536 results about "Oxalate" patented technology

The invention discloses high-purity hafnium oxide and a preparation method thereof, and relates to the technical field of hydrometallurgy. The preparation method of the high-purity hafnium oxide comprises the following steps: crushing a hafnium oxide raw material to obtain hafnium oxide powder; sequentially carrying out alkali fusion, water immersion and filtration treatment on the hafnium oxide powder to obtain a hafnium hydroxide filter cake; dissolving the hafnium hydroxide filter cake in a sulfuric acid solution to obtain a hafnium sulfate solution; adding sodium sulfate into the hafnium sulfate solution to obtain hafnium-containing double salt; dissolving the hafnium-containing double salt in a sulfuric acid solution, heating, evaporating, cooling and crystallizing to obtain hafnium sulfate crystals; dissolving the hafnium sulfate crystal in concentrated hydrochloric acid to obtain a hafnium oxychloride solution, heating, evaporating, cooling and crystallizing to obtain a hafnium oxychloride crystal; dissolving the hafnium oxychloride crystal in pure water, adding an oxalic acid solution, and precipitating to obtain hafnium oxalate; and calcining hafnium oxalate to obtain high-purity hafnium oxide. The preparation method of the high-purity hafnium oxide is green, environment-friendly, simple and efficient.

The invention provides a lithium oxalate lithium supplement agent, a preparation method thereof and a lithium battery, and belongs to the technical field of lithium batteries. The lithium oxalate lithium supplement agent comprises lithium oxalate, a conductive agent and a catalyst, wherein the catalyst is nonmetal doped manganese dioxide. The lithium oxalate, the non-metal doped manganese dioxide and the conductive agent are mixed in water, and then spray drying is performed to obtain the lithium oxalate lithium supplement agent. The nonmetal doped manganese dioxide catalyst has a nano flower cluster shape and can be in close contact with lithium oxalate to form homogeneous microspheres, efficient solid-solid catalysis is promoted, the decomposition voltage of a lithium oxalate lithium supplement agent can be reduced to 4.25 V from 4.8 V, and meanwhile good integrity and wettability are kept.

A non-aqueous electrolyte for a lithium-ion cell includes a base electrolyte consisting of lithium hexafluorophosphate or lithium bis(fluorosulfonyl)imide or a combination thereof in methyl propionate; about 2 to about 15 parts by weight, preferably about 6 to about 15 parts by weight of vinylene carbonate; and about 0.5 to about 5 parts by weight, preferably about 2 to about 5 parts by weight of an additive comprising lithium difluorophosphate, lithium difluoro(oxalate)borate, lithium bis(oxalate)borate, or a combination thereof, wherein the content of the vinylene carbonate and the additive are each based on a total weight of the base electrolyte, the vinylene carbonate, and the additives.

The invention provides a preparation method of a lithium manganese iron phosphate material, and relates to the technical field of positive electrode materials. The preparation method of the lithium manganese iron phosphate material comprises the following steps: mixing a first raw material component consisting of ferromanganese oxalate, a first lithium source, a first phosphorus source, a first carbon source and a first doping agent, adding deionized water, grinding, and then carrying out spray drying to obtain a precursor A; mixing a second raw material component consisting of carbon-coated ferromanganese oxalate, a second lithium source, a second phosphorus source, a second carbon source and a second doping agent, adding deionized water, grinding, and performing spray drying to obtain a precursor B; and uniformly mixing the precursor A and the precursor B, sintering in an inert atmosphere, and crushing to obtain the lithium manganese iron phosphate material. According to the lithium manganese iron phosphate material, on the premise of ensuring high specific capacity, relatively high compaction density and relatively high rate capability are realized at the same time.

The invention provides a lithium supplement agent. The lithium supplement agent comprises lithium oxalate particles, conductive carbon particles and additive particles, the conductive carbon particles comprise at least one of carbon black, carbon nanotubes, graphene and ketjen black; the additive particles comprise at least one of MnO2, NiO, Co3O4, TiO2, Fe3O4, MnC, TiC, Mo2C and MoO3, and the additive particles comprise at least one of MnO2, NiO, Co3O4, TiO2, Fe3O4, MnC, TiC, Mo2C and MoO3. According to the lithium supplementing agent disclosed by the invention, by limiting the structure and components of the lithium oxalate lithium supplementing agent, the carbon material is respectively coated in the lithium oxalate and the additive to form a good conductive network, and finally a composite material of the lithium oxalate, the carbon material and the additive is formed, so that the decomposition voltage can be sufficiently reduced; the lithium supplement effect of the lithium oxalate can be exerted to the maximum extent.

