Preparation method of Pd-cu co-modified ZnO composite nanomaterial based on bionic structure, product and application thereof

Abstract

The application discloses a preparation method of Pd-Cu co-modified ZnO composite nanomaterial based on a bionic structure and application of the Pd-Cu co-modified ZnO composite nanomaterial. The cold drying technology is adopted to dehydrate flower petals and keep the morphology of the flower petals unchanged. The atomic layer deposition technology is adopted to deposit a ZnO nanolayer on the surface of the dried flower petals. A layer of ZIF-8 is grown on the surface of the ZnO through a hydrothermal reaction, so that the specific surface area is increased. Then, the PdCl2 and CuCl2 are mixed in deionized water, ammonia water is added dropwise to adjust the pH value to 8.5-10, the NaBH4 is added under stirring to reduce the PdCl2 and CuCl2 in situ, and finally, the heat treatment is carried out in an inert gas atmosphere. After the temperature is reduced to room temperature, the Pd-Cu co-modified ZnO composite nanomaterial based on the bionic structure is obtained. The method provided by the application is simple in production, low in cost, and can realize high-sensitivity detection of ammonia gas and formaldehyde gas.

Description

Technical Field

[0001] This invention relates to the field of gas detection, specifically to a method for preparing semiconductor gas sensors, and particularly to a method for preparing Pd-Cu co-modified ZnO composite nanomaterials based on a biomimetic structure, as well as its products and applications. Background Technology

[0002] Gas sensors are widely used in consumer applications. Semiconductor gas sensors, in particular, have become the mainstream development direction due to their advantages such as low cost, high sensitivity, and portability. With societal development, the measurement accuracy requirements for gas sensors are increasing across various sectors. However, currently, high-precision gas sensors are often very expensive, making it difficult to meet the needs of the general consumer market. Furthermore, existing consumer-grade gas sensors have significant shortcomings in selectivity and stability, resulting in false alarms and missed alarms, causing substantial resource waste and economic losses. Therefore, breakthroughs in the technology and cost aspects of ordinary consumer-grade gas sensors are currently the key focus for the development of my country's gas sensor industry.

[0003] To address the shortcomings of current gas-sensitive materials and devices in terms of preparation methods, cost, and sensitivity, this study combines nanotechnology to enhance gas response sensitivity by constructing nanomaterials, surface modification, and heterojunctions. In particular, modifying the surface of metal oxides with specific catalysts can promote specific catalytic reactions with certain gases, thereby improving the sensitivity and selectivity of the gas response. Summary of the Invention

[0004] The present invention aims to provide a method for preparing Pd-Cu co-modified ZnO composite nanomaterials based on a biomimetic structure.

[0005] Another objective of this invention is to provide a Pd-Cu co-modified ZnO composite nanomaterial product based on a biomimetic structure prepared by the above method.

[0006] Another object of the present invention is to provide an application of the above-mentioned product.

[0007] The objective of this invention is achieved through the following method: a method for preparing Pd-Cu co-modified ZnO composite nanomaterials based on a biomimetic structure, comprising the following steps:

[0008] Step 1: Take fresh petals, rinse them with clean water, and then freeze-dry them at -80 ℃;

[0009] Step 2: Deposit a ZnO nanolayer on the dried petal surface using atomic layer deposition (ALD) technology;

[0010] The method for preparing ZnO nanolayers on a substrate using atomic layer deposition (ALD) is as follows: The temperature of the ALD system cavity is raised to 80°C–100°C, the cavity is opened, and the sample is placed in the sample cell. The pressure inside the cavity is reduced to below 50 hPa, and the reaction cavity is cleaned with an inert gas. Diethylzinc is introduced into the reaction cavity with a pulse duration of 1–10 s, followed by the introduction of an inert gas to clean the unreacted precursor with a pulse duration of 1–60 s. Then, an oxygen precursor is introduced with a pulse duration of 1–10 s. The unreacted oxygen precursor is then cleaned with an inert gas, completing one cycle of zinc oxide deposition. This process is repeated to deposit a ZnO layer on the substrate surface for 1000–2000 cycles.

