35 results about "Displacement reactions" patented technology

The invention provides a waste battery recovery method and device, the method uses a low-melting-point molten salt with reducibility as a reactant to strip Li, Co, Ni, Mn and other elements in a waste battery from an oxygen element, chlorine salt which is easier to carry out subsequent replacement reaction is generated, the Li, Co, Ni, Mn and other elements in the waste battery can be extracted step by step through the replacement reaction, and the recovery rate of the waste battery is improved. And the recovery process is simplified. The waste battery recycling method has the advantages of being low in cost, high in recycling yield, low in requirement for recycling equipment and the like.

The invention provides a preparation method of silver-coated copper powder, and belongs to the technical field of metal powder treatment. The used copper particle suspension contains a complexing agent, so that the activity of the copper particles can be reduced, the reaction rate of reduction coating can be reduced when a silver-ammonia complexing solution is added, and a compact silver layer slowly and uniformly grows on the surface of each copper particle; the reduction of the activity of the copper particles slows down the replacement reaction of silver ions and copper, and the situation that the coating surface is rough and loose due to the generation of overlarge silver particles is avoided; the silver grows slowly and compactly, so that the surface of the coated silver layer is smooth and compact on the basis of lower usage amount of the silver source; the preparation method is simple in process, low in silver content and low in production cost, and the coated silver layer is smooth and compact in surface.

The application discloses an intermediate processing liquid for an electroless nickel immersion gold (ENIG) production line and a chemical gold preparation method. The intermediate processing liquid is applied between the electroless nickel plating and immersion gold processes, and comprises (a) a pH buffer and a metal ion complexing agent: a total concentration of 50-150 g / L; (b) an adsorptive corrosion inhibitor: a concentration of 0.5-5.0 g / L; (c) a low-foam non-ionic surfactant: a concentration of 0.01-10 g / L; (d) an auxiliary antioxidant: a concentration of 0.5-30 g / L; (e) a dissolving agent: a concentration of 1-50 ml / L; (f) a pH regulator: an appropriate amount, which is added to maintain the pH value of the intermediate processing liquid at 4.0-6.5; and (g) deionized water: a balance, so that the concentrations of the above components reach the set target values; and the intermediate processing liquid has a design use temperature of 20-45 DEG C. The intermediate processing liquid removes residual nickel ions on the board surface and in micropores through strong complex cleaning, and blocks the pollution to the subsequent gold tank; meanwhile, the preferential adsorption of the corrosion inhibitor molecules at the nickel layer grain boundaries forms a controllable molecular-level protective film, effectively adjusts the immersion gold replacement reaction kinetics, and prevents the occurrence of intergranular corrosion (black plate).

The application discloses a continuous iron dissolving method for preparing iron phosphate, and comprises the following steps: S1, acid solution is added into a dynamic tubular reactor for pre-washing, and the flow of the acid solution is calibrated, and iron powder is added into the dynamic tubular reactor according to a reducing parameter; S2, a displacement reaction occurs in the dynamic tubular reactor, and the dynamic tubular reactor is in a closed and slightly negative pressure environment; acid mist and by-product hydrogen overflowing from the dynamic tubular reactor are pumped into a gas-liquid separator, and then the hydrogen is pumped into a hydrogen storage tank; S3, the iron phosphate solution obtained through the reaction of the dynamic tubular reactor is filtered through a bag filter through the gas-liquid separator, and then the iron phosphate solution is sampled and analyzed to obtain a clear iron dissolving solution. The application can accurately control the addition amount of raw materials, so that the iron powder is fully reacted in the reactor without residual iron powder, and the continuous iron dissolving process is realized. The safety problem caused by the high hydrogen concentration in the environment due to hydrogen production in the iron dissolving process is effectively solved.

