77results about How to "Improve gas sensitivity" patented technology

The invention provides a ZnO / SnO2 nano composite gas-sensitive material with a flower-shaped grading structure. The ZnO / SnO2 nano composite gas-sensitive material is prepared by the following steps: dripping a sodium hydroxide water solution into an ethanol solution of cetyl trimethyl ammonium bromide and stannous chloride dihydrate under electromagnetic stirring; after dripping, preparing a precursor solution by the continuous electromagnetic stirring; adding the precursor solution into a reaction kettle, reacting at 130 DEG C; carrying out centrifuging on a reactant, washing and drying to obtain a flower-shaped stannous oxide sacrifice template; adding the flower-shaped stannous oxide sacrifice template into a zinc acetate solution; agitating and carrying out ultrasonic treatment; removing a solvent to obtain a ZnO / SnO2 precursor; and carrying out heat preservation on the ZnO / SnO2 precursor for 2-4 hours in an air atmosphere of 700 DEG to obtain the composite gas-sensitive material. According to the ZnO / SnO2 nano composite gas-sensitive material with the flower-shaped grading structure, the controllable preparation of the composite gas-sensitive material on the appearance and components can be realized; the mass percent content of zinc oxide in the composite gas-sensitive material is 5%-15%; a flower shape is assembled by sheet-shaped tin dioxide and zinc oxide nano particles; the ZnO / SnO2 nano composite gas-sensitive material has a good gas sensitive performance and has a wide application prospect in the aspect of manufacturing a novel high-efficient gas sensor.

The invention discloses a kind of array sensor for gas and the preparing method. The sensor uses the aurum, platinum or argentum as electrode; the RuO2, MoSi2, W or Pt is as heating membrane material; the random one or several kinds of the ZnO, SnO2 or Fe2O, or ZnO, SnO2 or Fe2O3 and Pt0.1wt%-3wt%, Pd0.1wt%-3wt%, Ni1wt%-30wt%, TiO21wt%-30wt%, WO31wt%-40wt%, Co2O3 1wt%-15wt%, V2O51wt%-30wt%, Al2O31wt%-20wt%, MnO21wt%-30wt% is as the sensing layer material. It gets the gas sensing array on the alumina, aluminium nitride or silicon base sheet with anti high temperature, electric insulating and heat conducting by the screen printing technology. The gas sensing array is fixed on the basal seat by the axis to form the gas sensing array sensor by ultrasonic hot press welding electrode leg wire. The sensor has the low production cost, low power cost, good mechanism stability. Each unit has the good gas sensing character and the process is proper for the big batch production.

The multilayer nanometer porous SnO2 film and its synthesis process belongs to the field of gas sensitive material and gas sensor preparing technology. Nanometer porous SnO2 film in 6-12 layers are deposited successively onto monocrystalline silicon substrate through the following six steps: preparing solution with SnCl2.2H2O as the precursor and anhydrous alcohol as solvent, adding surfactant, preparing sol, homogenizing, annealing, etc. The present invention has simple technological process, and the multilayer nanometer porous SnO2 film has high chemical stability, small power consumption, great specific surface area and high gas sensitivity, and is suitable for making gas sensor for measuring micro amount of gas.

The invention discloses a gas-sensitive material for detecting NO2 and a method for manufacturing a gas-sensitive element made of the gas-sensitive material. The gas-sensitive material is prepared into a SnO2 nano-fiber with a rough surface and a hollow tubular structure by adopting an electrospinning method and high-temperature processing, the hollow SnO2 nano-fiber is of a rutile structure, the SnO2 nano-fiber diameter is about 250-300nm, and the thickness of a particle layer is about 40nm. Au particle modification is performed on the surface of SnO2 in an in-situ reduction manner without changing the crystal structure of SnO2. The specific surface area of the material is increased by the one-dimensional hollow nano-structure characteristic of the gas-sensitive material, the gas-sensitive performance of SnO2 is obviously improved by precious metal modification, and higher sensitivity to NO2 and a larger measurement range are presented. The obtained material is applied to the surface of a ceramic tube, annealing is performed, and a calcined ceramic tube core and a nickel-chromium heating wire are welded to a base, accordingly, the gas-sensitive element is manufactured.