[0011] Step 3: Take 0.5 g of the sample obtained in Step 2 and place it in a methanol solution of 2-methylimidazole. The molar concentration of 2-methylimidazole is 0.4~0.6 M and the volume of methanol is 80 mL. Place the solution in a reaction vessel and carry out a hydrothermal reaction to obtain sample A.

[0012] The hydrothermal reaction temperature is 120~150 ℃, and the reaction time is 3~5 hours;

[0013] Step 4: Take 0.1 g of the sample obtained in Step 3 and place it in deionized water. After sonicating for 10 min, add palladium chloride and copper chloride, and add ammonia water dropwise to adjust the pH value to 8.5~10. While stirring, add an aqueous solution of sodium borohydride with a molar concentration of 0.1M. After stirring for 10 min, centrifuge and dry the resulting precipitate.

[0014] The mass ratio of palladium chloride and copper chloride to sample A is 0.05~0.1:0.01~0.05:1; the molar amount of sodium borohydride is 2~4 times the total molar amount of palladium chloride and copper chloride;

[0015] Step 5: Place the dried sample from Step 4 into a crucible and heat-treat it under an inert gas atmosphere. After cooling to room temperature, Pd-Cu co-modified ZnO composite nanomaterials based on biomimetic structures are obtained.

[0016] Preferably, in step five, the heat treatment gas atmosphere is nitrogen or argon, the heat treatment is carried out at 650~750 ℃ ​​for 2~4 hours, and the heating rate is 3~6 ℃ / min;

[0017] The prepared nanomaterials were fabricated into MEMS devices. The specific steps were as follows: a MEMS device with Pt interdigitated electrodes was taken, ultrasonically cleaned with deionized water and ethanol, dried with a nitrogen gun, 0.5 g of the sample obtained in step two was taken and made into a slurry, which was uniformly coated on the surface of the MEMS device. After drying, it was placed in a muffle furnace for heat treatment at a temperature of 400 ℃, a holding time of 1 h, and a heating rate of 2 ℃ / min. After the chamber cooled to room temperature, it was taken out to obtain a MEMS gas sensor.

[0018] This invention provides a biomimetic Pd-Cu co-modified ZnO composite nanomaterial, which is prepared according to any of the methods described above.

[0019] This invention provides an application of Pd-Cu co-modified ZnO composite nanomaterials based on biomimetic structure in gas detection, achieving highly sensitive detection of triethylamine.

[0020] Freeze-drying was used to dehydrate petals while preserving their morphology. Atomic layer deposition (ALD) was then used to deposit a ZnO nanolayer on the dried petal surface. A ZIF-8 layer was then grown on the ZnO surface via a hydrothermal reaction to increase the specific surface area. This ZnO was then mixed with palladium chloride and copper chloride in deionized water, and ammonia was added dropwise to adjust the pH to 8.5–10. Sodium borohydride was added under stirring to reduce the palladium chloride and copper chloride in situ. Finally, the mixture was heat-treated under an inert gas atmosphere and cooled to room temperature to obtain a biomimetic Pd-Cu co-modified ZnO composite nanomaterial. The method provided by this invention is simple to prepare, low in cost, and enables highly sensitive detection of ammonia and formaldehyde gases. Detailed Implementation

[0021] Example 1:

[0022] A biomimetic Pd-Cu co-modified ZnO composite nanomaterial was prepared by freeze-drying petals while preserving their morphology, depositing a ZnO nanolayer on the dried petal surface using atomic layer deposition (ALD), and then growing a ZIF-8 layer on the ZnO nanolayer surface via hydrothermal reaction. The ZIF-8 was then mixed with palladium chloride and copper chloride in deionized water, and the pH was adjusted to 8.5–10. Sodium borohydride was added under stirring to reduce the palladium chloride and copper chloride in situ. Finally, the mixture was heat-treated under an inert gas atmosphere and cooled to room temperature to obtain the biomimetic Pd-Cu co-modified ZnO composite nanomaterial. The preparation steps are as follows:

[0023] Step 1: Take fresh petals, rinse them with clean water, and freeze-dry them at -80 ℃ to dehydrate the petals while maintaining their shape;

