105 results about "Cobalt selenide" patented technology

The invention provides a cobalt selenide / nitrogen-doped carbon composite material and a preparation method and an application therefor, and belongs to the technical fields of nanomaterial preparation and application. An organic metallic framework ZIF-67 is taken as a template for preparing the cobalt selenide / nitrogen-doped carbon composite material; the material adopts a rhombic dodecahedron shape with controllable sizes; and cobalt selenide is cobalt selenide or cobalt diselenide nanoparticles uniformly dispersed on a nitrogen-doped carbon framework. The compound has a good mesoporous structure and excellent conductivity; and when the composite material is used as the electrode material for a supercapacitor, a high specific capacitance and high stability are achieved.

The invention discloses a cobalt selenide / carbon sodium ion battery composite negative electrode material as well as a preparation method and application of the cobalt selenide / carbon-sodium ion battery composite negative electrode material. Cobalt selenide nano rods in a cobalt selenide / carbon composite material uniformly grow on the surface of carbon. The preparation method of the composite negative electrode material comprises the following steps: (1) preparing a selenium source and a cobalt source, which are uniformly dispersed; (2) after uniformly mixing the selenium source and the cobalt source, adding a carbon source, and carrying out ultrasonic treatment on a mixed solution; putting the mixed solution into a reaction kettle and carrying out a hydrothermal reaction; (3) filtering and washing, and drying in vacuum; carrying out heat treatment under a protection atmosphere to obtain the cobalt selenide / carbon sodium ion battery composite negative electrode material. The cobalt selenide / carbon composite material prepared by the method is good in dispersity and is of a uniform nano-rod-shaped structure; the cobalt selenide / carbon composite material is used as a sodium ion battery negative electrode material and has higher charge and discharge capacity, good rate performance and circulating stability. The cobalt selenide / carbon sodium ion battery composite negative electrode material has the advantages of simple method, easiness of obtaining the raw materials, high repeatability and no pollution, and has a very wide application prospect in the field of sodium ion batteries.

The invention relates to a MoSe2 / Co0.85Se composite material for electrocatalytic water decomposition. The microtopography of the composite material is that a micron / nano rod of a MoSe2 / Co0.85Se compound is loaded with a nano sheet of a molybdenum selenide / cobaltous selenide compound; the micron / nano rod has the length of is 1.5 to 3.5 microns and a diameter of 0.2 to 0.5 micron. A composite-material precursor CoMoO4 is firstly prepared and obtained through a hydrothermal reaction by using cobalt nitrate and sodium molybdate as reactive raw materials; afterwards, the composite material is made through the hydrothermal reaction by using sodium borohydride, selenium powder and the prepared composite-material precursor as raw materials. A preparation method of the MoSe2 / Co0.85Se composite material is simple; the raw materials are easily obtained; the cost is low; the industrialized production is easily realized; the prepared and obtained composite material is good in electrocatalytic effect, and further, has favorable stability.

The invention discloses a preparation method and applications of self-supported carbon cloth loaded cobaltous selenide nickel nanowires. The preparation method comprises following steps: conductive carbon cloth is taken as a substrate material, a cobalt nickel double metal salt and the hydrophilic carbon cloth are subjected to low temperature hydro-thermal reaction so as to obtain cobalt nickel nanowires uniformly grown on the carbon cloth; further high temperature selenylation is carried out so as to botain the cobaltous selenide nickel nanowires uniformly loaded by the carbon cloth, and theobtained product is taken as a self-supported electrode material in catalytic water electrolysis reaction. The double metal nanometer catalytic material is low in cost, simple in preparation technology, and unique in nanowire structure, and is capable of catalyzing water electrolysis hydrogen evolution and oxygen evolution reaction; in electrode preparation process, no binder is needed, excellentdurability is achieved, and a new idea is provided for preparation of non-noble metal based double function electrocatalysts.