The invention relates to the technical field of adsorbents, and discloses a moisture-resistant carbon dioxide trapping adsorbent, and a preparation method thereof comprises the following steps: S1, blending oxalic acid or oxalate or squaric acid and a zinc source in a reaction system to obtain a mixture I; s2, dissolving an organic ligand in a solvent to obtain a mixture II; s3, the mixture I and the mixture II are subjected to a reaction and post-treatment, and the adsorbent is obtained. According to the prepared adsorbent, a pore structure is formed in situ in the preparation process, the specific surface area is large, the porosity is large, the structure can be kept stable in the presence of water and steam, and the adsorbent is stable to wet acid gas.

Provided are a preparation method for lithium iron phosphate, a positive electrode active material, a positive electrode plate, a battery, and a power-consuming device. The preparation method for lithium iron phosphate comprises: dissolving a first iron source, a second iron source, a lithium source and a phosphorus source in a solvent to obtain a mixed slurry; and sintering the mixed slurry to obtain lithium iron phosphate, wherein the first iron source comprises at least one of iron oxide or first iron phosphate, and the second iron source comprises at least one of second iron phosphate or ferrous oxalate, the first iron phosphate has an iron to phosphorus ratio of 0.97-0.985, and the second iron phosphate has an iron to phosphorus ratio of 0.93-0.96. The primary particles of lithium iron phosphate, which have different particle sizes, can be mixed and matched, thus improving the compact density of lithium iron phosphate and the energy density of the battery.

The invention discloses an in-situ carbon-coated positive electrode lithium supplement agent, a preparation method and application, and belongs to the field of lithium ion batteries. The preparation method of the positive electrode lithium supplement agent comprises the following steps: S1, mixing lithium oxalate with a carbon source, and grinding to prepare mixed powder; s2, the mixed powder is placed in a reaction kettle, sealing and vacuumizing are conducted, carbon dioxide gas is introduced, and the pressure is controlled to be 10-20 Mpa; keeping the temperature at 30-60 DEG C and reacting for 10-24 hours; and S3, exhausting, washing with alcohol, centrifuging and drying to obtain the in-situ carbon-coated positive electrode lithium supplement agent. The invention provides a preparation method of an in-situ carbon-coated positive electrode lithium supplement agent, which comprises the following steps: placing lithium oxalate and a carbon source in a supercritical carbon dioxide fluid, stirring and dissolving, controlling the reaction temperature and pressure to promote the polymerization reaction of carbon source micromolecules, and depositing a layer of compact and uniform carbon material on the surface of lithium oxalate particles in situ, thereby obtaining the in-situ carbon-coated positive electrode lithium supplement agent. The conductivity and the ion mobility of the material are improved, so that the electrochemical activity of lithium oxalate is improved.

The invention discloses a preparation method of CoWO (cobalt tungsten oxide) modified NbOp-n heterojunction NbO5 / CoWO photocatalyst powder. The preparation method comprises the following steps: dissolving cobalt salt and tungsten salt in deionized water, stirring and mixing, carrying out hydrothermal reaction in an autoclave, washing and drying to obtain CoWO powder; the preparation method comprises the following steps: dissolving niobium oxalate and ammonium carbonate in deionized water, adding CoWO powder, carrying out a hydrothermal reaction in an autoclave, and carrying out washing and drying treatment to prepare NbO / CoWO photocatalyst powder. According to the method, the hydrothermal reaction temperature is regulated and controlled, and the mass ratio of raw materials is optimized, so that the catalyst forms a p-n heterojunction structure of NbOmicron flower loaded CoWOnano particles. The prepared catalyst has high norfloxacin wastewater degradation efficiency under visible light irradiation, has the advantages of simple preparation process, low reagent cost, high catalytic activity and good structural stability, and can be effectively applied to purification treatment of antibiotic polluted water.