[0024] Step 2: Deposit a ZnO nanolayer on the dried petal surface using atomic layer deposition (ALD) technology, following the procedure below: Raise the temperature of the ALD system chamber to 80°C, open the chamber, and place the sample into the sample cell; reduce the chamber pressure to below 50 hPa, and purge the reaction chamber with an inert gas; introduce diethylzinc into the reaction chamber with a pulse duration of 1 s, followed by purging the unreacted precursor with an inert gas pulse duration of 1 s, then introducing an oxygen precursor with a pulse duration of 1 s; purging the unreacted oxygen precursor with an inert gas completes one zinc oxide deposition cycle; repeat this process to deposit a ZnO layer on the substrate surface for 1000 cycles.

[0025] Step 3: Take 0.5 g of the sample obtained in Step 2 and place it in a methanol solution of 2-methylimidazole with a molar concentration of 0.4 M and a methanol volume of 80 mL. Place the solution in a reaction vessel and carry out a hydrothermal reaction at 120 °C for 3 hours to obtain sample A.

[0026] Step 4: Place 0.1 g of sample A in deionized water, sonicate for 10 min, then add palladium chloride and copper chloride, wherein the mass ratio of palladium chloride and copper chloride to sample A is 0.05:0.01:1; adjust the pH to 8.5 by adding ammonia dropwise, and add a 0.1 M sodium borohydride aqueous solution while stirring, wherein the molar amount of sodium borohydride is twice the total molar amount of palladium chloride and copper chloride; after stirring for 10 min, centrifuge and dry the resulting precipitate to obtain the dried sample;

[0027] Step 5: Place the dried sample from Step 4 into a crucible and heat-treat it at 650 °C for 4 hours in an inert gas atmosphere at a heating rate of 3 °C / min. After cooling to room temperature, Pd-Cu co-modified ZnO composite nanomaterials based on biomimetic structures are obtained.

[0028] The prepared nanomaterials were fabricated into MEMS devices. The specific steps were as follows: a MEMS device with Pt interdigitated electrodes was taken, ultrasonically cleaned with deionized water and ethanol, dried with a nitrogen gun, and the resulting sample was made into a slurry, which was uniformly coated on the surface of the MEMS device. After drying, it was placed in a muffle furnace for heat treatment at a temperature of 400 ℃, a holding time of 1 h, and a heating rate of 2 ℃ / min. After the chamber cooled to room temperature, it was taken out to obtain a MEMS gas sensor.

[0029] The MEMS device obtained in this embodiment, as a gas sensor, has a sensitivity of 7.9 for formaldehyde at a concentration of 1 ppm, a response time of 9 s, and a recovery time of 13 s at an operating temperature of 280 ℃. The optimal response temperature for ammonia is 80 ℃, and the sensitivity for ammonia at 1 ppm is 4.3, with a response time of 19 s and a recovery time of 28 s.

[0030] Example 2:

[0031] A biomimetic Pd-Cu co-modified ZnO composite nanomaterial is prepared according to the following steps, similar to those in Example 1:

[0032] Step 1: Take fresh petals, rinse them with clean water, and then freeze-dry them at -80 ℃;

[0033] Step 2: Deposit a ZnO nanolayer on the dried petal surface using atomic layer deposition (ALD) technology, following the procedure below: Raise the temperature of the ALD system chamber to 100°C, open the chamber, and place the sample into the sample cell; reduce the chamber pressure to below 50 hPa, and purge the reaction chamber with inert gas; introduce diethylzinc into the reaction chamber with a pulse duration of 5 s, followed by purging the unreacted precursor with inert gas for 60 s, then introducing an oxygen precursor with a pulse duration of 5 s; purging the unreacted oxygen precursor with inert gas completes one zinc oxide deposition cycle; repeat this process to deposit a ZnO layer on the substrate surface for 2000 cycles.

[0034] Step 3: Take 0.5 g of the sample obtained in Step 2 and place it in a 0.6 M methanol solution of 2-methylimidazole (80 mL volume). Place the solution in a reaction vessel and perform a hydrothermal reaction at 120 °C for 5 hours to obtain sample A.