The invention provides a cobalt selenide / nitrogen-doped carbon composite material and a preparation method and application thereof, and relates to the technical field of nanometer materials. The preparation method of a cobalt selenide / nitrogen doped carbon composite material includes the following steps: S1, mixing a cobalt salt solution and an imidazole compound solution, stirring and reacting atroom temperature to obtain a two-dimensional leaf-shaped precursor. S2, adding a reducing agent into a solution containing a selenium source, and obtaining selenium nanoparticles at 90 to 100 DEG C.S3, mixing the precursor and the selenium nanoparticles to obtain a mixture, and calcining the mixture in a protective atmosphere to obtain a cobalt selenide / nitrogen doped carbon composite material.The composite has two-dimensional leaf-like nitrogen-doped carbon matrix, and ultrafine cobalt selenide nanoparticles embedded in the matrix, so that the composite has good conductivity, limited volume expansion stress, and exhibits excellent cycle stability and rate performance as the negative electrode material of sodium ion battery. The preparation process of the composite is simple and the cost is low, so the composite has the potential of large-scale application.

The invention provides a carbon-coated nickel cobalt selenide (Ni0.67Co0.33Se2) nano material with excellent water electrolysis performance and a preparation method of the carbon-coated nickel cobaltselenide (Ni0.67Co0.33Se2) nano material. The method comprises the following steps: dissolving Co(NO3)2.6H2O, Ni(NO3)2.6H2O, polyvinylpyrrolidone (PVP-K30) and terephthalic acid in a mixed solution ofN,N-dimethylformamide (DMF) and ethanol at first; then transferring the solution into an autoclave with a polytetrafluoroethylene liner; after a Co-Ni-MOFs material is synthesized by high-temperaturereaction, washing, drying and grinding the Co-Ni-MOFs material, mixing the Co-Ni-MOFs material with selenium powder and then placing the mixture in a tube furnace; and carrying out high-temperature annealing treatment in a nitrogen atmosphere to obtain the carbon-coated nickel cobalt selenide (Ni0.67Co0.33Se2) nano material. The obtained carbon-coated Ni0.67Co0.33Se2 nano material has excellent characteristics of high preparation speed, high yield, good stability and the like, and has high application value in the aspect of water electrolysis catalysis under the alkaline condition.

The invention belongs to the technical field of chemical catalysts, and particularly relates to a cobalt diselenide / graphite carbon composite material, namely an oxygen reduction catalyst, and a preparation method thereof. The oxygen reduction catalyst provided by the invention is the cobalt diselenide / graphite carbon composite material and obtained by uniformly embedding cobalt diselenide nano-particles, the diameter of which is several nanometres, in a porous graphite carbon polyhedron. According to the invention, a synthesis method is simple; the production cost is low; large-scale preparation can be realized; compared with cobalt diselenide and a carbon materialwhich are subjected tomechanical mixing, the prepared composite material has the advantages of being high in interface coupling, uniform in cobalt diselenide particle distribution and the like; a carbon substrate has a mesoporous structure; and the oxygen reduction catalytic performance of the oxygen reduction catalyst in an alkaline environment is superior to that of the commercial platinum-carbon catalyst.

Relating to the technical field of composite materials, in order to solve the problems of high price and low catalytic activity of electrode catalytic materials in existing zinc-air batteries, the invention provides a cobalt diselenide / nitrogen-doped carbon nanomaterial composite electrode catalytic material, a preparation method and application thereof. The preparation method includes the steps of: (1) growing Co-MOF on carbon cloth subjected to hydrophilization treatment; (2) growing a nitrogen-doped carbon nanomaterial through CVD process to obtain a Co / nitrogen-doped carbon nanomaterial; wherein the nitrogen-doped carbon nanomaterial is a combination of nitrogen-doped carbon nanotube and nitrogen-doped carbon nanosheet; and (3) carrying out selenylation treatment to obtain the cobalt diselenide / nitrogen-doped carbon nanomaterial composite electrode catalytic material. The composite material provided by the invention retains the structural integrity of the cobalt diselenide porous frame / carbon nanosheet array obtained by taking the triangular lamellar MOF crystal as a template, has excellent properties of both the carbon nanotube and the cobalt diselenide porous frame, and has wide application prospects in the fields of adsorption, sensing, energy storage, catalysis and the like.