The invention provides a secondary battery and an electronic device, the secondary battery comprises a positive pole piece and a negative pole piece, the positive pole piece comprises a positive pole material layer, the positive pole material layer comprises a positive pole active material, and the positive pole active material comprises a manganese-containing material; the manganese-containing material comprises at least one of lithium manganate, lithium iron manganese phosphate, a lithium-rich manganese-based material or nickel cobalt lithium manganate. The negative pole piece comprises a first additive, the first additive comprises at least one of carboxylate, sulfonate or a metal organic framework compound, carboxylate comprises at least one of lithium oxalate, sodium citrate, sodium maleate or sodium tartrate, sulfonate comprises at least one of sodium benzenesulfonate, sodium dodecyl benzene sulfonate or sodium methanesulfonate, and metal organic framework compound comprises at least one of lithium oxalate, sodium citrate, sodium maleate or sodium tartrate. The metal organic framework compound is prepared from at least one of Zn (C4H7N2) 2, C48H28O32Zr6 or C14H16N2O8Mg2. The invention further discloses a preparation method of the metal organic framework compound. The secondary battery meets the characteristics, and the cycle performance of the secondary battery can be improved.

The present invention provides a soil conditioner and a preparation method and application thereof, belonging to the technical field of soil conditioners. The soil conditioner of the present invention comprises the following raw materials in parts by weight: 70 to 90 parts of modified pig manure biochar, 8 to 15 parts of polyaspartic acid, 5 to 10 parts of potassium titanium oxalate, 1 to 3 parts of ammonium molybdate, 40 to 60 parts of calcium silicate, and 20 to 30 parts of lime. The present invention uses a mixed modifier to modify pig manure biochar, which can greatly reduce the content of cadmium and arsenic in edible parts. In addition, the raw materials in the soil conditioner cooperate with each other to reduce the content of heavy metals in the edible parts to the greatest extent.

The invention relates to the technical field of analytical chemistry, and particularly discloses a double-signal ratio type up-conversion luminescent probe, a preparation method thereof and application of the double-signal ratio type up-conversion luminescent probe in oxalate detection, and the double-signal ratio type up-conversion luminescent probe comprises up-conversion nanoparticles UCNPs and an iron-chromium cyanine R compound. The upconversion nanoparticles UCNPs are combined with the iron-chromium cyanine R compound to construct a double-emission-peak regulation and control system, when the system is used for oxalate detection, oxalate can be chelated with Fe < 3 + > in the iron-chromium cyanine R compound, blue shift of an induced absorption spectrum is achieved, green and red emission peaks of the UCNPs are synchronously regulated and controlled, and the detection sensitivity is high. The fluorescent-colorimetric bimodal high-sensitivity detection of the oxalate is realized.

The invention discloses a method for preparing battery-grade iron phosphate by utilizing phosphated residues. The method comprises the following steps: pre-treating the phosphated residues; alkaline leaching is conducted on the phosphated residues, wherein the phosphated residues are placed in a sodium hydroxide solution with the mass fraction being 30%; decoloring is performed; acid treatment: adding hydrochloric acid into the filtrate to adjust the pH value, adding a solution composed of urotropin, thiourea, tetraethylammonium oxalate, hydrogen peroxide and polydodecyl acrylamide acrylic acid, and stirring; extracting: adding an extracting agent and an organic solution, and extracting under a stirring condition; precipitating: heating the raffinate, adding hexadecyl trimethyl ammonium chloride, and stirring; then adding a ferric nitrate solution to carry out precipitation reaction; the method for preparing the battery material ferric phosphate product by taking phosphated residue solid wastes generated in the steel metal product process as raw materials through the steps of pretreatment, alkaline leaching, decoloration, acid treatment, extraction, precipitation reaction and the like has the advantages of simple process, high product quality, low production cost, high recovery efficiency of phosphorus resources in the waste residues and the like.

