315results about "Binary selenium/tellurium compounds" patented technology

The invention belongs to the field of resource regeneration, and particularly relates to a method for separating and recycling copper, indium, gallium and selenium from a waste solar thin film battery. According to the method, the waste solar thin film cells are subjected to oxidizing roasting, deep eutectic leaching and extraction and reverse extraction, and high-quality conversion and purification of all valuable elements in the waste solar thin film cells to oxides of the valuable elements are achieved. According to the method, the process route is simple, high-selectivity extraction of indium is achieved through the synergistic effect of the deep eutectic solvent and P204, and meanwhile effective recovery of valuable elements such as copper and selenium is achieved. The recovered and prepared oxide can be widely applied to strategic emerging industries such as semiconductors, photovoltaics, aerospace, military and the like.

The invention discloses an Ag2Se-based thermoelectric material and a preparation method thereof, and belongs to the technical field of thermoelectric materials. The preparation method comprises the steps that Ag powder and Se powder are mixed and ground according to the molar ratio of (1.9-2.1): 1, and mixed powder is obtained; the mixed powder is subjected to cold pressing to form blocks, and prefabricated blocks are obtained; the prefabricated block is subjected to heat preservation for 20-120 minutes under the conditions that the pressure is 1-5 GPa and the temperature is 400-1000 DEG C, and an Ag2Se initial product is generated through reaction; crushing the primary product, and grinding into fine powder; and sintering the fine powder for 5-30 minutes under the conditions that the pressure is 1-5 GPa and the temperature is 300-900 DEG C, so as to obtain the composite material. The sample is prepared through high temperature and high pressure for the first time, the method is simple, operation is easy to control, the preparation period can be greatly shortened, and the energy utilization rate is increased; the electroacoustic transport performance of Ag2Se is effectively regulated and controlled by changing the pressure and the temperature, and finally the thermoelectric performance is effectively improved.

The invention discloses a bismuth telluride nanopore maskless direct writing preparation method based on electron beam irradiation, and belongs to the technical field of nanometer manufacturing. The method comprises the following steps: firstly, constructing an initial nanopore in a two-dimensional bismuth telluride material by utilizing a converged electron beam; and then the aperture size of the nanopore is accurately regulated and controlled by adjusting the beam density of the electron beam. The method effectively solves the key technical bottlenecks of interface chemical residue pollution caused by a traditional photoresist mask process, intrinsic defect formation caused by high-energy particle bombardment and the like, and breaks through the limitation of an existing etching technology in the aspect of sub-nanoscale structure precision control; precise control of the aperture of the nanopore can be achieved by adjusting the irradiation intensity of the electron beam, and the method has the advantages of being easy and convenient to operate, low in cost, environmentally friendly and the like and can be widely applied to the fields of nanometer electronic devices, sensors and the like.

The invention provides a method for recycling valuable metal from germanium-antimony-tellurium alloy waste. The method comprises the three steps of surface treatment, chlorine reaction and compartment condensation and discharging. Oxidation films on the surfaces of the waste materials are removed through surface treatment, and the subsequent chlorine reaction efficiency is improved; then a self-made chlorination-step condensation integrated device is utilized, germanium, antimony and tellurium react with chlorine at the high temperature to generate gaseous chloride, step-by-step condensation separation is achieved through partition temperature control based on the boiling point difference of tellurium tetrachloride, antimony pentachloride and germanium tetrachloride, and target products are collected respectively; and finally, introducing inert gas to purge residual chlorine, and discharging safely. The method has the advantages of short process flow, no need of complex wet process steps and low equipment investment; metal chlorides are efficiently separated through the integrated device, and recovery is thorough; and the pyrogenic process is mainly adopted, no wastewater is generated, only tail gas is treated in a compliance manner, and the method is environment-friendly. Compared with a traditional wet process, the method has the remarkable advantages of high efficiency, low cost, environment friendliness and the like.