The application discloses a kind of noble liquid zinc powder replacement reaction systems and control method thereof, belong to the field of dressing and smelting.The bottom end of deoxidation tower is connected with deoxidation tower liquid discharge pipe in system.Deoxidation tower liquid discharge pipe lower end is connected with circulating pump feed pipe and replacement pump feed pipe respectively.Circulating pump feed pipe is connected with circulating pump discharge pipe with pressure gauge by circulating pump.Circulating pump discharge pipe is connected with mixing tank feed pipe and is connected with circulating pipe by pipeline with valve.Mixing tank feed pipe is equipped with electromagnetic flowmeter and valve.Replacement pump feed pipe end with flowmeter and valve is connected with mixing tank discharge pipe and is connected with replacement cabinet by replacement pump and replacement pump outlet pipe.Replacement cabinet outlet main pipeline is connected with circulating pipe by pipeline with valve and is connected with replacement cabinet barren liquid pipe.Circulating pipe is connected with noble liquid pool, and replacement cabinet barren liquid pipe is connected with barren liquid pool.Solve the problem of scale formation of mixing device, improve the uniformity of zinc slurry and the stability of input replacement cabinet, strengthen the deoxidation effect of noble liquid, reduce the index fluctuation of barren liquid after replacement.

The invention discloses a synthesis method of trifluorosucrose, an atomization matrix, an electronic atomization device and a buccal product, the synthesis method comprises the following steps: in an organic solvent, sucralose and fluoride are subjected to a halogen replacement reaction to obtain the trifluorosucrose and chloride, and the reaction formula of the halogen replacement reaction is as follows: nC12H19Cl3O8 + 3MFn-nC12H19F3O8 + 3MCln, wherein M is a metal ion. According to the application, the trifluorosucrose can be synthesized, compared with the sucralose, the trifluorosucrose has better high temperature resistance, the sweetness of the trifluorosucrose is equivalent to that of the sucralose, and the trifluorosucrose can be used as a sweetening agent, and can be particularly suitable for application scenes in a relatively high temperature environment, for example, the trifluorosucrose can be used as one of components of an atomization matrix, so that the user experience is improved.

This invention discloses a method for preparing high-purity terbium-iron alloy, utilizing ferric fluoride as a chemical decalcification agent in the refining stage. Compared with existing technologies that rely solely on high-temperature volatilization and physical adsorption for calcium removal, this method provides a clear chemical driving force, converting calcium dissolved in the alloy melt into an insoluble calcium fluoride slag phase through a displacement reaction, thereby achieving efficient calcium removal. This invention can reduce the calcium content in terbium-iron alloy from 0.011-0.015% in traditional processes to 0.002-0.004%, a reduction of 70-85%. This method requires no special equipment; only the addition of ferric fluoride in the refining stage is needed, resulting in low process modification costs and good industrial applicability.

The invention discloses a transition metal sulfide single crystal with a macro-size asymmetric structure as well as a preparation method and application thereof. The preparation method comprises the following steps: providing a macro-size single-layer transition metal sulfide as a precursor; placing the substrate bearing the precursor in a reaction chamber in a non-horizontal orientation manner, so that a non-zero included angle is formed between the surface of the precursor and the dominant transmission direction of reactant flow in the reaction chamber; hydrogen plasma and a heterogeneous chalcogenide element source are introduced into the reaction chamber at the same time, an atomic layer replacement reaction is carried out under the room temperature condition, chalcogenide atoms on the top layer of the precursor are replaced by heterogeneous chalcogenide atoms, and after the replacement reaction is completely carried out, the transition metal sulfide single-layer material of the Janus structure is obtained. According to the method, the preparation of the high-quality Janus TMDC single crystal with the transverse size reaching the millimeter scale is realized, the prepared Janus single crystal has high spatial uniformity on the millimeter scale, and the process is simple, controllable and large-scale.

This invention provides an iridium cobalt oxide electrocatalyst, its preparation method, and its application. First, metallic Co is electrodeposited onto a Ti fiber mat, and then it is placed in an Ir... 3+ In solution, an electrochemical displacement reaction driven by the potential difference between two metals successfully deposited the noble metal Ir onto the surface of metallic Co. Finally, calcination in air yielded an iridium-cobalt oxide electrocatalyst. This invention utilizes an electrochemical displacement reaction to synthesize an iridium-cobalt oxide electrocatalyst simply and conveniently, by altering the noble metal Ir. 3+ By controlling the coordination environment of noble metal active sites through concentration and reaction time, a highly efficient and stable iridium-cobalt oxide was successfully constructed on the surface as an oxygen-generating active center. This solves the problems of high noble metal loading, low activity, and low stability in existing acidic oxygen-generating electrocatalysts, providing a simple, rapid, low-cost, and efficient solution for industrial-scale production.

