34 results about "Cobalt selenide" patented technology

The invention belongs to the technical field of electrocatalyst material preparation, and discloses a long-range disordered localized CoOOH ultrathin nanosheet electrocatalyst as well as a preparation method and application thereof, fluorine-doped cobalt selenide nanobelts prepared by a low-temperature annealing method are used as a base material, and the CoOOH ultrathin nanosheet electrocatalyst is prepared by in-situ reconstruction under an alkaline electrolyzed water anode oxygen evolution reaction condition. In the preparation process of the CoOOH ultrathin nanosheet provided by the invention, lattice cobalt is stabilized in the water electrolysis anode reconstruction process through fluorine ions with strong bonding action with cobalt ions, so that the long-range disordered structure of amorphous CoOOH generated after reconstruction is limited by localization, and the alkaline water electrolysis anode reaction performance is improved. The catalyst has activity and durability obviously superior to those of a commercial ruthenium oxide catalyst in industrial application of anion exchange membrane water electrolysis hydrogen production.

The invention belongs to the technical field of wave-absorbing materials, and particularly relates to a wave-absorbing material and a preparation method thereof, and a polyurethane composite wave-absorbing material and a preparation method thereof. The invention provides a wave-absorbing material. The wave-absorbing material comprises a carbon nano tube and selenide loaded on the carbon nano tube, the selenide comprises nickel selenide and cobalt selenide; a heterojunction structure is arranged between the nickel selenide and the cobalt selenide. According to the invention, a heterostructure is formed among selenide, and the structure can effectively enhance interface polarization of the material and promote an internal energy dissipation mechanism, so that electromagnetic waves are quickly converted into heat to be lost when passing through a heterointerface, and the electromagnetic wave absorption capability of the material can be optimized to a great extent; the wave-absorbing material not only can significantly improve the electromagnetic wave absorption performance, but also can maintain good environmental adaptability.

This invention provides a nitrogen-doped carbon composite cobalt-nickel diselenide nanocubic material, its preparation method, and its application in batteries. The invention involves dispersing cobalt salt, nickel salt, and hexadecyltrimethylammonium bromide in a solvent and mixing to obtain solution A; dispersing an organic ligand in the solvent and mixing to obtain solution B; pouring solution A into solution B and aging at room temperature to obtain a nanocubic precursor; then mixing with selenium powder and calcining under a protective atmosphere to obtain the CoNiSe2 / NC composite material. Compared with existing technologies, the synergistic effect of Co and Ni in this invention provides more active sites for the reaction and improves conductivity, resulting in a significant improvement in sodium-ion battery performance. Furthermore, the synthesis in this invention is performed at room temperature, simplifying the process; the porous structure design greatly improves the battery's cycle stability, extends its lifespan, and increases and stabilizes its capacity.

The invention discloses a production process of diuron, and belongs to the technical field of synthesis of diuron. The preparation method comprises the following specific steps: adding 3, 4-dichlorophenyl isocyanate, toluene and a catalyst into a reaction kettle, mixing, heating to 22-24 DEG C, adding a dimethylamine aqueous solution, heating to 40-50 DEG C, reacting, cooling to room temperature, preserving heat for 0.5-1 hour, centrifuging, washing and drying to obtain diuron, the catalyst is a cobalt selenium oxide loaded by a nitrogen-doped magnetic carbon nanotube, and the cobalt selenium oxide is expressed as Co3O4-SeO2 / N-MCNTs. The catalyst can improve the yield and purity of diuron due to abundant active sites, good chemical stability and effective avoidance of side reactions; the catalyst not only has high catalytic efficiency and mild reaction conditions, but also can be magnetically separated and is easy to recycle, so that the production cost is reduced.

The invention belongs to the technical field of nano materials and electro-catalysis, and relates to a preparation method of a bifunctional nickel cobalt selenide / molybdenum selenide composite nano material. The method is a three-step simple hydrothermal process. The preparation method comprises the following steps: firstly, constructing a rod-like nickel molybdate array precursor on foamed nickel to obtain a NiMoO4 nano array; then, the upper surface of the precursor is coated with a nickel-cobalt layered double hydroxide nanosheet, and a NiMoO4 (at) NiCo-LDH nano material is obtained; and finally, carrying out selenylation to obtain the bifunctional nickel cobalt selenide / molybdenum selenide composite nano material. The prepared bifunctional nickel-cobalt selenide / molybdenum selenide composite nanomaterial is good in structural dispersion, dead volume is avoided, active sites of oxidation-reduction reaction are increased, and by means of good heterogeneous interface effect and multi-metal synergistic effect, the bifunctional nickel-cobalt selenide / molybdenum selenide composite nanomaterial has excellent supercapacitor energy storage and electro-catalytic hydrogen production bifunctional characteristics at the same time.