The invention discloses a heterostructure sodium ion battery negative electrode material and a preparation method and application thereof, and belongs to the technical field of sodium ion batteries. The method comprises the following steps: (1) dissolving a carbon source, tin salt and antimony salt in a solvent to obtain a precursor solution; the carbon source is a nitrogen-containing organic compound; (2) removing a solvent in the precursor solution to obtain precursor powder; and (3) in a reducing atmosphere, carrying out gas-phase selenylation treatment by using selenium powder to obtain the sodium-ion battery negative electrode material with the heterostructure SnSe-Sb2Se3, namely the sodium-ion battery negative electrode material with the heterostructure. The method is simple and easy in process, good in repeatability and easy to adjust and realize industrial production, and the prepared heterostructure sodium ion battery negative electrode material relieves material volume expansion, has excellent sodium storage performance, brings excellent long cycle performance and rate capability, and has wide popularization and application prospects in the fields of electronic equipment, large-scale energy storage and the like.

The invention relates to a vacancy-assisted tin heterovalent doped bismuth selenide material as well as a preparation method and application thereof, Se vacancy defects existing in VSe-Bi2Se3 are utilized to assist in stable doping of Sn < 4 + > into Bi sites, so that the Sn-VSe-Bi2Se3 material is obtained. As the positive electrode material of the zinc ion battery, the Sn-VSe-Bi2Se3 shows high specific capacity, excellent rate capability and long-acting stable cycle performance, and has the advantages of simple and convenient process, mild conditions and suitability for large-scale production.

The invention discloses a nickel-cobalt-selenium (Co1-xNixSe2) nano material for electrocatalytic oxidation of ethylene glycol as well as a preparation method and application of the nickel-cobalt-selenium (Co1-xNixSe2) nano material. The material is prepared by a hydrothermal method which comprises the following steps: (1) pouring 20mL of deionized water containing 475.9 mg of CoCl2. 6H2O into a 1mol / L NaOH solution containing 0.32 g of selenium powder to prepare a precursor solution; (2) placing in a stainless steel autoclave with a polytetrafluoroethylene lining, carrying out hydrothermal reaction at 180 DEG C for 18 hours, washing with absolute ethyl alcohol and deionized water, and carrying out vacuum drying at 60 DEG C to obtain a CoSe2 material; and (3) the molar feeding ratio of CoCl2. 6H2O to NiCl2. 6H2O is adjusted, so that the nickel / cobalt ratio x is 0.25, 0.50 or 0.75, and materials with different components, namely Co < 0.75 > Ni < 0.25 > Se < 2 >, Co < 0.50 > Ni < 0.50 > Se < 2 > and Co < 0.25 > Ni < 0.75 > Se < 2 >, are prepared. The series of materials are applied to ethylene glycol oxidation under the alkaline condition, the catalytic performance of Co < 0.50 > Ni < 0.50 > Se < 2 > is optimal, the current density reaches 111 mA cm <-2 > under the electric potential of 1.6 V vs.RHE, the total Faraday efficiency reaches up to 91.4%, and the application prospect in the field of PET plastic recovery is wide.

The invention relates to the technical field of gas sensors for detecting H2S at room temperature, in particular to a preparation method of a high-sensitivity MoSe2-based gas sensitive material for detecting H2S at room temperature. The high-sensitivity MoSe2-based gas sensitive material for detecting H2S at room temperature is prepared by synthesizing MoSe2 nanoflowers by adopting a hydrothermal method and uniformly loading In2O3 nanoparticles on the surfaces of the MoSe2 nanoflowers by adopting a mechanical mixing method. The preparation method is simple and convenient in process and low in cost, the MoSe2 / In2O3 composite material prepared by the method has a relatively high specific surface area, and an II-type p-n heterojunction interface formed by the composite material effectively promotes separation and migration of current carriers. The response to 0.05 ppm H2S, 0.1 ppm H2S, 0.25 ppm H2S, 0.5 ppm H2S and 1ppm H2S at room temperature (the gas response is calculated according to the formula R = (Rg-Ra) / Ra) is 1.37, 1.47, 1.85, 2.74 and 4.82 respectively, the response is far better than that of an existing pure-phase MoSe2 gas sensitive material, and the working temperature is lower than that of an In2O3 pure-phase material. The research provides an effective method for constructing a gas sensitive material with a large specific surface area and II type p-n heterojunction, and further promotes the development of a gas sensitive technology.