The invention relates to a preparation method and system of high-molecular-weight polyethylene glycol oxalate, and the preparation method comprises the following steps: adding oxalic acid diester, ethylene glycol and a first catalyst, and carrying out transesterification to obtain an ester; adding a second catalyst, and carrying out a pre-polycondensation reaction on the esterified product to obtain a glycol oxalate oligomer; polymerizing the ethylene glycol oxalate oligomer, and carrying out final polymerization reaction to obtain polyethylene glycol oxalate; the molar ratio of the oxalic acid diester to the ethylene glycol is (1.05-1.3): 1. Compared with the prior art, by controlling excessive oxalic acid diester in the raw material ratio, namely controlling the molar ratio of oxalic acid diester to ethylene glycol to be greater than 1, the reaction rate of ethylene glycol is improved, self-polycondensation of ethylene glycol is prevented, further increase of molecular weight is facilitated, and meanwhile, the thermal performance of the product is improved.

The invention relates to an aminoguanidine oxalate second-order nonlinear optical crystal material and preparation and application thereof, the chemical formula of the crystal material is (CN4H7) + (C2O4H)-, the crystal material belongs to a monoclinic system, the space group is P21, the cell parameters are # imgabs0 # and # imgabs1 #, alpha is equal to 90 degrees, beta is equal to 95-100 degrees, gamma is equal to 90 degrees, and Z is equal to 2. The powder frequency-doubled effect of the nonlinear optical crystal (CN4H7) + (C2O4H)-disclosed by the invention under the irradiation of 1064nm laser is about 1.0 time of that of a KH2PO4 (KDP) crystal, and phase matching can be realized. In addition, the crystal material has the advantages of being short in ultraviolet absorption cut-off edge (290 nm), easy to grow and the like, and has important application value in the photoelectric conversion fields of stereolithography, solid-state lasers, optical communication, optical parametric amplifiers, optical parametric oscillators, laser frequency converters and the like.

The invention relates to the technical field of iron phosphate preparation, in particular to a preparation method of low-impurity iron phosphate with a high iron-phosphorus ratio, which at least comprises the following steps: preparing an iron source solution and a phosphorus source solution; mixing an oxidizing agent and a phosphorus source solution as a phosphorus source mixed solution; adding the phosphorus source mixed solution into the iron source solution, and controlling the molar ratio of iron to phosphorus to be 1: (1.1-1.3) to prepare slurry; dividing the slurry into two parts, respectively adding an impurity removal agent, and then carrying out segmented aging at 90 DEG C to prepare crystallized slurry; and filtering, washing, drying and calcining the crystallized slurry to obtain a target product iron phosphate finished product. The impurity removal agent is selected from one or more of ferrous sulfate, ferrous chloride, ferrous nitrate and ferrous oxalate. Seed crystals are formed through segmented aging crystal transformation to promote crystal growth, and autonomous grain size distribution is achieved; an impurity removing agent is added in the aging stage, impurities are reduced by using the same ion effect, the iron-phosphorus ratio is increased, and the compaction density and the electrical property of the prepared lithium iron phosphate are remarkably improved.

The invention relates to the technical field of oxamide synthesis, and provides a microchannel reactor and a method for synthesizing oxamide by using the microchannel reactor. The micro-channel reactor sequentially comprises a feeding area, a reaction area and a discharging area along the flowing direction of reaction materials; the feeding area comprises a main feeding hole; the reaction area comprises an 8-shaped reaction flow channel, and a plurality of segmented feeding holes are formed in the reaction flow channel; the discharging area comprises a discharging opening. According to the micro-channel reactor provided by the invention, full mixing of raw materials can be realized through segmented feeding, the reaction temperature is effectively controlled, and the local temperature is prevented from being too high; when the microchannel reactor provided by the invention is used for synthesizing oxamide, the process is simple, the reaction conditions are mild, efficient conversion of oxalate can be realized in a short time, continuous production of oxamide is realized, and the microchannel reactor is suitable for industrial production.

