30results about How to "Short response/recovery times" patented technology

The invention discloses a QCM (quartz crystal microbalance) formaldehyde sensor with chemical and physical adsorption effects and a preparation method thereof, belonging to QCM formaldehyde sensors in the technical field of gas sensors. A sensor substrate is a QCM, and formaldehyde sensitive films 4 with chemical and physical adsorption effects are deposited on two sides of a QCM electrode, respectively, wherein the sensitive films are composite sensitive films prepared from organic polymer sensitive materials and carbon nano tubes or graphene and other materials through processes such as gas blowout, dispensing or ink-jet printing. According to the sensor, the high specific surface area and supporting characteristics of materials such as the nano tubes or graphene as well as adsorption or specific response performance of polymer materials are fully utilized, chemical / physical enhancement effects of double-sided composite sensitive films are exerted, and the sensitivity and adsorption / desorption rate of the sensor are improved. The sensor has the advantages of simple preparation process, low cost, high sensitivity, capability of operating at room temperature and the like and the technical scheme disclosed by the invention can be widely applied to QCM formaldehyde sensors.

The invention provides a preparation method of a cobalt tetroxide / zinc oxide nanoflower heterojunction film that can be used for detecting low-concentration acetone, and belongs to the technical fieldof gas sensitive sensors. A ZIF-67 / ZIF-8 precursor is firstly prepared under solvothermal conditions by using a cobalt source, a zinc source and imidazole as reactants and using methanol as a solvent, then the ZIF-67 / ZIF-8 precursor is calcined in a tube furnace to obtain a cobalt tetroxide / zinc oxide nanoflower composite, and finally, a cobalt tetroxide / zinc oxide device is prepared by using a drop coating method, and the sensitivity of a pure cobalt tetroxide nanoflower and the composite cobalt tetroxide / zinc oxide nanoflower to acetone is compared. The sample still has a relatively high response value (298%) and a shorter response / recovery time (16 seconds / 25 seconds) at 10 ppm acetone. The preparation method of the sensor film is simple, the raw material cost is low, the material filmhas excellent performance, and the application value and prospect are very good.

The invention relates to a nano-material and a preparation method and application thereof.The nano-material is a nano WO3 precursor and sintered product which presents excellent gas-sensitive performance to dimethylbenzene gas.The preparation method includes: dissolving tungsten hexachloride as a tungsten source in a glycol solvent, using ammonia water as a precipitation agent, and while stirring, and adopting microwave heating at 170-190 DEG C for reaction on a gas-liquid interface for 50-80 min to obtain a nano WO3 precursor which is gear-shaped; calcining the precursor in air at 450-550 DEG C for 2h to obtain a doughnut-shaped nano WO3 sintered product with a middle hole.Both the precursor and the sintered product present excellent gas-sensitive performance to dimethylbenzene gas.The preparation method has the advantages of quick reaction, energy conservation and cost reduction, and a dimethylbenzene gas sensor obtained has the advantages of low working temperature, high sensitivity, high selectivity and short response / restoration time.

A method for preparing a hydrogen-sensitive sensing material based on a platinum nano-cluster / silicon carbide nanosheet comprises the following steps of 1 surface treatment of a silicon carbide nanosheet, 2 soaking with an ethanol solution to which chloroplatinic acid is dropwise added and 3 conduction of a high-temperature reducing reaction. The surface of the hydrogen-sensitive sensing materialbased on the platinum nano-cluster / silicon carbide nanosheet is uniformly loaded with platinum nano-clusters, selectivity and responsiveness to hydrogen are high, hydrogen in air can be subjected to quick and high-sensitivity in-situ detection especially in a high-temperature environment, and a stable responding value and short responding / restoring time are achieved; and the preparation method issimple, and wide application prospects are achieved.

The invention discloses a H2S gas sensitive sensor and a preparation method of Co-doped TiO2 nano-tube array films, and belongs to the technical field of electronic gas sensitive devices. According to the preparation method, TiO2 nano-tube arrays are prepared by the aid of an anodic oxidation method, transition metal is doped into the TiO2 nano-tube arrays, secondary treating of the TiO2 nano-tube arrays is omitted, complete transparent TiO2 nano-tube array films can be obtained, and the nano gas sensitive sensor is prepared by the aid of the array films and has good sensitivity and selectivity for hydrogen sulfide gas. The method is simple in preparation process, the prepared sensor has high selectivity and short response / recovery time for the hydrogen sulfide gas, and device of the gas sensitive sensor is achieved and has market development prospect.

