CN112357944B - Preparation method of lanthanum oxide composite material sensitive to low-concentration ammonia gas - Google Patents
Preparation method of lanthanum oxide composite material sensitive to low-concentration ammonia gas Download PDFInfo
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Abstract
The invention discloses a preparation method of a lanthanum oxide composite material sensitive to low-concentration ammonia gas, which comprises the steps of taking an aqueous solution of lanthanum nitrate and urea as a reaction reagent, preparing a lanthanum oxide precursor under the combined action of microwave and ultrasonic wave, washing, drying and calcining the lanthanum oxide precursor to obtain lanthanum oxide powder, dispersing the lanthanum oxide powder into deionized water under the ultrasonic condition, adding sodium borohydride, mixing, dropwise adding silver nitrate to react, centrifuging, washing and drying to obtain the lanthanum oxide composite gas-sensitive material. The method disclosed by the invention can be used for producing the lanthanum oxide composite gas-sensitive material with high sensitivity response performance on low-concentration ammonia gas, and has the advantages of simplicity in operation and strong process controllability, and the obtained composite material has the excellent characteristics of good selectivity, high response value and the like, and has a wide application prospect in the sensing field.
Description
Technical Field
The invention particularly relates to a preparation method of a lanthanum oxide composite material sensitive to low-concentration ammonia gas, and belongs to the technical field of gas-sensitive materials.
Background
Rare earth is an important strategic metal resource in China, lanthanum oxide is an important rare earth oxide, and the lanthanum oxide has the characteristics of high thermal stability, good hydrophobicity, high refractive index, low thermal expansion coefficient and the like, so that the lanthanum oxide is widely applied to various fields of catalysts, electrothermal materials, ceramics, glass, luminescent materials and the like, for example, a gas sensitive material prepared based on the rare earth oxide can be used for manufacturing various types of gas sensors, including semiconductor type, solid electrolyte type and contact combustion type gas sensors, and the sensitivity and the selectivity of the gas sensors to certain gases can be improved.
At present, the preparation method based on lanthanum oxide mainly comprises a hydrothermal method, an electrostatic spinning method, chemical vapor deposition, pulse laser deposition and the like. The hydrothermal method is characterized in that under the high-temperature and high-pressure environment, an aqueous solution is used as a medium, a temperature gradient is formed in a rare earth salt solution, convection, nucleation and crystallization are carried out, and the gas-sensitive material is obtained; the electrostatic spinning method is that the prepared mixed solution of rare earth metal salt and polymer is charged with high-voltage static electricity, the charged polymer liquid drops form Taylor cones at the top points of the capillaries under the action of an electric field, when the electric field force is large enough, the polymer liquid drops can overcome the surface tension to form jet trickle, the trickle gathers the solvent evaporation in the jetting process, and the dried nano fibers are finally deposited on a collecting device, so that the gas-sensitive material is obtained; the chemical vapor deposition is to directly utilize gas or change substances into gas through various means, so that the substances are subjected to chemical reaction in a gas state and finally condensed and grown in a cooling process to form nanoparticles with gas-sensitive performance; pulsed laser deposition is a vacuum physical deposition method, when a strong pulse laser beam irradiates a target, the surface material of the target is heated, melted and gasified by the laser beam until becoming plasma, then the plasma (usually in atmosphere gas) is transmitted from a target substrate, and finally, an ablation substance transmitted to the substrate is condensed and nucleated on the substrate to form a film with gas-sensitive performance. However, the methods have the defects of complex operation, difficult process control, high synthesis cost, long reaction time and the like. Therefore, a preparation method which can overcome the defects and is suitable for industrial production of the lanthanum oxide composite material is urgently needed.
Disclosure of Invention
Aiming at the defects, the invention discloses a preparation method of a lanthanum oxide composite material with high sensitivity response to low-concentration ammonia gas, which can be used for producing a lanthanum oxide composite gas-sensitive material with high sensitivity response performance to the low-concentration ammonia gas and has the advantages of simple operation and strong process controllability.
