41results about How to "Improve gas-sensing properties" patented technology

The invention belongs to the technical field of sensors, and particularly relates to a novel ammonia sensor and a preparation technology thereof. The novel ammonia sensor comprises a gas sensitive material and a substrate, wherein the gas sensitive material uniformly coats the surface of the substrate uniformly, and comprises the component of reducing graphene which is wrapped with a cobaltosic oxide composite nano material; the coating thickness of the gas sensitive material is 1micron-100microns. The ammonia sensor is relatively high in responsiveness of an ammonia gas, and meanwhile has the advantages of relatively good selectivity, flexibility and stability and relatively low operation temperature.

The invention discloses a methylbenzene gas sensor based on an alpha-Fe2O3/SnO2 heterostructure nanowire array and a preparation method of the methylbenzene gas sensor, and belongs to the technical field of gas sensors. The device is of a flat plate structure, and is composed of two separated copper-gold alloy probes (serving as test electrodes), a sensitive material thin film growing on a Pt-plated silicon wafer, and a mini-type high-temperature ceramic heating piece on the back face of the silicon wafer. The sensor has the advantages of being high in integration level, simple in structure, low in price, small in size, firm, durable and capable of being produced on a large scale. In addition, the test result of the gas-sensitive characteristic shows that the sensor can detect methylbenzene at low working temperature and has extremely-good long-term stability, and therefore the methylbenzene gas sensor can have important application prospects on the aspects of methylbenzene leakage detecting and alarming in industrial production.

The invention discloses an ethanol gas sensor based on a ZnO hollow flower ball and CdO nano-particle composite nanomaterial and a preparation method of the ethanol gas sensor and belongs to the technical field of oxide semiconductor gas sensors. The method comprises the steps of firstly taking zinc acetate dihydrate, glycine, sodium sulfate decahydrate and sodium hydroxide as starting raw materials, and a mixed solution of water and ethanol as a solvent and successfully preparing a ZnO hollow flower ball precursor by using a hydrothermal method; and burning in air to obtain ZnO hollow flower ball powder; and taking the ZnO hollow flower ball powder, cadimium nitrate tetrahydrate and thiourea as the starting raw materials, and a mixed solution of dimethylformamide (DMF) and isopropyl alcohol as the solvent, compounding CdO nano-particles on the ZnO hollow flower balls by using the hydrothermal method and then burning in air to obtain the ZnO hollow flower ball and CdO nano-particle composite nanomaterial. The defect that two materials are relatively poor in gas-sensing characteristics is overcome, and improvement of the detection sensitivity of an ethanol gas and reduction of a lower detection limit are achieved.

The invention relates to a flexible gas-sensitive sensor based on a tin oxide/gallium oxide heterojunction nano array and a manufacturing method of the flexible gas-sensitive sensor. The flexible gas-sensitive sensor comprises Ti/Au electrodes, a flexible glass fiber cloth substrate, an SnO2 film positioned on the flexible glass fiber cloth substrate and a beta-Ga2O3 nano column array which is positioned above the SnO2 film, wherein the SnO2 film is positioned on the beta-Ga2O3 nano column array and the flexible glass fiber cloth substrate; a contact surface between the SnO2 film and the beta-Ga2O3 nano column array forms a heterojunction; one of the Ti/Au electrodes is positioned above the SnO2 film and the other one is positioned above the beta-Ga2O3 nano column array. The gas-sensitivesensor has a three-dimensional space heterojunction interface structure, is stable in gas-sensitive characteristics, is flexible and bendable, is low in working temperature and power consumption, canbe used for flexibly wearable VOC gas detection, and has a very great application prospect in the fields of detection for indoor formaldehyde gas, acetone content of a diabetic patient, and drunk driving.

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 provides a nitrogen dioxide sensor based on a composite material blocking effect, and a preparation method thereof, and relates to the technical field of gas sensors and composite nanomaterials. The nitrogen dioxide sensor comprises a sensitive device, the sensitive device is provided with a gas sensitive layer, and the gas sensitive layer is made of a composite material with a blocking effect. The preparation method comprises the following steps: S1, carrying out pretreatment on a sensitive device substrate, wherein the pretreatment comprises cleaning, drying and hydrophilic treatment; S2, preparing a high-molecular polymer dispersion liquid and an inorganic conductive material dispersion liquid; S3, depositing the sensitive material dispersion liquid on the sensitive device substrate to form a gas sensitive layer; and S4, drying and aging the sensitive device with the gas sensitive layer to obtain the nitrogen dioxide sensor based on the blocking effect of the composite material. The nitrogen dioxide sensor disclosed by the invention has the characteristics of large response, high response/recovery speed, good recovery, good repeatability and the like, can work at room temperature, does not need auxiliary means such as illumination or heating and the like, and is beneficial to development of green, energy-saving and low-power-consumption devices.