The invention relates to a cobalt-nickel selenide nitrogen-doped amorphous carbon nano composite negative electrode material as well as preparation and application thereof. The preparation method specifically comprises the following steps of (a) adding a cobalt source, a nickel source and hexadecyl trimethyl ammonium bromide into a 2-methylimidazole aqueous solution, stirring to form a mixed solution, standing and separating to obtain a precipitate, washing and drying to obtain NiCo-ZIF-67; and (b) selenizing the NiCo-ZIF-67 obtained in the step (a) by adopting elemental selenium, and then washing and drying to obtain the cobalt-nickel selenide nitrogen-doped amorphous carbon nano composite negative electrode material. The cobalt nickel selenide nitrogen-doped amorphous carbon nano composite negative electrode material is prepared into a sodium-ion battery negative electrode plate, and then the sodium-ion battery negative electrode plate, a metal sodium plate and an electrolyte are assembled into a sodium-ion battery. Compared with the prior art, the nano composite negative electrode material provided by the invention improves the electrochemical performance of the battery, has excellent electrochemical sodium storage performance, and is a good sodium ion battery negative electrode material.

The invention discloses a selenide @ carbon-based fiber supercapacitor electrode material, which is a composite nanometer material of a core-shell structure, wherein the carbon-based fiber is taken asa core and the selenide is taken as a shell, and the selenide is grown on the surface of the carbon-based fiber. Also disclosed are a cobalt selenide @ carbon nanotube fiber composite nanomaterial and a preparation method thereof. The cobalt selenide @ carbon nanotube fiber composite nano material grows cobalt selenide material on the surface of the carbon nanotube fiber through a hydrothermal method, thereby forming the cobalt selenide @ carbon nanotube composite fiber. The synthesized selenide @ carbon-based fiber supercapacitor electrode material is tested in a three-electrode system. Theresults show that the electrode material exhibits high specific capcity of 359 Fg<-1> and good cycle stability. The invention has the advantages of simple preparation method and low cost. The preparedelectrode material of cobalt selenide @ carbon nanotube fiber supercapacitor has the advantages of large specific surface area, high specific capacitance and good cycle performance. In addition, dueto the high conductivity, strength and flexible knitting characteristics, the electrode material has great application prospects in wearable electronic equipment.

The invention provides a method for preparing a cobaltous selenide nanometer sheet which is a catalyst capable of efficiently decomposing hydrazine compounds. The method belongs to the field of nanometer material synthesis and application. The method comprises the following steps: respectively weighting a certain amount of cobalt source predecessor and selenium source predecessor, taking a solvent and a reducing agent in defined volumes, and putting the weighted and taken materials into a high-pressure reactor; stirring the materials for 20 minutes by using a stirrer; after fully dissolving the materials, sealing the reactor and placing the reactor in an oven at 140 DEG C; after reacting for 24 hours, taking out the reactor and naturally cooling; and using ethanol and distilled water to respectively wash a reaction product for three times, thereby acquiring a sample. According to the method, an organic mould plate and a surface active agent are unnecessary, the cobaltous selenide nanometer sheet is synthesized in one step, the yield is high and the thickness of the cobaltous selenide nanometer sheet is small. The method has simple and energy-saving preparation process and is fit for industrial production. The acquired cobaltous selenide nanometer sheet has the advantages of small thickness, big specific surface area and excellent function for catalyzing and degrading hydrazine compounds, such as hydrazine hydrate, hydrazine chloride, hydrazine sulfate, and the like.

The invention discloses a Co<0.85>Se nanometer material serving as an electrode material of a supercapacitor and a preparation method of the Co<0.85>Se nanometer material. The nanometer material adopts a fibrous nanometer structure. The Co<0.85>Se nanometer material adopts a two-step hydrothermal synthesis method, and the two-step hydrothermal synthesis method comprises the steps of firstly, preparing a precursor Co(OH)(CO<3>)<0.5> nanowire by a hydrothermal reaction method; and secondly, carrying out selenization processing on the precursor by the hydrothermal reaction method to obtain the Co<0.85>Se nanometer material. When placed in a three-electrode system for test, the nanometer electrode material is endowed with high specific capacity of 1,249F / g under current density of 2A / g, the specific volume over 80% still can be maintained after 3,000 cycles of charging and discharging under 100mA current, and the charge transfer impedance is 0.32 ohm / cm<2>. The Co<0.85>Se nanometer electrode material prepared according to the method has the advantages of high specific capacitance, good cycle performance, simplicity in preparation method and low cost.

