48results about How to "Improve gas sensing performance" patented technology

The invention relates to the technical field of sensor detection, and discloses a detection method and device based on a multi-mode gas sensor, and the method comprises the following steps: carrying out blending processing on a metal oxide semiconductor and a conductive material to obtain a bimodal nano composite material, and creating a multi-mode gas detection module, the preprocessed multi-mode signal data is acquired and obtained; acquiring and analyzing data of the temperature sensor and the humidity sensor to obtain environmental factor compensation parameters; performing adaptive calibration processing on the preprocessed multi-modal signal data according to the environmental factor compensation parameters to obtain calibrated multi-modal signal data; constructing a multi-input neural network model based on the calibrated multi-modal signal data, and training to obtain a gas recognition model; multi-mode signals collected and calibrated in real time are analyzed and judged based on the gas recognition model, gas type and concentration information is obtained, and high-precision and high-reliability gas detection is achieved.

The invention discloses a SnO2 modified WO3 nanosheet composite gas-sensitive material as well as a preparation method and application thereof, and belongs to the technical field of inorganic composite materials. The preparation method comprises the following steps: dissolving WCl6 in ethanol, adding into a reaction kettle provided with a ceramic tube, carrying out hydrothermal reaction at 170-190 DEG C for 5-8 hours, taking out the ceramic tube, drying, and annealing to obtain a ceramic tube loaded with WO3 nanosheets; the preparation method comprises the following steps: dissolving SnO2, tin chloride and urea in water to obtain a mixed solution, adding the mixed solution into a reaction kettle filled with a ceramic tube loaded with a WO3 nanosheet, carrying out a hydrothermal reaction at 90-100 DEG C for 1-4 hours, taking out the ceramic tube after the reaction is finished, and drying to obtain the SnO2 modified WO3 nanosheet composite gas sensitive material, and enabling the SnO2 modified WO3 nanosheet to grow on the ceramic tube in situ. The preparation method is simple, the product is high in crystallinity and good in stability and is suitable for preparing a gas sensitive sensor material with high economical efficiency, and a sensor prepared from the SnO2 modified WO3 nanosheet composite gas sensitive material can effectively improve the gas sensitive performance of WO3 and shows an extremely high response value to nitrogen dioxide at a low temperature.

The invention provides a zinc oxide-zinc ferrite hollow nanoflower composite material as well as a preparation method and application thereof, and belongs to the technical field of gas sensitive materials. The preparation method comprises the following steps: precipitating zinc acetate, polyvinylpyrrolidone and potassium ferricyanide at room temperature by adopting a chemical precipitation method to obtain solid Zn3 [Fe (CN) 6] 2 nanoparticles; the preparation method comprises the following steps: taking Zn3 [Fe (CN) 6] 2 nanoparticles as a template reactant, etching the Zn3 [Fe (CN) 6] 2 nanoparticles in water-N, N-dimethylformamide to obtain a ZnFe precursor, and carrying out high-temperature calcination treatment on the precursor to obtain the zinc oxide-zinc ferrite hollow nanoflower structure composite material. The ZnO / ZnFe2O4 composite material prepared by the method disclosed by the invention is good in morphology and relatively large in specific surface area, and is of a hollow nanoflower spinel structure. The structure has potential application value in the field of gas sensors, and a new thought is provided for expanding the application of the spinel type semiconductor oxide serving as a sensitive material to construct the gas sensors.

The invention discloses alkali metal doped MOF-74, a gas-sensitive material, a gas-sensitive sensor and a preparation method and application of the gas-sensitive sensor, and belongs to the technical field of gas-sensitive sensors. Magnesium nitrate hexahydrate and 2, 5-dihydroxyterephthalic acid are used as raw materials, alkali metal salt is added in situ for doping, triethylamine (TEA) is used as a deprotonation agent, a reaction process is optimized, alkali metal doped MOF-74 is rapidly synthesized at room temperature, miniaturization of MOF-74 is realized on the premise that crystallinity and high porosity are not lost, and the preparation method is simple and easy to implement. The gas-sensitive property of the material is favorably improved. The alkali metal doped MOF-74 is used for the gas sensitive sensor, has excellent selectivity and high sensing response to CO2 gas, and can meet the requirements of CO2 gas detection. The preparation period is short, heating is not needed, and large-scale production is facilitated.