The application discloses a preparation method of amorphous MOF derived ZIF and application thereof, and the preparation method comprises the following steps: preparing zinc nitrate hexahydrate and cobalt nitrate hexahydrate into solution A, preparing 2,5-dihydroxyterephthalic acid into solution B, carrying out a solvothermal reaction of solution A and solution B to obtain amorphous ZnCo-MOF powder; preparing the amorphous ZnCo-MOF powder into suspension C, dissolving 2-methylimidazole in an ethanol aqueous solution, adding triethylamine to form solution D, adding the suspension C into the solution D to react to obtain ZnCo-ZIF hollow nanosphere powder; placing the ZnCo-ZIF hollow nanosphere powder into argon for annealing treatment to obtain nitrogen-doped porous carbon hollow nanosphere material; uniformly mixing the nitrogen-doped porous carbon hollow nanosphere powder with selenium powder, and then placing the mixture into argon for annealing treatment to obtain zinc selenide / cobalt selenide@nitrogen-doped porous carbon hollow nanosphere material. The zinc selenide / cobalt selenide@nitrogen-doped porous carbon hollow nanosphere prepared by the method is mainly applied to preparation of a negative electrode material of a high-performance sodium ion battery.

The application provides a sulfur-doped C3N4-CoSe2 lithium-sulfur battery positive electrode catalyst and a preparation method and application thereof, and belongs to the technical field of nanometer material preparation. First, citric acid, thiourea, a cobalt salt, selenium powder and ethanol are ultrasonically mixed to obtain a slurry material, and then the slurry material is subjected to joule heat shock in an air atmosphere to obtain a two-dimensional sulfur-doped C3N4-CoSe2 lithium-sulfur battery positive electrode catalyst. The catalyst can fully exert the synergistic effect of the structural and component advantages, the two-dimensional structure endows it with a large specific surface area, meanwhile, the two-dimensional channel can promote the migration of particles and inhibit the shuttle effect of polysulfides, and the C3N4 and sulfur doping together endow it with the component advantages, wherein the C3N4 can effectively stabilize the structure of cobalt selenide, together with the sulfur doping, the catalytic activity and conductivity of the cobalt selenide are improved, the conversion of polysulfides is promoted, thereby the shuttle effect of the lithium-sulfur battery is inhibited and the stability of the cobalt selenide is improved, and excellent lithium-sulfur battery performance is exhibited.

This invention relates to a method for preparing cobalt selenide rich in double defects and its application in the electrocatalytic reduction of oxygen to hydrogen peroxide. First, selenium powder is mixed with sodium hydroxide solution to obtain material A. Cobalt salt is mixed with EDTA-2Na solution to obtain material B. Material B and material A are then mixed and subjected to a hydrothermal reaction. The resulting product is centrifuged, washed, and vacuum dried to obtain cobalt selenide powder. The cobalt selenide powder is dispersed in anhydrous ethanol, and then potassium thiocyanate powder is added. After vigorous stirring, ultrasonic exfoliation is performed. The product is centrifuged, washed, dried, and calcined to obtain cobalt selenide rich in double defects. This invention provides a simple preparation method that can rapidly and cost-effectively prepare double-defect cobalt selenide under mild conditions. The obtained double-defect cobalt selenide can effectively reduce oxygen to hydrogen peroxide under electrocatalytic conditions, solving the problems of high price and low efficiency of current catalysts for hydrogen peroxide production under acidic conditions.