A gas sensor for determining gas components in gas mixtures, e.g., for exhaust gases of internal combustion engines, includes a housing and a sensor element configured as a field effect transistor which has source, drain, and gate electrodes applied on a semiconductor substrate. A porous, catalytically active material is provided inside the housing of the gas sensor.

The invention provides a preparation method of a dendritic zinc oxide nanowire array. The preparation method comprises the following steps of (1) cleaning the surface of a substrate; (2) depositing a zinc oxide seed layer at the surface of the substrate by an atom layer depositing technology; (3) growing a zinc oxide nanowire array on the substrate by a hydration method; (4) cleaning the substrate, and drying, so as to form a bar-shaped zinc oxide nanowire array; (5) depositing one zinc oxide seed layer at the surface of the substrate by the atom layer depositing technology; (6) repeating the steps (3) to (4), so as to form the dendritic zinc oxide nanowire array. The preparation method of the dendritic zinc oxide nanowire array has the advantages that the preparation temperature is low, the nanometer dendritic structure has good uniformity and density, the preparation method is suitable for the substrate with a non-plane or complicated structure, and the preparation method is simple and feasible.

Disclosed are a high-sensitivity transparent gas sensor and a method for manufacturing the same. The transparent gas sensor includes a transparent substrate, a transparent electrode formed on the transparent substrate and a transparent gas-sensing layer formed on the transparent electrode. The transparent gas-sensing layer has a nanocolumnar structure having nanocolumns formed on the transparent electrode and gas diffusion pores formed between the nanocolumns.

A gas bag module includes a module housing (18), a gas bag (24) having a gas bag wall (26), a discharge opening (20) which can be closed by a closure device (22), and a limiting strap (28), the limiting strap (28) being coupled with the gas bag wall (26) and the closure device (22). The limiting strap (28) is tensioned in case of an unimpeded unfolding of the gas bag (24) such that the closure device (22) closes the discharge opening (20), and the limiting strap (28) is guided along the gas bag wall (26).

The invention provides a carbon doped boron-nitrogen nanotube / semiconductor oxide composite and a preparation method and application thereof, relating to a nano material / oxide composite and a preparation method and application thereof. The invention solves the problem that the current sensitive materials used for detecting oxynitride gases have low sensitivity at room temperature and slow response speed. The composite of the invention is prepared by carbon doped boron-nitrogen nanotubes, transition metal salts and a precipitant. The preparation method is characterized in that a catalyst, boron-containing materials and carbon nanotubes are synthesized in the ammonia after being ground, then the carbon doped boron-nitrogen nanotubes are obtained through purification and calcination, and finally the carbon doped boron-nitrogen nanotubes are dispersed in metal salt solution, modified by the precipitant and sintered to obtain the composite. The composite is used for detecting the oxynitride gases as a sensitive material, the lowest molarity of the gases which can be detected is 970ppb and the sensitivity of the material is not less than 2.37%. The time from start of change of resistance of the sensitive films during filling the oxynitride gases to complete stability of resistance is not more than 20s, thus the sensitive films have fast response speed and good reversibility of adsorption.

The invention discloses a low-temperature in-situ growing method of a semiconducting metal oxide with a nano-structure as well as an application. According to the method, polymeric nanofibers containing an inorganic salt solution are deposited on a substrate with an electrospinning method, and then are subjected to hydro-thermal treatment, so that inorganic salt contained in the polymeric nanofibers is converted into the semiconducting metal oxide with the nano-structure in situ, and the semiconducting metal oxide is tightly combined with the substrate. The method has the advantages as follows: equipment is simple, steps are simple and convenient, the energy consumption is low, high-temperature thermal treatment is not required, a semiconducting metal oxide nano material is obtained on different substrates in situ at the relatively low temperature lower than 180 DEG C and the like; the method can be used for preparation of a flexible semiconducting metal oxide device with polymer as the substrate, further realizes good composition of the semiconducting metal oxide nano material and organic polymer conveniently, can be used for preparation of organic / semiconducting metal oxide nanocomposite materials and devices, and has a good application prospect in the field of nano photoelectric devices.

