NH3 sensor based on GaN / (FeMnNiCoCr) 3O4 nano material and preparation method thereof
Through GaN/(FeMnNiCoCr)3O4 nanomaterial modification, an NH3 sensor with loose porous structure was formed, which solved the problems of low surface oxygen content of GaN and high calcining temperature of HEOs, and achieved high sensitivity and fast response NH3 detection.
Patent Information
- Application Number
- CN202510659090.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-21
- Publication Date
- 2025-08-05
AI Technical Summary
The existing GaN-based NH3 sensors have low surface chemical adsorption oxygen content, and the inherent defects suppress their gas-sensitive properties. The high calcining temperature of high entropy oxide HEOs leads to a decrease in specific surface area, affecting the sensitivity.
GaN/(FeMnNiCoCr)3O4 nanomaterial was used as sensitive material and prepared by solution combustion method and hydrothermal method. (FeMnNiCoCr)3O4 nanoparticles were modified to form a loose porous structure, increasing the number of oxygen vacancies, and increasing the gas diffusion and adsorption speed.
The sensor's sensitivity and response/recovery speed are significantly improved, and the detection lower limit reaches ppb level, which is suitable for large-scale production and is cheap.
Smart Images
Figure CN120427698A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of semiconductor gas sensors, and in particular relates to an NH3 sensor based on GaN / (FeMnNiCoCr)3O4 nanomaterials and a preparation method thereof. Background Art
[0002] Ammonia (NH3), an important chemical raw material, is widely used in chemical synthesis, refrigeration, medicine, and other fields. However, during this process, NH3 inevitably leaks into the atmosphere, causing harm to human health. High concentrations of NH3 can increase alveolar and capillary permeability, causing large amounts of fluid to leak into the alveoli and interstitium, leading to pulmonary edema. Long-term exposure to low concentrations of NH3 can also lead to chronic respiratory inflammation. Furthermore, measuring the concentration of NH3 in exhaled gas can enable early diagnosis of certain kidney diseases, such as kidney disease and Helicobacter pylori infection. Therefore, the development of high-performance NH3 gas sensors has a wide range of applications and is of great significance to environmental protection and human health.
[0003] Compared with traditional detection methods such as infrared spectroscopy and mass spectrometry, NH3 gas sensors using semiconductors as sensitive materials have attracted much attention due to their advantages such as low cost, high sensitivity, fast response / recovery time, and miniaturization.
[0004] Gallium nitride (GaN), as one of the most representative third-generation semiconductor materials, has important applications in the field of gas sensors due to its unique physical and chemical properties. High carrier density and electron mobility enable GaN to operate at room temperature and generate rapid electrical signal changes when interacting with the target gas. However, due to the low content of chemically adsorbed oxygen on the GaN surface, its intrinsic defect is nitrogen vacancies (V N ), thus inhibiting its gas-sensing performance.
[0005] High entropy oxides are structurally stable solid solutions composed of five or more metal elements. Due to their abundant active sites, stable crystal structure, unique geometric compatibility and electronic structure, they show broad application prospects in the field of chemical catalysis. From the perspective of gas-sensing reaction mechanism, the high configurational entropy effect and lattice distortion effect of HEOs are very conducive to the formation of oxygen vacancies (V O) is formed, thereby promoting the adsorption of oxygen on the surface. However, HEOs are difficult to become sensitive materials because their calcination temperature is generally above 600°C, which causes their specific surface area to drop sharply, affecting sensitivity. Although small-sized HEOs can be synthesized by specific methods, the initial resistance also increases sharply. However, as a modifier, it can not only greatly increase the oxygen vacancy content on the surface of the material, but also produce a synergistic effect and promote gas-sensing performance. Therefore, as a type of HEOs, if (FeMnNiCoCr)3O4 is used as a load to modify GaN, it may be a very effective method of enhancing sensitivity. Summary of the Invention
[0006] The present invention overcomes the deficiencies of the prior art and provides an NH3 sensor based on GaN / (FeMnNiCoCr)3O4 nanomaterials and a preparation method thereof.
