Gold-modified dysprosium samarium iron oxide as well as preparation method and application thereof

Abstract

The invention discloses a gold-modified dysprosium samarium iron oxide as well as a preparation method and application thereof, and relates to the technical field of n-butyl alcohol gas detection. According to the preparation method, a coprecipitation method is adopted, dysprosium nitrate, samarium nitrate and ferric nitrate are taken as raw materials, a lattice structure of SmFeO3 is optimized by doping a Dy element at an A site, and meanwhile, an Au element is introduced for surface modification, so that the gold-modified dysprosium-samarium-iron oxide is prepared. On the basis of the samarium iron oxide, the oxygen vacancy concentration is increased through A-site doping of the Dy element, and the adsorption capacity of the material to n-butyl alcohol molecules is improved; the Au element is adopted for surface modification, the energy barrier of the n-butanol oxidation reaction is reduced through the excellent catalytic performance of the Au element, and surface electron transfer and reaction activity are promoted. The working temperature of the gas-sensitive material is remarkably reduced through synergistic doping modification of the element Dy and the element Au, and the element Dy and the element Au have a synergistic effect on improving the response value to n-butyl alcohol gas.

Description

Technical Field

[0001] The present invention relates to the technical field of n-butanol gas detection, and particularly to a gold-modified dysprosium samarium iron oxide, a preparation method thereof, and an application thereof. Background Art

[0002] n-Butanol is a volatile organic compound (VOC) with an irritating odor, which is widely present in chemical production, fuel processing, and alcohol evaporation environments. Long-term exposure to n-butanol gas can cause harm to human health, such as respiratory irritation, dizziness, and even central nervous system depression. In addition, n-butanol gas is flammable, can form explosive compounds in the air, burn and explode violently when encountering an open flame, posing a huge safety threat. Therefore, real-time monitoring of the n-butanol concentration in the environment is of great significance.

[0003] Currently, the methods available for detecting n-butanol include: gas chromatography, electrochemical sensors, and gas-sensitive sensors. Among them, although gas chromatography can detect the n-butanol concentration at the ppb level, it requires professional equipment and the sample pretreatment is cumbersome. Although electrochemical sensors have the advantages of real-time monitoring and simple operation, they have poor gas selectivity and are affected by changes in environmental temperature and humidity. Compared with gas chromatography and electrochemical sensors, gas-sensitive sensors have become a research hotspot in the current gas detection field due to their small size, low cost, easy integration, and fast response speed.

[0004] As the core of a gas-sensitive sensor, the role of a gas-sensitive material in n-butanol detection is mainly manifested as follows: when the surface of the material comes into contact with n-butanol molecules, the electrical properties (such as resistance) of the material will change, thereby realizing the efficient detection of the n-butanol concentration. The materials that can be used for gas-sensitive sensors mainly include n-type and p-type semiconductors. Among them, perovskite-type composite oxides, as typical p-type semiconductors, have become the focus of research due to their stable crystal structure, dual ionic and electronic conductivity, and dopable and modifiable characteristics.

[0005] In the prior art, CN118032875A discloses a highly sensitive n-butanol gas-sensitive material, a preparation method thereof, and an application thereof. The chemical formula of the n-butanol gas-sensitive material is X wt% Pd-Ho y Sm 1-y FeO3, 0.5 ≤ x ≤ 1.5, 0.85 ≤ y ≤ 0.95. The above patent enhances the responsiveness and selectivity of the gas-sensitive material through Pd and Sm doping and modification of the HoFeO3 material, and can be used to detect low-concentration n-butanol. However, when this gas-sensitive material is used for n-butanol detection, its working temperature is as high as 220°C. Such a high working temperature will increase the energy consumption of the sensor, accelerate the aging of the gas-sensitive material, cause oxidation or migration of the electrode material, and may also cause thermal expansion or cracking of the encapsulation material at high temperatures.