The invention discloses a polyaniline / graphene capsule three-dimensional hollow hybrid structure as well as a preparation method and application thereof, and belongs to the technical field of resistive gas sensors. In the polyaniline / graphene capsule three-dimensional hollow hybrid structure, a graphene capsule is of a hollow opening structure, polyaniline nanoparticles are polymerized on the inner surface and the outer surface of the graphene capsule in situ and form pi-pi bond conjugation with the graphene capsule, and the particle size of the polyaniline nanoparticles is 18-40 nm. The graphene capsule is of a hollow open capsule structure; the bent part of the capsule has many five-membered ring, seven-membered ring and other heterocyclic structures, and pi-pi bond conjugation effect can be formed with polyaniline, and therefore, polyaniline is not simply attached to the inner surface and the outer surface of the graphene capsule, but forms relatively strong chemical bond effect, and selective surface growth of polyaniline is realized, so that the three-dimensional hollow hybrid structure is more stable, carrier transmission is more convenient, and rapid response to gas and improvement of sensitivity are facilitated.

The invention discloses a composite nano-film material based on the functionalization of graphene quantum dots. The composite nano-film material is in the shape of a film, the main body is ZnO nanosheets, and the surface is covered with graphene quantum dots and tin dioxide quantum grains; as The main ZnO nanosheets are hexagonal, with an average side length of 1.5-2.4 μm and an average thickness of 50-100 nm; the average size of graphene quantum dots is 3.2-4.3 nm, and the average size of tin dioxide quantum grains is 3.5- 5.2nm. The invention comprehensively uses the hydrothermal method and the post-heat steaming method to prepare the multi-level structure sensing material, and the synthesis method is simple and the cost is low.

A kind of synthesis of Au-doped WO from scheelite concentrate 3 The method and application of nanosheets relate to the field of semiconductor oxide gas sensors. A kind of synthesis of Au-doped WO from scheelite concentrate 3 The method of nanosheets, the method is as follows: use NaOH leaching process to convert and initially purify scheelite concentrate to obtain a leach solution containing sodium tungstate, dilute the solution into a solution with a concentration of sodium tungstate of 0.019-0.044mol / L as a precursor Body, with HAuCl 4 solution, CaCl 2 The solutions are mixed, and the mixing ratio is that the molar ratio of Au, W and Ca is 0.3%-1%:1:3-14. Au-doped WO prepared based on the method of the present invention 3 Nanosheet NO 2 Gas sensor, can achieve low concentration, even ppb level NO 2 High sensitivity, high selectivity and rapid detection of gases. Using cheap and low-pollution scheelite concentrate as the tungsten source greatly reduces the cost from the raw materials and the preparation process.

The polyaniline / graphene capsule three-dimensional hollow hybrid structure, preparation method and application belong to the technical field of resistive gas sensor. In the polyaniline / graphene capsule three-dimensional hollow hybrid structure, the graphene capsule has a hollow opening structure, and the polyaniline nanoparticles are in-situ polymerized on the inner and outer surfaces of the graphene capsule, and form a π-π with the graphene capsule bond conjugation, wherein the polyaniline nanoparticles have a particle size of 18-40nm. The graphene capsule of the present invention is a hollow open capsule structure, and its curved part has more heterocyclic structures such as five-membered rings and seven-membered rings, which can form π-π bond conjugation with polyaniline, which makes polyaniline not a simple Attached to the inner and outer surfaces of graphene capsules, it forms a strong chemical bond and realizes the selective surface growth of polyaniline, so that the three-dimensional hollow hybrid structure is more stable and the carrier transport is more convenient, which is beneficial to the Fast response and increased sensitivity to gases.