[0007] The GaN / (FeMnNiCoCr)3O4 nanomaterial is used as the sensitive material. On the one hand, the loose and porous structure of the GaN nanomaterial as the substrate accelerates gas diffusion and adsorption, while also providing a favorable matrix morphology for modification of the (FeMnNiCoCr)3O4. On the other hand, the modification of the (FeMnNiCoCr)3O4 causes the GaN morphology to collapse, forming a more loose and porous nanostructure, which promotes gas diffusion and adsorption. These two aspects work together to significantly improve the sensitivity of the sensor. This invention provides a new strategy for oxygen vacancy regulation engineering and offers an alternative approach for the development of ppb-level NH3 sensors.
[0008] To address the aforementioned technical issues, the present invention employs a novel NH3 sensor based on GaN / (FeMnNiCoCr)3O4 nanomaterials. The sensor comprises interdigitated electrodes with silver, an Al2O3 ceramic substrate, and a sensitive material coated on the interdigitated electrodes. The sensitive material is a GaN / (FeMnNiCoCr)3O4 nanomaterial with a heterojunction structure. The walnut-shaped GaN is composed of irregular nanosheets and nanoparticles. The addition of (FeMnNiCoCr)3O4 causes the GaN morphology to collapse, forming a more porous nanostructure.
[0009] As a further limitation of the technical solution of the present invention, the size of the Al2O3 ceramic substrate is 10 mm*10 mm.
[0010] As a further limitation of the technical solution of the present invention, the GaN / (FeMnNiCoCr)3O4 nanomaterial is prepared by the following steps: (1) Cobalt nitrate, nickel nitrate, iron nitrate, chromium nitrate, manganese chloride and glycine were added to deionized water respectively, the above solutions were mixed, and magnetically stirred at room temperature. The resulting solution was then directly transferred to a drying oven to obtain a brown gel; (2) The obtained brown gel was placed in a clean crucible and placed in a tube furnace. The temperature was raised to 650 °C at a rate of 10 °C / min and calcined in an air environment for one hour. After cooling to room temperature, the (FeMnNiCoCr)3O4 nanomaterial was obtained. (3) Gallium nitrate was added to deionized water, followed by dropwise addition of ammonia until the pH value reached 10, and the (FeMnNiCoCr)3O4 prepared in step (2) was added, and magnetic stirring was performed at room temperature to obtain a hydrothermal synthesis precursor reaction solution; the precursor was transferred to a stainless steel autoclave lined with polytetrafluoroethylene for hydrothermal reaction, and after cooling to room temperature, the reaction product was collected by centrifugation, and then washed with deionized water and anhydrous ethanol three times respectively, and the reaction product was placed in a drying oven; (4) The dried reaction product was placed in a clean crucible and placed in a tube furnace. The temperature was raised to 1000°C at a heating rate of 10°C / min and calcined in an ammonia atmosphere for two hours. After cooling to room temperature, the obtained GaN / (FeMnNiCoCr)3O4 nanomaterial was collected.
[0011] As a further limitation of the technical solution of the present invention, in step (1), the mass volume ratio of cobalt nitrate, nickel nitrate, ferric nitrate, chromium nitrate, manganese chloride and glycine to deionized water is 17-19 g:17-19 g:23-25 g:21-24 g:11-13 g:10 g:60 mL.
[0012] As a further limitation of the technical solution of the present invention, the magnetic stirring time in step (1) is 1 to 1.5 hours, and the drying condition in the drying oven is drying at 80° C. for 12 hours.
[0013] As a further limitation of the technical solution of the present invention, in step (3), the mass volume ratio of gallium nitrate to deionized water is 12-13 g:250 mL, magnetic stirring is carried out at room temperature for 3-4 h, the hydrothermal reaction conditions are reaction at 140° C. for 10 h; and the drying conditions in the drying oven are drying at 80° C. for 12 hours.
[0014] As a further limitation of the technical solution of the present invention, the molar ratio of GaN to (FeMnNiCoCr)3O4 in the GaN / (FeMnNiCoCr)3O4 nanomaterial prepared in step (4) is 100:1-5.
[0015] A preparation method for an NH3 sensor based on GaN / (FeMnNiCoCr)3O4 nanomaterials is disclosed. The specific steps are as follows: GaN / (FeMnNiCoCr)3O4 nanomaterials and anhydrous ethanol are placed in a mortar and ground into a paste slurry; the paste is then evenly coated on a 10×10 mm alumina substrate with a silver electrode deposited thereon; the substrate is then placed on a heating table and baked; and after the sensitive material is dried, an NH3 sensor based on the GaN / (FeMnNiCoCr)3O4 nanomaterial is obtained.