[0006] Therefore, it is urgent to develop perovskite gas-sensitive materials for detecting n-butanol and reduce the working temperature during detection to promote the development of gas sensors towards low energy consumption and high safety. Summary of the Invention

[0007] In view of the above-mentioned prior art, the purpose of the present invention is to provide a gold-modified dysprosium samarium iron oxide with the chemical formula Xwt% Au-Dy x Sm 1-x FeO3, where 0 < X ≤ 10 and 0 < x ≤ 0.5. Based on the SmFeO3 material, the present invention prepares the gold-modified dysprosium samarium iron oxide through the doping of Dy element at the A site and the surface modification of Au element. The doping of Dy optimizes the lattice structure and increases the oxygen vacancy concentration, while the modification of Au enhances the catalytic activity of the material, thereby reducing the working temperature for detecting n-butanol and improving the response value. Specifically, at a working temperature of 190 °C, the response value of the gold-modified dysprosium samarium iron oxide prepared by the present invention to 1 ppm n-butanol gas is 12.68.

[0008] To achieve the above purpose, the present invention adopts the following technical solutions:

[0009] In the first aspect of the present invention, there is provided a gold-modified dysprosium samarium iron oxide with the chemical formula Xwt% Au-Dy x Sm 1-x FeO3, where 0 < X ≤ 10 and 0 < x ≤ 0.5.

[0010] Preferably, the gold-modified dysprosium samarium iron oxide is nanoparticles with an average particle size of 80 - 200 nm.

[0011] In the second aspect of the present invention, there is provided a preparation method of the above gold-modified dysprosium samarium iron oxide, including the following steps:

[0012] (1) After mixing dysprosium nitrate, samarium nitrate and iron nitrate, add them to deionized water and mix well, then add citric acid to obtain a mixed solution; adjust the pH of the mixed solution with an alkali solution to cause the co-precipitation of metal ions, stir and then filter, collect the solid, wash and dry to obtain the Dy x Sm 1-x FeO3 precursor;

[0013] (2) Disperse the Dy x Sm 1-x FeO3 precursor in water, add chloroauric acid and react. After the reaction ends, filter, wash, dry and then calcine to obtain the gold-modified dysprosium samarium iron oxide.

[0014] Preferably, the molar ratio of dysprosium nitrate, samarium nitrate, iron nitrate, chloroauric acid, citric acid and deionized water added is (0.002-1) mol:(0.01-5) mol:(0.01-5) mol:(0.01-100) g:(10-50) g:(50-200) mL.

[0015] Preferably, in step (1), the alkali solution is a NaOH solution, and the concentration of the NaOH solution is 1-2 mol / L.

[0016] Preferably, in step (1), the pH is adjusted to 9-11.

[0017] Preferably, in step (1), the stirring time is 1-2 h.

[0018] Preferably, in step (1), the specific operation of washing is: washing the solid 2-3 times with deionized water and ethanol.

[0019] Preferably, in step (1), the drying method is vacuum drying, the drying temperature is 70-90 °C, and the drying time is 6-12 h.

[0020] Preferably, in step (2), the reaction temperature is 60-80 °C, and the reaction time is 2-4 h.

[0021] Preferably, in step (2), the calcination temperature is 400-600 °C, and the calcination time is 2-4 h.

[0022] In the third aspect of the present invention, there is provided the use of the above-mentioned gold-modified dysprosium samarium iron oxide in 1) or 2):

[0023] 1) Detecting n-butanol gas;

[0024] 2) Preparing an n-butanol gas sensor.

[0025] Preferably, the concentration of the n-butanol gas is 1-10 ppm.

[0026] Preferably, the n-butanol gas sensor is prepared by the following method:

[0027] Mixing the gold-modified dysprosium samarium iron oxide, deionized water and terpineol in a ratio of (1-5) g:(3-15) mL:(1-5) mL to obtain a slurry; spin-coating the slurry on an alumina substrate to form a gas-sensitive film with a thickness of 100-300 μm, and aging the gas-sensitive film at 180-220 °C for 10-24 hours to obtain the n-butanol gas sensor.

[0028] Preferably, the working temperature of the n-butanol gas sensor is 185-195 °C.

