-based fiber membrane is prepared on a hydrophilic paper base layer through electrospinning; a microfluidic channel is written on the hydrophilic side of the composite paper-based fiber membrane; a bromocresol green aqueous solution is added into the microfluidic channel and dried to obtain a pH detection module; a mixed solution of ferric chloride and potassium ferricyanide is added into the microfluidic channel, a mixed solution of chitosan and sodium alginate is added after drying, and lactic acid oxidase or glucose oxidase is added, and a color developing agent is added after drying to obtain a lactic acid detection module and a glucose detection module respectively; the detection device has the characteristics of simple structure, convenient operation, high detection accuracy and good color developing effect, and can realize colorimetric detection of pH, lactic acid and glucose without cross interference.

The invention belongs to the technical field of electrode materials, and discloses a multi-metal Prussian blue analogue composite material and a preparation method and application thereof.The method comprises the steps that a copper source, a cobalt source and a chelating agent are jointly dissolved in water and stirred to be completely dissolved, and a uniform and transparent metal precursor solution is obtained; wherein the chelating agent adopts sodium citrate; mixing a potassium ferricyanide solution with the uniform and transparent metal precursor solution, carrying out a co-precipitation reaction, and standing and aging to obtain a CuCoHCF crystal; mixing the CuCoHCF crystal, electrically exfoliated graphene and bacterial cellulose, adding a solvent, and performing ultrasonic dispersion to obtain composite slurry; and preparing the multi-metal Prussian blue analogue composite material by using the composite slurry, the crystal lattice vacancy defect and the crystal water content in the CuCoHCF crystal are effectively reduced, so that the structural stability of the material is greatly improved, and the electrochemical cycle life of the material is greatly prolonged.

The invention belongs to the technical field of nano material synthesis, and relates to an iron-doped cobalt phosphide hollow nanocage hydrogen evolution catalyst and a preparation method thereof. The catalyst is a composite porous material of Fe-doped CoP nano-particles and nitrogen-doped carbon, and the Fe-doped CoP nano-particles coated with the nitrogen-doped carbon are uniformly loaded on dodecahedral porous nitrogen-doped carbon with the size of 200nm microcosmically. The preparation method comprises the following three steps: (1) reacting cobalt nitrate hexahydrate with 2-methylimidazole in methanol at room temperature, and centrifuging to obtain a ZIF-67 precursor; (2) performing oil bath reflux on ZIF-67 and potassium ferricyanide in ethanol-deionized water, and performing centrifugal drying to obtain a CoFe-PBAs precursor; and (3) annealing CoFe-PBAs for 2 hours at 400 DEG C under the protection of argon, thereby obtaining the target catalyst. The catalyst is excellent in hydrogen evolution activity in a whole pH range, 0.01 Acm <-2 > overpotentials in an acidic system, an alkaline system and a neutral system are 61mV, 133mV and 188mV respectively, only 1.91 V is needed for realizing 1.0 Acm <-2 > current density in a proton exchange membrane electrolytic cell, and the 200-hour operation voltage attenuation rate is as low as 0.1 mVh <-1 >. The method is simple in preparation process, low in cost, outstanding in catalyst activity and stability and suitable for industrial green hydrogen preparation scenes.

The invention discloses a compound enzyme solution for improving total cholesterol test current, which is prepared from the following components in percentage by weight: 20 to 200mM of buffer solution, 0.5 to 200mg / mL of cholesterol oxidase, 0.1 to 100mg / mL of cholesterol esterase, 0.1 to 25mg / mL of peroxidase, 1 to 6 percent of potassium ferricyanide, 0.1 to 8 percent of glucoside and the balance of water. And the cellulose accounts for 0.01%-2%. When a whole blood sample is tested, the compound enzyme liquid of lipoprotein can be quickly decomposed, so that the test current is improved, and the test time is shortened.