[0035] Step 4: Take 0.1 g of the sample obtained in Step 3 and place it in deionized water. After sonicating for 10 min, add palladium chloride and copper chloride. The mass ratio of palladium chloride and copper chloride to sample A is 0.05:0.05:1. Add ammonia water to adjust the pH value to 9. While stirring, add an aqueous solution of sodium borohydride with a molar concentration of 0.1 M. The molar amount of sodium borohydride is 2 to 4 times the total molar amount of palladium chloride and copper chloride. After stirring for 10 min, centrifuge and dry the resulting precipitate.

[0036] Step 5: Place the dried sample from Step 4 into a crucible and heat-treat it under an inert gas atmosphere (nitrogen gas) at 700 ℃ for 2 hours at a heating rate of 3 ℃ / min. After cooling to room temperature, Pd-Cu co-modified ZnO composite nanomaterials based on biomimetic structures are obtained.

[0037] The prepared biomimetic Pd-Cu co-modified ZnO composite nanomaterials were fabricated into MEMS devices. The steps are as follows: The MEMS device with Pt interdigitated electrodes was ultrasonically cleaned with deionized water and ethanol, dried with a nitrogen gun, and the resulting sample was made into a slurry. It was uniformly coated on the surface of the MEMS device, dried, and then placed in a muffle furnace for heat treatment at 400 ℃ for 1 h with a heating rate of 2 ℃ / min. After the chamber cooled to room temperature, it was taken out to obtain a MEMS gas sensor.

[0038] The gas sensor of the device obtained in this embodiment has a sensitivity of 10.4 for formaldehyde at a concentration of 1 ppm, a response time of 10 s, and a recovery time of 15 s at an operating temperature of 280 ℃. The optimal response temperature for ammonia is 80 ℃, and the sensitivity for ammonia at a concentration of 1 ppm is 6.9, the response time is 19 s, and the recovery time is 28 s.

[0039] Example 3:

[0040] A biomimetic Pd-Cu co-modified ZnO composite nanomaterial is prepared according to the following steps, similar to those in Example 1:

[0041] Step 1: Take fresh petals, rinse them with clean water, and then freeze-dry them at -80 ℃;

[0042] Step 2: Atomic layer deposition (ALD) was used to deposit a ZnO nanolayer on the dried petal surface, following the procedure below: The temperature inside the ALD system was raised to 100°C, the chamber was opened, and the sample was placed in the sample cell; the pressure inside the chamber was reduced to below 50 hPa, and the reaction chamber was purged with an inert gas; diethylzinc was introduced into the reaction chamber with a pulse duration of 10 s, followed by the introduction of an inert gas to purge unreacted precursors with a pulse duration of 50 s, and then the introduction of an oxygen precursor with a pulse duration of 10 s; the unreacted oxygen precursor was then purged with an inert gas to complete one cycle of zinc oxide deposition; this process was repeated to deposit a ZnO layer on the substrate surface for 1500 cycles.

[0043] Step 3: Take 0.5 g of the sample obtained in Step 2 and place it in a methanol solution of 2-methylimidazole with a molar concentration of 0.5 M and a methanol volume of 80 mL. Place the solution in a reaction vessel and carry out a hydrothermal reaction to obtain sample A. The hydrothermal reaction temperature is 150 ℃ and the reaction time is 3 hours.

[0044] Step 4: Take 0.1 g of the sample obtained in Step 3 and place it in deionized water. After sonicating for 10 min, add palladium chloride and copper chloride. The mass ratio of palladium chloride and copper chloride to sample A is 0.1:0.05:1. Add ammonia water to adjust the pH value to 10. While stirring, add an aqueous solution of sodium borohydride with a molar concentration of 0.1 M. The molar amount of sodium borohydride is 3 times the total molar amount of palladium chloride and copper chloride. After stirring for 10 min, centrifuge and dry the resulting precipitate.

[0045] Step 5: Place the dried sample from Step 4 into a crucible and heat-treat it under an inert gas atmosphere. The heat treatment gas atmosphere is nitrogen or argon. The heat treatment temperature is 750 ℃, the time is 4 hours, the heating rate is 3 ℃ / min, and after cooling to room temperature, Pd-Cu co-modified ZnO composite nanomaterials based on biomimetic structure are obtained.