The invention is realized by adopting the following technical scheme:
a preparation method of a lanthanum oxide composite material sensitive to low-concentration ammonia gas comprises the following steps:
(1) Adding cetyl trimethyl ammonium bromide into 0.8mol/L urea solution, and uniformly mixing to obtain solution A, wherein the mass ratio of the added cetyl trimethyl ammonium bromide to the urea solution is 0.2; uniformly mixing a lanthanum nitrate solution with the solution A to obtain a solution B, wherein the molar ratio of lanthanum ions to urea in the solution B is 1;
(2) Washing the lanthanum oxide precursor obtained in the step (1) with deionized water for 3 times, then washing with absolute ethyl alcohol for 3 times, then putting the lanthanum oxide precursor into a drying box at 60 ℃ for drying, calcining at 450-850 ℃ for 1.5h, and then cooling to room temperature to obtain lanthanum oxide powder;
(3) Dissolving the lanthanum oxide powder obtained in the step (2) in deionized water to obtain a solution C, and dissolving 0.01g of lanthanum oxide powder in each 15ml of deionized water; performing ultrasonic treatment on the solution C for 30min under the action of ultrasonic waves, and then cooling to 4 ℃ in a water bath; taking NaBH with concentration of 0.03mol/L 4 The solution is placed in an ice bath to be cooled to 4 ℃, and then the solution is added into a solution C with the temperature of 4 ℃ to be stirred and mixed evenly to obtain a solution D, wherein the solution C and NaBH 4 And (2) dropwise adding a silver nitrate solution into the solution D, reacting for 10min under the stirring condition of the speed of 1000 rpm, so that Ag nanoparticles are loaded on the surface of the lanthanum oxide, the Ag nanoparticles account for 0.8-3 wt% of the lanthanum oxide, centrifuging for 10min, washing the obtained precipitate with deionized water for 3 times, washing with absolute ethyl alcohol for 3 times, and drying at room temperature to obtain the lanthanum oxide composite gas-sensitive material.
Further, the power of the microwave in the step (1) is 200-600W, and the power of the ultrasonic wave is 50-450W.
Further, in the step (2), the temperature of the dried lanthanum oxide precursor is raised to the calcination temperature at a temperature raising rate of 6 ℃/min in the air atmosphere, and then the lanthanum oxide precursor is calcined.
Further, the centrifugation conditions in the step (3) are carried out at a speed of 10000 r/min.
Further, the concentration of the silver nitrate solution in the step (3) is 0.01mol/L.
Compared with the prior art, the technical scheme has the following beneficial effects:
1. the invention adopts a microwave-ultrasonic assisted synthesis method, which is a novel material preparation method and has the synergistic effect characteristic of microwave heating and ultrasonic cavitation. The microwave process has dipole polarization and ion conduction effects, charged particles lanthanum ions, hydroxyl ions and carbonate ions in the solution oscillate under the action of a microwave field and collide with adjacent molecules, and the collisions can cause movement to generate heat; the cavitation effect of the ultrasonic waves has strong penetrability and is easy to concentrate, so that reactants in the solution can be fully dispersed. The microwave and the ultrasound are combined with each other, so that mass transfer obstacles can be eliminated, heat transfer is enhanced, and the rapid reaction is promoted.
2. According to the invention, the lanthanum oxide composite gas-sensitive material is rapidly prepared by a microwave-ultrasonic auxiliary method, and Ag ions are reduced by sodium borohydride, so that Ag nanoparticles are loaded on the surface of lanthanum oxide to prepare the lanthanum oxide composite gas-sensitive material.
Drawings
FIG. 1 is an X-ray diffraction pattern of lanthanum oxide powders obtained according to the method described in example 1 at different calcination temperatures;
FIG. 2 is an X-ray diffraction spectrum of the lanthanum oxide powder and the lanthanum oxide composite material obtained in example 1;
FIG. 3 is an SEM photograph of the lanthanum oxide composite obtained in example 1, wherein (a) is the SEM photograph of the lanthanum oxide material obtained in example 1, and (b) is the SEM photograph of the lanthanum oxide material obtained in example 2;
FIG. 4 is an XPS plot of the lanthanum oxide powder and lanthanum oxide composite obtained in example 1;
FIG. 5 is a graph showing the diffuse reflectance ultraviolet spectrum of the lanthanum oxide powder and the lanthanum oxide composite obtained in example 1;
FIG. 6 is a diagram showing the forbidden band widths of the lanthanum oxide powder and the lanthanum oxide composite material obtained in example 1;
FIG. 7 is a graph showing the response of lanthanum oxide composite to ammonia gas obtained in this experimental example by adjusting different Ag loadings according to the method described in example 1;
FIG. 8 is a graph showing the response of the lanthanum oxide powder and the lanthanum oxide composite obtained in example 1 to ammonia gas at a concentration of 100ppm at different operating temperatures;
FIG. 9 is a graph showing the selectivity of the lanthanum oxide powder and lanthanum oxide composite obtained in example 1 to 100ppm of different gases at 350 ℃;
FIG. 10 is a graph of response versus time of the lanthanum oxide composite obtained in example 1 at 350 ℃ for different concentrations of ammonia;
fig. 11 is a graph of the logarithm of the response value of the lanthanum oxide composite material obtained in example 1 to different concentrations of ammonia gas at 350 ℃ and the ammonia gas concentration.