[0016] As a further limitation of the technical solution of the present invention, the mass volume ratio of GaN / (FeMnNiCoCr)3O4 nanomaterial to anhydrous ethanol is 1~2g:5~10ml.
[0017] As a further limitation of the technical solution of the present invention, the baking condition is baking at 85° C. for 30 to 45 minutes.
[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. A simple solution combustion and hydrothermal method was used to prepare GaN nanocomposites modified with (FeMnNiCoCr)3O4 nanoparticles. The synthesis method is simple and low-cost. 2. By preparing GaN nanocomposites modified with (FeMnNiCoCr)3O4 nanoparticles, the number of oxygen vacancies on the material surface is greatly increased, thereby improving the sensitivity to NH3. It has extremely high response / recovery speed, good repeatability, and a detection limit as low as 100 ppb, which has broad application prospects in the detection of NH3 content.
[0019] 3. The device process is simple, the size is small, and it is suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 The SEM morphology of the sensor of Comparative Example 1 and Example 2 of the present invention is shown in FIG. Figure 1 (ab) are SEM images of comparative example 1, Figure 1 (cd) are SEM images of Example 2.
[0021] Figure 2 This is the XRD pattern of the GaN / (FeMnNiCoCr)3O4 nanomaterial prepared in Example 2 of the present invention.
[0022] Figure 3 The sensitivity comparison curves of the sensors of Comparative Example 1, Example 1, Example 2, and Example 3 of the present invention to different concentrations of NH3 are shown.
[0023] Figure 4This is the dynamic response curve of the sensor of Example 2 of the present invention to different concentrations of NH3. DETAILED DESCRIPTION
[0024] The present invention will be further described below with reference to specific embodiments. Example 1
[0025] The NH3 gas sensor is made using nanomaterials with a molar ratio of GaN / (FeMnNiCoCr)3O4 of 100:1 as the sensitive material. The specific production process is as follows: (1) 0.9 g of cobalt nitrate, 0.9 g of nickel nitrate, 1.2 g of ferric nitrate, 1.15 g of chromium nitrate, 0.6 g of manganese chloride, and 0.5 g of glycine were added to 3 mL of deionized water, respectively. The above solutions were mixed and magnetically stirred at room temperature for 1-1.5 h. The resulting solution was then directly transferred to a drying oven and dried at 80 °C for 12 h to obtain a brown gel. (2) The obtained brown gel was placed in a clean crucible, and then placed in a tube furnace, and heated to 650°C at a heating rate of 10°C / min, and calcined in an air environment for one hour. After cooling to room temperature, the (FeMnNiCoCr)3O4 nanomaterial was obtained; (3) Add 2.5g of gallium nitrate to 50mL of deionized water, then add ammonia water dropwise until the pH reaches 10, then add 0.09g of the previously prepared (FeMnNiCoCr)3O4 (the molar ratio of GaN to (FeMnNiCoCr)3O4 is 100:1), and stir magnetically at room temperature for 3-4h to obtain a hydrothermal synthesis precursor reaction solution. The precursor is transferred to a stainless steel autoclave lined with polytetrafluoroethylene and hydrothermally reacted at 140℃ for 10h. After cooling to room temperature, the reaction product is collected by centrifugation and washed with deionized water and anhydrous ethanol three times respectively. The reaction product is placed in a drying oven and dried at 80℃ for 12 hours. (4) The dried reaction product was placed in a clean crucible, and then placed in a tube furnace, heated to 1000°C at a heating rate of 10°C / min, and calcined in an ammonia atmosphere for two hours. After cooling to room temperature, the obtained GaN / (FeMnNiCoCr)3O4 nanomaterial was collected; (5) 0.15 g of GaN / (FeMnNiCoCr)3O4 nanomaterial was mixed with 0.1 ml of deionized water and ground into a paste. A small amount of the paste was then evenly coated on the interdigital electrode. The electrode was then placed on a heating table and baked at 85 °C for 30-45 min. After the sensitive material was dried, an NH3 sensor based on GaN / (FeMnNiCoCr)3O4 nanomaterial was obtained. Example 2