The invention provides a preparation method and application of a surface modified Pd-SnO2 microsphere. The preparation method of the surface modified Pd-SnO2 microsphere comprises the following stepsthat a palladium chloride acid solution and a CTAB solution are sequentially added into a stannic chloride solution, and a hydrothermal reaction is conducted for 20-24 hours at the temperature of 160-180 DEG C; the molar ratio of stannic chloride to palladium in palladium chloride acid is 1 to (0.01-0.009); and the molar ratio of stannic chloride to CTAB is 1 to (1-10). A CTAB surface modifying agent is used to conduct surface modification on a Pd-loading SnO2 nano material, and the surface modified Pd-SnO2 microsphere is obtained. The method is simple and easy to repeat, the obtained surfacemodified Pd-SnO2 microsphere is in a three-dimensional nano spherical shape, a great amount of Pd nano particles exist on the surface of the sphere, the catalytic sites of gas are increased which is conductive to adsorption and desorption of gas, and accordingly the gas sensibility is improved.

The invention relates to a preparation method of an aluminum-titanium codoped ZnO-based acetone gas sensor. The preparation method is applicable to the field of preparation of gas sensor device with high selectivity characteristic on acetone steam. The preparation method comprises the following steps: preparing Zn(OH)2 sol by adopting a sol-gel method, quantitatively adding dopants, namely aluminum nitrate and hexadecyl trimethyl ammonium bromide, and additionally preparing Ti(OH)4 sol as a titanium doping agent; respectively drying, grinding and cleaning the two kinds of colloids, mixing thetitanium doping agent and Zn(OH)2 powder according to a molar ratio of aluminum to titanium of 1:(1-3), then annealing, mixing a powder material with hexadecyl trimethyl ammonium bromide, coating theceramic tube, and annealing again, so that a side heating type thick film gas-sensitive element is obtained; and ageing the element for 5-7 days. The preparation method provided by the invention is simple, the obtained element has good selectivity on acetone, and effective detection on trace amount of acetone is realized.

The invention discloses an OFET (Organic Field Effect Transistor) ammonia gas sensor containing a functional insulation layer. The OFET ammonia gas sensor comprises a substrate, an insulation layer a, the functional insulation layer, an insulation layer b and an organic semiconductor layer which are sequentially arranged from bottom to top, wherein the organic semiconductor layer is provided with a source electrode and a drain electrode; a gate electrode is arranged between the substrate and the insulation layer a; the insulation layer a and the insulation layer b are formed by polymer insulation materials which do not contain hydroxyl; the functional insulation layer is formed by a polymer insulation material which contains the hydroxyl. According to the OFET ammonia gas sensor disclosed by the invention, a functional insulation layer material containing the hydroxyl is introduced between two insulation layers, so that the gas sensing property of an OFET is increased; -OH contained in the hydroxyl in the functional insulation layer can be subjected to reversion when ammonia gas molecules permeate into an interface of the insulation layers/the organic semiconductor layer, so that hole charges in corresponding number can be induced, parameters of saturation current, a migration rate and the like of devices are enabled to change, and detection on ammonia gas can be realized.

The invention discloses a preparation method for an Ag doped ZnO nanometer gas sensitive material. Water soluble zinc salt and silver nitrate are dissolved in 80 mL of deionized water according to the molar ratio of 100: (1-5), and the positive ion concentration ranges from 0.1 M to 0.2 M; a two-composition complexing agent and deionized water are premixed, the volume ratio of water to the complexing agent is (10-20): 1, and stirring is carried out till the complexing agent is completely dissolved; the positive ion solution and the complexing agent solution are mixed, after being stirring for 10 min, the mixed solution is added into a polytetrafluoroethylene reaction kettle, a reaction is conducted for 6-12 hours at the temperature of 65-120 DEG C, after the reaction is finished, a sample in subjected to centrifugation and repeatedly washed with deionized water and absolute ethyl alcohol for 2-3 times, the sample is dried for 4-12 hours at the temperature of 60-70 DEG C, and the Ag doped ZnO nanometer material is obtained. After Ag doping, the selectivity and sensitivity of the ZnO nanometer material can be greatly improved, and the problem that the selectivity of the ZnO is poor is solved. The preparation method has the beneficial effects that the preparation process is simple, the preparation cost is low, the performance is stable, the gas selectivity is good, and the preparation method has wide application prospects.