Detailed Description
The invention is further illustrated by the following examples, which are not to be construed as limiting the invention thereto. The specific experimental conditions and methods not indicated in the following examples are generally conventional means well known to those skilled in the art.
Example 1:
a preparation method of a lanthanum oxide composite material sensitive to low-concentration ammonia gas comprises the following steps:
(1) Adding cetyl trimethyl ammonium bromide into 0.8mol/L urea solution, and uniformly mixing to obtain solution A, wherein the mass ratio of the added cetyl trimethyl ammonium bromide to the urea solution is 0.2; uniformly mixing a lanthanum nitrate solution with the solution A to obtain a solution B, wherein the molar ratio of lanthanum ions to urea in the solution B is 1; the power of the microwave is 600W, and the power of the ultrasonic wave is 200W;
(2) Washing the lanthanum oxide precursor obtained in the step (1) with deionized water for 3 times, then washing with absolute ethyl alcohol for 3 times, then drying the lanthanum oxide precursor at 60 ℃, heating the dried lanthanum oxide precursor to 850 ℃ at the heating rate of 6 ℃/min in the air atmosphere, calcining for 1.5h, and then cooling to room temperature to obtain lanthanum oxide powder;
(3) Dissolving the lanthanum oxide powder obtained in the step (2) in deionized water to obtain a solution C, and dissolving 0.01g of lanthanum oxide powder in each 15ml of deionized water; performing ultrasonic treatment on the solution C for 30min under the action of ultrasonic waves, and then cooling to 4 ℃ in a water bath; taking the concentration of 0.03mol/LNaBH 4 The solution is placed in an ice bath to be cooled to 4 ℃, and then the solution is added into a solution C with the temperature of 4 ℃ to be stirred and mixed evenly to obtain a solution D, wherein the solution C and NaBH 4 The volume ratio of the solution is 15.
Example 2:
a preparation method of a lanthanum oxide composite material sensitive to low-concentration ammonia gas comprises the following steps:
(1) Adding cetyl trimethyl ammonium bromide into 0.8mol/L urea solution, and uniformly mixing to obtain solution A, wherein the mass ratio of the added cetyl trimethyl ammonium bromide to the urea solution is 0.2; uniformly mixing a lanthanum nitrate solution with the solution A to obtain a solution B, wherein the molar ratio of lanthanum ions to urea in the solution B is 1; the power of the microwave is 200W, and the power of the ultrasonic wave is 450W;
(2) Washing the lanthanum oxide precursor obtained in the step (1) with deionized water for 3 times, then washing with absolute ethyl alcohol for 3 times, then drying the lanthanum oxide precursor at 60 ℃, heating the dried lanthanum oxide precursor to 750 ℃ at the heating rate of 6 ℃/min in the air atmosphere, calcining for 1.5h, and then cooling to room temperature to obtain lanthanum oxide powder;
(3) Dissolving the lanthanum oxide powder obtained in the step (2) in deionized water to obtain a solution C, and dissolving 0.01g of lanthanum oxide powder in each 15ml of deionized water; performing ultrasonic treatment on the solution C for 30min under the action of ultrasonic waves, and then cooling to 4 ℃ in a water bath; taking the concentration of 0.03mol/LNaBH 4 The solution is placed in an ice bath to be cooled to 4 ℃, and then the solution is added into a solution C with the temperature of 4 ℃ to be stirred and mixed evenly to obtain a solution D, wherein the solution C and NaBH 4 The volume ratio of the solution is 15.