[0029] Advantages of the present invention:

[0030] The present invention adopts the co-precipitation method, using dysprosium nitrate, samarium nitrate and iron nitrate as raw materials. By doping Dy element at the A site to optimize the lattice structure of SmFeO3, and at the same time introducing Au element for surface modification, a gold-modified dysprosium-samarium-iron oxide is prepared. Based on samarium-iron oxide (SmFeO3), the present invention increases the oxygen vacancy concentration by doping Dy element at the A site, improving the adsorption ability of the material to n-butanol molecules; uses Au element for surface modification, and reduces the energy barrier of the n-butanol oxidation reaction through its excellent catalytic performance, promoting surface electron transfer and reaction activity. The synergistic doping modification of Dy element and Au element significantly reduces the working temperature of the gas-sensitive material, and the two have a synergistic effect in improving the response value to n-butanol gas. Specifically, the optimal working temperature of the gold-modified dysprosium-samarium-iron oxide (5wt% Au-Dy 0.2 Sm 0.8 FeO3) prepared in the present invention is 190 °C, and at the working temperature of 190 °C, the response value to 1 ppm n-butanol gas is 12.68.

[0031] In addition, the co-precipitation method has a simple and controllable preparation process. The obtained material has a nanoparticle structure and a large specific surface area, further enhancing the gas-sensitive performance, selectivity and long-term stability. Description of the Drawings

[0032] Figure 1 : XRD pattern of the gold-modified dysprosium-samarium-iron oxide prepared in Example 1;

[0033] Figure 2 : SEM image of the gold-modified dysprosium-samarium-iron oxide prepared in Example 1;

[0034] Figure 3 : EDS Mapping images of gold element, dysprosium element and samarium element in the gold-modified dysprosium-samarium-iron oxide prepared in Example 1;

[0035] Figure 4 : Relationship diagram of the gas-sensitive performance and temperature of the materials prepared in Example 1 and Comparative Examples 1-3 to 1 ppm n-butanol gas;

[0036] Figure 5 : Relationship diagram of the gas-sensitive performance and humidity of the gold-modified dysprosium-samarium-iron oxide prepared in Example 1 to 1 ppm n-butanol gas;

[0037] Figure 6 : Schematic diagram of the long-term gas-sensitive stability of the gold-modified dysprosium-samarium-iron oxide prepared in Example 1 to 1 ppm n-butanol gas. Detailed Embodiments

[0038] It should be noted that the following detailed description is illustrative and aims to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0039] As a volatile organic compound, n-butanol is harmful to human health. At the same time, n-butanol is flammable and may explode. From this, it can be seen that it is particularly necessary to develop a n-butanol gas-sensitive material for detecting n-butanol. In the prior art, although a n-butanol material with the chemical formula X wt% Pd-Ho y Sm 1-y FeO3 is disclosed, its operating temperature is as high as 220 °C. Such a high operating temperature will increase the energy consumption of the gas sensor and there are certain safety hazards.

[0040] Based on this, the present invention provides a gold-modified dysprosium samarium iron oxide, and the chemical formula of the gold-modified dysprosium samarium iron oxide is Xwt% Au-Dy x Sm 1-x FeO3, where 0 < x ≤ 10 and 0 < y ≤ 0.5. Based on SmFeO3, through the doping of Dy element at the A site and the surface modification of Au element, the prepared gold-modified dysprosium samarium iron oxide as a n-butanol gas-sensitive material significantly reduces the operating temperature and improves the sensitivity and selectivity to n-butanol. Specifically, the optimal operating temperature of the gold-modified dysprosium samarium iron oxide is 190 °C, and the response value to 1 ppm n-butanol gas at 190 °C is 12.68.

[0041] In the present invention, through the doping of Dy element at the A site, the lattice structure of SmFeO3 is adjusted, the oxygen vacancy concentration is increased, the surface charge distribution and electronic structure are optimized, thereby enhancing the adsorption ability to n-butanol molecules; at the same time, the surface modification of Au element reduces the reaction energy barrier of n-butanol decomposition through the catalytic effect, promotes the formation and regeneration of oxygen vacancies, and accelerates the reaction kinetics of n-butanol molecules with active sites. The synergistic effect of Dy and Au not only improves the response value but also enhances the high selectivity to n-butanol and inhibits the response to other interfering gases. In addition, the material prepared by the co-precipitation method has a nanoparticle structure (particle size 80 - 200 nm), a large specific surface area, provides more adsorption and reaction sites for n-butanol molecules, and exhibits excellent sensitivity, selectivity and fast response characteristics.