The invention relates to a surface-modified co-doped lithium-rich manganese-based positive electrode material and a preparation method thereof. The surface-modified co-doped lithium-rich manganese-based positive electrode material comprises a bulk phase part and a surface part, the bulk phase part is a cation co-doped lithium-rich manganese-based material, the chemical formula is Li < 1.2 > Ni < 0.17 > Co < 0.16-x > M < x > Ru < y > Mn < 0.47-y > O < 2 >, in the formula, M is at least one of V, Cr and Fe, x is more than or equal to 0.06 and less than or equal to 0.14, and y is more than or equal to 0.05 and less than or equal to 0.2; the surface part is a selenium-halogen composite modified layer coating the bulk phase part in situ, contains selenide and lithium halide, and is formed by heat treatment of a bulk phase material, a selenium source and a halogen source in an inert atmosphere. The positive electrode material provided by the invention has excellent structural stability and high lithium ion diffusion coefficient, has good interface compatibility with halide electrolyte, and has high energy density and long cycle stability when being used in a halide all-solid-state battery.

The invention relates to the technical field of preparation of electro-catalysis electrode materials, in particular to a preparation method and application of a SeO2 doped RuO2 electrolyzed water catalyst.The preparation method comprises the steps that S1, ruthenium acetate and selenium dioxide are dissolved in deionized water together and continuously stirred to obtain a mixed solution A, then sodium citrate is dissolved in deionized water, and the PH value is adjusted to be 9 with ammonia water to obtain a solution B; s2, mixing the solution A and the solution B, reacting at 80 DEG C for 12 hours, naturally cooling, ultrasonically washing with deionized water and ethanol in sequence, centrifuging, and drying in a drying oven to obtain a catalyst precursor; and S3, carrying out two-step pyrolysis on the precursor, namely heating to 250 DEG C, annealing for 4 hours, heating to 400 DEG C, annealing and heating for 2 hours, so as to obtain the SeO2-doped RuO2 nanosheet. By introducing a proper amount of SeO2 for doping, the electronic structure of RuO2 is optimized, the adsorption and desorption balance effect of the catalyst on a reaction intermediate is adjusted, the Ru site catalytic performance is improved, and the obtained SeO2-doped RuO2 nanosheet has efficient acidic OER catalytic performance.

The invention discloses a preparation method of an ultrathin two-dimensional nanosheet, the ultrathin two-dimensional nanosheet and application of the ultrathin two-dimensional nanosheet, and the preparation method comprises the following steps: (1) mixing a raw material containing a layered solid-phase material I with an intercalator, and carrying out intercalation reaction to obtain an intercalated layered solid-phase material II; and (2) mixing the intercalated layered solid-phase material II obtained in the step (1) with a solvent, and carrying out ultrasonic treatment to obtain the ultrathin two-dimensional nanosheet, the chemical formula of the layered solid-phase material I is MQ2. The material has potential application value in catalysis, energy storage and quantum devices.

The present invention belongs to the field of silicon negative electrode battery materials and specifically discloses a method for preparing a MSe / Si / C composite material. The method comprises mixing M-MOF and a selenium source and performing a calcination reaction to obtain an MSe / C product. The MSe / C is then subjected to a vapor deposition treatment in a silicon source atmosphere to obtain an MSe / Si / C composite material. The M is a transition metal element; and the M-MOF is a metal framework material of a transition metal element. The present invention also provides a material obtained by the preparation method and its application in a battery. The process of the present invention can induce uniform and efficient deposition of silicon, facilitates the in-situ construction of an electronic and ion conduction network of M and Li2Se during the charge and discharge phase, and helps improve the low-temperature fast charging performance of the material.

The present invention relates to the synthesis of pure metal or multi-metal derivatives of ZIF-11, ZIF-12 or amorphous ZIF structures in high yield followed by calcination under inert conditions to produce in composite nanostructures one or more metal selenide dispersed on the surface of or embedded in a carbon matrix, and using these composites as electrodes for lithium ion batteries, sodium ion batteries, potassium ion batteries, supercapacitors or fuel cells.