[0046] The prepared biomimetic Pd-Cu co-modified ZnO composite nanomaterials were used to fabricate MEMS devices. The specific steps were as follows: the MEMS device with Pt interdigitated electrodes was ultrasonically cleaned with deionized water and ethanol, dried with a nitrogen gun, and the resulting sample was made into a slurry, which was uniformly coated on the surface of the MEMS device. After drying, it was placed in a muffle furnace for heat treatment at a temperature of 400 ℃, a holding time of 1 h, and a heating rate of 2 ℃ / min. After the chamber cooled to room temperature, it was taken out to obtain a MEMS gas sensor.

[0047] The gas sensor of the device obtained in this embodiment has a sensitivity of 8.2 for formaldehyde at a concentration of 1 ppm, a response time of 13 s, and a recovery time of 19 s at an operating temperature of 280 ℃. The optimal response temperature for ammonia is 80 ℃, and the sensitivity for ammonia at a concentration of 1 ppm is 6.8, the response time is 21 s, and the recovery time is 30 s.

Claims

1. A method for preparing Pd-Cu co-modified ZnO composite nanomaterials based on a biomimetic structure, characterized in that, Petals were dehydrated using freeze-drying while maintaining their morphology. A ZnO nanolayer was deposited on the dried petal surface using atomic layer deposition (ALD). A ZIF-8 layer was then grown on the ZnO nanolayer surface via hydrothermal reaction. This ZIF-8 was then mixed with palladium chloride and copper chloride in deionized water, and the pH was adjusted to 8.5–10. Sodium borohydride was added under stirring to reduce the palladium chloride and copper chloride in situ. Finally, the mixture was heat-treated in an inert gas atmosphere (nitrogen or argon) at 650–750 °C for 2–4 hours. After cooling to room temperature, a biomimetic Pd-Cu co-modified ZnO composite nanomaterial was obtained, comprising the following steps: Step 1: Take fresh petals, rinse them with clean water, and freeze-dry them at -80 °C to dehydrate the petals while maintaining their shape; Step 2: Deposit a ZnO nanolayer on the dried petal surface using atomic layer deposition (ALD) technology; Step 3: Take 0.5 g of the sample obtained in Step 2 and place it in a methanol solution of 2-methylimidazole with a molar concentration of 0.4~0.6 M and a methanol volume of 80 mL. Place the solution in a reaction vessel and carry out a hydrothermal reaction to obtain sample A. Step 4: Place 0.1 g of sample A in deionized water, sonicate for 10 min, then add palladium chloride and copper chloride, wherein the mass ratio of palladium chloride and copper chloride to sample A is 0.05~0.1:0.01~0.05:1; adjust the pH value to 8.5~10 by adding ammonia dropwise, and add a 0.1M sodium borohydride aqueous solution while stirring, wherein the molar amount of sodium borohydride is 2~4 times the total molar amount of palladium chloride and copper chloride; after stirring for 10 min, centrifuge and dry the resulting precipitate to obtain the dried sample; Step 5: Place the dried sample from Step 4 into a crucible and heat-treat it under a nitrogen or argon inert atmosphere. After cooling to room temperature, Pd-Cu co-modified ZnO composite nanomaterials based on biomimetic structure are obtained. In step two, the method for depositing a ZnO nanolayer on the dried petal surface using atomic layer deposition (ALD) is as follows: The temperature inside the ALD system is raised to 80°C–100°C, the chamber is opened, and the sample is placed in the sample cell. The pressure inside the chamber is reduced to below 50 hPa, and the reaction chamber is cleaned with an inert gas. Diethylzinc is introduced into the reaction chamber with a pulse duration of 1–10 s, followed by the introduction of an inert gas to clean the unreacted precursor with a pulse duration of 1–60 s. Then, an oxygen precursor is introduced with a pulse duration of 1–10 s. Finally, the unreacted oxygen precursor is cleaned with an inert gas, completing one cycle of zinc oxide deposition. This process is repeated to deposit a ZnO layer on the substrate surface for 1000 to 2000 cycles.