The invention discloses a preparation method and application of a Cu-BTC / phoenix tree flocculus biomass charcoal composite material, and belongs to the technical field of room temperature gas sensing materials. The invention aims to solve the problems that the existing MOFs nano material is relatively high in synthesis cost, complex in synthesis process, easy to accumulate and relatively small in pore diameter, so that the gas mass transfer resistance is relatively large, and the sensing efficiency is limited. The phoenix tree flocculus porous carbon is prepared from phoenix tree flocculus by adopting a chemical activation and calcination combined process, and the biomass carbon material retains a natural tubular structure of biomass and is beneficial to adsorption or diffusion of to-be-detected gas. The Cu-BTC / phoenix tree flocculus biomass charcoal composite material is prepared from biomass charcoal derived from phoenix tree flocculus for the first time, and the Cu-BTC / phoenix tree flocculus biomass charcoal composite material is successfully applied to NO2 gas-sensitive application to solve the problems of low sensitivity, high detection limit, poor restorability, high cost and the like when NO2 is detected in the prior art. The method has the characteristics of simplicity and convenience in operation and high NO2 sensing efficiency.

The invention relates to the technical field of detection, in particular to a sensing element and a preparation method thereof, a gas sensing device and an isobutanol detection method. The sensing element comprises a base body and a coating arranged on the surface of the base body, and the coating comprises MgO and SiO2 (silicon dioxide). The gas sensing device of the present invention comprises: a reaction chamber; a heating base and the sensing element are arranged in the reaction chamber; and the sensing element is flatly placed on the heating base. The isobutanol detection method comprises the step of detecting the gas to be detected by adopting the gas sensing device. According to the sensing element provided by the invention, isobutanol can be rapidly detected with high sensitivity and high selectivity based on the MgO-SiO2 coating, the anti-interference capability is strong, and the precision is high; the gas sensing device adopting the sensing element can accurately monitor isobutanol on line for a long time.

The present invention discloses a method for preparing a chemical resistance type sensor using an amino functionalized metal organic framework material, which comprises the following specific steps: S1: preparing or preparing an amino functionalized metal organic framework (NH 2 ‑MOFs) nanosheet powder; S2: NH 2 ‑MOFs nanosheet powder is dissolved in an organic solvent to prepare a paste, and then the paste is evenly coated on a non-conductive substrate, and the two ends of the non-conductive substrate are fixedly connected with wires, and heated to prepare a chemical resistance sensor. 2 ‑MOFs gas-sensitive materials have an ultra-high specific surface area, which greatly improves the material's adsorption of gas, while the amino functional groups can selectively adsorb gas, thereby improving the gas-sensing performance and selectivity of the gas, enabling it to detect nitro explosives and nitro-containing explosive raw materials in real time with high sensitivity and selectivity.

The invention belongs to the technical field of microbial monitoring, and discloses a cobalt-doped zinc oxide nanofiber and a preparation method thereof.The preparation method comprises the steps that firstly, polyvinylpyrrolidone (PVP) is added into an N, N-dimethylformamide (DMF) solution, zinc nitrate hexahydrate and cobaltous acetate tetrahydrate are added after the PVP is evenly dissolved, and the PVP and the cobaltous acetate tetrahydrate are stirred to be evenly dissolved; then carrying out electrostatic spinning on the obtained precursor solution; carrying out drying treatment on a membrane obtained by electrostatic spinning; finally, the dried membrane is subjected to calcination treatment; the cobalt-doped zinc oxide nanofiber can be used for preparing a gas sensor for detecting a biomarker 3-hydroxy-2-butanone gas of listeria monocytogenes. The Co-ZnO nano-fiber has excellent gas sensitivity to the biomarker 3H-2B, the response speed is high, the sensitivity is high, the Listeria monocytogenes are monitored by detecting the 3H-2B gas through the Co-ZnO nano-fiber, the possibility is provided for real-time monitoring of the Listeria monocytogenes, and the Co-ZnO nano-fiber has great application potential.