The invention provides a preparation method of a Mo-doped FeSe2 electrode material and application of the Mo-doped FeSe2 electrode material as a sodium-ion battery anode, and the preparation method comprises the following steps: mixing FeCl3. 6H2O, terephthalic acid and N, N-dimethylformamide, loading into a reaction kettle, and heating at high temperature to obtain an MIL-88B metal organic framework precursor; and then dispersing the MIL-88B precursor, sodium molybdate, selenium powder and hydrazine hydrate in a solvent, and doping Mo atoms into a FeSe2 electrode material through hydrothermal synthesis to obtain the Mo-FeSe2 sodium ion battery anode. According to the preparation method, Mo atoms are doped into FeSe2, so that the strength of Fe-Se bonds is enhanced, the structure collapse effect of the electrode material is effectively relieved from the structure level, an SEI film on an electrode liquid interface is compact and uniform, and the multiplying power and the cycle service life of the electrode material are effectively improved.

The invention belongs to the field of nano materials, and particularly relates to an indium selenide nanosheet compound as well as a preparation method and application thereof. The preparation method provided by the invention comprises the following steps: mixing indium selenide nanosheets and silver ions in a second solvent, so that silver nanoparticles grow on the surfaces of the indium selenide nanosheets; the second solvent is a polar solvent, the Hansen solubility parameter delta of the third solvent is greater than or equal to 18MPa < 1 / 2 >, and the mass ratio of the indium selenide nanosheets to the silver ions is (5-50): 1. And growing silver nano-silver particles on the surface of indium selenide by utilizing a spontaneous oxidation-reduction reaction of indium selenide and silver nitrate, so as to prepare the indium selenide nanosheet compound with the surface modified by the silver nano-silver particles. The silver nanoparticles have strong absorption, and the photoelectric response effect of the indium selenide nanosheet is remarkably improved by compounding the silver nanoparticles and the indium selenide nanosheet.

The utility model relates to a device for producing tellurium powder by using tellurium dioxide, and belongs to the technical field of tellurium powder production equipment. Comprising a leaching kettle, a plate-and-frame filter press, a primary reduction kettle, a primary reduction filter barrel, a secondary reduction kettle, a secondary reduction filter barrel and a waste liquid tank which are sequentially connected, materials in the leaching kettle are conveyed into the plate-and-frame filter press through a first conveying pump, and the leaching kettle is further connected with a hydrochloric acid storage tank through a pipeline; the opening of the primary reduction kettle is positioned right above the primary reduction filter barrel, and the primary reduction kettle is also connected with a sulfur dioxide steel cylinder; materials in the primary reduction filter barrel are conveyed into a secondary reduction kettle through a second conveying pump; an outlet of the secondary reduction kettle is positioned right above the secondary reduction filter barrel, and the secondary reduction kettle is also connected with a sulfur dioxide steel cylinder; materials of the secondary reduction filter barrel are input into the waste liquid tank through a third conveying pump; the tellurium dioxide is produced by adopting the method, the technological operation is simple, the production efficiency is high, the tellurium content of the liquid after secondary reduction is low, the liquid can be reused in a leaching kettle, and the use amount of hydrochloric acid is reduced.

The invention discloses a preparation method of a NiS / NiSe2 heterojunction containing a non-interface Ni vacancy. The preparation method comprises the steps of precursor preparation and in-situ selenylation treatment. The invention further discloses the NiS / NiSe2 heterojunction containing the non-interface Ni vacancy. The NiS / NiSe2 heterojunction containing the non-interface Ni vacancy is prepared through the method.

The invention belongs to the technical field of nano materials and anti-tumor treatment medicines, and discloses cordyceps sinensis mycelium polysaccharide-copper selenide with dual effects of inducing tumor cell apoptosis and copper death as well as a preparation method and application thereof. The preparation method of the cordyceps sinensis mycelium polysaccharide-copper selenide comprises the following steps: taking cordyceps sinensis mycelium polysaccharide as a template, adopting a soft template method, reducing Na2SeO3 through Vc, and adding CuSO4 to prepare the cordyceps sinensis mycelium polysaccharide-copper selenide. The cordyceps sinensis mycelium polysaccharide-copper selenide can selectively kill tumor cells and induce apoptosis and copper death of the tumor cells at the same time, and has huge application potential in the aspect of tumor prevention and treatment.

