114results about How to "Fast response and recovery" patented technology

The invention discloses a gas sensor array and a manufacturing method thereof. The gas sensor array comprises a substrate and a group of resistive gas sensors formed on the substrate, wherein each gas sensor in the array comprises a gas sensing resistor formed by a graphic graphene film on the substrate and a polymer film with which the graphene film is covered; the substrate is provided with a graphic metal electrode array; the metal electrode array constructs a conductive lead for each gas sensing resistor; the film type and / or film thickness of the polymer film of each gas sensor is different. By adopting the gas sensor array, the sensitivity and selectivity of the gas sensors can be improved remarkably during detection of the presence of ppb-level VOCs (Volatile Organic Compounds).

The invention discloses an extensible semiconductor resistive flexible gas sensor with micro-wrinkle film structure and a preparation method thereof. Insulating substrate-polyacrylate double-sided foam tape (VHB, very high bond) that is extensible is unilaterally pre-extended to certain extent and fixed to a rigid substrate; a patterned graphene electrode and a colloidal quantum dot film are prepared on a VHB substrate that is pre-extended, and the sensor is prepared by retracting the VHB substrate slowly. The gas sensor prepared in the method has a gas-sensitive layer of micro-wrinkle film structure and a patterned graphene electrode, the gas sensor features extensibility, manufacturing temperature and operating temperature of the sensor can be lower than room temperature, transient or minor changes in gas concentration can be detected at room temperature, and the gas sensor has high response restoring speed and sensitivity, has certain resistance to ambient humidity interference and has better long-term stability.

The invention provides an acetone sensor based on a NiO / ZnO heterostructure nanoflower sensitive material and a preparation method of the acetone sensor, and belongs to the technical field of semiconductor oxide gas sensors. The NiO / ZnO heterostructure nanoflower sensitive material which is used is a NiO-ZnO heterostructure nanoflower sensitive material prepared through a water-bath method and a dipping method. The sensitivity of the sensor to acetone is effectively improved through the catalysis effect of NiO nanoparticles on organic gas and the heterostructure of NiO and ZnO. In addition, The sensor is structurally composed of an Al2O3 insulating ceramic pipe which is sold on the market and comprising two annular cold electrodes, a semiconductor sensitive material with which the annular gold electrodes and the Al2O3 insulating ceramic pipe are coated, and a nichrome alloy heating coil penetrating through the Al2O3 insulating ceramic pipe. The device is simple in process, small in size and suitable for mass production, and therefore the acetone sensor has wide application prospects on the aspect of the acetone content in detection microenvironments.

The invention discloses a preparation method of an ethanol gas sensor component having an ultrafast response recovery property. In the preparation method, LaFexO3 nano particles in non-stoichiometric ratio prepared through a sol-gel method are employed as a working substance to prepare a beside-heating-type ceramic tube gas sensor component. By means of reduction of a relative element ratio of iron to lanthanum in a precursor, the carrier concentration is increased and the resistance of the component is reduced. By means of selection of a proper La / Fe element ratio, size of crystal grains is reduced and oxygen adsorption capacity is improved, so that the gas sensor is improved in sensitivity on ethanol, is reduced in working temperature and is reduced in response recovery time. A LaFe0.8O3 beside-heating-type ethanol gas sensor prepared in the invention can reach 138 in the sensitivity on ethanol in 1000 ppm at the working temperature of 140 DEG C, wherein the response and recovery times are respectively 1 s and 1.5 s. The gas sensor is less than 22 in all sensitivities on methane, acetone, carbon dioxide and glycerol in 1000 ppm. The gas sensor is high in sensitivity, is low in the working temperature, is ultrafast in response recovery property and is high in selectivity at the same time on ethanol, and is low in cost and is environmental-friendly.

The invention discloses a humidity sensor based on graphene oxide / graphene / silicon and a preparation method thereof, wherein the humidity sensor comprises an n-type silicon substrate, a silicon window, a silicon dioxide insulation layer, graphene, graphene oxide, a top electrode and a bottom electrode. A graphene / silicon schottky junction in the humidity sensor is high in multiple transmission speed and is sensitive in reaction, and meanwhile, because that graphene is high in transparence, is high in electric conductivity and heat conductivity and is high in mechanical strength, the humidity sensor is available in various special applications under ultra-common conditions. By means of the graphene oxide as a humidity sensitive layer, electrical characters of the graphene / silicon schottky junction are influenced. The humidity sensor having such structure is simple to manufacture, allows quick and simple measurement, is high in sensitivity, can be used for manufacturing an integrated sensor through combination of mature semiconductor silicon technologies in a packaging manner. The humidity sensor has significant market prospect.