The invention belongs to the technical field of electrocatalytic materials, and discloses an electrocatalyst for selectively preparing hydrogen peroxide by controlling an oxygen reduction reaction path and application. The electrocatalyst is a composite material in which a Fe3O4 dispersion liquid, an amino-containing monomer, an aldehyde-containing monomer and a zinc salt are subjected to a Schiff base reaction in the presence of a catalyst to obtain a product, and the product and a magnetic metal salt are subjected to a replacement reaction to prepare a metal monatomic covalent organic framework which coats the surface of a magnetic matrix Fe3O4 in a shell form; the Fe3O4 dispersion liquid is prepared by mixing Fe3O4 nanoparticles and a dispersing aid, and the size of the Fe3O4 nanoparticles is smaller than or equal to 100 nm. The electrocatalyst according to the present invention is used to control an oxygen reduction reaction path (2 electron path), thereby achieving high-selectivity production of hydrogen peroxide.

The purpose of this invention is to provide a carbon framework supported and embedded Ni3ZnC 0.7 This paper describes the preparation method and application of NiPt1 single-atom alloy catalysts, belonging to the field of functional materials technology. Using a core-shell structure ZIF-8@Ni-MOF as a precursor, porous carbon-supported Ni3ZnC catalysts are prepared by controlling the pyrolysis temperature, time, and Zn / Ni molar ratio. 0.7 Ni particles; Pt single atoms are anchored in situ using current displacement to form a supported single-atom alloy catalyst. Because Pt 4+ with Ni 0 A current displacement reaction occurs, causing Ni nanoparticles to be etched into small nanoclusters, while simultaneously anchoring Pt single atoms to their surface, thus producing a Ni3ZnC coating. 0.7 The outer layer is a NiPt1 single-atom alloy. Ni3ZnC 0.7 The tunable electronic structure of Ni can alleviate OH blockage and lower the water dissociation energy barrier, providing a new pathway for the development of highly efficient alkaline HER catalysts.

The invention discloses a preparation method of trialkyl boron, and belongs to the technical field of organic boron compounds. According to the preparation method, an alkyl aluminum compound or an alkyl zinc compound is taken as a first raw material, a boron-containing compound is taken as a second raw material, and trialkyl boron is synthesized through metal replacement reaction; the boron-containing compound is selected from boron trihalide or borate. A single-step metal replacement reaction path of an alkyl aluminum compound or an alkyl zinc compound and a boron-containing compound is adopted, so that the three defects of long synthesis route, high energy consumption and more byproducts in the prior art are remarkably overcome. Compared with a high-temperature and high-pressure seed method, the method has the advantages that the high yield is realized under the mild conditions of normal pressure and less than or equal to 120 DEG C, the energy is saved, and the high-pressure risk is avoided; compared with a multi-step organic metal method, the atom utilization rate is greatly increased, byproducts are reduced, and resource utilization can be achieved.

The invention discloses a method for synchronously removing copper and chlorine in zinc hydrometallurgy, which comprises the following steps: S1, taking a pre-copper deposition solution with the pH value of 2.5-3.0, adding iron powder which is 0.9-1.2 times of a theoretical calculation value to carry out a replacement reaction, and carrying out solid-liquid separation to obtain copper slag and a post-replacement solution; and S2, the copper slag obtained in the S1 and the replaced liquid are added into waste electrolyte, the pH is adjusted to range from 1.5 to 2.0, an oxidation-reduction reaction is carried out under the weak acid condition, and cuprous chloride and dechlorinated liquid are obtained. Copper removal and dechlorination are combined into one procedure, and copper removal and dechlorination are realized under a weak acid condition, so that valuable metal recovery and impurity removal of the whole zinc smelting system are improved.