The invention provides a method for preparing and synthesizing a ferroferric-oxide-supported cobalt selenide magnetic nano composite material by a hydrothermal process and application thereof, belonging to the technical field of preparation and application of nano materials. The invention does not need to previously prepare any template or use any surfactant, has the advantage of mild reaction process, and is easy to control; and the obtained ferroferric-oxide-supported cobalt selenide magnetic nano composite material has high activities in catalyzing reduction of nitrophenol and adsorbing methylene blue. The result indicates that 1mg of ferroferric-oxide-supported cobalt selenide magnetic nano composite material can completely catalyze the nitrophenol in 0.1ml of 5.0*10<-3>M nitrophenol solution by only 13 minutes; and 50mg of ferroferric-oxide-supported cobalt selenide magnetic nano composite material can completely adsorb the methylene blue in 50ml of 5mg / L methylene blue solution by only 25 minutes. Besides, the prepared sample has magnetic property, thus, can be conveniently separated and collected with a magnet, and is convenient for recycling.

The invention discloses a cobalt diselenide@porous nitrogen-doped carbon nano composite material, a potassium ion battery and a preparation method thereof. The composite material comprises cobalt diselenide particles and porous nitrogen-doped carbon, and the cobalt diselenide particles are limited on a carbon shell of the porous nitrogen-doped carbon. A cobalt-based metal frame ZIF-67 is firstly carbonized and then selenized in a high-temperature inert atmosphere, and the cobalt diselenide@porous nitrogen-doped carbon nano composite material is obtained. The preparation method of the negative electrode material is simple and easy to operate, the raw materials are easy to obtain, the repeatability is good, the problems that active substances are pulverized and fall off from a current collector due to large volume fluctuation of a transition metal sulfide negative electrode in the charging and discharging process are successfully solved, and through optimal matching with an electrolyte, a potassium ion battery system which is higher in capacity, stable in circulation and better in rate capability is finally constructed.

The invention provides a process for preparing cobalt selenide composite carbon paper. The process includes the steps that firstly, a hydrothermal method is adopted to prepare cellulosic fibers wrapped with a cobalt selenide slice layer; then, a wet method papermaking method is adopted to make cobalt selenide cellulose composite paper, and after the cobalt selenide cellulose composite paper is clipped or folded into any shape, the cobalt selenide composite carbon paper is finally prepared under protection of inert gases through a high-temperature carbonization process. The cobalt selenide composite carbon paper is used for electrodes of electrolysed water and meanwhile has high catalytic oxygen evolution and hydrogen evolution activity.

The invention discloses a difunctional cobalt diselenide material as well as a preparation method and application thereof. The preparation method comprises the following steps: (1) jointly performingthe hydrothermal reaction for a mixed aqueous solution of soluble cobalt salt, soluble ammonium salt and a carbon-containing precipitant and a conducting substrate, and obtaining a cobalt element-containing precursor growing on the conducting substrate; (2) jointly performing the hydrothermal selenylation reaction for a mixed solution of selenium powder, alkali, a reduction agent and organic solvent and the cobalt element-containing precursor in step (1), after the reaction is ended, drying, and obtaining the cobalt diselenide material. By combining the oxidation of hydrazine hydrate and the specific application of a hydrogen evolution catalyst, the preparation of the cobalt diselenide material is re-designed; and specifically by designing the overall process of the preparation method andselecting and optimizing parameter conditions adopted in each step and by optimally controlling the specific composition and microscopic morphology of the cobalt diselenide material, the cobalt diselenide bifunctional catalyst with greatly-improved catalytic activity can be correspondingly obtained.

The invention relates to the technical field of electrocatalysts, and discloses a defect-rich molybdenum-doped cobalt selenide / nanocarbon electrocatalyst, and a preparation method and an application thereof. The preparation method comprises the following steps: (1) dissolving a cobalt salt and a molybdate, adding a 2-methylimidazole solution, conducting stirring and mixing, and conducting centrifugal drying to obtain a molybdenum-doped cobalt-based metal organic framework precursor; (2) mixing the precursor with selenium powder, conducting grinding, and conducting calcining to obtain a molybdenum-doped cobalt selenide / nanocarbon electrocatalyst; and (3) carrying out heat treatment on the catalyst prepared in the step (2) to obtain the defect-rich molybdenum-doped cobalt selenide / nanocarbonelectrocatalyst. The obtained catalyst has excellent electro-catalytic activity on a water electrolysis cathode hydrogen evolution reaction under an alkaline condition, and still has relatively goodstability under long-term work.