The invention belongs to the technical field of sodium-ion batteries, and particularly relates to an iron-manganese-based sodium-ion battery positive electrode material as well as a preparation method and application thereof. The preparation method of the iron-manganese-based sodium ion battery positive electrode material comprises the following steps: adding ferric nitrate and manganese nitrate into water for dissolving, performing spray pyrolysis to obtain an iron-manganese oxide precursor, performing ball-milling mixing on sodium carbonate, the iron-manganese oxide precursor and lanthanum telluride, and calcining in an inert gas atmosphere to obtain a composite material; and adding Ni4O4 cubic alkane modified carbazole, the composite material and manganese dioxide into dilute sulphuric acid for ultrasonic dispersion, stirring for reaction, centrifuging, washing and drying to obtain the iron-manganese-based sodium ion positive electrode material. The iron-manganese-based sodium ion battery positive electrode material provided by the invention has the advantages of stable rate cycle, high specific capacity and excellent capacity retention rate.

The application discloses a transfer method of a two-dimensional material film, which comprises the following steps: coating photoresist on the surface of a two-dimensional material film directly grown on a growth substrate and solidifying the photoresist to form a transfer medium layer; separating the growth substrate from the transfer medium layer / two-dimensional material film; after the transfer medium layer / two-dimensional material film is attached to a target substrate, heating is performed to melt the transfer medium layer; and the transfer medium layer is removed. The transfer method of the application utilizes the characteristic that the photoresist can be softened at a low melting point after being solidified, and firstly solidifies the photoresist on the surface of the two-dimensional material film to be transferred to serve as a support medium for the transfer of the film, so that the transfer of the film is realized. After being transferred to the target substrate, the solidified photoresist can be softened, so that the transferred two-dimensional material film can be fully contacted with the target substrate, and the complete and intact transfer of the two-dimensional material film can be realized. The transfer method of the application is especially suitable for the transfer to a rough target substrate.

The invention discloses an electrochemical method for regulating and controlling the phase, resistance and magnetism of a two-dimensional layered material, and belongs to the field of two-dimensional transition metal chalcogenide. The electrochemical method comprises the steps that an electrode system is provided, the electrode system comprises a working electrode and a counter electrode, the working electrode comprises a two-dimensional layered material, the chemical formula of the two-dimensional layered material is MX2, M represents a transition metal element, and X represents a group VI element where a sulfur element is located; providing an electrolyte, wherein the electrolyte is a soluble salt solution containing magnetic transition metal ions; the electrode system is placed in the electrolyte, and under the action of an external electric field, the magnetic transition metal ions are embedded and separated from the two-dimensional layered material, so that the phase, the resistance and the magnetism of the two-dimensional layered material are synergistically regulated and controlled. According to the technology, magnetic transition metal ions are driven by an electric field to be reversibly embedded into and separated from a two-dimensional layered material, so that the phase, the resistance and the magnetism of the two-dimensional layered material are synergistically and dynamically regulated and controlled, and the problems that the traditional external field regulation and control dimension is single, and intrinsic physical property coupling change is difficult to realize are solved. And multi-physical-property combined regulation and control is realized by adjusting an electric field, so that a basis is provided for application of the material in the fields of photoelectric devices, magnetoelectric storage, sensors and the like.