The invention relates to a cyanide-free chemical displacement gold plating solution and a gold plating method, which are particularly suitable for deposition of an ultrathin gold layer (less than or equal to 0.1 mu m) on the surface of a nickel base material. The gold plating solution comprises a buffering agent, gold salt and a double-complexing-agent system composed of L-glutamine and 2-furancarboxylic acid. Amido and amino of L-glutamine synergistically act on the surface of nickel, so that mild activation is realized; furan epoxy atoms in 2-furancarboxylic acid and carboxyl form a steric-hindrance effect, so that gold ion release kinetics is regulated and controlled, and excessive substitution reaction is inhibited. The two synergistically solve the problems of unstable gold plating liquid, uneven coverage and the like in replacement gold plating on the nickel layer, and the obtained gold layer is compact and non-porous, and the gold plating liquid is stable. The process is environment-friendly and is suitable for high-reliability gold plating of the microelectronic packaging nickel substrate.

The application discloses a cutting fluid regeneration method, which comprises the following steps: 100, using an electrolytic device to electrolyze used cutting fluid, so that the chloride ions in the used cutting fluid are adsorbed and gathered on an anode and are oxidized into chlorine gas; 200, passing the used cutting fluid through a hydrogen type cation exchange resin, so that hydrogen functional groups of the hydrogen type cation exchange resin and metal cations in the cutting fluid are subjected to a displacement reaction. The cutting fluid regeneration method can significantly reduce the chloride ion content and the conductivity of the cutting fluid through cooperation of electrolysis and ion exchange, the chloride ion content in the cutting fluid can be reduced by 50-60%, and the same level as that of newly prepared cutting fluid is reached, in addition, the conductivity can be significantly reduced, and the rust resistance of the cutting fluid is improved.

The application provides a preparation method of 1,4-bis(chlorodifluoromethyl)benzene, which comprises the following steps: (1) performing a chlorination reaction on terephthaldehyde, a chlorination reagent and a catalyst to obtain 1,4-bis(dichloromethyl)benzene; (2) performing a fluorine-chlorine displacement reaction on the 1,4-bis(dichloromethyl)benzene obtained in the step (1) and a fluorination reagent to obtain 1,4-bis(difluoromethyl)benzene; (3) performing a reaction on the 1,4-bis(difluoromethyl)benzene obtained in the step (2) and an electrophilic chlorination reagent to obtain the 1,4-bis(chlorodifluoromethyl)benzene. The preparation method has the advantages of simple operation, low toxicity of raw materials, high yield and high purity, solves the problems of difficult scale production, low yield and high toxicity and high cost of raw materials in the prior art, and has great industrial value.

The invention discloses a quantitative characterization method for a mutual diffusion coefficient after a replacement reaction of refractory metal salt and matrix metal. The quantitative characterization method comprises the following steps: (1) preparing a diffusion couple, wherein the prepared diffusion couple structurally comprises the refractory metal salt, the matrix metal and a heat-resistant cladding covering the refractory metal salt and the matrix metal; (2) melting diffusion: heating the diffusion couple prepared in the step (1) to a temperature T, carrying out heat preservation, rapidly cooling after heat preservation is finished, and removing a heat-resistant cladding of the diffusion couple to obtain a diffused alloy material; (3) drawing a'concentration-distance 'curve: surveying and mapping the'concentration-distance' curve of the refractory metal in the matrix metal, wherein the concentration is the mass or volume concentration of the refractory metal at the measurement point; the distance is the distance between the measuring point and the bottommost point of the sample; and (4) calculating the mutual diffusion coefficient through a Boltzmann-Matano method. The method has universality, and is beneficial to standardization of research on dissolution and diffusion behaviors of the refractory metal in the matrix metal melt.