The invention provides a cobalt selenide and carbon composite material for a negative electrode of a high-performance potassium ion battery, a preparation method of the cobalt selenide and carbon composite material and a matched electrolyte. The mass content of cobalt selenide in the composite material is 50-80%, and the mass content of carbon in the composite material is 20-50%. The microstructure of the cobalt selenide and carbon composite material is that cobalt selenide nanoparticles are uniformly distributed in a carbon skeleton of a cubic block structure, and the carbon skeleton of the cubic block structure is uniformly coated with an additional carbon layer. The invention also provides a preparation method of the composite material and an electrolyte matched with the composite material. The unique cubic carbon skeleton structure of the composite material can enhance charge transfer in the embedding / de-embedding process of potassium ions, and volume change in the discharging / charging process can be buffered to the maximum extent. By optimizing the electrolyte, the cycling stability of the composite material applied to the potassium ion battery is further improved. The preparation method of the cobalt selenide and carbon composite material is simple in synthesis process and easy to operate.

The invention relates to the technical field of new energy materials, in particular to a preparation method and application of a cobalt diselenide / carbon-based flexible electrode material with an interface enhancement structure. The preparation method comprises the following steps: (1) carrying out hydrophilization treatment on carbon cloth; (2) preparing a metal salt solution containing Co<2+>, adding a 2-methylimidazole solution, carrying out uniform mixing to obtain a mixed solution, adding the hydrophilized carbon cloth into the mixed solution, and conducting standing for reaction; (3) growing a carbon nanotube by adopting a CVD method; (4) carrying out selenylation treatment to obtain a CoSe2 / N-CNT@CC composite material; and (5) compounding theCoSe2 / N-CNT@CC composite materialwith a gel electrolyte to obtain the cobalt diselenide / carbon-based flexible electrode material with the interface enhancement structure. The preparation method disclosed by the invention is simple to operate, mild in condition, easy to control, free of special requirements on equipment and beneficial to industrial production; and the prepared cobalt diselenide / carbon-based flexible electrode material with the interface enhancement structure has a high contact area and high stability, and has wide application prospects in the field of flexible devices.

The invention provides a preparation method of an iron-doped cobalt diselenide nanosheet / reduced graphene composite electrode material. The preparation method comprises the following steps: (1) dispersing graphene oxide in a mixed solvent and carrying out ultrasonic dispersion to obtain a graphene oxide dispersion liquid; (2) adding cobalt salt and ferric salt into the graphene oxide dispersion liquid in the step (1) and stirring and dispersing to obtain a mixed dispersion liquid; and (3) adding selenium salt into the mixed dispersion liquid obtained in the step (2), stirring, soaking, heating, reacting, centrifuging, washing and drying to obtain the composite electrode material. The simple method is adopted, the iron-doped cobalt diselenide nanosheet and the composite material of the iron-doped cobalt diselenide nanosheet and graphene are prepared by taking low-cost transition metal salt as a precursor and adopting a one-step solvothermal method through optimization of the structure and composition of the material, and the material has the advantages of high specific capacity, good rate capability, long cycle life and the like as the negative electrode material of the sodium ion battery.

The invention belongs to the field of nano-functional materials and particularly relates to a cobalt diselenide material having a micro / nano three-dimensional multilevel structure as well as a preparation method and an application thereof. By the controllable synthesis of dual surfactants, a cobalt diselenide material having a three-dimensional nanometer multilevel structure is obtained and the three-dimensional multilevel structure has higher specific surface area and exhibits excellent microwave absorption property. The maximum reflection loss of the cobalt diselenide three-dimensional multi-level structure reaches -26.93 dB at 7.28 GHz. In addition, the microwave-absorbing material is low in preparation cost and high in efficiency, is convenient to industrially scale to solve practical application problems, is used as a novel microwave-absorbing material widely used for electromagnetic shielding and microwave absorption and has broad application prospects.