The invention belongs to the technical field of battery materials, and relates to a preparation method and application of a silicon-based composite material. The preparation method comprises the following steps: dissolving a PDDA solution in water and ethanol, adding nano silicon powder, then adding selenium dioxide, and uniformly stirring; then, a cobalt source, a nickel source and a reducing agent are added, pH is adjusted, and a precursor solution is obtained; carrying out hydrothermal reaction on the precursor solution, centrifuging, washing, filtering and drying to obtain a Si / NiyCo (1-y) Sex nanowire powder sample; and grinding and sieving the powder sample, then carrying out chemical vapor deposition, and growing a carbon nanotube on the surface of the nanowire to obtain the final silicon-based composite material. In the silicon-based composite material, the nickel-cobalt selenide nanowires and the carbon nanotubes are uniformly distributed on the surfaces of the nano silicon particles, the nickel-cobalt selenide nanowires and the carbon nanotubes are interwoven to form a cage-like conductive network structure, and the nano silicon particles are effectively coated and fixed, so that the overall electrochemical performance of the composite material is greatly improved.

The invention relates to a preparation method and application of a Se defect induced Zn1-Co / CoSe2-x catalyst. The preparation method comprises the following steps: firstly, preparing Se-defective orthorhombic phase cobalt selenide o-CoSe2-x powder, weighing a certain amount of zinc salt and o-CoSe2-x powder, mixing, adding absolute ethyl alcohol, stirring for 12 hours, standing for 12 hours, drying to obtain Zn-doped CoSe2-x powder, and roasting the Zn-doped CoSe2-x powder in a quartz boat and a tube furnace to obtain the Zn-doped CoSe2-x-doped cobalt selenide. According to the method, Zn monatomic atoms are anchored and formed on defect type CoSe2-x through simple hydrothermal, dipping and roasting methods, and the Zn monatomic atoms and Co form relatively long-distance Zn-Co para-sites, so that an electronic structure of active sites is modulated, the selectivity of a Co-based catalyst to a two-electron oxygen reduction reaction under an acidic condition is improved, and the Co-based catalyst can be applied to the field of catalytic reduction. And the catalyst has high yield and excellent stability, and can solve the problems of high price, low efficiency and the like of a catalyst for producing hydrogen peroxide under an acidic condition at present.

The invention relates to a preparation method and application of a negative electrode material, and the preparation method comprises the following steps: S1, carrying out carbonization treatment on ZIF-67 in an inert atmosphere to obtain a carbonized product; s2, the carbonized product and selenium powder are subjected to a hydrothermal reaction in the presence of a reducing agent and water, and a hydrothermal product is obtained; and S3, reacting the hydrothermal product with a phenolic monomer, an organic polymer and an organic phosphorus compound in the presence of a solvent, cooling to separate a solid, washing, drying, and then transferring to an inert atmosphere for carbonization treatment to obtain the negative electrode material. The nitrogen-doped porous cobalt diselenide material which is stable in structure and uniform in selenium element distribution is formed through hydrothermal in-situ selenylation, then a coating layer with P uniformly doped with hard carbon is formed on the surface of the nitrogen-doped porous cobalt diselenide material through in-situ polymerization and carbonization, and the prepared negative electrode material has the advantages of high energy density, excellent structural stability and electron / ion transmission. Therefore, the secondary battery containing the negative electrode material has high capacity and excellent rate capability and cycle performance.

The present invention discloses a nano-cobalt selenide@three-dimensional honeycomb carbon composite material, its preparation method, and its application in preparing lithium-ion battery negative electrodes. In the nano-cobalt selenide@three-dimensional honeycomb carbon composite material, carbon presents a three-dimensional honeycomb pore structure, and cobalt selenide CoSe grows densely and evenly on the inner surface of the honeycomb pores of the honeycomb carbon in the form of nanoparticles. Preparation method: First, PS pellets are synthesized, and then the PS pellets and a solution containing dissolved Co(NO)2 and PVP are slowly evaporated and dried, followed by calcination under a protective atmosphere, and finally selenization by a vapor phase method to obtain the nano-cobalt selenide@three-dimensional honeycomb carbon composite material. The present invention can significantly improve the specific capacity, cycle performance, and rate performance of cobalt selenide.

The application provides a three-dimensional flower-shaped silicon@zinc selenide / cobalt selenide@carbon composite material and a preparation method thereof, a lithium ion battery silicon-based negative electrode and a battery. Compared with the prior art, the silicon particles are first prepared to grow in nanometer flower sheets, then the silicon particles are carbon-coated, and then the silicon particles are put into a tube furnace to be converted into the Si@ZnSe / CoSe@C composite material by using selenium powder. The flower-shaped structure can not only increase a large number of surface active sites but also effectively relieve the volume expansion of the silicon particles, so that the cycle stability of the battery is improved, and the battery obtains an extremely high specific capacity.