[0026] The NH3 gas sensor is made using nanomaterials with a molar ratio of GaN / (FeMnNiCoCr)3O4 of 100:3 as the sensitive material. The specific production process is as follows: (1) 0.9 g of cobalt nitrate, 0.9 g of nickel nitrate, 1.2 g of ferric nitrate, 1.15 g of chromium nitrate, 0.6 g of manganese chloride, and 0.5 g of glycine were added to 3 mL of deionized water, respectively. The above solutions were mixed and magnetically stirred at room temperature for 1-1.5 h. The resulting solution was then directly transferred to a drying oven and dried at 80 °C for 12 h to obtain a brown gel. (2) The obtained brown gel was placed in a clean crucible, and then placed in a tube furnace, and heated to 650°C at a heating rate of 10°C / min, and calcined in an air environment for one hour. After cooling to room temperature, the (FeMnNiCoCr)3O4 nanomaterial was obtained; (3) Add 2.5 g of gallium nitrate to 50 mL of deionized water, then add ammonia water dropwise until the pH reaches 10, then add 0.27 g of the previously prepared (FeMnNiCoCr)3O4 (the molar ratio of GaN to (FeMnNiCoCr)3O4 is 100:3), and stir magnetically at room temperature for 3 to 4 hours to obtain a hydrothermal synthesis precursor reaction solution. The precursor is transferred to a stainless steel autoclave lined with polytetrafluoroethylene and hydrothermally reacted at 140 ° C for 10 hours. After cooling to room temperature, the reaction product is collected by centrifugation and then washed with deionized water and anhydrous ethanol three times respectively. The reaction product is placed in a drying oven and dried at 80 ° C for 12 hours; (4) The dried reaction product was placed in a clean crucible, and then placed in a tube furnace, heated to 1000°C at a heating rate of 10°C / min, and calcined in an ammonia atmosphere for two hours. After cooling to room temperature, the obtained GaN / (FeMnNiCoCr)3O4 nanomaterial was collected; (5) 0.15 g of GaN / (FeMnNiCoCr)3O4 nanomaterial was mixed with 0.1 ml of deionized water and ground into a paste slurry. A small amount of the slurry was then evenly coated on the interdigital electrode. The electrode was then placed on a heating table and baked at 85 °C for 30-45 min. After the sensitive material was dried, an NH3 sensor based on GaN / (FeMnNiCoCr)3O4 nanomaterial was obtained. Example 3
[0027] The NH3 gas sensor was fabricated using nanomaterials with a molar ratio of GaN / (FeMnNiCoCr)3O4 of 100:5 as the sensitive material. The specific fabrication process is as follows: (1) 0.9 g of cobalt nitrate, 0.9 g of nickel nitrate, 1.2 g of ferric nitrate, 1.15 g of chromium nitrate, 0.6 g of manganese chloride, and 0.5 g of glycine were added to 3 mL of deionized water, respectively. The above solutions were mixed and magnetically stirred at room temperature for 1-1.5 h. The resulting solution was then directly transferred to a drying oven and dried at 80 °C for 12 h to obtain a brown gel. (2) The obtained brown gel was placed in a clean crucible, and then placed in a tube furnace, and heated to 650°C at a heating rate of 10°C / min, and calcined in an air environment for one hour. After cooling to room temperature, the (FeMnNiCoCr)3O4 nanomaterial was obtained; (3) Add 2.5g of gallium nitrate to 50mL of deionized water, then add ammonia water dropwise until the pH reaches 10, then add 0.45g of the previously prepared (FeMnNiCoCr)3O4 (the molar ratio of GaN to (FeMnNiCoCr)3O4 is 100:5), and stir magnetically at room temperature for 3-4h to obtain a hydrothermal synthesis precursor reaction solution. The precursor is transferred to a stainless steel autoclave lined with polytetrafluoroethylene and hydrothermally reacted at 140℃ for 10h. After cooling to room temperature, the reaction product is collected by centrifugation and washed with deionized water and anhydrous ethanol three times respectively. The reaction product is placed in a drying oven and dried at 80℃ for 12 hours. (4) The dried reaction product was placed in a clean crucible, and then placed in a tube furnace, heated to 1000°C at a heating rate of 10°C / min, and calcined in an ammonia atmosphere for two hours. After cooling to room temperature, the obtained GaN / (FeMnNiCoCr)3O4 nanomaterial was collected; (5) 0.15 g of GaN / (FeMnNiCoCr)3O4 nanomaterial was mixed with 0.1 ml of deionized water and ground into a paste. A small amount of the paste was then evenly coated on the interdigital electrodes. The electrodes were then placed on a heating table and baked at 85 °C for 30-45 min. After the sensitive material was dried, an NH3 sensor based on GaN / (FeMnNiCoCr)3O4 nanomaterial was obtained.