The invention discloses a controlled preparation method of a three-dimensional honeycomb-structured ZnO nano-material. The controlled preparation method comprises the following steps: (1) preparing nano carbon balls; (2) soaking the nano carbon balls in deionized water, and preparing a wrapping reaction base solution; and regulating pH value of the wrapping reaction base solution; (3) separately dropwise adding a zinc salt solution and an alkali solution in the wrapping reaction base solution simultaneously at a certain speed ratio, controlling the pH value of reaction and constant reaction temperature, stirring the wrapping reaction base solution, finishing reaction, and centrifuging, washing and drying to obtain a Zn(OH)2 / carbon ball composite material; and (4) calcining the Zn(OH)2 / carbon ball composite material to obtain the three-dimensional honeycomb-structured ZnO nano-material. The prepared three-dimensional honeycomb-structured ZnO nano-material is large in specific surface area and high in surface activity, and the gas sensitivity and photocatalytic performance of the material can be improved effectively; and the three-dimensional honeycomb-structured ZnO nano-material islow in cost, high in yield, good in stability and pollution-free, and is expected to be popularized and used in the fields of gas sensitivity and photocatalysis.

A gas sensor (3) includes: a base (30), two electrodes (31, 32) formed on the base, a zinc oxide layer (34) formed on surfaces of the base and the electrodes. The zinc oxide layer includes a plurality of zinc oxide nanofibers, each having a columnar or a tubular microstructure. Preferably, the zinc oxide nanofibers are substantially parallel to each other and substantially perpendicular to the base and electrodes. Numerous apertures between adjacent zinc oxide nanofibers can retain gas molecules. If the microstructure is tubular, apertures within the zinc oxide nanofibers can also retain gas molecules. In either case, the sensitivity of the gas sensor is improved. A method is also provided.

A gas sensor on a semiconductor substrate. The gas sensor includes an elongate sensor element extending across an opening and has first and second opposed surfaces exposed for contact with a gas to be sensed. The first surface faces away from a major surface of the substrate. The second surface faces toward said major surface. The electrical conductivity of the elongate sensor element is sensitive to a composition and / or concentration of said gas to which the opposed first and second surfaces are exposable. The gas sensor further includes a support structure arranged to increase the mechanical robustness of the gas sensor by supporting the elongate sensor element in the opening.

The invention provides quantum size zinc oxide, a preparation method thereof and application of the quantum size zinc oxide used as a gas-sensitive material. The method comprises the following steps of: performing an ethanol heat reaction of solution of zinc salt and solution of sodium hydroxide, and successfully preparing a zinc oxide quantum dot material with high crystallinity by adding a surface modification agent and controlling reaction conditions. The dimensions of quantum dots of the zinc oxide are 1 to 10nm. Compared with the conventional method for preparing the quantum dots of the zinc oxide, the method has the advantages of low cost, low energy consumption, high product crystallinity and the like and is easy to operate. A prepared nanometer zinc oxide material has excellent gas sensitivity to nitrogen dioxide gas, and is a good gas-sensitive material.

The invention discloses a polyaniline / iron oxide nano composite resistance-type material sensor, and a preparation method thereof. The polyaniline / iron oxide nano composite resistance-type material sensor comprises a ceramic substrate, an interdigital gold electrode, and a gas sensitive material which are arranged successively; the gas sensitive material is composed of a polyaniline / iron oxide nano composite, wherein p-n junction effects formed on the interface of p-type polyaniline and n-type iron oxide are capable of increasing response sensitivity of the polyaniline / iron oxide nano composite resistance-type material sensor on gas at room temperature greatly, accelerating response, and improving stability, and a polyaniline layer is capable of reducing element resistance value greatly, and is convenient for testing on sensor resistance response characteristics. The polyaniline / iron oxide nano composite resistance-type material sensor possesses high response sensitivity on ammonia gas at room temperature; resilience is excellent; response is rapid; stability is high; and the polyaniline / iron oxide nano composite resistance-type material sensor can be widely applied to accurate measuring and controlling of ammonia gas concentration in industrial and agricultural production processes and the atmosphere environment. The invention also provides a preparation method of the polyaniline / iron oxide nano composite resistance-type material sensor; and the preparation method is simple, is low in cost, and is especially suitable for batch production.