The invention discloses a preparation method of an efficient lithium oxalate lithium supplement agent, and relates to the field of preparation of lithium ion battery positive electrode lithium supplement agents, and the preparation method comprises the following steps: S1, adding CNTs into an organic solvent for ultrasonic cleaning, then cleaning the CNTs with pure water, and finally drying; s2, concentrated sulfuric acid and concentrated nitric acid are prepared into a mixed acid solution, CNTs are added, and ultrasonic reflux is carried out; then cleaning the CNTs until the washing water is neutral, and finally drying to obtain oxidized CNTs; s3, the oxidized CNTs and (NH4) 2MoS4 are dissolved in water, then the precursor solution is atomized into micron-sized liquid drops, the micron-sized liquid drops are cracked in an inert atmosphere, and a three-dimensional composite material MoSx-CNTs is prepared; and S4, dissolving the three-dimensional composite material MoSx-CNTs and lithium oxalate in an ethanol solution, and drying in an inert atmosphere in a high-pressure spray dryer to obtain the lithium oxalate-coated MoSx-CNTs composite material. According to the invention, low-voltage and efficient decomposition of lithium oxalate is realized by regulating and controlling metal nodes and pore structures of MOFs, and meanwhile, the damage of residues to the microstructure of the battery is avoided.

The invention discloses a method for preparing hafnium oxide from hafnium oxalate feed liquid through an oxidation precipitation method, and belongs to the technical field of hydrometallurgy. The specific method comprises the following steps: adding an oxidizing agent into hafnium oxalate feed liquid to destroy oxalate ions in hafnium oxalate so as to enable hafnium to form hydroxide precipitates; and separating the generated white precipitate, and roasting at high temperature to obtain hafnium oxide. The strong oxidant used in the method is low in cost, high in precipitation efficiency, green, environmentally friendly, free of large pollution to equipment and the environment and wide in application range. The method is simple in process, does not involve a complex process flow, does not need precise equipment, avoids a large amount of alkali liquor required by metal ion precipitation, is simpler in process flow, higher in efficiency and lower in cost, avoids the generation of a large amount of wastewater, and is very environment-friendly. And meanwhile, the process is wide in application range and suitable for various oxalic acid metal feed liquid.

The invention relates to a preparation method of a lithium difluoro bis (oxalate) phosphate concentrated solution, and belongs to the technical field of lithium battery electrolyte additives. Adding lithium oxalate into a solvent, stirring and dissolving to obtain a lithium oxalate solution; the method comprises the following steps: adding a modified fluorine ion chelating agent into a lithium oxalate solution, stirring, filtering, putting into a reactor, and slowly introducing phosphorus pentafluoride gas; after the introduction is finished, heating and stirring for reaction; after the reaction is finished, filtering reaction liquid to remove unreacted solid impurities, so as to obtain a lithium difluoro bis (oxalate) phosphate concentrated solution; the modified fluorine ion chelating agent is prepared from D301 ion exchange resin, dichloroethane, propylene-1-base boronic acid pinacol ester, mercaptoethyl guanidine dihydro bromide and sodium tert-butoxide. The lithium difluoro bis (oxalate) phosphate prepared by the method is high in purity and high in yield, and meets the use requirements of lithium ion battery electrolyte on lithium salt.

The invention relates to an SNCR (selective non-catalytic reduction) denitration synergist, a denitration composition and a denitration method. The SNCR denitration synergist comprises an organic solvent and alkali metal carboxylate, the mass ratio of the organic solvent to the alkali metal carboxylate is (0.1-1): 1, and the organic solvent is selected from one or more of alcohol, ketone, ether and aldehyde. The alkali metal carboxylate is selected from at least one of formate, acetate, citrate, oxalate, ascorbate and tartrate of alkali metal. According to the SNCR denitration synergist, the denitration efficiency can be remarkably improved in a medium and low temperature interval (600-800 DEG C), ammonia escape is reduced, and secondary pollution is reduced.

The invention belongs to the technical field of synthetic ester, and particularly relates to a preparation method of fatty acid pentaerythritol ester base oil, which comprises the following steps: carrying out esterification reaction on pentaerythritol and fatty acid in the presence of a catalyst and a color retention agent, and carrying out post-treatment to obtain the fatty acid pentaerythritol ester base oil, the catalyst comprises at least one of stannous octoate, stannous oxalate, stannous oxide, tetrabutyl titanate, isopropyl titanate and sodium hydrogen sulfate; the color retention agent comprises at least one of sodium hypophosphite, hypophosphorous acid, activated carbon and sodium sulfite. The color retention agent sodium hypophosphite is matched with the specific catalyst such as stannous oxalate, so that the petroleum color number of the produced fatty acid pentaerythritol ester base oil is smaller, and meanwhile, the esterification reaction time is shorter.