Example 3:
a preparation method of a lanthanum oxide composite material sensitive to low-concentration ammonia gas comprises the following steps:
(1) Adding cetyl trimethyl ammonium bromide into 0.8mol/L urea solution, and uniformly mixing to obtain solution A, wherein the mass ratio of the added cetyl trimethyl ammonium bromide to the urea solution is 0.2; uniformly mixing a lanthanum nitrate solution with the solution A to obtain a solution B, wherein the molar ratio of lanthanum ions to urea in the solution B is 1; the power of the microwave is 400W, and the power of the ultrasonic wave is 50W;
(2) Washing the lanthanum oxide precursor obtained in the step (1) with deionized water for 3 times, then washing with absolute ethyl alcohol for 3 times, drying the lanthanum oxide precursor at 75 ℃, heating the dried lanthanum oxide precursor to 450 ℃ at the heating rate of 6 ℃/min in the air atmosphere, calcining for 1.5 hours, and then cooling to room temperature to obtain lanthanum oxide powder;
(3) Dissolving the lanthanum oxide powder obtained in the step (2) in deionized water to obtain a solution C, and dissolving 0.01g of lanthanum oxide powder in each 15ml of deionized water; performing ultrasonic treatment on the solution C for 30min under the action of ultrasonic waves, and then cooling to 4 ℃ in a water bath; taking the concentration of 0.03mol/LNaBH 4 The solution is placed in an ice bath to be cooled to 4 ℃, and then the solution is added into a solution C with the temperature of 4 ℃ to be stirred and mixed evenly to obtain a solution D, wherein the solution C and NaBH 4 The volume ratio of the solution is 15.
Example 4:
a preparation method of a lanthanum oxide composite material sensitive to low-concentration ammonia gas comprises the following steps:
(1) Adding cetyl trimethyl ammonium bromide into 0.8mol/L urea solution, and uniformly mixing to obtain solution A, wherein the mass ratio of the added cetyl trimethyl ammonium bromide to the urea solution is 0.2; uniformly mixing a lanthanum nitrate solution with the solution A to obtain a solution B, wherein the molar ratio of lanthanum ions to urea in the solution B is 1; the power of the microwave is 600W, and the power of the ultrasonic wave is 200W;
(2) Washing the lanthanum oxide precursor obtained in the step (1) with deionized water for 3 times, then washing with absolute ethyl alcohol for 3 times, then drying the lanthanum oxide precursor at 60 ℃, heating the dried lanthanum oxide precursor to 850 ℃ at the heating rate of 6 ℃/min in the air atmosphere, calcining for 1.5h, and then cooling to room temperature to obtain lanthanum oxide powder;
(3) Dissolving the lanthanum oxide powder obtained in the step (2) in deionized water to obtain a solution C, and dissolving 0.01g of lanthanum oxide powder in each 15ml of deionized water; performing ultrasonic treatment on the solution C for 30min under the action of ultrasonic waves, and then cooling to 4 ℃ in a water bath; taking the concentration of 0.03mol/LNaBH 4 The solution is placed in an ice bath to be cooled to 4 ℃, and then the solution is added into a solution C with the temperature of 4 ℃ to be stirred and mixed evenly to obtain a solution D, wherein the solution C and NaBH 4 The volume ratio of the solution is 15.
Example 5:
a preparation method of a lanthanum oxide composite material sensitive to low-concentration ammonia gas comprises the following steps:
(1) Adding cetyl trimethyl ammonium bromide into 0.8mol/L urea solution, and uniformly mixing to obtain solution A, wherein the mass ratio of the added cetyl trimethyl ammonium bromide to the urea solution is 0.2; uniformly mixing a lanthanum nitrate solution with the solution A to obtain a solution B, wherein the molar ratio of lanthanum ions to urea in the solution B is 1; the power of the microwave is 350W, and the power of the ultrasonic wave is 200W;
(2) Washing the lanthanum oxide precursor obtained in the step (1) with deionized water for 3 times, then washing with absolute ethyl alcohol for 3 times, then drying the lanthanum oxide precursor at 60 ℃, heating the dried lanthanum oxide precursor to 800 ℃ at a heating rate of 6 ℃/min in an air atmosphere, calcining for 1.5h, and then cooling to room temperature to obtain lanthanum oxide powder;
(3) Dissolving the lanthanum oxide powder obtained in the step (2) in deionized water to obtain a solutionC, dissolving 0.01g of lanthanum oxide powder in each 15ml of deionized water; performing ultrasonic treatment on the solution C for 30min under the action of ultrasonic waves, and then cooling to 4 ℃ in a water bath; taking the concentration of 0.03mol/LNaBH 4 The solution is placed in an ice bath to be cooled to 4 ℃, and then the solution is added into a solution C with the temperature of 4 ℃ to be stirred and mixed evenly to obtain a solution D, wherein the solution C and NaBH 4 The volume ratio of the solution is 15.