The application relates to the field of surface-enhanced Raman scattering, and specifically provides a three-dimensional SnSe2 surface-enhanced Raman scattering substrate and a preparation method thereof. The three-dimensional SnSe2 surface-enhanced Raman scattering substrate comprises a filter layer, a plurality of filter holes are arranged on the filter layer, a SnSe2 nanostructure layer is fixedly arranged on the upper side of the filter layer, the SnSe2 nanostructure layer is composed of SnSe2 nanostructures, the SnSe2 nanostructure is SnSe2 nanoflower, the SnSe2 nanoflower covers the filter layer, and the SnSe2 nanoflower blocks the filter holes on the filter layer. No vertical gap exists in the SnSe2 nanoflower structure, which makes the local effect of the SnSe2 nanoflower on a light field better, so that the Raman signal enhancement factor is improved. The preparation method of the three-dimensional SnSe2 surface-enhanced Raman scattering substrate comprises the following steps: S1, preparing SnSe2 nanoflower; S2, preparing an aqueous solution of the SnSe2 nanoflower; and S3, performing suction filtration to obtain the SnSe2 surface-enhanced Raman scattering substrate. The preparation method does not use a molecular beam epitaxy method, and the cost is low.

The present invention belongs to the field of nanomaterial technology, and provides a bimetallic chalcogenide composite material, and a preparation method and application thereof. The composite material of the present invention includes a two-dimensional layered carrier, and a first metal chalcogenide and a second metal chalcogenide loaded on the two-dimensional layered carrier; the two-dimensional layered carrier is a MXene material, and the MXene material is an M metallized carbon material; the first metal chalcogenide is MX2; the second metal chalcogenide is AX2; wherein M is a first metal, A is a second metal, and X is a chalcogen element. The present invention uses a two-dimensional layered carrier as a carrier to load the bimetallic chalcogenide, which can make the structure of the bimetallic chalcogenide complete; and the two-dimensional layered carrier can form a stable heterogeneous interface with the bimetallic chalcogenide, which is beneficial to the charge transfer between different components and the rapid storage of lithium ions, so that the composite material can be better applied to the field of lithium storage negative electrodes.

This invention discloses a superhydrophobic unsaturated transition metal chalcogenide compound, its synthesis method, and its applications. The invention involves heating chalcogenide powder to above its melting temperature to form a molten chalcogenide. This molten chalcogenide is then mixed with a reducing agent to undergo a disproportionation reaction. A strongly acidic solution containing transition metal cations is then added for aging, yielding a transition metal chalcogenide compound with a uniform porous structure, numerous surface defect sites, and a superhydrophobic surface. This transition metal chalcogenide compound exhibits good water resistance and high selective adsorption performance for nonpolar atoms and molecules, making it suitable for the removal of heavy metals or oxides from high-humidity flue gas. Furthermore, its unique porous structure and numerous catalytically active sites demonstrate good adsorption, capture, and catalytic conversion activity for oxidizing gases, making it suitable as an electroreduction catalyst.

The invention discloses a zinc selenide leftover material regeneration method and system and a high-purity zinc selenide evaporation material, and relates to the technical field of semiconductor material cyclic regeneration. The zinc selenide leftover material regeneration method sequentially comprises a pretreatment step, a low-temperature devolatilization step, a medium-temperature impurity removal step, an ultrafine crushing step and a vacuum directional sublimation purification step, and the low-temperature devolatilization step is characterized in that the zinc selenide leftover material is heated to a first preset temperature under a dynamic vacuum condition to remove free selenium and elemental zinc impurities; in the medium-temperature impurity removal step, the zinc selenide leftover materials are heated to a second preset temperature to promote lattice recombination of ZnO impurities, a double-temperature-zone vacuum deposition furnace is adopted in the vacuum directional sublimation purification step, the temperature of an evaporation zone is 1100-1150 DEG C, the temperature of a condensation zone is 400-450 DEG C, the steam transmission distance is smaller than 30 cm, and products in the condensation zone are collected. The technical scheme provided by the invention has the advantages of high recycling rate, high purity of the regenerated zinc selenide evaporation material, low energy consumption and high process safety.

This application relates to the field of electrolyte materials technology, and in particular to a method for preparing lithium selenide. The method includes: obtaining a precursor source, the precursor source including lithium nitride and a selenium source, and subjecting the precursor source to multiple calcination treatments to obtain lithium selenide. The present invention uses lithium nitride as a lithium source and a selenium source to undergo a redox reaction to generate lithium selenide and nitrogen gas. This method has a low cost, does not produce carbon impurities in the prepared product, and the prepared lithium selenide can be used directly as a high-purity raw material for solid electrolytes. In addition, the reaction between lithium nitride and selenium has low exothermic reaction, the reaction is easy to control, and the safety is higher, avoiding the problem of low safety caused by high exothermic reaction of elemental selenium and elemental lithium in the prior art.