[0028] Comparative Example 1 The specific production process of the NH3 gas sensor using GaN as the sensitive material is as follows: (1) 2.5 g of gallium nitrate was added to 50 mL of deionized water, and then ammonia was added dropwise until the pH value reached 10. The mixture was magnetically stirred at room temperature for 3 to 4 hours to obtain a hydrothermal synthesis precursor reaction solution. The hydrothermal synthesis precursor reaction solution was transferred to a stainless steel autoclave lined with polytetrafluoroethylene and hydrothermally reacted at 140 ° C for 10 hours. After cooling naturally to room temperature, the reaction product was collected by centrifugation and washed with deionized water and anhydrous ethanol three times respectively. The reaction product was then placed in a drying oven and dried at 80 ° C for 12 hours. (2) The dried reaction product was placed in a clean crucible, and then placed in a tube furnace, heated to 1000°C at a heating rate of 10°C / min, and calcined in an ammonia atmosphere for two hours. After cooling to room temperature, the prepared gallium nitride nanomaterial was collected; (3) 0.02 g of GaN nanomaterial was mixed with 0.1 ml of anhydrous ethanol and ground into a paste. A small amount of the paste was then evenly coated on the interdigital electrode. The electrode was then placed on a heating table and baked at 60 °C for 30-45 min. After the sensitive material was dried, an NH3 sensor based on GaN nanomaterial was obtained.
[0029] The performance of the sensors prepared in Examples 1-3 and Comparative Example 1 was studied as follows: like Figure 1 As shown, Figure 1 (ab) It can be seen that the GaN material prepared in Comparative Example 1 is walnut-shaped and is assembled from irregular nanosheets and nanoparticles; Figure 1 (cd) It can be seen that the addition of (FeMnNiCoCr)3O4 prepared in Example 2 causes the GaN morphology to collapse, forming a more loose and porous nanostructure.
[0030] like Figure 2 As shown in the XRD spectrum of the GaN / (FeMnNiCoCr)3O4 nanomaterial, characteristic peaks of GaN and (FeMnNiCoCr)3O4 can be seen. (As a new material, (FeMnNiCoCr)3O4 has not yet established a standard chart for its diffraction pattern in the standard diffraction database (ICDD-PDF-4). Currently, researchers typically determine the formation of (FeMnNiCoCr)3O4 by comparing it to a NiFe2O4 standard chart.) like Figure 3 As shown in FIG1 , the sensitivity curves of the sensors of comparative example 1, example 1, example 2 and example 3 to ammonia at different concentrations are shown. As can be seen from the figure, example 2 has the best loading ratio.
[0031] like Figure 4 As shown, the sensitivity of the sensor of Example 2 increases with the increase of NH3 concentration at room temperature.
[0032] Note: The sensitivity of a device is defined as its resistance in the gas being measured (R g ) and the resistance in air (R a ) ratio, that is, S = R g / R a During the test, a static test system is used. The device is placed in a gas chamber, a certain amount of test gas is injected into it, and the change in resistance is observed and recorded. The corresponding sensitivity value is calculated.
Claims
1. An NH3 sensor based on GaN / (FeMnNiCoCr)3O4 nanomaterials, characterized in that: The invention consists of silver interdigital electrodes, an Al2O3 ceramic substrate and a sensitive material coated on the interdigital electrodes. The sensitive material is a GaN / (FeMnNiCoCr)3O4 nanomaterial with a heterojunction structure.