The invention discloses a precious metal-doped WO3 coating having an ultrathin porous submicron structure and a preparation method thereof. The preparation method comprises depositing a precious metal nanoparticle-doped WO3 suspension liquid as a spraying raw material on a matrix by a thermal spraying technology to obtain the precious metal-doped WO3 coating having thickness of 5-20 microns and a porous submicron structure. The precious metal-doped WO3 coating has precious metal content of 0.067-2.440wt%. The precious metal-doped WO3 coating has a high specific surface area and through use of the precious metals, the gas-sensitive characteristics of the precious metal-doped WO3 coating are effectively improved. The preparation method adopts simple equipment, has simple and easily-controllable processes, has high deposition efficiency and a low cost, is suitable for industrial production and can produce large social and economic benefits.

The invention discloses an MEMS organic polymer surface acoustic wave hydrogen sensor. The MEMS organic polymer surface acoustic wave hydrogen sensor comprises a surface acoustic wave device and an intelligent control module, the surface acoustic wave device is connected with a frequency measuring device, the intelligent control module is connected with the frequency measuring device, a temperature sensor, a pressure sensor and a humidity sensor through a data acquiring and processing unit, and the intelligent control module is connected with a neural network error compensation unit, an RFID Internet-of-Things communication module and the frequency measuring device; and the surface acoustic wave device is a three-delayed surface acoustic wave device, the intersection of three surface acoustic wave delay lines is provided with a hydrogen sensitive film, and the hydrogen sensitive film is a polypyrrole organic polymer sensitive material with a long chain netted nanostructure containing a short chain. The MEMS organic polymer surface acoustic wave hydrogen sensor is sensitive to hydrogen at room temperature, improves the measuring precision of a characteristic quantity, realizes high-precision filtering and compensation of error interference of the temperature, the humidity and the pressure, and realizes the wireless transmission of sensing data, and greatly improves the informatization level of a surface acoustic wave hydrogen sensor.

The invention discloses a thin-layer MXene / hexagonal crystal phase molybdenum disulfide composite material, and a preparation method and application thereof, and relates to an MXene composite material, and a preparation method and application thereof. The invention aims to solve the problems of low sensitivity, high detection limit, poor restorability, high cost and long detection time due to the need of other auxiliary means for testing when a gas sensitive element prepared from the existing MoS2 or MoS2 composite material as a sensitive material is used for detecting NO2. The thin-layer MXene / hexagonal crystal phase molybdenum disulfide composite material is prepared from two-dimensional transition metal carbide, a molybdenum-containing compound, a sulfur-containing compound, weak acid and a surfactant. The method comprises the following steps: 1, preparing thin-layer MXene; 2, compounding; and 3, post-processing. The thin-layer MXene / hexagonal crystal phase molybdenum disulfide composite material is used as a sensitive material to prepare the gas sensitive element, and the gas sensitive element is used for detecting low-concentration NO2 in air at room temperature.

A highly sensitive carbon-nanomaterial-based gas sensor for use in high-humidity environments and a method of improving the sensitivity thereof, the gas sensor being configured such that a functional group for binding to a water molecule is formed on the surface of a first detector composed of a carbon nanomaterial, whereby a hydronium ion (H3O+) is produced and thus an additional ion conduction path is formed, thereby obtaining an additional reaction path in high-humidity environments, ultimately improving the sensitivity and detection threshold of the sensor. The gas sensor includes a substrate, a first detector disposed on the substrate, electrodes electrically connected to the first detector, and a second detector disposed on the first detector, wherein the second detector has a hydrophilic functional group.