[0042] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the following will specifically describe the technical solution of the present invention in combination with specific embodiments.

[0043] The experimental materials used in the embodiments of the present invention are all conventional experimental materials in the art and can be obtained through commercial channels.

[0044] Example 1: 5wt% Au-Dy of gold-modified dysprosium samarium iron oxide 0.7 Sm 0.3 Preparation of SmFeO3

[0045] (1) After mixing Dy(NO3)3·6H2O, Sm(NO3)3·6H2O and Fe(NO3)3·9H2O, dissolve them in deionized water, stir to mix evenly, and then add citric acid to obtain a mixed solution;

[0046] Add 1mol / L NaOH solution to the mixed solution to adjust the pH to 10.0 to cause the metal ions to co-precipitate. After the precipitation is completed, stir for 1.5h and then filter. Collect the precipitate, wash it 3 times with deionized water and ethanol, and then place it in a vacuum dryer at 80°C for 8h to obtain the Dy 0.7 Sm 0.3 SmFeO3 precursor;

[0047] (2) Disperse the Dy 0.7 Sm 0.3 SmFeO3 precursor in 50mL of deionized water. After adding chloroauric acid, stir and react at 70°C for 3h. After the reaction is completed, filter, collect the solid, wash it 3 times with deionized water, dry it, and then calcine it at 500°C for 3h to obtain 5wt% Au-Dy of gold-modified dysprosium samarium iron oxide 0.7 Sm 0.3 SmFeO3.

[0048] During the preparation process, the addition amount ratio of Dy(NO3)3·6H2O, Sm(NO3)3·6H2O, Fe(NO3)3·9H2O, chloroauric acid, citric acid and deionized water is 31.157g: 13.151g: 40.404g: 2.05g: 20g: 100mL.

[0049] Example 2: 3wt% Au-Dy of gold-modified dysprosium samarium iron oxide 0.7 Sm 0.3 Preparation of SmFeO3

[0050] (1) After mixing Dy(NO3)3·6H2O, Sm(NO3)3·6H2O and Fe(NO3)3·9H2O, dissolve them in deionized water, stir to mix evenly, and then add citric acid to obtain a mixed solution;

[0051] Add 1mol / L NaOH solution to the mixed solution to adjust the pH to 9.0 to cause the metal ions to co-precipitate. After the precipitation is completed, stir for 2h and then filter. Collect the precipitate, wash it 3 times with deionized water and ethanol, and then place it in a vacuum dryer at 80°C for 10h to obtain the Dy 0.7 Sm0.3 DySmFeO3 precursor

[0052] (2) Disperse the Dy 0.7 Sm 0.3 DySmFeO3 precursor in 50 mL of deionized water. After adding chloroauric acid, stir and react at 80 °C for 2 h. After the reaction is completed, filter, collect the solid, wash it 3 times with deionized water, dry it, and then calcine it at 600 °C for 2 h to obtain gold-modified dysprosium samarium iron oxide 3wt% Au-Dy 0.7 Sm 0.3 FeO3.

[0053] During the preparation process, the addition ratio of Dy(NO3)3·6H2O, Sm(NO3)3·6H2O, Fe(NO3)3·9H2O, chloroauric acid, citric acid and deionized water is 31.157 g: 13.151 g: 40.404 g: 1.23 g: 30 g: 150 mL.