The invention discloses a composite nano-film material based on graphene quantum dot functionalization. The composite nano-film material is in a film shape, the main body is a ZnO nanosheet, and the surface is covered with graphene quantum dots and stannic oxide quantum crystal grains; the ZnO nanosheet serving as the main body is hexagonal, the average side length is 1.5 to 2.4 mu m, and the average thickness is 50 to 100nm; the average size of the graphene quantum dots ranges from 3.2 nm to 4.3 nm, and the average size of the stannic oxide quantum crystal grains ranges from 3.5 nm to 5.2 nm.The multistage structure sensing material is prepared by comprehensively using a hydrothermal method and a post thermal evaporation method, the synthesis method is simple, and the cost is low.

A method for preparing a hydrogen-sensitive sensing material based on platinum nanoclusters / silicon carbide nanosheets, comprising the following steps: (1) surface treatment of silicon carbide nanosheets; (2) dripping an ethanol solution of chloroplatinic acid for infiltration; (3) High temperature reduction reaction. The surface of the platinum nanocluster / silicon carbide nanosheet hydrogen-sensitive sensing material prepared by the present invention is uniformly loaded with platinum nanoclusters, and has high selectivity and responsiveness to hydrogen, especially in a high temperature environment, which can detect hydrogen in the air. The in-situ detection is fast and highly sensitive, and has stable response value and short response / recovery time. The preparation method is simple and has wide application prospects.

The invention discloses an NH3 gas-sensitive element prepared from a WO3 micrometer spindle formed through self-assembly of nanometer rods and a preparing method of the gas-sensitive element, and belongs to the technical field of gas-sensitive elements of semiconductor oxide. The gas-sensitive element is mainly composed of an electrode element body and the WO3 micrometer spindle uniformly coatingthe electrode element body. The WO3 micrometer spindle is formed through self-assembly of the WO3 nanometer rods, the diameter of the WO3 micrometer spindle is 0.4-1.5 micrometers, the length of the WO3 micrometer spindle is 0.6-1.4 micrometers, the diameter of each WO3 nanometer rod is 15-33 nm, the length of each WO3 nanometer rod is 80-1,050 nm, and the WO3 micrometer spindle is of a hexagonal-phase crystal structure. The WO3 micrometer spindle formed through self-assembly of the nanometer rods has the advantages that the crystal phase is single, the crystallinity degree is high, the morphology is uniform and consistent, the porosity is high, and the specific surface area is large. The gas-sensitive element has the advantages of high selectivity on NH3 gas, quick responses to low working temperature and the like.

The invention belongs to the field of gas sensor materials, and discloses an α-Fe 2 o 3 / TiO 2 Nanocomposite material and H2S gas sensor made from it. α‑Fe 2 o 3 Colloid and TiO 2 The colloids are ultrasonically mixed evenly, and then heated to 400-500°C for 2-4 hours to obtain α-Fe 2 o 3 / TiO 2 nanocomposites. α‑Fe 2 o 3 / TiO 2 The nano-composite material is mixed with ethanol and terpineol evenly, and then added dropwise to the surface of the cleaned flat electrode, dried at room temperature to form a gas-sensitive film, then heated to 400-500°C for 2-4 hours, and then cooled to obtain H 2 S gas sensor. The gas sensor of the invention has the advantages of low working temperature, fast response / recovery time, high sensitivity and good selectivity, and has great market development prospects.

The invention relates to the technical field of humidity sensors, in particular to a capacitive humidity sensor based on an "arch" structure, its preparation method and application. The humidity sensor includes: a top electrode and a bottom electrode, both of which have an "arch" structure; a medium layer, the top electrode and the bottom electrode are all provided with a medium layer of an arrayed nanocone structure, and the cone points are facing away from it The surface of the electrode where it is located; wires, wires are arranged on the top electrode and the bottom electrode; the top electrode and the bottom electrode are assembled to form a ring structure, and the dielectric layers on the two electrodes are located inside the ring structure. Compared with some existing technologies, the present invention proposes a high-performance capacitive humidity sensor with high sensitivity, short response / recovery time, good repeatability and its low cost, simple process, controllable shape and large-scale Production method of preparation.