Example 6:
a preparation method of a lanthanum oxide composite material sensitive to low-concentration ammonia gas comprises the following steps:
(1) Adding cetyl trimethyl ammonium bromide into 0.8mol/L urea solution, and uniformly mixing to obtain solution A, wherein the mass ratio of the added cetyl trimethyl ammonium bromide to the urea solution is 0.2; uniformly mixing a lanthanum nitrate solution with the solution A to obtain a solution B, wherein the molar ratio of lanthanum ions to urea in the solution B is 1; the power of the microwave is 250W, and the power of the ultrasonic wave is 100W;
(2) Washing the lanthanum oxide precursor obtained in the step (1) with deionized water for 3 times, then washing with absolute ethyl alcohol for 3 times, then drying the lanthanum oxide precursor at 60 ℃, heating the dried lanthanum oxide precursor to 550 ℃ at the heating rate of 6 ℃/min in the air atmosphere, calcining for 1.5h, and then cooling to room temperature to obtain lanthanum oxide powder;
(3) Dissolving the lanthanum oxide powder obtained in the step (2) in deionized water to obtain a solution C, and dissolving 0.01g of lanthanum oxide powder in each 15ml of deionized water; subjecting the solution C to ultrasonic treatment for 30min, and cooling in water bath4 ℃; taking the concentration of 0.03mol/LNaBH 4 The solution is placed in an ice bath to be cooled to 4 ℃, and then the solution is added into a solution C with the temperature of 4 ℃ to be stirred and mixed evenly to obtain a solution D, wherein the solution C and NaBH 4 The volume ratio of the solution is 15.
Experimental example:
(1) XRD (X-ray diffraction) tests are carried out on lanthanum oxide powder obtained at different calcination temperatures, and the results are shown in figure 1, and as the calcination temperature is increased, the diffraction peak of lanthanum oxide becomes sharper and has no other miscellaneous peaks, which indicates that the crystallinity of the lanthanum oxide material is better and better.
(2) XRD (X-ray diffraction) tests are carried out on the lanthanum oxide powder and the lanthanum oxide composite material obtained in the example 1, the result is shown in figure 2, the X-ray diffraction spectrum is consistent with that of Jade standard card (PDF # 02-0688), and the main phase of the lanthanum oxide composite material obtained by the reaction is hexagonal lanthanum oxide;
(3) SEM test of the lanthanum oxide composite materials obtained in the examples 1 and 2 shows that the lanthanum oxide composite materials have a rod-like structure, smooth surface and uniform distribution as shown in FIG. 3;
(4) XPS tests of the lanthanum oxide and lanthanum oxide composite materials obtained in example 1 showed that La3d, la4s, la4d and La4p peaks appeared in both lanthanum oxide and lanthanum oxide composite materials, but the 3d peak of Ag was 1wt% Ag-La 2 O 3 (iii) is present; ag and La 2 O 3 The electron transfer between the two makes the compound 1wt% Ag-La 2 O 3 The binding energy of (2) is reduced, which indicates that Ag particles are deposited on La mainly by means of physical adsorption or electrostatic adsorption 2 O 3 The surface of the nano rod;
(5) The results of ultraviolet diffuse reflection tests on the lanthanum oxide and the lanthanum oxide composite material obtained in example 1 are shown in fig. 5 and fig. 6, and it can be seen from fig. 5 that the lanthanum oxide composite material has greater absorption, which indicates that the prepared material has strong ultraviolet-visible light absorption capacity; as can be seen from fig. 6, the band gap width of the lanthanum oxide composite material decreases with the increase of the doping amount of Ag, and the band gap width decreases, so that the surface of the material is more likely to generate electronic transition, and charges are more likely to transfer;
(6) According to the method in example 1, after the mass of the lanthanum oxide occupied by different Ag nanoparticles is adjusted, the lanthanum oxide composite gas sensitive material with different Ag loadings is subjected to ammonia response test at the working temperature of 350 ℃ in an ammonia environment with the concentration of 100ppm, and the obtained result is shown in fig. 7, and when the Ag loadings occupy 0.8 to 3wt% of the lanthanum oxide mass, the lanthanum oxide composite material has the best response effect on ammonia.