The invention provides chiral porous alloy nanoparticles and a preparation method thereof based on an electric replacement reaction. The preparation method comprises the following steps: preparing CNPs which is composed of Cu or Ag and has inherent structure chirality as a sacrificial template by adopting a glancing angle deposition method; and the sacrificial template is placed in an electrolyte containing ions of the metal A to be stirred, an electric replacement reaction is conducted for 1 h or above, and the Cu < 1-x > Ax or Ag < 1-x > Ax chiral porous alloy nanoparticles are obtained. According to the technical scheme, transferring of chirality from a sacrifice template to newly-generated nano-particles is achieved, a new way is provided for preparation of chiral nano-materials, the synthesis method and the application range of the chiral materials are expanded, and the obtained binary alloy nano-particles not only have a porous structure with an enhanced specific surface area, but also have a good application prospect. Moreover, the compound has unique chiral optical activity, and has potential application value in the fields of asymmetric catalysis, enantiomer distinguishing, enantiomer separation, biological detection, biological imaging and the like.

Disclosed in the present invention is a preparation method, comprising the following steps: S1. preparing a salt solution of metal A ions and a solution containing elemental metal B particles, the reducing ability of metal B being greater than the reducing ability of metal A; and S2. simultaneously introducing the salt solution of metal A ions and the solution containing elemental metal B particles into a reaction vessel, while synchronously applying a negative pressure to the reaction vessel, so that the salt solution of metal A ions and the solution containing elemental metal B particles both form a turbulent flow state within the reaction vessel, and performing a displacement reaction, such that surface atoms of the elemental metal B particles are replaced by elemental nanoscale metal A, thereby forming a multiphase composite core-shell material, so as to obtain a metallization slurry for a package substrate. The preparation method for a metallization slurry for a package substrate proposed by the present invention is beneficial for simplifying a preparation process, improving production efficiency, and facilitating industrial-scale production, while ensuring the uniformity of the obtained multiphase composite core-shell material, thereby ensuring the stability of the performance of the metallization slurry.

The invention relates to the technical field of pharmaceutical chemicals, in particular to a preparation process of hydrocortisone acetate. The preparation process comprises the following steps: carbonyl protection reaction: sequentially adding ethylene glycol, triethyl orthoformate and a compound 1 into a reaction flask, then adding p-toluenesulfonic acid, adding water for crystallization, filtering and drying to obtain a compound 2; a reduction hydrolysis reaction; and a replacement reaction: adding the compound 3 into the reaction solvent, adding potassium acetate, carrying out a heating reaction, after the reaction is completed, cooling, adding water for crystallization, filtering to obtain a crude product of hydrocortisone acetate, dissolving with dichloromethane and water for desalting, washing with water for layering, concentrating to be dry, crystallizing with an alcohol solvent, and discharging to obtain a refined product of hydrocortisone acetate. According to the present invention, the method has characteristics of simple and convenient operation, high product yield, and high purity, and the method of cooling after the reaction, adding water, precipitating, filtering, removing most of the impurities, dissolving to remove the salt, and carrying out alcohol refining and discharging is provided, such that the method has characteristics of simple and convenient operation, and the obtained product has characteristics of high yield and high purity.

The invention relates to the technical field of preparation of patterned flexible conductive films, in particular to a roll-to-roll preparation method and device of a patterned flexible conductive film. A flexible base material passes through the unwinding module, is activated / cleaned and then enters the light projection patterning unit to obtain a metallized pattern, then chemical plating or replacement reaction is carried out through the metal deposition module to further enhance the conductivity, and finally a prepared sample is collected by the winding module. According to the invention, the roll-to-roll process, the digital light processing technology and the copper plating or replacement reaction process are combined for the first time, and efficient and continuous preparation of the patterned flexible conductive film is realized.

Dense ceramic-metal composites and components and methods of manufacturing. A method of manufacturing a ceramic-metal composite includes forming a metal containing component into preform having a desired shape and dimensions with pores therein, infiltrating the pores of the preform with a multi-element liquid reactant, and reacting the metal containing component with the multi-element liquid reactant in a displacement reaction at an elevated temperature to form a less porous ceramic-metal composite.