The invention relates to the technical field of new energy, in particular to a negative pole piece for a battery without a negative active material, a preparation method and application. The preparation method comprises the following steps: under the protection of inert gas, dissolving a fluoroborate-containing oxalate material in an in-situ polymerization monomer to form a solution; and then uniformly coating the surface of a metal current collector and carrying out heating in-situ polymerization to obtain the negative pole piece for the battery without the negative active material. The negative pole piece is applied to the battery, so that lithium (sodium) can be prevented from directly contacting with other components of the battery to generate side reaction, and high-temperature gas expansion of the battery is inhibited; meanwhile, the negative pole piece without the negative active material has a certain lithium (sodium) supplementing effect, can effectively induce uniform deposition of lithium (sodium) and inhibit generation of dendrites and dead lithium (sodium), and the first efficiency and the cycle capacity retention ratio of the battery are greatly improved.

The invention provides a strong smoke suppression flame retardant PVC wood-plastic material and a preparation method thereof, and relates to the technical field of wood-plastic composites, the PVC wood-plastic material comprises the following components by weight: 70-100 parts of PVC resin, 20-30 parts of wood flour, 20-30 parts of calcium carbonate, 15-20 parts of a smoke suppression material, 10-15 parts of a flame retardant, 1-6 parts of a foaming agent, 5-10 parts of a stabilizer, 1-2 parts of a coupling agent, 5-10 parts of a processing aid, and 1-4 parts of a lubricant; wherein the smoke suppression material comprises a molybdenum compound, ferrocene and oxalate dihydrate in a mass ratio of 1: (0.5-1.5): (5-10); the preparation method comprises the steps of wood powder end-capping modification and PVC wood-plastic material preparation. The PVC wood-plastic material prepared by the invention has excellent flame retardant property and smoke suppression property.

The invention discloses a lithium supplement agent, a preparation method thereof and a battery, and belongs to the technical field of battery materials. The lithium supplement agent comprises a porous spongy substrate and lithium salt filled in the surface and pores of the porous spongy substrate, wherein the porous spongy substrate contains a thickening agent, conductive carbon black and a modified catalyst. The modified catalyst is obtained by sintering at least three of cobalt nitrate, nickel nitrate, calcium nitrate and titanium dioxide with graphene or carbon nanotubes; the lithium salt comprises at least two of lithium hydroxide, lithium carbonate and lithium oxalate. The lithium supplement agent is stable in structure, the first sufficient solution voltage can be as low as 4.0 V, and the preparation method is simple and suitable for large-scale production.

The invention discloses a system and method for directly preparing battery-grade ferrous oxalate based on dimethyl oxalate, and the system comprises a rectifying tower which is used for carrying out hydrolysis reaction on dimethyl oxalate and discharging a hydrolysis solution through a liquid phase outlet; the decolorizing kettle is used for decolorizing the hydrolysis solution; the precipitation reaction kettle is used for carrying out mixed reaction and aging on the hydrolysis solution and ferric salt; the product recovery unit is connected with the precipitation reaction kettle and is used for separating and recovering reaction products to obtain battery-grade ferrous oxalate. According to the method, the hydrolysis solution of the dimethyl oxalate and the iron salt are directly mixed for precipitation reaction to prepare the battery-grade ferrous oxalate, high-energy-consumption steps such as crystallization and drying in the oxalic acid solid production process are reduced, meanwhile, the step of dissolving the solid oxalic acid is not needed, the heating energy consumption needed in the dissolving process is reduced, and the production efficiency is improved. The production energy consumption is greatly reduced, the production equipment and process are reduced, the cost is reduced, and the product yield is favorably improved.