The invention relates to the technical field of gas sensing, and discloses a preparation method of nano tin oxide, nano tin oxide, tin oxide ink, a gas sensor and a preparation method of the gas sensor. The preparation method of the nano tin oxide comprises the following steps: mixing tin chloride dehydrate and ethanolamine to obtain a precursor mixed solution; treating the precursor mixed solution to obtain a complex solution; adding propionic acid into the complex solution to obtain tin oxide precipitate; and carrying out sintering treatment on the tin oxide precipitate to obtain the nano tin oxide. Ethanolamine and propionic acid are added in the process of preparing the nano tin oxide by using a sol-gel method, so that the health and safety risks are avoided, the pH value stability is favorably controlled, the uniformity and consistency of the nano tin oxide are ensured, and the gas sensing performance can be improved when the nano tin oxide is applied to a gas sensor. According to the invention, a sol-gel method and an ink-jet printing technology are combined, so that the preparation process of the gas sensor is simplified.

The present invention relates to the research field of metal oxide semiconductor materials, specifically to a metal oxide and a preparation method thereof, and a gas sensor. A preparation method of a metal oxide comprises the following steps: reacting a pretreated metal oxide with a surfactant, and placing the metal oxide in a dielectric barrier discharge device close to a negative electrode and not in a discharge region after the reaction is completed. And introducing methane gas into the dielectric barrier discharge device. The metal oxide material is bombarded with methane plasma prepared by the dielectric barrier discharge device, so that the metal oxide powder has a loose and porous structure on the basis of the original structure. The increase in the pore structure can increase the contact area between the metal oxide and the gas, and at the same time, the carbon atoms in the methane plasma are doped on the surface of the metal oxide, which can reduce the reaction activation energy of the metal oxide, enhance the metal oxide's adsorption capacity for gas and electron mobility, and improve the prepared metal oxide's gas sensitivity to gas.

The invention discloses a preparation method of a WO3 nano-wall gas-sensitive material, which comprises the following steps: by taking WCl6 as a raw material, 1-dodecyl-3-methyl pyridine bromide as a surfactant and n-butyl alcohol as a solvent, immersing a ceramic tube in the solution, reacting in a stainless steel reaction kettle with a polytetrafluoroethylene lining at 140-180 DEG C for 20-50 minutes, filtering, washing and drying to obtain the WO3 nano-wall gas-sensitive material. After the reaction is finished, naturally cooling the ceramic tube, respectively washing the ceramic tube with absolute ethyl alcohol and ultrapure water for multiple times, and then placing the ceramic tube in a vacuum drying oven for vacuum drying at 60-80 DEG C for 8-12 hours. The dried ceramic tube is calcined in the air atmosphere at the temperature of 400-600 DEG C, the gas sensitive element coated with the WO3 nano-wall film sensitive layer is obtained, and the gas sensitive element still has the characteristic of quick response to N2H4 steam at the low operation temperature of 70 DEG C. The method has the effective benefits that the WO3 nano wall film sensitive layer is constructed on the surface of the ceramic tube in situ, and the sensitive layer can still keep the two-dimensional morphology of a basic construction unit after being calcined at high temperature; according to the method, the problems of material stacking, poor homogeneity of a sensitive layer, infirm connection with a substrate and the like caused when the surface of the ceramic tube is coated with WO3 sensitive material slurry are solved, and a brand new way is explored for development of volatile nitrogen-containing compound (VNCs) gas-sensitive new materials and elements.

The invention discloses a method for in-situ construction of a Fe2O3 nanosheet array material on the surface of a ceramic tube, which comprises the following steps: by taking K3 [Fe (CN) 6] as a reaction raw material, 1-hexadecyl-3-methylimidazolium hexafluorophosphate as a surfactant and water as a reaction solvent, putting a mixed solution composed of the substances into a stainless steel reaction kettle, immersing the ceramic tube in the stainless steel reaction kettle, and carrying out in-situ construction of the Fe2O3 nanosheet array material on the surface of the ceramic tube; the preparation method comprises the following steps: putting a ceramic tube into a reaction kettle, reacting at 150-180 DEG C for 6-10 hours, after the reaction is finished, naturally cooling the ceramic tube to room temperature, respectively washing the ceramic tube with absolute ethyl alcohol and ultrapure water for multiple times, and then putting the ceramic tube into a vacuum drying oven for vacuum drying at 60-80 DEG C for 6-10 hours. The dried ceramic tube is subjected to roasting treatment in the air atmosphere at the temperature of 300-600 DEG C, the gas sensitive element covered with the Fe2O3 nanosheet array film sensitive layer is obtained, and the gas sensitive element has the good response characteristic to H2S gas at the operation temperature of 130 DEG C. The method has the effective benefit of solving the problem that almost all Fe2O3 materials constructed on the surface of a ceramic tube in situ by the existing method have one-dimensional nanorods and nanotube arrays, and the method is the first application of the Fe2O3 nanosheet array material in a gas sensor.