The invention discloses a preparation method of a cobalt diselenide / iron oxyhydroxide composite material with a nano petal-shaped structure, and belongs to the field of new-generation energy storage and catalysis. The cobalt diselenide / iron oxyhydroxide composite material with the nano petal-shaped structure is prepared through preparation of a cobalt-containing precursor, namely a one-step solvothermal method, preparation of cobalt diselenide, namely a chemical vapor deposition method, and preparation of a cobalt diselenide / iron oxyhydroxide heterojunction interface composite material, namely a water bath deposition method. Compared with the prior art, the cobalt diselenide and iron oxyhydroxide interface composite material with the petal-shaped geometric structure prepared by the invention shows excellent electrocatalytic activity and good stability in the process of driving the anode end catalysis of electrolyzed water, and is suitable for popularization and application.

The invention provides a preparation method and application of in-situ carbon-coated cobalt selenide nano materials. The method synthesizes a one-dimensional rod-like precursor by a hydrothermal method without adding any template or surfactant, and then prepares the cobalt selenide nanorod materials by simultaneous in-situ carbon coating and selenization. The method solves the problems such as high cost, complicated process and uneven coating of common carbon coating, and uniformly coats a layer of amorphous carbon around the cobalt selenide nanoparticles by the in-situ carbon coating method,thereby improving the stability and conductivity of the cobalt selenide materials. And the prepared cobalt selenide is in a rod-like structure with controlled size and length. The obtained carbon-coated cobalt selenide nano materials, used as negative electrode material for sodium ion batteries, exhibit high capacity, long cycle life and excellent rate performance. The preparation method has the advantages of simple process, low cost, high yield and good repeatability, and has very high practical value.

The invention provides a preparation method of a cobalt selenide / graphite carbon composite material. With Co(NO3)2-6H2O, 2-methylimidazole, methanol and selenium powder as raw materials, through the preparation of a polyhedral metal organic framework compound ZIF-67, the cobalt selenide / graphite carbon composite material is prepared based on MOFs template construction. The ZIF-67 prepared by the invention is a rhombohedral dodecahedron, a framework has a small grain diameter controlled to be about 300nm and is uniform, the specific surface area is large, and the overall distribution is uniform. The composite material of the invention has high crystallinity and high specific surface area and porosity, the homogeneous distribution can be formed, the prepared framework has the small grain size, and the overall distribution is uniform. At the same time, the electric shock capacity is large, the service life is long, the lithium storage performance is excellent and is not degraded after upto 200 times of charging and discharging cycles, the stability of the use process is good, the current is not suddenly large and small, the purity of a product is high, the preparation method of the invention has high yield which can reach 70% or more, the preparation process is simple and feasible, and the method is worth marketing.

The invention relates to a preparation method and application of a nitrogen-doped porous carbon-coated cobalt diselenide composite material, and the preparation method comprises the following steps: respectively dissolving cobalt salt and selenium powder in a solvent, and carrying out first stirring to respectively obtain a cobalt salt solution and a selenium powder solution; pouring the selenium powder solution into the cobalt salt solution, adding a liquid acrylonitrile oligomer, stirring for the second time, and adding a hydrazine hydrate solution after stirring to obtain a mixed solution; transferring the mixed solution into a hydrothermal reaction kettle, carrying out hydrothermal reaction, and then cooling, centrifuging and drying to obtain a precipitate; and calcining the precipitate, cooling, grinding and sieving to obtain the nitrogen-doped porous carbon coated cobalt diselenide composite material. The prepared nitrogen-doped porous carbon coated cobalt diselenide composite material is prepared into a lithium ion battery negative electrode, and the lithium ion battery negative electrode still has the specific discharge capacity of 644mAh / g after 300 times of charge-discharge cycles under the current density of 0.2 A / g.

The invention discloses preparation and application of a molybdenum-doped cobalt selenide foamed nickel composite electrode for electrolyzing water. The composite electrode is formed by depositing a molybdenum-doped cobalt selenide compound on a foamed nickel electrode, and the composite electrode is marked as Mo-CoSe2NS-NF. The electrode is applied to water electrolysis and has good electro-catalytic performance and stability on hydrogen evolution and oxygen evolution at the same time, the catalytic hydrogen evolution [eta]10 is 89mV, and the Tafel slope is 69mV dec-1; the catalytic oxygen evolution [eta]10 is 234 mV, the Tafel slope is 58 mV dec-1, the Tafel serves as a cathode and an anode to form an electrolytic cell, and the electrolytic voltage is only 1.56 V when the current densityin an alkaline medium reaches 10 mA cm <-2>. The catalytic active substance of the composite electrode is directly deposited on the foamed nickel electrode, the synthesis method is simple, green andenvironment-friendly, and the composite electrode has an efficient bifunctional catalytic effect, so that the designed water electrolysis tank is simple in structure and suitable for industrial large-scale application of water electrolysis.