The invention discloses a preparation method of a ZnO-CuO composite nano material. The preparation method comprises the following steps: stirring and dripping a potassium ethyl xanthate liquid into a zinc salt liquid; mixing obtained sediment with de-ionized water; drying to obtain zinc ethyl xanthate powder; stirring and dripping the potassium ethyl xanthate liquid into a copper salt liquid and drying to obtain copper ethyl xanthate powder; mixing copper ethyl xanthate and zinc ethyl xanthate to obtain powder A, and pre-mixing the powder A with the de-ionized water; adding an organic dispersant and an inorganic dispersant into a mixed liquid; drying and roasting, wherein the roasting temperature is 400 DEG C-500 DEG C, the temperature rising speed is 3 DEG C/min-10 DEG C/min and the roasting time is 2h-5h; and then cooling to room temperature to obtain the ZnO-CuO composite nano material. The method disclosed by the invention adopts a simple preparation process, is low in preparation cost, stable in performance and good in gas selectivity and has wide application prospect.

The invention discloses a low-temperature H2S (hydrogen sulfide) gas-sensitive material and a preparation method thereof, and belongs to the technical field of electrochemistry, which solves the problem that the existing gas-sensitive material cannot be used to detect gas under the superlow-temperature extreme condition. The low-temperature hydrogen sulfide gas-sensitive material is of a nanowire cyclic array structure consisting of continuously distributed Cu2O and cyclically spaced Co3O4. The preparation method comprises the following steps of (1) preparing an electrolyte; (2) by using a silicon sheet or a glass sheet as a substrate, dropwise adding the electrolyte liquid between two copper foil electrodes; (3) refrigerating and icing the electrolyte liquid in a temperature-controllable growth room, and placing for 20 to 40min; (4) applying semi-sine waveform deposition voltage onto the electrodes to deposit electrolyte; (5) after depositing is finished, fetching out the substrate, and cleaning by deionized water, so as to obtain the Cu2O/Co3O4-based low-temperature H2S gas-sensitive material attached to the substrate. The low-temperature hydrogen sulfide gas-sensitive material can be used for detecting H2S gas under the superlow-temperature extreme condition.

The invention belongs to the field of a gas sensor, and particularly relates to a preparation method of a carbon-coated gold-doped tin dioxide composite material. Firstly, ammonia water is added intoa tin dichloride water solution; stirring, hydrothermal reaction, centrifugation, washing and drying are sequentially performed to obtain tin dioxide; secondly, the tin dioxide is added into water; stirring is performed; chloroauric acid and ammonia water are added; centrifugation, washing, drying and roasting are performed to prepare gold-doped tin dioxide; finally, the gold-doped tin dioxide isadded into helium gas; the temperature is raised; the temperature is constant; acetylene is introduced; meanwhile, helium gas is introduced; the temperature lowering and annealing treatment is performed; the carbon-coated gold-doped tin dioxide composite material is prepared. The preparation method is simple; the cost is low; the prepared carbon-coated gold-doped tin dioxide composite material hasthe large specific surface area; through the gold doping and carbon coating, the gas sensitive characteristics of the composite material is greatly improved; the optimum response temperature is reduced; the maximum response value is improved; good gas sensitive performance is realized.

The invention provides a method for preparing a ZnO thick film. The method comprises the following steps: dispersing flaky basic zinc salt grains into water to form precursor slurry; filtering the precursor slurry by a microporous filtering film to make the flaky basic zinc salt grains autogenously assembled into an orientation basic zinc salt thick film; transferring the basic zinc salt thick film on the microporous filtering film onto a substrate; and heating and decomposing the thick film to obtain the ZnO thick film. The method uses the flaky basic zinc salt as the precursor to prepare the ZnO thick film, and the prepared ZnO thick film has the advantages of good orientation, even thickness and stable structure.

The invention relates to a preparation method of a novel titanium-doped tungsten oxide-based methylbenzene steam detection sensor and is suitable for the field of preparation of a gas sensor with methylbenzene steam with a high selective characteristic. The preparation method comprises the following steps: by adopting a sol-gel method, adding hexadecyl trimethyl ammonium bromide in a sol process;then drying and grinding a colloid, cleaning the colloid and carrying out annealing at high temperature; coating a ceramic tube with the prepared powder material through hexadecyl trimethyl ammonium bromide; and carrying out secondary annealing to prepare a gas sensitive sensor; and then carrying out aging. In the colloid preparation process, hexadecyl trimethyl ammonium bromide is added to be beneficial to generation of a stable colloid favorably; during coating, hexadecyl trimethyl ammonium bromide is added, so that the specific surface area of the material is increased, and in the apparatuspreparation process, the molar ratio of titanium to tungsten is controlled to be 1:5 to 1:9, so that the sensitivity and selectivity of the gas sensitive element are improved. The gas sensitive element prepared by the method has a sensitive characteristic on methylbenzene steam, and can detect the methylbenzene steam from much organic steam.