The invention relates to a preparing method of a nano-rod-shaped indium oxide (In2O3) gas-sensitive material, and belongs to the technical field of preparation of inorganic nanometer functional materials. The preparing method comprises the steps of with indium(III) chloride tetrahydrate being an indium source, by adopting hexadecyl trimethyl ammonium bromide as surface active agent, conducting a hydrothermal reaction under the alkaline condition of sodium hydroxide to prepare indium hydroxide and finally, conducting thermal roasting to obtain the indium oxide gas-sensitive material of a nano-rod-shaped structure. Finally prepared indium oxide is In2O3 with the cubic phase and of the nano-rod-shaped structure, has very good performance of sensing and detecting both nitrogen dioxide gas andhydrogen sulfide gas and is insensitive to other gases (carbon monoxide, ethyl alcohol, ammonia, hydrogen, formaldehyde and the like); the indium oxide also has low working temperature, a quick response and restoration, very high sensitivity, a low detection limit, high selectivity and high stability. Besides, the indium oxide gas-sensitive material can also be used in the fields of catalyst, battery materials, photoelectric materials and the like.

A flexible plane-type NH3 gas sensor based on a PANI (at) flower-like WO3 nanoscale sensitive material and application thereof belong to the technical field of gas sensors. The flexible plane-type NH3gas sensor of the invention is composed of a PET substrate with two mutually independent interdigital gold electrodes of 80-120 nm thick vapor-plated on the upper surface and a PANI(at) flower-like WO3 nanoscale sensitive material which is grown in situ on the upper surface of the PET substrate and the interdigital gold electrodes. The invention develops a high-performance NH3 gas sensor which has quick response to NH3 in the atmospheric environment at room temperature. Sensitivity of the sensor to 100 ppm NH3 reaches up to 20.1, and lower detection limit can reach 500 ppb. The developed sensor also has quick response recovery rate. In addition, the sensor also shows good selectivity and repeatability, and has a wide application prospect in the field of room-temperature detection of NH3 in the atmospheric environment and in the field of flexible electronic devices.

The invention discloses a molybdenum disulfide thin film gas sensitive material, a preparation method and application. A MoS2 thin film material obtained through a CVD method is adopted as the gas sensitive material. Firstly, a SiO2 / Si substrate is pre-plated with a molybdenum atom layer of a certain thickness at the deposition rate of 0.1 A / s through electronic beam evaporation; and then at a certain temperature, the SiO2 / Si substrate and S steam generate a combination reaction to generate the MoS2 thin film gas sensitive material. The two ends of the obtained substrate with a MoS2 nanosheetgrowing on the surface are plated with gold electrodes correspondingly; and a wire and the gold electrodes are bonded through a conductive silver adhesive, finally an insulation AB adhesive is used for fixing so as to increase the strength of a gas sensitivity testing device, the testing device is aged and packaged, and therefore preparation of a NO2 gas sensitive element is achieved. The preparedgas sensitive element can achieve detection to NO2 gas under room temperature, energy consumption is low, selectivity to distribution gas is good, and great significance is achieved on real-time monitoring of the NO2 gas.

The invention discloses a method for preparing a gas sensitive element by taking houghite as a precursor, which belongs to the technical field of gas sensitive sensors. The method comprises the following steps of: preparing houghite by using a co-precipitation method; roasting the houghite at different temperatures to form a compound semiconductor metal oxide material; and preparing into a gas sensitive element, wherein the gas sensitive element can be used for detecting various gases by measuring the resistance values of the element in different gases. The gas sensitive element has the major advantages of simple preparation steps, low cost, diversified element compositions, and uniform distribution of elements of a compound oxide formed by roasting. The gas sensitive element prepared from the method has the advantages of high sensitivity, quick response and recovery, high stability, great developing potential and contribution to popularization.