[0054] Example 3: Preparation of gold-modified dysprosium samarium iron oxide 7wt% Au-Dy 0.7 Sm 0.3 FeO3

[0055] (1) Mix Dy(NO3)3·6H2O, Sm(NO3)3·6H2O and Fe(NO3)3·9H2O, dissolve them in deionized water, stir to make them uniform, and then add citric acid to obtain a mixed solution;

[0056] Add 1 mol / L NaOH solution to the mixed solution to adjust the pH to 11.0 to cause the co-precipitation of metal ions. After the precipitation is completed, stir for 1 h and then filter. Collect the precipitate, wash it 3 times with deionized water and ethanol, and then place it in a vacuum dryer at 80 °C for 6 h to obtain Dy 0.7 Sm 0.3 SmFeO3 precursor;

[0057] (2) Disperse the Dy 0.7 Sm 0.3 SmFeO3 precursor in 50 mL of deionized water. After adding chloroauric acid, stir and react at 60 °C for 4 h. After the reaction is completed, filter, collect the solid, wash it 3 times with deionized water, dry it, and then calcine it at 400 °C for 4 h to obtain gold-modified dysprosium samarium iron oxide 7wt% Au-Dy 0.7 Sm 0.3 FeO3.

[0058] During the preparation process, the ratio of the addition amounts of Dy(NO3)3·6H2O, Sm(NO3)3·6H2O, Fe(NO3)3·9H2O, chloroauric acid, citric acid and deionized water is 31.157 g: 13.151 g: 40.404 g: 2.87 g: 10 g: 50 mL.

[0059] Example 4: Preparation of n-butanol sensor

[0060] The gold-modified dysprosium samarium iron oxide (5wt% Au-Dy 0.7 Sm 0.3 FeO3) prepared in Example 1, deionized water and terpineol were mixed in a ratio of 1 g: 3 mL: 1 mL to obtain a slurry;

[0061] The slurry was spin-coated on the surface of an alumina ceramic tube at a speed of 600 rpm to form a gas-sensitive film with a thickness of 150 μm. The gas-sensitive film was placed in air and aged at 200 °C for 15 hours to obtain an n-butanol gas-sensitive sensor.

[0062] Comparative Example 1: Preparation of samarium iron oxide DyFeO3

[0063] The difference between this comparative example and Example 1 is that: during the reaction process, Sm(NO3)3·6H2O and chloroauric acid were not added. The specific preparation steps are as follows:

[0064] (1) After mixing Dy(NO3)3·6H2O and Fe(NO3)3·9H2O, they were dissolved in deionized water, stirred to mix evenly, and then citric acid was added to obtain a mixed solution;

[0065] 1 mol / L NaOH solution was added to the mixed solution to adjust the pH to 10.0 to cause co-precipitation of metal ions. After the precipitation was completed, it was stirred for 1.5 h and then filtered. The precipitate was collected, washed 3 times with deionized water and ethanol, and then placed in a vacuum dryer at 80 °C for 8 h to obtain a Dy 0.7 Sm 0.3 FeO3 precursor;

[0066] (2) The Dy 0.7 Sm 0.3 FeO3 precursor was dispersed in 50 mL of deionized water and stirred at 70 °C for 3 h. After the reaction was completed, it was filtered, the solid was collected, washed 3 times with deionized water, dried, and then calcined at 500 °C for 3 h to obtain the gold-modified dysprosium samarium iron oxide DyFeO3.

[0067] During the preparation process, the ratio of the addition amounts of Dy(NO3)3·6H2O, Fe(NO3)3·9H2O, citric acid and deionized water is 31.157 g: 40.404 g: 20 g: 100 mL.

[0068] Comparative Example 2: Preparation of dysprosium samarium iron oxide Dy 0.7 Sm 0.3 FeO3

[0069] The difference between this comparative example and Example 1 is that chloroauric acid was not added during the preparation process. The specific steps are as follows:

[0070] (1) After mixing Dy(NO3)3·6H2O, Sm(NO3)3·6H2O, and Fe(NO3)3·9H2O, dissolve them in deionized water, stir to mix them evenly, and then add citric acid to obtain a mixed solution;

[0071] Add 1 mol / L NaOH solution to the mixed solution to adjust the pH to 10.0 to cause the metal ions to co-precipitate. After the precipitation is completed, stir for 1.5 h and then filter. Collect the precipitate, wash it 3 times with deionized water and ethanol, and then place it in a vacuum dryer at 80 °C for 8 h to obtain the Dy 0.7 Sm 0.3 FeO3 precursor;

[0072] (2) Disperse the Dy 0.7 Sm 0.3 FeO3 precursor in 50 mL of deionized water, stir and react at 70 °C for 3 h. After the reaction is completed, filter, collect the solid, wash it 3 times with deionized water, dry it, and then calcine it at 500 °C for 3 h to obtain the gold-modified dysprosium samarium iron oxide Dy 0.7 Sm 0.3 FeO3.