The application discloses a preparation method of a suspended two-dimensional material film and the suspended two-dimensional material film. The preparation method comprises the following steps: providing a substrate, wherein the substrate has a first surface and a second surface opposite to each other; forming a sacrificial layer film on the first surface of the substrate; forming a through hole on the second surface of the substrate, and the through hole exposes the sacrificial layer film; obtaining a two-dimensional material film, transferring the two-dimensional material film to the sacrificial layer film, and the two-dimensional material film covers the through hole; etching the sacrificial layer film from the second surface of the substrate until the two-dimensional material film is exposed, and a suspended two-dimensional material film is formed. The preparation method of the suspended two-dimensional material film and the suspended two-dimensional material film have the advantages that the two-dimensional material film has low transfer difficulty, the light source has little influence on the test, and the test means is effectively widened.

A method for adjusting the wide spectrum detection of transition metal chalcogenides by using vacancy defects belongs to the field of two-dimensional materials. In the method, transition metal oxides are used as metal sources, two different chalcogen elements are used as sulfur sources, and a single-layer ternary transition metal chalcogen compound with uniform element distribution is grown by using a chemical vapor deposition method. By using the difference in the stability of the chemical bonds between alloy elements, the unstable chemical bonds are broken by hydrogen-assisted annealing, and the generated chalcogen element vacancy defects are uniformly distributed in the ternary transition metal chalcogen compound. The chalcogen element vacancy defects introduce defect energy levels between the conduction band and the valence band of the transition metal chalcogen compound, generate new photoluminescence peaks, and widen the spectrum detection range. The experimental method is simple in process, good in repeatability, can accurately control the type, distribution and number of defects, and is suitable for large-scale production.

The application belongs to the field of inorganic semiconductor material synthesis, and particularly relates to a preparation method and application of large-size two-dimensional cadmium selenide nanosheet, wherein the preparation method is to select cadmium acetate and selenium powder as solutes, mix them uniformly with amine as a solvent, and then heat to controllably synthesize two-dimensional wurtzite cadmium selenide nanosheet with ultraviolet absorption peaks of 429 nm, 456 nm and 485 nm, 518 nm; the application avoids high-temperature and high-pressure operation by controlling reaction conditions, and obtains a convenient preparation method of cadmium selenide nanosheet by selecting suitable raw materials, thereby solving related problems existing in the synthesis of cadmium selenide nanosheet; the preparation method has low cost and wide application range, the prepared cadmium selenide nanosheet has excellent optical performance in addition to different thicknesses obtained by changing temperature and reaction time, and can be widely applied in the fields of biological sensing and photocatalysis.

The invention discloses a carbon nanotube / cadmium selenide quantum dot heterojunction photoelectric catalyst as well as a preparation method and application thereof. The method comprises the following steps: activating single-wall and / or multi-wall carbon nanotubes by aqua regia at room temperature, dispersing the single-wall and / or multi-wall carbon nanotubes in an aqueous solution containing CdCl2. 5H2O, adding a Na2SeSO3 selenium source and 3-mercaptopropionic acid, and reacting at 110-150 DEG C, so that CdSe quantum dots with the particle size of 1-5 nm are subjected to in-situ nucleation growth on the surfaces and / or the interiors of the carbon nanotubes and form a heterojunction interface. The obtained catalyst and Nafion are prepared into ink drops, the ink drops are coated on conductive glass to construct a photocathode, in an H-type electrolytic tank with a light path, a high-purity CO2 saturated bicarbonate aqueous solution is used as an electrolyte, Ag / AgCl is used as a reference electrode, and under irradiation of an LED light source with the maximum wavelength being 450 nm and bias voltage ranging from-0.1 V (vs. RHE) to-1.0 V (vs. RHE), CO is generated through water-phase photoelectrocatalysis CO2 reduction. The photoelectrocatalyst has the characteristics of simple synthesis method and excellent photoelectrocatalytic reduction effect of carbon dioxide.