The invention discloses a preparation method of an ethane oxidative dehydrogenation supported catalyst. The catalyst is formed by supporting a transition metal oxide on the surface of an M1 catalyst, the preparation method of the M1 catalyst comprises the following steps: dissolving ammonium heptamolybdate tetrahydrate, ammonium metavanadate, telluric acid and a dispersing agent in deionized water to form a mixed solution; and adding an aqueous solution of niobium oxalate into the mixed solution within 15-50 minutes to form a suspension, aging, carrying out hydrothermal crystallization, drying, roasting, and removing the M2 phase to obtain the M1 catalyst. The pore structure and the specific surface area of the molybdenum-vanadium-tellurium-niobium catalyst can be improved by adding a dispersing agent in the preparation process of the M1 catalyst and limiting the time for adding an aqueous solution of niobium oxalate into a mixed solution, and through mutual cooperation of all steps and parameters, the pore structure and the specific surface area of the molybdenum-vanadium-tellurium-niobium catalyst can be improved; and then the transition metal oxide is loaded on the surface of the M1 catalyst for phase interface coupling, and the transition metal oxide and the M1 catalyst cooperate with each other, so that the catalytic performance of the loaded catalyst can be remarkably improved.

The invention discloses a preparation method and application of a high-density iron-nitrogen-carbon monatomic catalyst. The method specifically comprises the following steps: S1, uniformly mixing nitrogen-doped carbon and ferrous oxalate; s2, in an inert atmosphere, carrying out a first pyrolytic reaction at 340-360 DEG C to obtain an intermediate, and meanwhile, carrying out etching on the carbon carrier by using CO2 gas generated by the reaction, so that a plurality of microporous structures are formed on the carbon carrier; s3, the intermediate continues to be subjected to a second pyrolytic reaction in the inert atmosphere at the temperature of 850-950 DEG C, the FeOx nano-particles are converted into Fe-N4 active sites, and a pyrolytic product is obtained; and S4, naturally cooling to room temperature to obtain the high-density iron-nitrogen-carbon monatomic catalyst. Superfine ferric oxide (FeOx) nano-particles are generated through a precursor to serve as intermediates, carbon defects are created through CO2 gas released in the decomposition process of the FeOx nano-particles, and therefore the oxygen reduction reaction performance of the catalyst is remarkably improved, and the catalyst is applied to fuel cells.

The application discloses a radial flow fixed bed catalytic reactor for CO carbonylation coupling to generate oxalate, which comprises a cylindrical container composed of an upper head, a cylindrical barrel and a lower head from top to bottom in sequence, and the cylindrical container is externally provided with a reaction gas feeding port, a reaction gas discharging port, a heat exchange medium inlet, a heat exchange medium outlet, a catalyst feeding port and a catalyst discharging port; a catalytic bed is divided into an adiabatic zone and a heat exchange zone from inside to outside, and the heat exchange zone is provided with multiple groups of concentric circular arranged heat exchange pipes which are arranged in two rows as a group. The radial flow fixed bed catalytic reactor for CO carbonylation coupling to generate oxalate has the characteristics of uniform axial distribution of reaction gas, reasonable bed temperature distribution, high catalyst utilization rate and small reactor pressure drop, and is suitable for the reaction of carbonylation coupling to generate ester and is also suitable for other exothermic gas-solid phase catalytic reactions.

The present invention provides a preparation method of lithium difluorooxalate borate, belonging to the technical field of lithium battery electrolyte additives. The present invention obtains a bis(methylsilyl) oxalate compound by a substitution reaction between a methylchlorosilane compound and oxalic acid, and mixes the bis(methylsilyl) oxalate compound with lithium oxalate, a boron trifluoride complex and an organic solvent to obtain lithium difluorooxalate borate; wherein the bis(methylsilyl) oxalate compound is used as a raw material, has strong reaction activity, generates a stable methylfluorosilane gas byproduct while introducing oxalate into the system, and does not cause chloride ions and free acid residues; in addition, when the raw material is bis(trimethylsilyl) oxalate, even if there is a small amount of raw material residue, it can be used as a new multifunctional electrolyte additive, play a certain synergistic role, and can improve the compatibility between electrolytes. The whole process is simple, the product yield obtained by the reaction is high, the product purity is high, and the separation is easy, which is suitable for industrial production.