The invention discloses a QCM (quartz crystal microbalance) formaldehyde sensor with chemical and physical adsorption effects and a preparation method thereof, belonging to QCM formaldehyde sensors in the technical field of gas sensors. A sensor substrate is a QCM, and formaldehyde sensitive films 4 with chemical and physical adsorption effects are deposited on two sides of a QCM electrode, respectively, wherein the sensitive films are composite sensitive films prepared from organic polymer sensitive materials and carbon nano tubes or graphene and other materials through processes such as gas blowout, dispensing or ink-jet printing. According to the sensor, the high specific surface area and supporting characteristics of materials such as the nano tubes or graphene as well as adsorption or specific response performance of polymer materials are fully utilized, chemical / physical enhancement effects of double-sided composite sensitive films are exerted, and the sensitivity and adsorption / desorption rate of the sensor are improved. The sensor has the advantages of simple preparation process, low cost, high sensitivity, capability of operating at room temperature and the like and the technical scheme disclosed by the invention can be widely applied to QCM formaldehyde sensors.

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 provides a high-sensitivity surface acoustic wave nitrogen dioxide sensor, which sequentially includes a piezoelectric substrate, an electrode layer, and a NO sensor by ultraviolet light irradiation. 2 Sensing composite sensitive layer with three-dimensional porous structure of silver nanoparticles doped reduced graphene oxide-polypyrrole. This application uses the 3D porous sensitive material rGO‑PPy / Ag as the sensitive film, uses Ag nanoparticles doping to improve the repeatability of the sensor, and uses ultraviolet light to irradiate the sensitive film to assist NO 2 sensing. This rGO‑PPy / Ag surface acoustic wave NO2 sensor based on UV-assisted irradiation can realize NO at room temperature 2 Sensing with high sensitivity (127.68 Hz / ppm) and fast response / recovery speed (39.7 s / 58.5 s), exhibiting good repeatability and selectivity.

This application discloses a CdS / Co 3 o 4 Composite material and its preparation method and application, the CdS / Co 3 o 4 Composite materials include Co 3 o 4 Nanofibers are well attached to the Co 3 o 4 CdS nanoparticles between nanofibers, where the Co 3 o 4 The diameter of the nanofiber is 200-300nm, the diameter of the CdS nano-particle is 300-400nm, and the CdS / Co 3 o 4 The composite material can be made into a gas sensor, an acetone gas sensor, and a light-excited gas-sensing test platform. The CdS / Co 3 o 4 Composite materials and their products can detect acetone gas at room temperature (25°C), and have the advantages of high sensitivity, short response recovery time, good selectivity, etc., and a wide detection range, effectively solving the problem of traditional acetone gas sensors at low temperature and low temperature. The problem of poor gas sensitivity characteristics in the gas concentration area.

The invention provides a method of improving MoS by W doping 2 A method for gas sensor performance comprising the following steps: In MoS 2 During the growth process, the introduction of Mo 4+ W with a similar ionic radius 4+ Ions can fill the material vacancies and improve the adsorption / desorption behavior of gas molecules on the material surface. Synthesized W-doped MoS via a hydrothermal method 2 material, and further produced a planar interdigitated NO 2 gas sensor. The results show that the doping of W makes MoS 2 Gas sensor for NO 2 The response / recovery behavior of the gas has been greatly improved, and the response / recovery time has been reduced by an order of magnitude, from hundreds of seconds to tens of seconds. The present invention utilizes a cost-effective hydrothermal method to achieve vacancy compensation and enhance the MoS 2 The gas sensor has the advantages of response / recovery speed, simple preparation process, low requirements for the required instruments under reaction conditions, simple process, and low cost, and has great application prospects in the field of rapid gas detection at room temperature.

The invention relates to a nanometer material and its preparation method and application. The material, that is, the nano-WO3 precursor and the sintered body exhibit excellent gas-sensing properties to xylene gas. In the present invention, tungsten hexachloride is used as a tungsten source and dissolved in ethylene glycol solvent, ammonia water is used as a precipitant, and microwave heating is adopted at 170-190°C for 50-80 minutes at the gas-liquid interface under stirring conditions to obtain a gear-shaped The nano-WO3 precursor, after the precursor is calcined at 450-550°C for 2 hours in the air, the sintered product of nano-WO3 with intermediate pores is obtained, and both the precursor and the sintered product exhibit excellent gas Sensitivity, the method has the advantages of fast response, energy saving and cost reduction, and the prepared xylene gas sensor has the advantages of low operating temperature, high sensitivity, good selectivity, and short response / recovery time.