[0073] During the preparation process, the addition amount ratio of Dy(NO3)3·6H2O, Sm(NO3)3·6H2O, Fe(NO3)3·9H2O, citric acid, and deionized water is 31.157 g: 13.151 g: 40.404 g: 20 g: 100 mL.

[0074] Comparative Example 3: Preparation of 5wt% Au-DyFeO3 of gold-modified dysprosium iron oxide

[0075] The difference between this comparative example and Example 1 is that Sm(NO3)3·6H2O was not added during the preparation process. The specific preparation is as follows:

[0076] (1) After mixing Dy(NO3)3·6H2O and Fe(NO3)3·9H2O, dissolve them in deionized water, stir to mix them evenly, and then add citric acid to obtain a mixed solution;

[0077] Add 1 mol / L NaOH solution to the mixed solution to adjust the pH to 10.0, causing the metal ions to co-precipitate. After the precipitation is completed, stir for 1.5 h and then filter. Collect the precipitate, wash it three times with deionized water and ethanol, and then place it in a vacuum dryer at 80 °C for 8 h to obtain the DyFeO3 precursor;

[0078] (2) Disperse the DyFeO3 precursor in 50 mL of deionized water. After adding chloroauric acid, stir and react at 70 °C for 3 h. After the reaction is completed, filter, collect the solid, wash it three times with deionized water, dry it, and then calcine it at 500 °C for 3 h to obtain the gold-modified dysprosium samarium iron oxide 5wt% Au-DyFeO3.

[0079] During the preparation process, the addition ratio of Dy(NO3)3·6H2O, Fe(NO3)3·9H2O, chloroauric acid, citric acid and deionized water is 31.157 g: 40.404 g: 2.05 g: 20 g: 100 mL.

[0080] Experimental Example 1: Structure Characterization

[0081] Perform structure characterization on the gold-modified dysprosium samarium iron oxide 5wt% Au-Dy 0.7 Sm 0.3 FeO3 prepared in Example 1, and the results are as Figures 1-3 shown.

[0082] Figure 1 is the XRD pattern of the gold-modified dysprosium samarium iron oxide prepared in Example 1. It can be seen from Figure 1 that the crystallization peaks correspond to the crystal phases of DyFeO3 (No. 74-1478) such as (112), (020) and (200). Figure 2 is the SEM image of the gold-modified dysprosium samarium iron oxide prepared in Example 1 at 200 nm. It can be seen from Figure 2 that the gold-modified dysprosium samarium iron oxide exhibits a typical nanoparticle structure, with a large specific surface area and porosity, and many reaction sites and transport channels for gas molecules. From Figure 3 the EDS-Mapping schematic diagram of the Au, Dy and Sm elements, it can be seen that the elements Au, Dy and Sm exist in the material. Thus, it can be seen that the Au and Sm elements are successfully doped into DyFeO3.

[0083] Experimental Example 2: Gas Sensing Performance

[0084] Coat the materials prepared in Example 1 and Comparative Examples 1-3 on the sensing film, and detect their gas sensing response (Rg / Ra) to n-butanol gas. The results are as Figures 4-5 shown. Among them, Ra is the resistance of the sensor in air, and Rg is the resistance of the gas to be measured. The experimental environment is: RH is 20%, and the ambient temperature is 20 °C.

[0085] It can be seen from Figure 4 that the optimal working temperature of the gold-modified dysprosium samarium iron oxide prepared by the present invention is 190 °C. At the working temperature of 190 °C, the response value of the gold-modified dysprosium samarium iron oxide 5wt% Au-Dy 0.7 Sm 0.3 FeO3 to 1 ppm of n-butanol gas is 12.68. The response value of DyFeO3 prepared in Comparative Example 1 to 1 ppm of n-butanol gas is 3.57. The response value of Dy 0.7 Sm 0.3 FeO3 prepared in Comparative Example 2 to 1 ppm of n-butanol gas is 4.76. The response value of 5wt% Au-DyFeO3 prepared in Comparative Example 3 to 1 ppm of n-butanol gas is 9.28. Thus, it can be seen that by loading and modifying the surface noble metal Au of the DyFeO3 material and doping the Dy element at the B site, there is a synergistic effect in improving the response value of the material to n-butanol gas.