2. The NH3 sensor based on GaN / (FeMnNiCoCr)3O4 nanomaterial according to claim 1, characterized in that: The size of the Al2O3 ceramic substrate is 10 mm*10 mm.
3. The NH3 sensor based on GaN / (FeMnNiCoCr)3O4 nanomaterial according to claim 1, characterized in that: The GaN / (FeMnNiCoCr)3O4 nanomaterial is prepared by the following steps: (1) Cobalt nitrate, nickel nitrate, iron nitrate, chromium nitrate, manganese chloride and glycine were added to deionized water respectively, the above solutions were mixed, and magnetically stirred at room temperature. The resulting solution was then directly transferred to a drying oven to obtain a brown gel; (2) The obtained brown gel was placed in a clean crucible and placed in a tube furnace. The temperature was raised to 650 °C at a rate of 10 °C / min and calcined in an air environment for one hour. After cooling to room temperature, the (FeMnNiCoCr)3O4 nanomaterial was obtained. (3) Gallium nitrate was added to deionized water, followed by dropwise addition of ammonia until the pH value reached 10, and the (FeMnNiCoCr)3O4 prepared in step (2) was added, and magnetic stirring was performed at room temperature to obtain a hydrothermal synthesis precursor reaction solution; the precursor was transferred to a stainless steel autoclave lined with polytetrafluoroethylene for hydrothermal reaction, and after cooling to room temperature, the reaction product was collected by centrifugation, and then washed with deionized water and anhydrous ethanol three times respectively, and the reaction product was placed in a drying oven; (4) The dried reaction product was placed in a clean crucible and placed in a tube furnace. The temperature was raised to 1000°C at a heating rate of 10°C / min and calcined in an ammonia atmosphere for two hours. After cooling to room temperature, the obtained GaN / (FeMnNiCoCr)3O4 nanomaterial was collected.
4. The NH3 sensor based on GaN / (FeMnNiCoCr)3O4 nanomaterial according to claim 3, characterized in that: In step (1), the mass volume ratio of cobalt nitrate, nickel nitrate, iron nitrate, chromium nitrate, manganese chloride and glycine to deionized water is 17-19 g: 17-19 g: 23-25 g: 21-24 g: 11-13 g: 10 g: 60 mL.
5. The NH3 sensor based on GaN / (FeMnNiCoCr)3O4 nanomaterial according to claim 3, characterized in that: The magnetic stirring time in step (1) is 1 to 1.5 hours, and the drying condition in the drying oven is drying at 80° C. for 12 hours.
6. The NH3 sensor based on GaN / (FeMnNiCoCr)3O4 nanomaterial according to claim 3, characterized in that: In step (3), the mass volume ratio of gallium nitrate to deionized water is 12-13 g:250 mL, magnetic stirring is performed at room temperature for 3-4 h, the hydrothermal reaction condition is 140° C. for 10 h, and the drying condition in the drying oven is 80° C. for 12 hours.
7. The NH3 sensor based on GaN / (FeMnNiCoCr)3O4 nanomaterial according to claim 3, characterized in that: The molar ratio of GaN to (FeMnNiCoCr)3O4 in the GaN / (FeMnNiCoCr)3O4 nanomaterial prepared in step (4) is 100:1-5.
8. The method for preparing an NH3 sensor based on GaN / (FeMnNiCoCr)3O4 nanomaterial according to claim 1, characterized in that: GaN / (FeMnNiCoCr)3O4 nanomaterials and anhydrous ethanol were placed in a mortar and ground into a paste-like slurry. The slurry was then evenly coated on a 10×10 mm alumina substrate with a silver electrode deposited thereon. The substrate was then placed on a heating table and baked. After the sensitive material was dried, an NH3 sensor based on GaN / (FeMnNiCoCr)3O4 nanomaterial was obtained.
9. The method for preparing an NH3 sensor based on GaN / (FeMnNiCoCr)3O4 nanomaterial according to claim 8, characterized in that: The mass volume ratio of GaN / (FeMnNiCoCr)3O4 nanomaterials to anhydrous ethanol is 1~2g:5~10ml.
10. The method for preparing an NH3 sensor based on GaN / (FeMnNiCoCr)3O4 nanomaterial according to claim 8, wherein the baking condition is baking at 85°C for 30-45 minutes.