This invention discloses a chemiluminescence gas sensor based on polyoxometalates (POMs), and relates to its fabrication method and application. The sensor is suitable for detecting ammonia at room temperature. The gas sensor includes an adapter base and a sensing element, wherein the sensing element consists of interdigitated electrodes and a sensitive material loaded on the electrode surface. This sensitive material is a composite material of POMs and SnO2. POMs, as excellent electron acceptors, possess good redox properties, thermal stability, and photosensitivity. When combined with SnO2, they can effectively suppress electron-hole recombination, thereby significantly improving the gas-sensing performance of the semiconductor material. Compared with existing technologies, the sensor provided by this invention exhibits high response characteristics to ammonia at room temperature, while also demonstrating excellent selectivity and repeatability.

The invention relates to a laser modified ZnO-based gas sensor and a preparation method thereof. The ZnO-based gas sensor comprises an electrode substrate and a ZnO film arranged on the electrode substrate; the ZnO thin film is prepared through a magnetron sputtering method, annealing and laser etching treatment are sequentially carried out, and a regular net structure is formed on the surface of the ZnO thin film after laser etching. The preparation method comprises the following steps: preparing a ZnO film on the surface of an electrode substrate through magnetron sputtering; carrying out annealing treatment on the electrode substrate attached with the ZnO thin film; carrying out laser etching treatment on the surface of the annealed ZnO thin film to form a regular net-shaped structure; and assembling the electrode substrate attached with the laser modified ZnO film to finally obtain the ZnO-based gas sensor. Compared with the prior art, the surface of the ZnO film is modified through laser etching, and the assembled ZnO-based gas sensor has excellent sensitivity, selectivity, cycling stability and moisture resistance.

The invention belongs to the field of nano materials, and particularly relates to a Ga-doped Co3O4 nano flower, a preparation method and application of the Ga-doped Co3O4 nano flower as a gas sensitive material. The Ga-doped Co3O4 nanoflower is in a flower-ball shape, and the diameter of the Ga-doped Co3O4 nanoflower is 10 microns; the doping amount of the metal Ga is 1%-5% of the substance amount of the metal Co; the preparation method of the Ga-doped Co3O4 nanoflower comprises the following steps: synthesizing a multi-metal Co (OH) 2 nanoflower by a wet impregnation and freeze drying method, taking the multi-metal Co (OH) 2 nanoflower as a template, and roasting in an air atmosphere to prepare a Ga-Co3O4 gas sensitive material with a nanoflower morphology; the Ga-Co3O4 nanoflower gas sensitive material prepared by the preparation method disclosed by the invention has a good sensitive characteristic on CO; according to the invention, the heterogeneous element is used for replacing and preparing the bimetallic MOS to improve the gas-sensitive performance of the metal oxide, and the cost is low; the method is low in raw material cost, wide in source, simple in step, environmentally friendly, free of pollution, free of impurity ion introduction, capable of achieving mass production and convenient to achieve large-scale industrial production.

The invention provides a Sn-MOF (at) SnO2 / Fe2O3 multilevel structure nano composite material, a preparation method thereof and an n-butyl alcohol gas sensor, belongs to the technical field of material synthesis, and aims to solve the technical problem of poor gas sensitivity of a Sn-MOF induced metal oxide nano composite material. The preparation method of the Sn-MOF (at) SnO2 / Fe2O3 multilevel structure nano composite material comprises the following steps: adding a tin source, a ligand and alkali into a solvent I to prepare a mixed solution I, and then reacting to prepare Sn-MOF; adding the Sn-MOF, an iron source and an alkali precipitator into a solvent II to prepare a mixed solution II, and reacting under the microwave-assisted condition to prepare an Sn-MOF (at) SnO2 / Fe2O3 precursor; and calcining the Sn-MOF (at) SnO2 / Fe2O3 precursor to prepare the Sn-MOF (at) SnO2 / Fe2O3 nano composite material with the multilevel structure. According to the invention, the n-butanol gas sensor prepared by using the Sn-MOF-coated SnO2 / Fe2O3 multilevel structure composite material as the sensitive layer has good gas sensing performance. The optimal detection working temperature of the sensor on n-butyl alcohol gas is 200 DEG C, and meanwhile, the sensor has the advantages of high response speed, large response value, good long-term stability and the like.