The invention discloses a nickel-doped cobalt selenide electrocatalytic hydrogen evolution catalyst and a preparation method thereof, and relates to an electrocatalytic hydrogen evolution catalyst anda preparation method thereof. The invention aims to solve the technical problems of complex preparation steps, high cost and poor safety of existing cobalt selenide-doped electrocatalytic hydrogen evolution catalysts. The general chemical formula of the catalyst is CoxNiySe2, wherein x is in a range of 0.6-0.8, and y is in a range of 0.1-0.35. The preparation method comprises the following steps:dissolving selenium powder in a potassium hydroxide solution, then adding Co(NO3)2.6H2O, Ni(NO3)2.6H2O, ethylene diamine tetraacetic acid-2Na (EDTA-2Na) and ultrapure water, carrying out uniform stirring to obtain a mixed solution, transferring the mixed solution into a reaction kettle for a hydrothermal reaction, and then carrying out cleaning and drying to obtain the catalyst. The overpotentialof the catalyst reaches 170-195 mV VS RHE, and after 1000 circles of continuous cyclic voltammetry tests, a polarization curve is almost overlapped with an initial curve, so that stability is high, and the catalyst can be used in electrocatalytic hydrogen evolution reactions.

The invention discloses a preparation method of ZIF-67 and a ZIF-67 derivative cobalt selenide / carbon electrode material, which comprises the following steps: dissolving 2-methylimidazole and KOH in deionized water to obtain a transparent solution, adding a Co(NO3)2.6H2O solution into the transparent solution, and stirring to obtain ZIF-67 powder, wherein the amount-of-substance ratio of the 2-methylimidazole to the Co(NO3)2.6H2O is 8:1, and the amount-of-substance concentration of the KOH is 0.1 to 3 mol L <-1>; and carbonizing the polyhedral ZIF-67 precursor, and preparing the cobalt selenide / carbon composite material by adopting different selenylation methods. According to the invention, the ZIF-67 with different morphologies is synthesized in an aqueous solution under the assistance of KOH for the first time, and the derived cobalt selenide / carbon composite material shows excellent lithium storage performance. The method has the characteristics of green solvent, simple process, short reaction time, high yield and controllable product morphology.

The invention discloses a carbon sphere coated cobalt selenide nano-composite material and a preparation method and an application thereof. The material includes a cobalt selenide nano-material with the particle size being 3-10nm and porous carbon spheres coating the cobalt selenide nano-material, wherein the particle size of the porous carbon spheres is 100-700nm. The nano-composite material usesthe porous carbon spheres to disperse cobalt selenide nano-material, and uses the porous carbon spheres to play a role of electron conduction at the same time. As a negative electrode material of sodium-ion batteries, the nano-composite material can accommodate the volume change of the cobalt selenide nano-material in the charging and discharging process and improve the cycle stability of the sodium-ion batteries.

The invention discloses a method of preparing nano porous cobalt selenide in a low-eutectic ionic liquid via electrodeposition and belongs to the technical field of material preparation. The method includes steps of: 1) adding a cobalt salt precursor and SeO2 to the low-eutectic ionic liquid to form an electrodeposition solution; 2) employing a triple-electrode system, wherein a Pt electrode or agraphite electrode is an electro-deposition pair electrode, a silver wire electrode is a reference electrode, and copper or nickel is a working electrode, performing electrodeposition at 333-343 K toprepare a nano porous cobalt selenide thin film. In the method, the nano porous cobalt selenide is produced as a bifunctional electrode material for catalytically splitting water to separate hydrogen / oxygen. The material can be applied to alkaline solution in different concentrations and has stable performance. The preparation method has gentle conditions and simple operations, is easy to controland is good in product quality. The material has practical significance to industrial production and application and development of micron / nano cobalt selenide materials, and has a wide application prospect.