[0086] Figure 5 shows the long-term stability of the gold-modified dysprosium samarium iron oxide 5wt% Au-Dy 0.7 Sm 0.3 FeO3 prepared by the present invention to 1 ppm of n-butanol gas. It can be seen from Figure 5 that within one month, the change rate of the response value of the gold-modified dysprosium samarium iron oxide 5wt% Au-Dy 0.7 Sm 0.3 FeO3 prepared by the present invention to 1 ppm of n-butanol gas is within 5%, indicating that the material has extremely high long-term stability of gas sensitivity.

[0087] Figure 6 shows the relationship diagram between the gas sensitivity performance of the gold-modified dysprosium samarium iron oxide 5wt% Au-Dy 0.7 Sm 0.3 FeO3 prepared by the present invention to 1 ppm of n-butanol gas and humidity. It can be seen from Figure 6 that with the increase of relative humidity, the gas sensitivity performance gradually decreases. When the relative humidity exceeds 40%, the gas sensitivity performance drops sharply. However, within 40%, the change rate of the n-butanol gas sensitivity performance of the gold-modified dysprosium samarium iron oxide is within 8%, indicating that it has extremely high resistance to relative humidity of gas sensitivity.

[0088] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A gold-modified dysprosium samarium iron oxide, characterized in that, The chemical formula of the gold-modified dysprosium samarium iron oxide is Xwt% Au-Dy x Sm 1-x FeO3, where 0 < X ≤ 10 and 0 < x ≤ 0.

5.

2. The preparation method of the gold-modified dysprosium-samarium iron oxide according to claim 1, characterized in that, It includes the following steps: (1) After mixing dysprosium nitrate, samarium nitrate and iron nitrate, add them to deionized water and mix well, then add citric acid to obtain a mixed solution; add an alkali solution to the mixed solution to adjust the pH to cause co-precipitation of metal ions, stir and then filter, collect the solid, wash and dry to obtain a Dy x Sm 1-x FeO3 precursor; (2) Disperse the Dy x Sm 1-x FeO3 precursor in water, then add chloroauric acid for reaction. After the reaction is completed, filter, wash, dry and calcine to obtain gold-modified dysprosium samarium iron oxide.

3. The preparation method of the gold-modified dysprosium samarium iron oxide according to claim 2, wherein The addition ratio of dysprosium nitrate, samarium nitrate, iron nitrate, chloroauric acid, citric acid and deionized water is (0.002 - 1) mol : (0.01 - 5) mol : (0.01 - 5) mol : (0.01 - 100) g : (10 - 50) g : (50 - 200) mL.

4. The preparation method of the gold-modified dysprosium samarium iron oxide according to claim 2, characterized in that, In step (1), the pH is adjusted to 9 - 11, the stirring time is 1 - 2 h, the drying method is vacuum drying, the drying temperature is 70 - 90 °C, and the drying time is 6 - 12 h.

5. The preparation method of the gold-modified dysprosium-samarium iron oxide according to claim 2, characterized in that, In step (2), the reaction temperature is 60 - 80 °C and the reaction time is 2 - 4 h.

6. The preparation method of the gold-modified dysprosium-samarium iron oxide according to claim 2, characterized in that, In step (2), the calcination temperature is 400 - 600 °C and the calcination time is 2 - 4 h.

7. Application of the gold-modified dysprosium samarium iron oxide described in claim 1 in 1) or 2): 1) Detecting n-butanol gas; 2) Preparing an n-butanol gas sensor.

8. The application according to claim 7, wherein The concentration of the n-butanol gas is 1 - 10 ppm.

9. The application according to claim 7, characterized in that The working temperature of the n-butanol gas sensor is 185 - 195 °C.

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