The invention discloses an Ag monatomic modified In2O3 single crystal film prepared based on pulse voltage discharge, a method thereof and a gas sensitive sensor, and the method comprises the following steps: 1) placing a substrate in a vacuum cavity of magnetron sputtering equipment, taking an indium oxide target as an In source, and growing on the substrate through a magnetron sputtering technology to obtain an indium oxide single crystal film; the substrate is yttrium oxide stabilized zirconia (YSZ); (2) placing the indium oxide single crystal thin film obtained in the step (1) on a vacuum chamber sample table which is internally provided with a pulse voltage discharge electrode and an Ag target material, evaporating Ag particles based on a pulse voltage discharge process, and depositing the Ag particles on the surface of the indium oxide single crystal thin film material to form dispersed clusters; and annealing to obtain the Ag single atom modified In2O3 single crystal thin film. The synthesis of a sensitive material with a high atom utilization rate and a stable structure is realized, and an advanced NO2 gas sensing device with high sensitivity and high selectivity is obtained.

The invention discloses an NO2 gas sensing material, an NO2 gas sensor and a preparation method and application of the NO2 gas sensing material and the NO2 gas sensor. The NO2 gas sensing material is a semiconductor substrate material doped with variable-valence metal elements; the material of the semiconductor substrate is BiOX, and the element X is at least one of Cl, Br and I; the variable-valence metal element is a variable-valence transition metal element. The invention provides a design and preparation method of a gas sensor capable of rapidly detecting NO2 at room temperature. The method can realize reversible detection of NO2 at room temperature.

The invention relates to the technical field of gas sensors, and discloses a gas sensitive material, a preparation method thereof, a gas sensor and application, the preparation method of the gas sensitive material comprises the following steps: (1) mixing polyvinylpyrrolidone, polyacrylonitrile, MoS2 and N, N-dimethylformamide to obtain a spinning solution; (2) performing electrostatic spinning on the spinning solution to obtain a nanofiber membrane; (3) carrying out in-situ synthesis on SnO2 nanoparticles on the nanofiber membrane by adopting a solvothermal method; and (4) carrying out pre-oxidation treatment on the SnO2-loaded nanofiber membrane, and then calcining. The gas-sensitive material prepared by the method not only combines SnO2 and MoS2 which have high recognition ability to gas, but also combines CNFs (carbon nanofibers) which have high conductivity, high aspect ratio, large specific surface area and high stability, and the gas-sensitive material well maintains the structure of the carbon nanofibers, so that the gas-sensitive material has good application prospects. The gas-sensitive material has relatively high gas-sensitive performance and good selectivity and repeatability stability on hydrogen.

The application discloses a nano-needle self-assembled flower-shaped microsphere metastable indium oxide gas-sensitive material, a gas-sensitive element and a preparation method and application. The nano-needle self-assembled flower-shaped microsphere metastable indium oxide gas-sensitive material has a three-dimensional flower-shaped microsphere formed by nano-needle self-assembly, the diameter of the nano-needle is about 8 nm, the diameter of the flower-shaped microsphere is about 2-3 microns, the main exposed crystal face of the material is (104), and the crystal structure is a metastable rhombohedral corundum phase. The prepared nano-needle self-assembled flower-shaped microsphere metastable indium oxide successfully realizes preparation of pure metastable indium oxide material under mild conditions and realizes application in the field of gas-sensitive detection, especially in the detection of H2S, and has the advantages of low working temperature, high sensitivity, high selectivity and low detection limit. Meanwhile, the synthesis preparation method is simple in synthesis, low in cost and has good industrial production prospects.