The application belongs to the technical field of two-dimensional nanomaterial electrocatalyst preparation, and particularly relates to an amorphous Sr-CoOOH v Ultra-thin nanosheet electrocatalyst, preparation method and application. Strontium-doped cobalt selenide nanobelt is prepared as a substrate by a hydrothermal method, and in-situ electrochemical reconstruction is generated under alkaline electrolytic water anode oxygen evolution reaction conditions. The Sr-CoOOH v The ultra-thin nanosheet can not only enhance cobalt-oxygen covalence to activate lattice oxygen, but also improve hydroxyl affinity to fill lattice oxygen due to the existence of metal cobalt vacancies, so that the catalyst exhibits excellent catalytic activity and durability in industrial application of anion exchange membrane electrolytic water hydrogen production.

The invention discloses a preparation method and application of a self-supporting iron-manganese co-doped nickel-cobalt selenide nanorod array catalyst, belonging to the technical field of electrocatalytic materials, and comprising the following steps: using nickel foam as a growth substrate, first preparing an iron-manganese co-doped precursor by a hydrothermal method according to a certain stoichiometric ratio of a nickel source, a cobalt source, an iron source, and a manganese source, and then obtaining the catalyst through selenization treatment. The invention uses the double doping of inexpensive and abundant transition metal elements to adjust the electronic structure of the bimetallic selenide, improving its intrinsic activity; the nanorod array structure increases the active sites and specific surface area of the catalyst, improving its apparent activity; the conductive substrate nickel foam improves the conductivity and stability of the catalyst, thereby synergistically promoting its electrolytic water activity and stability, and applying it to electrolytic water hydrogen production, improving the electrolytic water efficiency. The preparation method of the invention is simple and easy to prepare in batches.

The invention belongs to the technical field of electrocatalytic oxygen evolution reaction, and particularly relates to a method for preparing a cobalt diselenide reduced graphene oxide electrocatalyst by taking ZIF-67 as a precursor. The invention solves the problems of poor conductivity and easy agglomeration of cobalt diselenide, and develops an electro-catalytic oxygen evolution reaction catalyst with low cost and high catalytic performance. The electrocatalyst provided by the invention adopts foamed nickel to bear cobalt diselenide and graphene oxide. The preparation method comprises the following steps: step 1, mixing a 2-methylimidazole solution with a cobalt nitrate hexahydrate solution to obtain a ZIF-67 precursor; 2, the foamed nickel is sequentially cleaned with ethyl alcohol and deionized water in an ultrasonic cleaner and then dried; and 3, dispersing the ZIF-67 precursor in water, adding graphene oxide, sodium hydroxide, ethylenediamine tetraacetic acid, sodium borohydride and sodium selenite into the solution, mixing, carrying out a hydrothermal reaction with foamed nickel, washing the product after the reaction, and drying.

The invention discloses a Cr-doped cobalt selenide-based water electrolysis catalyst and a preparation method thereof, and belongs to the field of water electrolysis catalysts. The chemical formula of the Cr-doped cobalt selenide-based water electrolysis catalyst is Crx-CoSe2, 0.1 lt, and the chemical formula is as shown in the specification. Xlt; the particle size of the catalyst is 6 to 70 [mu] m. The preparation method of the catalyst comprises the following steps: (1) cleaning a foamed nickel base material to obtain pretreated foamed nickel; (2) sequentially adding Co (NO3) 2.6 H2O, Cr (NO3) 3.9 H2O and CO (NH2) 2 into water, and stirring until solids are completely dissolved; (3) putting the solution obtained in the step (2) into a reaction kettle in which pretreated foamed nickel is inserted, and carrying out hydrothermal reaction to obtain a precursor; and (4) calcining the precursor and selenium to obtain the catalyst. The catalyst provided by the invention can achieve the effects of low cost, high activity and high stability.

The invention provides a nitrogen-doped carbon composite cobalt nickel diselenide nanocube material and a preparation method and application thereof in a battery. Cobalt salt, nickel salt and hexadecyl trimethyl ammonium bromide are dispersed in a solvent and evenly mixed, and a solution A is obtained; dispersing an organic ligand in a solvent, and uniformly mixing to obtain a solution B; pouring the solution A into the solution B, and aging at room temperature to obtain a nanocube precursor; and mixing the CoNiSe2 / NC composite material with selenium powder, and calcining in a protective atmosphere to obtain the CoNiSe2 / NC composite material. Compared with the prior art, due to the mutual synergistic effect of Co and Ni, more active sites are provided for the reaction, and the conductivity is improved, so that the performance of the sodium-ion battery is remarkably improved. In addition, synthesis is carried out at room temperature, and conditions are simple; the design of the porous structure greatly improves the cycling stability of the battery, prolongs the service life, and increases and stabilizes the capacity.