The invention discloses an SnO2 film and a preparation method used for vehicle-bone ethanol detection; the SnO2 film used for the vehicle-bone ethanol detection mainly comprises three layers: a silicon underlay, an electrode layer and a film sensitive material layer; wherein, the sensitive material layer mainly consists of an SnO2 semiconductor oxide material film; the electrode layer is a comb-shaped electrode; the preparation method of the invention comprises the steps as follows: electric deposition and a DNA regulation nanometer film preparation process are used for generating the nanometer-class oxide film of stannum; subsequently, gold doping and annealing are carried out so as to prepare the nanometer crystal grain jewellers putty film. The jewellers putty film prepared by the invention has the advantages of small granularity, large specific surface area, uniform surface, and high sensitiveness and quick response recovery, etc. to the detection of the easily volatile gas ethanol in the automobile. The preparation method of the invention has the advantages of uniform and orderly deposition on substrates with various complex structures, precisely controlling the thickness, the chemical composition and the structure, etc. of the deposition layer, little fabrication equipment investment, simple process, and easy operation.

The invention relates to a preparation method for a gold-loaded tin oxide nanometer material for detecting hydrogen. In order to deal with the conditions that hydrogen detecting gas sensitive materials are low in sensitivity, low in response speed and poor in stability, the gold-loaded tin oxide nanometer material is made from potassium stannate, chloroauric acid and glucose and prepared through the steps of hydro-thermal synthesis through a reaction still, vacuum heat treatment and grinding and sieving. According to the preparation method, the process is advanced, and data are full and accurate; products are atropurpureus crystals, the crystal particle diameter is smaller than or equal to 80 nm, and the product purity is high and reaches 99.6%; the gas sensitivity of the material on 100 ppm hydrogen reaches 25, response time is 1 s, and recovery time is 3 s; the sensitivity is high, response and recovery are fast, and the material can be applied to a gas sensor for detecting hydrogen. The preparation method for the gold-loaded tin oxide nanometer material is quite advanced.

The invention relates to a sensing material and a preparation method of the sensing material and in particular relates to a Fe-doped bimodal mesoporous nickel oxide formaldehyde gas sensitive material and a preparation method of the Fe-doped bimodal mesoporous nickel oxide formaldehyde gas sensitive material. The Fe-doped bimodal mesoporous nickel oxide formaldehyde gas sensitive material is formed by Fe-doped nickel oxide spiral nanowires through cubic periodic arrangement; the preparation method of the Fe-doped bimodal mesoporous nickel oxide formaldehyde gas sensitive material comprises the steps of mixing surface active agents, water and hydrochloric acid until the surface active agents are completely dissolved, adding with n-butyl alcohol, stirring for 2h, then adding with tetraethoxysilane and stirring for one day, carrying out hydrothermal reaction for one day at 35-100 DEG C, cooling, performing suction filtration, washing, and drying to obtain white powder; calcining in air to remove the surface active agent; by using the calcined ordered mesoporous silica as a hard template, adding the hard template into ethanol solution of nickel nitrate and ferric nitrate, and calcining in air; and adding sodium hydroxide solution into the calcined product, stirring, centrifuging, and filtering to obtain the Fe-doped bimodal mesoporous nickel oxide material. The Fe-doped bimodal mesoporous nickel oxide formaldehyde gas sensitive material has high sensitivity and good stability.

The present invention belongs to the technical field of preparation of a humidity sensor, and particularly relates to a method for preparation of a fast-response and wide-range ceramic-based nano-fiber humidity sensor by adopting an electrospinning technique. Soluble metal salts, esters, conductive polymers and organic solvents are used as raw materials. The method comprises the following steps: preparing composite fibers containing the conductive polymers and composite metal oxide precursors by adopting the electrospinning technique, calcining the fibers to remove organic polymer components, and obtaining ceramic-based perovskite-type composite metal oxide nanofibers. The humidity sensor made with the one-dimensional, ultra-long and continuous perovskite-type composite metal oxide ceramic nanofibers has the advantages of wide range of humidity measurement, small humidity hysteresis, high linearity, rapid response and recovery and the like. The method is suitable for preparation of ceramic oxides and composite oxides with various soluble metal salts as the raw materials, has the advantages that the equipment has a simple structure, a good performance and a low cost, is easy to promote, can satisfy the requirements of industrial technologies, and is widely applied in such fields as the industry, agriculture, storage, meteorology and the like.