The invention provides a three-dimensional layered Co-Al double hydroxide composite material and a preparation method and application thereof, relates to a double hydroxide composite material and a preparation method and application thereof, and aims at solving the problem that the cost of an existing NOx sensor is high. The three-dimensional layered Co-Al double hydroxide composite material is prepared from cobalt nitrate, aluminum nitrate, ammonium fluoride and a precipitating agent. The preparation method comprises the steps that the raw materials are weighed and put into deionized water toobtain a mixed solution, the mixed solution is subjected to a hydrothermal reaction, obtained precipitates are subjected to impurity removal, washing and drying, and then the three-dimensional layered Co-Al double hydroxide composite material is obtained. The three-dimensional layered Co-Al double hydroxide composite material is high in sensitivity, short in response time, simple in preparation method, good in capacity of resisting interference of the external environment and low in cost and has the adsorption reversibility. The preparation method is suitable for preparing the three-dimensional layered Co-Al double hydroxide composite material.

The invention relates to a gas-sensitive element based on TiO2 / InVO4 heterostructure nanometer fiber, and applications thereof. The gas sensitive material in the gas-sensitive element is TiO2 / InVO4 heterostructure nanometer fiber; in the TiO2 / InVO4 heterostructure nanometer fiber, the molar ratio of TiO2 to InVO4 is 0.25-4:1. The gas sensitive material possesses excellent selectivity on ammonia gas; when the temperature is 250 DEG C, and gas concentration is 100ppm, the sensitivity of the gas sensitive material on ammonia gas is 30.5, the response time on ammonia gas is 10s, the recovery timeis 10s. Compared with TiO2 nanometer fiber, the gas sensitivity of the TiO2 / InVO4 heterostructure gas sensitive material obtained via InVO4 coupling modification is improved greatly, the response / recovery time is shortened, and the operating temperature is reduced.

The invention discloses a preparation method of Sn mono-atom modified NiO nanometer material for formaldehyde sensor as well as a product and application thereof. According to the preparation method,a hydrothermal method is utilized to synthesize the NiO nanometer material; then anhydrous SnCl4 is adsorbed on the surface of the NiO nanometer material in an organic solvent with addition of 1-2 drops of nitric acid to prevent the hydrolysis of SnCl4; the obtained mixture is premixed with a NiO powder at 0 DEG C to obtain a solution, then the solution is placed at 18 DEG C, and pretreated with alow temperature, making the system to have a large amount of vacancies; and then the solution is calcined at a high temperature of 450-550 DEG C, so that the Sn mono-atom modified NiO nanometer material is obtained. The method has the advantages that the preparation process is simple, the preparation cost is low; and the obtained Sn mono-atom modified NiO nanometer material has stable performance, can greatly improve gas sensitivity of p-type semiconductors, and has a broad application prospect.

The invention discloses a PCF (Pohotonic Crystal Fiber)-SPR (Surface Plasma Resonance) structure sensor capable of simultaneously measuring hydrogen and methane. The PCF-SPR structure sensor is composed of a broadband light source, an optical attenuator, an air chamber, a PCF-SPR sensor and a spectrograph. Small air holes with a diameter of 1.5 microns are arranged at an angle of 45 degrees and 135 degrees on the cross section of the PCF-SPR sensor, and four ultra-large air holes with a diameter of 5 microns are vertically and horizontally distributed on the cross section of the PCF-SPR sensor, wherein the inner surfaces of the two ultra-large side holes are respectively coated with a hydrogen-sensitive film made of gold and a palladium-WO3 composite film, and a methane sensitive film madeof gold and an ultraviolet light curing fluorosilicone nano film. A gas sensing channel causes different peak shifts at different wavelengths; through structural parameter optimization, a gas mixtureof methane and hydrogen can be accurately measured by combining a side hole structure and polarization filtering without interfering with each other; and the PCF-SPR structure sensor has good multi-channel gas sensing repeatability, and a selective detection method can be applied to gases and other sensing applications, and has a good application prospect.