The application discloses a hollow dahlia-shaped nickel-cobalt selenide composite electrocatalytic material and a synthesis method and application thereof. The hollow dahlia-shaped nickel-cobalt selenide composite electrocatalytic material is prepared by adopting a hydrothermal-solvothermal combined method with SiO2 balls as a template. Specifically, a nickel silicon hydroxide precursor is prepared by a hydrothermal reaction method. The method is simple in operation, environment-friendly and energy-saving, and the morphology structure is easy to control. Then, a NiSe / Co9Se8 hollow nanoflower composite material is prepared by a solvothermal method. The method can effectively inhibit oxidation and has the advantages of wide application range, easy control of a reaction process, low crystallization temperature and the like. Therefore, the combination of the two methods can precisely control crystal growth and a microstructure, so that an electrocatalyst with high activity, high stability and high specific surface area is prepared, and the electrocatalyst exhibits excellent electrocatalytic HER and OER performance under alkaline conditions.

The invention belongs to the technical field of potassium ion battery negative electrode materials, and particularly relates to a tomato-like cobalt diselenide / carbon composite material and a preparation method and application thereof.The preparation method comprises the steps that firstly, a cobalt precursor is prepared through a hydrothermal reaction, then the cobalt precursor, tris (hydroxymethyl) aminomethane and an oxygen-containing carbon source are dissolved in a homogeneous solution to be subjected to a coating reaction, and the tomato-like cobalt diselenide / carbon composite material is obtained; the core-shell structure material with the cobalt precursor coated with the polymer is obtained; and dispersing the core-shell structure material in a selenylation solution for hydrothermal reaction to obtain a polymer-coated cobalt diselenide black powder material, and calcining the polymer-coated cobalt diselenide black powder material in an inert atmosphere to obtain the tomato-like cobalt diselenide / carbon composite material. According to the method, zinc salt does not need to be introduced as a template, the process is simple, the synthesis cost is low, and the prepared tomato-like cobalt diselenide / carbon composite material has good conductivity and stability and is suitable for potassium ion batteries.

This invention relates to a composite anode material, its preparation method, and a battery. The composite anode material has a hollow core-shell structure. From its center to its outer surface, the composite anode material sequentially includes a cobalt selenide sulfide layer and a hard carbon coating layer, with the cobalt selenide sulfide layer enclosing a cavity. The thickness of the cobalt selenide sulfide layer is 30%–65% of the total thickness from the center to the outer surface of the composite anode material (assuming 100% thickness). The cobalt selenide sulfide layer includes an outer shell layer and a core layer. The outer shell layer is in contact with the hard carbon coating layer, and the core layer is in contact with the cavity. The thickness of the outer shell layer and the core layer are both 10%–25% of the total thickness (assuming 100% thickness). The chemical formula of the cobalt selenide sulfide is CoS. x Se 2‑x The values ​​of x are 0.3 ≤ x ≤ 1.7, and the x value decreases from the core layer to the outer shell layer. This composite anode material exhibits excellent structural stability, low expansion, high conductivity, and good cycle stability and rate performance.

The application belongs to the technical field of battery materials, and relates to a preparation method and application of a silicon-based composite material. The preparation method comprises the following steps: dissolving a PDDA solution in water and ethanol, adding nano-silicon powder, and then adding selenium dioxide and stirring uniformly; subsequently, a cobalt source, a nickel source and a reducing agent are added, and pH is adjusted to obtain a precursor solution; the precursor solution is subjected to hydrothermal reaction, and after centrifugation, washing, filtration and drying, a Si / Ni y Co (1‑y) Se x nanowire powder sample; after the powder sample is ground and sieved, chemical vapor deposition is performed to grow carbon nanotubes on the surface of the nanowires, and finally, the silicon-based composite material is obtained. In the silicon-based composite material, the surface of the nano-silicon particles is uniformly distributed with nickel-cobalt selenide nanowires and carbon nanotubes, the two are interwoven to form a cage-like conductive network structure, the nano-silicon particles are effectively coated and fixed, and therefore the overall electrochemical performance of the composite material is greatly improved.