The invention discloses a graphene / tin dioxide quantum dot composite material-based NO2 sensor and a preparation method thereof, and belongs to the technical field of gas sensors. The NO2 sensor adopts a side-heating structure, and comprises a nickel-cadmium alloy heating coil, an Al2O3 ceramic tube, a sensitive layer, Pt conductive wires and two gold electrodes, wherein the nickel-cadmium alloy heating coil is positioned inside the Al2O3 ceramic tube and is used for heating the NO2 sensor; the two gold electrodes are positioned on the surface of the Al2O3 ceramic tube, each gold electrode is connected with the Pt conductive wire, and through measurement on the DC resistance values of the two gold electrodes in different atmospheres, a function of measuring the concentration of NO2 is achieved; the sensitive layer coats the Al2O3 ceramic tube and completely covers the two gold electrodes. By virtue of a synergistic effect of a composite material, a sensitive material has both a high specific surface area and a size effect, and the high-performance NO2 sensor is prepared; through change of the ratio of the graphene to tin dioxide quantum dots, the sensitive characteristic of the sensor can be controlled; the sensor prepared according to the preparation method provided by the invention has a good application prospect in environmental monitoring.

The invention relates to a flexible plane type NH3 gas sensor based on a PANI@Au-In2O3 sensitive material, a preparation method of the NH3 gas sensor and application of the NH3 gas sensor to the aspect of detecting NH3 at room temperature and in the atmospheric environment, and belongs to the technical field of gas sensors. The sensor consists of a flexible PET substrate and the PANI@Au-In2O3 sensitive material which grows on the surface of the PET substrate in situ. The sensor developed by the invention has high sensitivity, also has low detection lower limit and can detect the NH3 of 500 ppb; the sensitivity on the NH3 of 100 ppm can reach to 46; and very high selectivity and repeatability are shown. The flexible bendable plane type structure sensor is simple in manufacturing process, small in size, safe and harmless, and has important application value.

The invention relates to an isopropanol gas sensor based on a NiCoxFe2-xO4 (x=0.01-0.1) nano cube material prepared through a metal organic framework template and a preparation method of the sensor and belongs to the technical field of gas sensors. The sensor is composed of a Al2O3 substrate with a PD metal interdigital electrode and a NiCoxFe2-xO4 nano cube material sensitive layer prepared by adopting a coating technology on the PD metal interdigital electrode and the Al2O3 substrate from bottom to top in sequence, and the grain size of a nano cube is 50-80 nanometers. When the cube is dopedwith trace cobalt, due to the radius difference of cobalt atoms and iron atoms, the lattice defects are possibly caused, the defects are beneficial to generation of oxygen vacancies, oxygen absorption is enhanced accordingly, and the gas sensitive response is improved. The technology is simple, and the prepared sensor is small in size and suitable for large-batch production and has important application value.

The invention discloses a preparation method for an MOF-based Co-doped tin dioxide gas-sensitive nano material as well as a product and application. MOF (a metal organic framework structure) of Co andSn is utilized, and the Co-doped SnO2 gas-sensitive nano material is prepared by regulating conditions such as concentration, proportion, reaction time and a reaction temperature of a precursor. Thepreparation method is characterized in that Co doping amount is controllable, and Co element is uniformly distributed. The Co-doped gas-sensitive nano material prepared by the preparation method is high in purity, is uniform in dimension, is greatly improved in gas-sensitive response in comparison with a pure SnO2 gas-sensitive material, and is quick in response recovery speed.