The invention provides a palladium sulfide composite molybdenum disulfide hierarchical nanostructure based nitrogen dioxide sensor and a preparation method thereof, and belongs to the technical field of sensors and composite nanomaterials. The sensor comprises a substrate and a gas sensitive layer loaded on the substrate, the gas sensitive layer is a palladium sulfide-molybdenum disulfide composite nanomaterial, PdS nanoparticle clusters in the palladium sulfide-molybdenum disulfide composite nanomaterial are embedded in the surface of MoS2 nanoflowers, and PdS and MoS2 form a heterojunction, so that the separation and transmission rate of current carriers is increased, and the performance of the gas sensor is improved. Therefore, the gas-sensitive performance of the nitrogen dioxide sensor is improved, and the nitrogen dioxide sensor has a high response value and fast response recovery time for NO2 with ppm-level concentration.

The invention relates to a silver oxide / tungsten trioxide hollow microsphere composite material as well as a preparation method and application thereof, and belongs to the field of gas sensors. The microstructure of the silver oxide / tungsten trioxide hollow microsphere composite gas-sensitive material is that silver adheres to and grows on the surfaces of tungsten trioxide hollow microspheres in the form of silver oxide nanoparticles, silver oxide is of a cubic crystal system structure, tungsten trioxide is of a monoclinic crystal system structure, and the particle size of the silver oxide / tungsten trioxide hollow microsphere composite gas-sensitive material is 1-5 microns. And an interface region formed by the contact of the silver oxide and the tungsten trioxide is a p-n heterojunction. The three-dimensional graded hollow microsphere silver oxide / tungsten trioxide p-n heterojunction material is prepared by a simple hydrothermal method, has a biological olfactory sensing characteristic, reduces the preparation cost of a sensitive layer material of a bionic olfactory gas sensor, and has huge production and application prospects. The bionic olfactory sensor prepared by using the material as a sensitive layer material has the advantages of ultrahigh sensitivity, quick response capability, low detection lower limit, high selectivity and reliable stability.

The invention discloses a CuBTC / PAN composite nanofiber adsorption film and a preparation method and application thereof. The preparation method comprises the steps that copper salt and dimethyl sulfoxide are mixed, heated and stirred to obtain a metal salt solution; heating, stirring, separating, washing, heating and drying the organic ligand and a metal salt solution to obtain CuBTC precipitate; mixing polyacrylonitrile with dimethylformamide to obtain a faint yellow transparent viscous liquid, and carrying out electrostatic spinning to obtain a polyacrylonitrile nanofiber membrane; mixing the CuBTC precipitate with isopropanol, and performing ice-bath ultrasonic dispersion to obtain dark blue dispersion liquid; and spraying the dark blue dispersion liquid on the surface of the polyacrylonitrile nanofiber membrane, and drying to obtain the CuBTC / PAN composite nanofiber adsorption membrane. According to the present invention, the requirement of the good adsorption effect on the SF6 / N2 mixed gas decomposition components SO2F2 and NF3 is met.

The invention discloses an In 2 O 3 / 2D‑MoS 2 Heterojunction thin film material and preparation method and application thereof, the preparation method comprising the following steps: using magnetron sputtering method to deposit 2D-MoS 2 Surface preparation 2 O 3 The film forms a heterojunction thin film material; wherein, during magnetron sputtering, the gas flow is 15-25sccm, the gas pressure is 1-2Pa, the power is 10-20W, and the sputtering time is 25-35s. The present invention uses a method combining physical vapor deposition and chemical vapor deposition to design and construct In 2 O 3 / 2D‑MoS 2 Heterojunction. By optimizing the thickness, interface structure, interface quality, surface morphology, uniformity and crystallinity of heterojunction films, a new method was obtained that can significantly improve the gas (NO x ) Sensitivity of heterostructures In 2 O 3 / 2D‑MoS 2 Gas sensing materials.

The invention relates to a preparation method and application of a gas sensitive material, in particular to a preparation method and application of a flower-like sulfur-doped zinc oxide gas sensitive material for rapidly and nondestructively detecting methamphetamine. The problems that in an existing methamphetamine detection method, a sample needs to be pretreated, cost is high, real-time detection cannot be achieved, and consumed time is long are solved. The method comprises the following steps: 1, mixing zinc nitrate with thiourea, and then adding the mixture into a solvent for heating reaction; and 2, centrifugally separating, washing and drying the precursor solution, and then carrying out heat treatment. According to the application, under the condition that the working temperature is 100-180 DEG C, the gas sensitive element is used for detecting methamphetamine as a gas sensitive element. The invention relates to preparation and application of the flower-like sulfur-doped zinc oxide gas-sensitive material for detecting methylamphetamine.