The invention belongs to the technical field of functional composite materials, and provides a fast-response highly-sensitive polymer-based gas-sensitive material and a preparation method thereof in order to solve the problem of long gas response time of a silicon rubber gas-sensitive material filled with conductive particles. The gas-sensitive material comprises, by mass, 2-35 parts of conductive nano-particles, 100 parts of silicone rubber and 0.05-7 part of montmorillonite. The preparation method comprises the steps of solution blending, and casting film molding. The material has detection and early warning functions to toxic and flammable solvent vapor, obviously shortens the gas response time, can reach a high gas sensitivity within a short time, and has a very good reusable stability.

The invention discloses a flexible conductive film with gas sensitivity performance and application thereof and belongs to the technical field of gas sensing material preparation. The flexible conductive film is a composite film formed by stacking a two-dimensional nano material on a PET film substrate into a three-dimensional network structure, and attaching the conductive polymeric materia to the three-dimensional network structure. The two-dimensional nano material is one or more of molybdenum trioxide, tungsten trioxide, tricobalt tetroxide, tin oxide, and zinc oxide and is in the shape ofa slice, a bar, a needle, a wire or a hollow tube. The conductive polymeric material is protonated polyaniline, polypyrrole or polythiophene. According to the invention, the gas concentration of triethylamine, ethylenediamine, ammonia gas, ethanol, acetone and nitrogen dioxide at room temperature can be detected, and the high temperature monitoring defects of the inorganic nano material are overcome.

The invention relates to a preparation method of an In2O3 / SnO2 gas sensitive material with a porous structure. The method comprises the following steps: mixing commercial In2O3 powder and SnO2 powder in a weight ratio of 4:1 or 7:3 or 3:2 place and mixing, compressing into a green body, and then placing the green body in a sintering furnace with oxygen atmosphere and carrying out solid phase sintering to finally obtain the In2O3 / SnO2 gas sensitive material with the porous structure. The method of the invention controls the sintering temperature to obtain the In2O3 / SnO2 gas sensitive material with the micron or submicron grade porous structure with regular holes, thus the porous structure is adopted to increase the specific area so as to increase the gas sensitivity and the weight of In2O3 / SnO2 is controlled to increase the selectivity to different gases. Therefore, the gas sensitive material with the porous structure which has high sensitivity and selectivity can be obtained. The method adopted by the invention has the advantages of easy preparation of raw material, low cost, clean production, is easy to control, and the like.

The invention discloses a tungsten oxide composite gas sensitive material used for detecting low concentration acetone gas, and belongs to the field of gas sensitive material. The tungsten oxide composite gas sensitive material used for detecting low concentration acetone gas is composed of WO3 and C3N4; the mass amount of C3N4 accounts for 1 to 5% of the total material mass; C3N4 in the tungstenoxide composite gas sensitive material is capable of increasing the sensitivity of tungsten oxide on acetone gas, reducing sensitivity of tungsten oxide on interface gas such as formaldehyde, and improving the gas sensitivity of the tungsten oxide composite gas sensitive material on acetone. A side-heating gas-sensitive element is prepared from the tungsten oxide composite gas sensitive material,at a working temperature of 310 DEG C, the sensitivity of the element on 1000ppm acetone ranges from 61 to 83, the sensitivity on 0.1ppm acetone gas ranges from 1.2 to 1.6, the response time and the recovery time on 0.1 to 1000ppm acetone gas are shorter than 60s, and the response time on 0.1ppm acetone is shorter than 10s. At a same working temperature, the sensitivity of the side-heating gas-sensitive element on 1000ppm formaldehyde is lower than 7, so that it is confirmed that the side-heating gas-sensitive element is high in gas sensitivity on acetone.

A gas sensor for detecting combustible gases is provided with a catalytic sensor element. The catalytic sensor element is arranged in a housing (1) surrounding the catalytic sensor element on all sides. The housing has a gas-permeable inlet opening. The gas sensor has electric lines, which are in connection with the sensor element and have terminals located outside of the housing (1). The housing has a gas-permeable inlet opening (2) and a gas-permeable outlet opening (3) and a flow channel (4) connecting the gas-permeable inlet opening (2) and the gas-permeable outlet opening (3). The sensor element is arranged in the flow channel