(7) Taking the lanthanum oxide powder and the lanthanum oxide composite material obtained in the example 1 as samples, respectively, placing the samples in a mortar, adding a small amount of ethanol, grinding the samples into paste, uniformly coating the paste on a ceramic substrate by using a capillary brush, placing the ceramic substrate in an oven at 180 ℃ for aging for 12 hours, and then carrying out gas-sensitive performance tests on the samples, wherein the gas-sensitive performance tests comprise the following tests:
A. performing gas-sensitive performance test on a sample at the optimal working temperature in an ammonia environment with the concentration of 100ppm, wherein the results are shown in fig. 8, and the optimal working temperatures of the lanthanum oxide powder and the lanthanum oxide composite material are both 350 ℃;
B. at the working temperature of 350 ℃, the test sample carries out selectivity test on different gases with the concentration of 100ppm, and the result is shown in fig. 9, the lanthanum oxide composite material has the best selectivity to ammonia gas than the lanthanum oxide powder, and has the maximum response to ammonia gas;
C. the gas-sensitive performance test of ammonia gas with different concentrations was performed on the lanthanum oxide composite material sample in an environment with an indoor temperature of 25 ℃ and a relative humidity of 40%, and the result is shown in fig. 10, wherein the lanthanum oxide composite material has a response value which is continuously increased along with the increase of the ammonia gas concentration, and has a good linear relationship.
Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.
Claims (3)
1. A preparation method of a lanthanum oxide composite material sensitive to low-concentration ammonia gas is characterized by comprising the following steps: the method comprises the following steps:
(1) Adding cetyl trimethyl ammonium bromide into 0.8mol/L urea solution, and uniformly mixing to obtain solution A, wherein the mass ratio of the added cetyl trimethyl ammonium bromide to the urea solution is 0.2; uniformly mixing a lanthanum nitrate solution with the solution A to obtain a solution B, wherein the molar ratio of lanthanum ions to urea in the solution B is 1;
the power of the microwave is 200-600W, and the power of the ultrasonic wave is 50-450W;
(2) Washing the lanthanum oxide precursor obtained in the step (1) with deionized water for 3 times, then washing with absolute ethyl alcohol for 3 times, then putting the lanthanum oxide precursor into a drying oven at 60 ℃ for drying, then calcining at 450-850 ℃ for 1.5h, and then cooling to room temperature to obtain lanthanum oxide powder;
heating the dried lanthanum oxide precursor to the calcining temperature at the heating rate of 6 ℃/min in the air atmosphere for calcining;
(3) Dissolving the lanthanum oxide powder obtained in the step (2) in deionized water to obtain a solution C, and dissolving 0.01g of lanthanum oxide powder in each 15ml of deionized water; performing ultrasonic treatment on the solution C for 30min under the action of ultrasonic waves, and then cooling to 4 ℃ in a water bath; taking NaBH with concentration of 0.03mol/L 4 The solution is placed in an ice bath to be cooled to 4 ℃, and then the solution is added into a solution C with the temperature of 4 ℃ to be stirred and mixed evenly to obtain a solution D, wherein the solution C and NaBH 4 The volume ratio of the solution was 15Reacting for 10min under the stirring condition with the speed of 1000 rpm to load Ag nano particles on the surface of the lanthanum oxide, wherein the Ag nano particles account for 0.8-3 wt% of the lanthanum oxide, centrifuging for 10min, washing the obtained precipitate with deionized water for 3 times, washing with absolute ethyl alcohol for 3 times, and drying at room temperature to obtain the lanthanum oxide composite gas-sensitive material.
2. The method for preparing a lanthanum oxide composite material sensitive to low-concentration ammonia gas according to claim 1, wherein the lanthanum oxide composite material comprises the following steps: the centrifugation condition in the step (3) is carried out at a speed of 10000 r/min.
3. The method for preparing the lanthanum oxide composite material sensitive to low-concentration ammonia gas as claimed in claim 1, wherein the method comprises the following steps: and (4) the concentration of the silver nitrate solution in the step (3) is 0.01mol/L.
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| 印润远等.移动互联网技术实用教程.《移动互联网技术实用教程》.中国铁道出版社有限公司,2019,(第1版),第104页. * |
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