The application discloses alkali metal doped MOF-74, a gas sensitive material, a gas sensitive sensor and a preparation method and application thereof, and belongs to the technical field of gas sensitive sensors. The application takes magnesium nitrate hexahydrate and 2,5-dihydroxyterephthalic acid as raw materials, in-situ adds alkali metal salt doping, takes triethylamine (TEA) as a deprotonating agent, optimizes a reaction process, rapidly performs synthesis of the alkali metal doped MOF-74 at room temperature, realizes miniaturization of the MOF-74 without losing crystallinity and high porosity, and is favorable for improving the gas sensitive performance of the material. The alkali metal doped MOF-74 is used for the gas sensitive sensor, has excellent selectivity and high sensing response to CO2 gas, and can meet the demand of CO2 gas detection. Moreover, the preparation period is short, heating is not needed, and the method is favorable for large-scale production.

The invention discloses SnS2 / ZnO nanoflowers as well as a preparation method and application thereof, and belongs to the technical field of gas sensing materials. According to the technical scheme, the preparation method comprises the following steps: 1) respectively dissolving tin chloride and thiourea into polyethylene glycol and deionized water, stirring, transferring the solution into a reaction kettle, carrying out hydrothermal reaction, cooling, washing and drying to obtain SnS2 nanoflowers; and 2) placing the SnS2 nanoflower in an ALD reaction chamber, and depositing ZnO on the SnS2 nanoflower by multiple ALD cycles to obtain the ZnO-loaded SnS2 nanoflower. According to the preparation method, the SnS2 / ZnO nanoflower is prepared by using an atomic layer deposition (ALD) technology, and the SnS2 / ZnO heterojunction is constructed, the method is based on an ALD surface self-limiting reaction, uniform nano materials are allowed to be deposited on a large area, and high-response sensors are allowed to be produced on a large scale.

The invention provides a Pd-WO3 gas-sensitive sensing material as well as a preparation method and application thereof, WO3 in the gas-sensitive sensing material is a two-dimensional ultrathin nanosheet, the crystal structure is a monoclinic phase crystal structure, and Pd nanoparticles are uniformly dispersed on the surface of the WO3 material. The Pd-WO3 gas-sensitive sensing material prepared by the method can be used for preparing a gas sensor of mustard gas and a simulating agent thereof, and can realize rapid and high-performance detection of the mustard gas and the simulating agent gas thereof; the gas sensor has good response / recovery, stability, high response, selectivity and the like to mustard gas and simulation agent gas thereof under the condition of lower than 300 DEG C.

The invention provides a novel In2O3 / g-C3N4 heterojunction material and a preparation method thereof. The In2O3 / g-C3N4 heterojunction material is applied to a CO2 gas sensing material based on visible light excitation at room temperature. The nano material combines the unique electronic property of In2O3 and the excellent visible light absorption characteristic of g-C3N4, and the photogenerated charge separation efficiency is improved through the heterojunction effect, so that the CO2 detection performance is remarkably improved. The sensor is high in sensitivity and low in detection limit, has good stability and reusability, is environment-friendly, conforms to the development trend of environmental protection, and has wide application prospects in the fields of environmental monitoring and the like.

The invention discloses a preparation method of a phosphorane room-temperature gas-sensitive material, which comprises the following steps: respectively adding Bi (NO3) 3.5 H2O and Na2MoO4. 2H2O into ethylene glycol, stirring until the Bi (NO3) 3.5 H2O and the Na2MoO4. 2H2O are completely dissolved, mixing the two solutions, and adding isopropanol to prepare a mixed solution; and transferring the obtained mixed solution into a high-pressure reaction kettle, carrying out solvothermal reaction at 160 DEG C for 15 hours, naturally cooling to room temperature after the reaction is finished, centrifuging, washing and freeze-drying to obtain the gas-sensitive material. The gas-sensitive material prepared by the method has good morphology and structure, and the successful preparation of the special litchi-shaped structure improves the electronic characteristics of the material and effectively enhances the gas-sensitive performance of the material.