The invention relates to a preparation method of a tin based nano composite material for detecting low concentration acetone gas, and aims to solve the problems that in the prior art, a gas sensitive material for detecting acetone gas does not respond to low concentration acetone gas, the sensitivity on high concentration acetone gas is low, the responding speed is slow, and the selectivity stability is bad. The composite material comprises the following raw materials: stannous chloride, sodium chloride, sodium citrate, and praseodymium nitrate, and is prepared by the following steps: hydrothermal synthesis in a reactor, microwave heating high temperature heat treatment, grinding, and sieving. The technology is advanced, the data is precise, the product morphology is good, the product has a sheet flower-shaped layered structure, the sheet thickness is not more than 30 nm, the product purity is good and can reach 99%; the sensitivity of the composite material on acetone gas (100 ppm) can reach 27, the responding time is 2 seconds, the recovery time is 36 seconds, the sensitivity on acetone gas (1 ppm) can reach 1.86, the responding speed is quick, the composite material is suitable for low concentration acetone detection, and can be used to prepare sensors for detecting acetone gas, and the provided preparation method is advanced.

The invention discloses a formaldehyde gas sensor based on a CoFe<2>O<4> / Co<3>O<4> double-shell structure cubic material and a preparation method thereof, and belongs to the technical field of gas sensors. The sensor consists of an Al<2>O<3> substrate, a Pd metal interdigital electrode, and a CoFe<2>O<4> / Co<3>O<4> double-shell structure cubic material prepared on the Al<2>O<3> substrate having thePd metal interdigital electrode by using a coating technology. When CoFe<2>O<4> is modified to a Co<3>O<4> hollow structure cube, lattice defects can be caused due to lattice mismatch; and these lattice defects can generate an oxygen vacancy to improve a gas sensitive response of a gas sensitive material. The invention has simple process, is small in prepared sensor, is applied to large-scale production and has an important application value. The formaldehyde gas sensor has the characteristics of simple preparation method, low cost, fast response recovery rate and low detection lower limit, and is expected to be produced in a large scale.

The invention discloses a window type intelligent fresh air purification system. The window type intelligent fresh air purification system comprises a purification window composed of a frame A, a frame B, a frame C, a frame D and a frame E, the frame A, the frame B and the frame C are hollow rectangular frames, the frame A and the frame B are connected to the upper end and the lower end of the frame C, a communication I structure is formed by the frame A, the frame B and the frame C, the frame D and the frame E are located on the two sides of the frame C, and an air flue, a draught fan, a shutter and an outdoor exhaust opening are formed inside and outside the frame A; an air flue, a draught fan, a shutter and an indoor air inlet are formed inside and outside the frame B; the system has the beneficial effects that the ultra-high safety and the ultra-high energy saving are achieved, 24-hour all-weather purification detection is achieved, indoor environment pollution is solved, the system and a window are integrated, no space is occupied, and the system is suitable for being applied to many occasions of homes, schools, hospitals, office buildings, administration centers and the like.

The invention discloses a window-type intelligent fresh air purification system. The window-type intelligent fresh air purification system comprises an indoor intake system, an exhaust system and window borders, wherein the window borders comprise a border A, a border B, a border C, a border D and a border E; the border A is provided with an outdoor exhaust opening; the border B is provided with an indoor intake opening; an outdoor intake opening spaced by a partition is formed in the outdoor border surface of the border C; an indoor exhaust opening spaced by a partition is formed in the indoor border surface of the border C; the indoor intake system and the outdoor exhaust system are embedded in the border C; and a blower I drives indoor air to circulate outdoors, and a blower II drives outdoor air to circulate indoors to form an integral fresh air purification cycle system. The window-type intelligent fresh air purification system has ultrahigh security and ultrastrong energy saving performance, realizes 24-hour purification detection, solves the confusion of family patients with respiratory diseases, is integrated with a window to occupy no other space, is long in service life and is suitable for being popularized in schools and other more occasions.

The invention provides a sensitive material for detecting acetone gas. The sensitive material is prepared by compounding a WO3 nano-sheet with C3N4, wherein the WO3 nano-sheet is used as a matrix, C3N4 is used as sensitizer, and the mass percentage of C3N4 in the sensitive material is between 0.5wt% and 10wt%. The invention also provides a preparation method of the sensitive material, which comprises: preparing an ultra-thin WO3 nano-sheet by a self-assembly method; ultrasonically peeling prepared C3N4 in a solvent to obtain a dispersion liquid; and dropwise adding the dispersion liquid to theWO3 nano-sheet layer according to the mass percentage to form a composite gas sensitive material. According to the invention, the acetone detection performance of the sensitive material is improved by modifying the WO3 nano-sheet with C3N4 with a two-dimensional layered structure. A gas sensitive test result shows that the gas sensitive element has the advantages of high sensitivity to acetone vapor, fast response recovery, good anti-interference ability, good stability and the like, and can be used to selectively detect acetone gas in respiratory gases.