The application relates to the technical field of supercapacitor electrode materials, in particular to a sulfur-doped nickel cobalt selenide composite material and a preparation method and application thereof. The preparation method comprises the following steps: taking SeO2 as a selenium source, taking hydrazine hydrate as a strong reducing agent, mixing a SeO2 ethylene glycol solution with the hydrazine hydrate and a NiCo-PBA@NiCo-LDH multi-level core-shell precursor, and performing a selenization reaction to obtain NiCoSe2; mixing the NiCoSe2 with sulfur powder, and performing calcination treatment to obtain the sulfur-doped nickel cobalt selenide composite material. Through the synergistic effect of the multi-level core-shell structure and the hetero-doping, the sulfur-doped nickel cobalt selenide composite material is endowed with excellent electrochemical energy storage performance, and the problems of poor rate performance and decreased cycle stability caused by the insufficient intrinsic electrochemical activity and large volume change in the charging and discharging process of the transition metal selenide as a supercapacitor electrode material are effectively solved.

The invention belongs to the technical field of preparation of two-dimensional nano material electrocatalysts, and particularly relates to an amorphous Sr-CoOOHv ultrathin nanosheet electrocatalyst as well as a preparation method and application thereof. The strontium-doped cobalt selenide nanobelt is prepared through a hydrothermal method to serve as a substrate, and in-situ electrochemical reconstruction is carried out under the alkaline electrolyzed water anode oxygen evolution reaction condition to obtain the strontium-doped cobalt selenide nanobelt. According to the Sr-CoOOHv ultrathin nanosheet rich in cobalt vacancies, due to the existence of the metal cobalt vacancies, cobalt-oxygen covalence can be enhanced, lattice oxygen can be activated, meanwhile, hydroxyl affinity can be improved, and the lattice oxygen can be filled, so that the catalyst shows excellent catalytic activity and durability in industrial application of anion exchange membrane water electrolysis hydrogen production.

The invention discloses a preparation method of a SiC (at) CoSe2-VSe wave-absorbing material containing a large amount of Se vacancies. The preparation method comprises the following steps: loading a cobalt precursor on the surface of a SiC nanowire through a hydrothermal method, calcining by using a muffle furnace to prepare a SiC-coated Co3O4 nano composite material, converting cobalt oxide into cobalt selenide through a hydrothermal method, putting the product into a reductive KBH4 solution, and regulating and controlling a vacancy to obtain the SiC-coated CoSe2-VSe wave-absorbing material. CoSe2 is added, so that the material has good impedance matching, a CoSe2 nanosheet is formed on the SiC nanowire, a phase interface is also generated in the structure, and extra charges and dipoles are introduced into all defects and interfaces, so that the dielectric loss is enhanced, dipole polarization is generated by taking various defect structures as dipole centers, and the dielectric loss is reduced. The device plays an important role in attenuation of incident electromagnetic waves. Due to the synergistic effect of the multiple losses, the designed SiC-coated CoSe2 nano composite material with the vacancy has excellent electromagnetic wave absorption performance. A good foundation is provided for development of SiC-based materials, and a good design thought is provided for preparation of electromagnetic wave absorbing materials. Various problems caused by current electromagnetic pollution can be well solved due to the excellent performance of the composite material, and the composite material has a wide application prospect.

The invention provides a vanadium-doped cobalt selenide nanosheet array rich in selenium vacancy as well as a preparation method and application of the vanadium-doped cobalt selenide nanosheet array. The invention provides a preparation method of a vanadium-doped cobalt selenide nanosheet array rich in selenium vacancy, which comprises the following steps: dissolving cobalt salt and 2-methylimidazole in deionized water, adding foamed nickel, and reacting at room temperature to obtain ZIF-L; the method comprises the following steps: dissolving a vanadium source in deionized water, adding ZIF-L, and carrying out hydrothermal reaction to obtain CoV-ZIF; then adding the CoV-ZIF into a selenium source solution, and carrying out selenylation to obtain V-Co9Se8; and finally, soaking in a NaBH4 solution to obtain the nanosheet array. The formed nanosheet structure can provide a larger active specific surface area; the electron transfer rate can be improved through the synergistic effect of Co and V; the introduction of selenium vacancies can enhance the conductivity and active sites. Practice shows that when the Vse-V-Co9Se8 is used as the water electrolysis electrode material, the Vse-V-Co9Se8 shows low overpotential and high cycle stability.