The invention belongs to the technical field of preparation of anhydrous aluminum trichloride, and particularly relates to a method and device for preparing anhydrous aluminum trichloride based on a low-temperature indirect chlorination method, and the method comprises the following steps: introducing chlorine gas into a molten medium material Me at 185-650 DEG C, so that the molten medium material Me and chlorine gas are subjected to chlorination reaction to generate chloride, then, AlCl3 is generated through a replacement reaction between the solid Al and chloride, aluminum chloride generated through the reaction is sublimated and enters a trap, and an anhydrous aluminum trichloride finished product is obtained after trapping; wherein the melting point of the medium material Me is 185-650 DEG C, the medium material Me can react with chlorine to generate chloride, and the chloride of the medium material Me can be subjected to replacement reaction with aluminum to generate metal or alloy of AlCl3; according to the method and the device for preparing the anhydrous aluminum trichloride based on the low-temperature indirect chlorination process, the aim of preparing the high-purity anhydrous aluminum trichloride with low cost, low energy consumption, low investment and high yield can be achieved.

The invention provides micron-sized spherical silver-coated copper powder and a preparation method thereof, and belongs to the technical field of metal powder.The preparation method comprises the following steps that copper powder is pretreated, and pretreated copper powder is obtained; under the condition of constant temperature, a part of the silver complexing solution is dropwise added into the copper powder mixed solution to obtain a reaction solution, and then the remaining silver complexing solution and the reduction solution are dropwise added into the reaction solution at the same time; and after the reaction is finished, carrying out solid-liquid separation, washing and drying to obtain the micron-sized spherical silver-coated copper powder. According to the invention, a replacement and chemical reduction method silver plating process is realized through a continuous feeding method. The method comprises the following steps: adding a small amount of silver complexing solution to perform replacement reaction with copper powder to generate silver nanoparticles on the surface of the copper powder; and then the reducing solution and the silver complexing solution are added into the copper powder at the same time, generated silver particles can be evenly deposited along the silver nanoparticles on the surface of the copper powder under the action of the reducing agent, and the utilization rate of silver ions is high.

The invention provides a Cu-OCTA-coated NF catalyst as well as a preparation method and application thereof, belongs to the technical field of electro-catalysis and clean energy, and is used for solving the technical problems of poor structural controllability, insufficient stability and limited catalytic activity of a copper-based catalyst in a urea oxidation reaction. The preparation method of the Cu-OCTA-coated NF catalyst comprises the following steps: (1) soaking foamed nickel in an acid solution, and then taking out and drying for later use; (2) dissolving copper salt to prepare a precursor solution; and (3) dipping the foamed nickel obtained in the step (1) into a precursor solution, and carrying out replacement reaction. The method is easy and convenient to operate and mild in condition, the obtained material has high dispersity and an exposed high-activity crystal face, meanwhile, strong interface coupling is formed between metal Cu and substrate nickel, and the charge transfer rate and the reaction stability are remarkably improved. When being used for urea oxidation reaction, the composite material shows excellent electro-catalytic performance, has a good application prospect, and is suitable for the fields of green hydrogen energy preparation, urine-containing wastewater treatment and the like.

This invention belongs to the field of oil extraction and relates to a method for characterizing the breakthrough point of bio-nano-based unblocking and injection enhancement. The method includes: measuring the porosity and permeability of the core sample; injecting a bio-nano-based unblocking agent using KCl or NH4Cl solution for displacement, and analyzing the breakthrough point of the bio-nano-based unblocking agent; flushing the pipeline with simulated formation water, shutting off the displacement device, injecting the bio-nano-based injection enhancement agent, and measuring the porosity and permeability of the core sample again; dividing the unblocking process into a linear flow model into contaminated and uncontaminated zones, determining the contaminated skin coefficient based on Darcy's formula and the definition of the skin factor, and determining the fluid viscosity in the contaminated zone and the fluid viscosity in the uncontaminated zone at any given time; deriving the relationship between pressure difference and time during the core displacement reaction process based on the fitting relationship between pressure difference and the rising and falling phases of the injected PV number, and the relationship between the unblocking agent propulsion time and the injected PV number; and determining the relationship between fluid viscosity and the unblocking agent injection time based on the relationship between pressure difference and time during the core displacement reaction process.