The invention relates to a triple-mesopore indium oxide formaldehyde gas-sensitive material and a preparation method thereof. The invention is characterized in that the formaldehyde gas-sensitive material is formed by periodically arranging indium oxide spiral nanowires in a cubic mode, wherein every two nanowires are connected through a 2-5nm-long indium oxide nanorod, the diameter of the nanowires is 4-8nm, and the formaldehyde gas-sensitive material has the mesopores with three different sizes (2-4nm, 5-8nm and 10-17nm). The material is unique, and has the mesopore distribution of three different sizes (large, medium and small), thereby being beneficial to dispersion of gas molecules and increasing the response reset rate: the triple-mesopore indium oxide is formed by periodically arranging indium oxide spiral nanowires in a cubic mode, the distribution ratio of the three kinds of mesopores can be controlled by adjusting the pore size and connectivity of the mesopore silicon oxide template and the mass ratio of the indium nitrate to the mesopore silicon oxide, and the gap between the nanowires is beneficial to the dispersion of the gas molecules, thereby increasing the response reset rate.

The invention discloses a method for preparing a lanthanum cobaltate-doped nanorod array gas-sensitive sensor. The method is suitable for preparing lanthanum cobaltate nanorod array gas-sensitive sensors doped with elements such as strontium, cerium and palladium. The method comprises the following steps: preparing a nanorod array template by adopting an anodic oxidation method, forming a lanthanum cobaltate-doped nanorod on the template by adopting a sol-gel method, and contacting the nanorod with an electrode substrate by adopting a seed crystal method. According to the method, the morphology of the nanorod can be remained in an undamaged mode, and carbon monoxide can be well responded at room temperature. The room temperature carbon monoxide sensor prepared by adopting the method is simple in structure and excellent in performance.

The invention relates to a ZnO nanocluster gas-sensitive sensor with FTO conductive glass subjected to laser etching treatment as an electrode element, and belongs to the technical field of gas sensors. The gas-sensitive sensor consists of two parts, namely a gas-sensitive electrode element and a gas-sensitive material, and is characterized in that the gas-sensitive electrode element is obtained by carrying out laser etching treatment on the FTO conductive glass with the specific pattern and line width, the etched pattern is in an interdigital shape, the width of interdigital stripes is 300-500 mum, and the interval of the interdigital stripes is 20-80 mum; the gas-sensitive material is a ZnO nano-cluster array of a hexagonal wurtzite structure, the diameter of a nanowire is 70-100 nm, andthe length of the nanowire is 2-3.5 mum. The FTO gas-sensitive electrode element has the advantages of low cost, good stability, easiness in in-situ growth of the gas-sensitive material and the like;the sensor has the advantages of low cost, simple process, excellent gas sensitivity, good stability and the like, shows excellent response capability to gases such as ethanol, methanol, hydrogen sulfide and the like, and is a novel gas-sensitive sensor with wide development and application prospects.

The invention provides a preparation method for a fast-responding Pd-TiO2 nano-particle hydrogen-sensitive material. The preparation method for the fast-responding Pd-TiO2 nano-particle hydrogen-sensitive material comprises the following steps: 1) adding a certain amount of palladium chloride into a diluted hydrochloric acid solution and uniformly stirring, thereby acquiring a palladium chloride solution; 2) dropping in tetra-n-butyl titanate and hydrofluoric acid solution while stirring, and then uniformly stirring; 3) pouring the solution uniformly stirred in step 2) into a reaction kettle for performing hydrothermal reaction; 4) naturally cooling the reaction kettle after hydrothermal reaction, centrifuging the acquired sediment, performing suction filtration, drying and annealing, thereby acquiring a Pd-TiO2 nano-particle hydrogen-sensitive composite material. The invention has the beneficial effects that the Pd-TiO2 nano-particle hydrogen-sensitive material prepared according to the preparation method for the fast-responding Pd-TiO2 nano-particle hydrogen-sensitive material is short in hydrogen responding time and recovery time and is wide in range of detectable hydrogen concentration.