The invention relates to a flexible gas sensitive sensor based on a gallium oxide/zinc gallate hetero-junction nano-array and a preparation method thereof. The flexible gas sensitive sensor comprisestwo Ti/Au (Titanium Gold) electrodes, a flexible glass fiber cloth substrate, a ZnGa2O4 film located on the flexible glass fiber cloth substrate, and a beta-Ga2O3 nano-column array located on the ZnGa2O4 film; the two Ti/Au electrodes are respectively located above the ZnGa2O4 film and the beta-Ga2O3 nano-column array; the gallium oxide/zinc gallate hetero-junction nano-array is formed by the ZnGa2O4 film and the beta-Ga2O3 nano-column array. The sensor provided by the invention is an MSSM type hetero-junction flexible gas sensitive sensor in a Ti/Au/beta-Ga2O3/ZnGa2O4/Ti/Au structure, has a three-dimensional space hetero-junction interface structure, is stable in gas sensitive characteristics, flexible and bendable and low in working temperature and power consumption, can be used for detection of flexible wearable ethanol gas, and has great application prospects in fields such as production and monitoring of industrial alcohol and detection of drunk driving.

The invention discloses the gas-sensitive film sensor of the graphene oxide and graphene composite structure acquired by CVD graphene through non-pollution transfer technology and method thereof, process of which comprises: firstly, spin-coating graphene oxide dispersion liquid on the graphene surface of CVD graphene with a metal substrate to obtain a structure A; drying the structure A at 40-80 DEG C for 1-30 minutes; then removing the metal substrate of the structure A to obtain the composite film with the composite structure of graphene oxide and graphene; then rinsing the obtained composite film; finally, the rinsed composite film is transferred to the electrode structure and dried to obtain the gas-sensitive film sensor of the graphene oxide and graphene composite structure. The preparation method can overcome the problems of organic residual pollution, cracks and wrinkles introduced during the graphene transfer process, meanwhile, the prepared gas-sensitive film of the graphene oxide and graphene composite structure makes up the defect of the graphene well, so that the gas-sensitive property of the graphene is greatly improved.

The invention relates to an FET type gas sensor having a composite insulating structure and a preparing method thereof. The gas sensor and the method are characterized in that the gas sensor includes a gate electrode, first to second supporting layers, a source region, a drain electrode region and a micro-nano single crystal semiconductor; the top two sides of the gate electrode are provided with the first and second supporting layers; the top of the first supporting layer is adhered and fixed to the source region; the part in the first supporting layer, which is longer than the source region, is a solid insulation layer; the inside of the bottom of the source region is provided with a first groove; the top of the second supporting layer is adhered and fixed to the drain electrode region; the second supporting layer is flushed with the inner end part of the drain electrode region; the inside of the bottom of the drain electrode region is provided with a second groove; the micro-nano single crystal semiconductor is fixed at the tops of the first and second supporting layers; two ends of the micro-nano single crystal semiconductor are inserted into the first and second grooves respectively; a cavity formed by the gate electrode, the first supporting layer, the second supporting layer and the micro-nano single crystal semiconductor is an air gap insulating layer; and the gas sensor can be widely used in the field of gas sensors.

The invention discloses a xylene gas sensor based on a V2O5 nanoflower structure and a preparation method of the xylene gas sensor based on the V2O5 nanoflower structure. The outer surface of the ceramic tube substrate is provided with two annular platinum electrodes which are arranged in parallel and are separated from each other, the outer surface of a ceramic tube and gold electrodes are coated with the sensitive material, the nickel-chromium heating coil is arranged in the ceramic tube, and the sensitive material is V2O5 nanoflower structure powder. According to the invention, the V2O5 material is modified by adopting a mode of a V2O5 nanoflower structure, so that the gas-sensitive characteristic of the gas sensor is remarkably improved.

The invention relates to the technical field of new materials, in particular to a three-dimensional porous In2O3 nano-cube bread gas sensitive material and a preparation method thereof, which solve the problems of particle aggregation and grain growth caused by heat-induced growth of In2O3 serving as a gas sensitive material at present and gas sensitive property recession due to film peeling caused by the traditional sensitive film transfer process. The preparation method adopted by the invention comprises the steps of: cleaning an Ag interdigital electrode plate; (2) growing a seed layer; (3)and growing the In2O3.