This invention provides an apparatus for recovering copper from waste ionic liquids, comprising: a displacement reactor and a sedimentation tank. The displacement reactor includes, from bottom to top, a water and gas distribution zone, a displacement reaction zone, a three-phase separation zone, and an effluent zone, all connected sequentially. The effluent zone surrounds the upper part of the three-phase separation zone. The water and gas distribution zone is provided with a reactor inlet and a reactor gas inlet. The displacement reaction zone includes, from bottom to top, a support layer and an aluminum particle layer. The three-phase separation zone is provided with a three-phase separator, the aqueous phase outlet of which is connected to the effluent zone. The effluent zone is connected to the sedimentation tank, and the sedimentation tank is provided with a sedimentation tank outlet, a circulating water outlet, and a sedimentation outlet at its upper, middle, and bottom parts, respectively. This invention also provides a method for recovering copper from waste ionic liquids. This apparatus is space-saving, has a high copper displacement recovery rate, strong shock resistance, and can effectively recover copper resources and reduce wastewater treatment costs, showing broad application prospects.

The present application belongs to the technical field of silver-coated copper powder, and particularly relates to a preparation method of silver-coated copper powder, comprising the following steps: (1) preparing silver-coated copper powder seeds by using displacement reaction; (2) preparing silver-coated copper powder by using liquid phase oxidation-reduction reaction. The present application has the beneficial effect that a layer of silver is coated on the surface of copper powder by displacement method first, then the silver-coated copper powder obtained by displacement method is used as seeds to perform liquid phase oxidation-reduction reaction of silver ions, and a dense silver layer is slowly grown on the surface of the silver-coated copper powder seeds, so that the preparation method of the silver-coated copper powder has low production cost and simple process, can control the thickness of the silver layer on the surface of the copper powder, and the coated silver layer is dense and smooth, the silver layer is firm and not easy to fall off, and the prepared silver-coated copper powder has excellent conductivity and thermal stability.

The application relates to the field of electrochemistry and discloses a preparation method of a low-overpotential anode and application of the low-overpotential anode in electrocatalytic water splitting and oxygen evolution. The preparation method comprises the following steps: 1) loading molybdenum metal on foamed nickel after acid pickling pretreatment; 2) immersing the foamed nickel molybdenum in a soaking solution containing uranium and / or thorium metal salt and iron salt to carry out a displacement reaction, and taking out and drying; and 3) oxygen calcining the product obtained in the step 2) at 100-200 DEG C for 0.5-1.5 h to obtain the low-overpotential anode. The anode prepared by the application is foamed nickel as a carrier, after loading molybdenum metal, uranium and / or thorium and iron elements are deposited on the carrier through a displacement reaction between elements, and finally the interaction between the deposited elements and the carrier is strengthened through calcining, and the metal elements in the carrier form corresponding oxides. The anode is applied to electrocatalytic splitting of alkaline water or alkaline seawater and oxygen evolution, and has reduced overpotential and strong stability.

The application provides a gold nanoflower SERS substrate and a preparation method and application thereof, the preparation method removes the surface oxide film of an aluminum foil by using an etching solution, and realizes in-situ growth of the gold nanoflower on the surface of the aluminum foil by combining with a spontaneous displacement reaction of chloroauric acid. The preparation process is simple to operate, does not need an external power supply, raw materials are easy to obtain, and the cost is low; in addition, the substrate can be prepared in a large area, and the problems of a traditional SERS substrate, such as complicated process, high cost and difficulty in large-scale production, are effectively solved. The prepared substrate has a multi-stage rough microstructure, a high-density and uniformly-distributed SERS hot spot is formed on the surface, and the Raman signal enhancement effect is excellent. The substrate does not need sample labeling and substrate surface modification, and can quickly complete Raman spectrum detection of pseudomonas aeruginosa; in addition, the five types of carbapenemases can be accurately identified, and the detection process is efficient, and the result is stable and reliable.