The invention relates to a wafer-level gold etchant which is characterized by being prepared from the following raw materials in percentage by weight: 8-12% of a sodium thiosulfate solution, 28-32% of a thiourea solution, 8-12% of a potassium ferricyanide solution and 48-52% of a potassium iodide solution. The wafer-level gold corrosive liquid disclosed by the invention has the advantages that the wafer-level gold corrosive liquid can be widely applied to a circuit which has a gold film layer thickness of more than 0.5 mu m and has a relatively high requirement on sidetrack control, so that the problems of overlarge sidetrack, line CD (Compact Disc) over-limit and even metal falling caused by corrosion of the original gold corrosive liquid are avoided. When the wafer-level gold etching liquid is used for etching, smaller sidetracking is achieved, a process window is wider, process compatibility is better, and process support is provided for high-speed and high-power photoelectric semiconductors and micro-system devices.

The invention discloses a method for preparing phase-stable ammonium nitrate in a eutectic mode, and belongs to the technical field of crystal preparation. The eutectic method specifically comprises the following steps: (1) adding ammonium nitrate into water, heating and dissolving to obtain an ammonium nitrate saturated solution; (2) adding potassium ferrocyanide into the ammonium nitrate saturated solution, and stirring for reaction to obtain an ammonium nitrate / potassium ferrocyanide mixed solution; and (3) drying and grinding the ammonium nitrate / potassium ferrocyanide mixed solution to obtain the ammonium nitrate / potassium ferrocyanide eutectic. According to the invention, the AN / KFCT eutectic with the mass ratio of 3-4% is prepared by adopting an evaporative crystallization method through a eutectic technology, the phase change problem of ammonium nitrate in storage, transportation and use temperature ranges is solved, meanwhile, the structure-activity relationship between the crystal form and thermal stability is constructed, the thermal stability of ammonium nitrate is improved through crystal form regulation and control, and the application range of ammonium nitrate is widened. The invention provides a unique idea for solving the phase change of ammonium nitrate, and has application value.

The application provides a preparation method of 4,4'-diamino-2,2'-dimethylbiphenyl, which comprises the following steps: under the protection of a protective gas, m-methylaniline is reacted in a mixed solvent of water and an organic solvent under the catalysis of potassium ferricyanide and an alkali to obtain 4,4'-diamino-2,2'-dimethylbiphenyl shown in formula I. The m-methylaniline is used for oxidative coupling to obtain 4,4'-diamino-2,2'-dimethylbiphenyl, the reaction steps are short, the selectivity is higher, the reaction yield is high, and the cost is lower, so that the preparation method is novel, the selectivity is good, the overall preparation cost is low, and the yield is high.

The acid-base indicator has important application in the fields of chemical industry, food, medicine and the like, so that a plurality of inorganic and organic acid-base indicators are invented by people. The invention prepares two novel acid-base indicators with similar processes and properties. The method specifically comprises the following steps: firstly, dissolving chitosan by using an aqueous solution of lactic acid, then adding a ferrous sulfate solution into the solution, and dialyzing and standing to obtain a solution containing ferrous ions. Adding potassium ferricyanide into the solution to obtain an indicator A; adding ammonium thiocyanate and a small amount of sulfuric acid into the indicator A to obtain an indicator B; the two indicators are blue and faint yellow when the pH value is 9-10 or above. Wherein the indicator B can still turn blue after being added into the acid solution again.

The invention is applicable to the technical field of preparation of functional materials, and provides a preparation method and application of a cobalt-manganese Prussian blue material based on an acid inhibition strategy, the method comprises the following steps: dissolving cobalt salt, manganese salt, potassium ferricyanide and a chelating agent in water to form a mixed solution, respectively adding a certain volume of acid into the mixed solution, and uniformly stirring; then adding the mixed solution with the acid into a reaction kettle, and carrying out hydrothermal reaction; and after the high-pressure reaction kettle is cooled to room temperature, washing, centrifuging and drying a product to finally obtain the high-stability low-space CoMnPBA material. The method is simple in synthesis process and low in production cost, has relatively low vacancy and interstitial water content, has relatively high desalination capacity and good cycle stability in the presence of high-concentration NaCl, and has a good application prospect.