The invention relates to a sensing material and a preparation method thereof, in particular to a silver and indium oxide composite nanorod array formaldehyde air-sensitive material and a preparation method thereof. The material is formed by hexagonally and periodically arraying silver and indium oxide composite nanorods. The preparation method comprises mixing and stirring surfactant, water and hydrochloric acid until the surfactant is dissolved totally; then adding ethyl orthosilicate in the mixture and stirring; performing hydrothermal reaction for 1-5 days at the temperature of 130 DEG C after standing; performing suction filtration, washing and drying after cooling so as to obtain white powder; using solvent to extract mesoporous silica which is a hard template; adding the mesoporous silica into ethanol solution with indium nitrate and silver nitrate, stirring and dipping; repeating the steps; and finally adding caustic soda solution in a calcined product, and centrifugally filtering to obtain an orderly silver and indium oxide composite nanorod array material after stirring. The silver and indium oxide composite nanorod array formaldehyde air-sensitive material and the preparation method thereof have the advantages of high sensitivity and fine stability.

The invention discloses an isopropanol gas-sensitive element based on ZnSnO3 nanospheres of perovskite structures and a preparation method of the element and belongs to the technical field of semiconductor metal oxide gas-sensitive elements. The gas-sensitive element is mainly composed of an electrode element and the ZnSnO3 nanospheres evenly coating the electrode element, the diameters of the ZnSnO3 nanospheres are 500+ / -50 nanometers, the ZnSnO3 nanospheres are of the perovskite structures, and the isopropanol concentration detection range of the gas-sensitive element is 500 ppb-500 ppm. Theoperation process is simple, the reaction conditions are mild, and easy control and large-batch production can be achieved. The ppb-grade isopropanol gas-sensitive element based on the ZnSnO3 nanospheres of the perovskite structures has the advantages of ppb-grade detection, quick response restoration, good reversibility and high selectivity, the maximum sensitivity to isopropanol gas at the working temperature of 200 DEG C is obtained, and the isopropanol gas-sensitive element has good development prospects.

The invention discloses a preparation method of a hierarchical structure ZnO@ZnO nano-composite gas-sensitive material. The preparation method comprises the following steps: dissolving 2-methylimidazole in an N,N-dimethylformamide and water mixed solution, and performing ultrasonic treatment to prepare a precursor solution; weighing a certain amount of zinc oxide nano-powder, adding the zinc oxidenano-powder into the prepared precursor solution, adding the obtained solution into a reaction kettle, performing a reaction at 70-100 DEG C for 12-48 h, taking out the obtained reaction product, performing suction filtration, washing the reaction product with ethanol multiple times, and drying the washed reaction product to obtain a hierarchical structure ZnO@ZnO precursor material; and placingthe obtained precursor material in a tubular furnace, and calcining the precursor material in an air atmosphere for 1 h to obtain the hierarchical structure ZnO@ZnO nano-composite gas-sensitive material. The preparation method does not produce toxic or harmful substances and facilitates environmental protection; ad the gas-sensitive material prepared in the invention has high sensitivity and selectivity to ethanol.

The invention discloses a composite nanoscale semiconductor material AZO / Nb2O5 / Pt gas-sensitive element and a preparation method thereof and relates to a composite nanoscale semiconductor material gas-sensitive element and a preparation method thereof. The invention aims to solve a technical problem that the conventional ethanol gas sensor taking aluminum-doped zinc oxide as a sensitive element has high detection limit. The composite nanoscale semiconductor material AZO / Nb2O5 / Pt gas-sensitive element disclosed by the invention is formed by loading a layer of nanoscale semiconductor material AZO / Nb2O5 / Pt on an Al2O3 ceramic tube. The preparation method comprises the following steps: preparing AZO powder; mixing an AZO solution and an Nb2O5 solution to obtain a white precipitate, washing anddrying the white precipitate, and sintering to obtain AZO / Nb2O5 powder; adding H2PtCl6 into the powder for size mixing, coating the Al2O3 ceramic tube, and sintering, thereby obtaining the gas-sensitive element. The gas-sensitive element has an ethanol concentration detection range of 5-500ppm and can be used for online monitoring and trace detection.