The application discloses a hollow multi-shell layer cobalt selenide modified diaphragm for lithium-sulfur batteries and a preparation method thereof. Ammonium metavanadate is heated in a water bath to form a light yellow clear solution, then cobalt chloride hexahydrate and hexamethylenetetramine are added, and after stirring, washing and drying, the obtained product is dispersed in ethylene glycol with sodium selenite, and hydrazine hydrate is added to carry out hydrothermal reaction to prepare hollow multi-shell layer cobalt selenide. The hollow multi-shell layer cobalt selenide is dissolved in an organic solvent with a conductive agent and a binder, and the mixture is uniformly attached to the diaphragm of the lithium-sulfur battery by vacuum filtration to obtain the hollow multi-shell layer cobalt selenide modified diaphragm for lithium-sulfur batteries. The hollow multi-shell layer cobalt selenide has strong adsorption and catalytic capacity, can effectively inhibit the shuttle effect of polysulfides, accelerate the redox kinetic process and improve the utilization rate of active substances, so that the lithium-sulfur battery prepared by using the hollow multi-shell layer cobalt selenide has excellent discharge specific capacity, good cycle stability and excellent rate performance.

This invention relates to a method for preparing and applying a cobalt-deficient cobalt selenide-anchored high-loading Pt single-atom catalyst. Selenium powder is mixed with sodium hydroxide solution to obtain material A. Cobalt salt is mixed with EDTA-2Na solution to obtain material B. Material B and material A are mixed and subjected to a hydrothermal reaction. The resulting product is centrifuged, dried, and dispersed in anhydrous ethanol. Potassium thiocyanate powder is then added, and the mixture is ultrasonically exfoliated, centrifuged, washed, dried, and calcined to obtain Co-deficient cobalt selenide. This cobalt selenide is uniformly dispersed in an ammonium hydroxide aqueous solution. Under alkaline conditions, an ammonia solution containing tetraammineplatinum nitrate is added, and the reaction is carried out at room temperature for 24 hours. After centrifugation, washing, drying, and calcination, the desired product is obtained. This invention provides a simple preparation method that enables rapid and low-cost preparation of Co-deficient cobalt selenide under mild conditions. The Co-deficient cobalt selenide can anchor high-loading Pt single atoms, improving the stability of the Pt single atoms and thus enhancing the catalytic activity and selectivity of the catalyst for oxygen reduction to H₂O₂.

The present invention discloses a tin cobalt selenide @C heterostructure composite material, a preparation method thereof and an application, comprising the following steps: A. preparing a precursor SnCo(OH)6 by a coprecipitation method; B. coating a carbon layer on the precursor SnCo(OH)6 to obtain a composite material; C. performing a selenization reaction on the above composite material to obtain a selenized composite material; D. performing a carbonization reaction on the selenized composite material to obtain a tin cobalt selenide @C heterostructure composite material. Compared with the single structure of traditional anode materials for sodium-ion batteries, the present invention enhances the adsorption of sodium ions by the material by introducing a heterostructure, thereby improving the rate performance of the sodium-ion battery. At the same time, the box-type buffer structure can effectively maintain the volume change of the material during long-term cycling, improving the cycle stability of the sodium-ion battery.

The invention relates to a preparation method of a cobalt diselenide carbon composite electrode material with multiple crystal phases. The preparation method comprises the following steps: a, preparing ZIF-67; b, accurately weighing ZIF-67 and Se powder according to the mass ratio of 1: 1 or 1: 2, mixing and grinding the weighed ZIF-67 and Se powder according to the corresponding ratio, and then transferring into a primary-secondary crucible; and c, placing the primary-secondary crucible filled with the material in a microwave oven, carrying out microwave reaction on the material, taking out the material after the reaction is finished, and cooling to room temperature to obtain the cobalt diselenide carbon composite electrode material with multiple crystal phases. The cobalt diselenide carbon composite electrode material with two crystal phase structures of an orthorhombic phase and a cubic phase at the same time can be prepared, and the electrode material enables a battery to have excellent sodium storage capacity and rapid charging and discharging characteristics; the method is simple and easy to implement, short in period, high in yield and beneficial to large-scale production, economic benefits are improved, and meanwhile the quality of battery products is improved.