2. The preparation method of Pd-Cu co-modified ZnO composite nanomaterials based on biomimetic structure according to claim 1, characterized in that: In step three, the hydrothermal reaction temperature is 120~150 °C and the reaction lasts for 3~5 hours.

3. The method for preparing Pd-Cu co-modified ZnO composite nanomaterials based on biomimetic structures according to any one of claims 1 to 2, characterized in that, Prepare according to the following steps: Step 1: Take fresh petals, rinse them with clean water, and freeze-dry them at -80 °C to dehydrate the petals while maintaining their shape; Step 2: Deposit a ZnO nanolayer on the dried petal surface using atomic layer deposition (ALD) technology, following the procedure below: Raise the temperature of the ALD system chamber to 80°C, open the chamber, and place the sample into the sample cell; reduce the pressure inside the chamber to below 50 hPa, and purge the reaction chamber with an inert gas; introduce diethylzinc into the reaction chamber with a pulse duration of 1 s, then introduce an inert gas to purge the unreacted precursor with a pulse duration of 1 s, followed by the introduction of an oxygen precursor with a pulse duration of 1 s; finally, purge the unreacted oxygen precursor with an inert gas to complete one cycle of zinc oxide deposition. This process is repeated to deposit a ZnO layer on the substrate surface for 1000 cycles; Step 3: Take 0.5 g of the sample obtained in Step 2 and place it in a methanol solution of 2-methylimidazole with a molar concentration of 0.4 M and a methanol volume of 80 mL. Place it in a reaction vessel and carry out a hydrothermal reaction at 120 °C for 3 hours to obtain sample A. Step 4: Place 0.1 g of sample A in deionized water, sonicate for 10 min, then add palladium chloride and copper chloride, wherein the mass ratio of palladium chloride and copper chloride to sample A is 0.05:0.01:1; adjust the pH to 8.5 by adding ammonia dropwise, and add a 0.1 M sodium borohydride aqueous solution while stirring, wherein the molar amount of sodium borohydride is twice the total molar amount of palladium chloride and copper chloride; after stirring for 10 min, centrifuge and dry the resulting precipitate to obtain the dried sample; Step 5: Place the dried sample from Step 4 into a crucible and heat-treat it at 650 °C for 4 hours in an inert gas atmosphere at a heating rate of 3 °C / min. After cooling to room temperature, Pd-Cu co-modified ZnO composite nanomaterials based on biomimetic structures are obtained.

4. The method for preparing Pd-Cu co-modified ZnO composite nanomaterials based on biomimetic structures according to any one of claims 1 to 2, characterized in that, Prepare according to the following steps: Step 1: Take fresh petals, rinse them with clean water, and then freeze-dry them at -80 °C; Step 2: Deposit a ZnO nanolayer on the dried petal surface using atomic layer deposition (ALD) technology, following the procedure below: Raise the temperature of the ALD system chamber to 100°C, open the chamber, and place the sample into the sample cell; reduce the pressure inside the chamber to below 50 hPa, and purge the reaction chamber with inert gas; introduce diethylzinc into the reaction chamber with a pulse duration of 5 s, followed by purging unreacted precursors with inert gas for a pulse duration of 60 s. Then, an oxygen precursor is introduced with a pulse duration of 5 seconds; afterwards, the unreacted oxygen precursor is cleaned with an inert gas to complete one cycle of zinc oxide deposition. This process was repeated to deposit a ZnO layer on the substrate surface for 2000 cycles; Step 3: Take 0.5 g of the sample obtained in Step 2 and place it in a 0.6 M methanol solution of 2-methylimidazole (80 mL in volume). Place the solution in a reaction vessel and perform a hydrothermal reaction at 120 °C for 5 hours to obtain sample A. Step 4: Take 0.1 g of the sample obtained in Step 3 and place it in deionized water. After sonicating for 10 min, add palladium chloride and copper chloride. The mass ratio of palladium chloride, copper chloride and sample A is 0.05:0.05:

1. Add ammonia water to adjust the pH value to 9. While stirring, add an aqueous solution of sodium borohydride with a molar concentration of 0.1 M. The molar amount of sodium borohydride is 2 to 4 times the total molar amount of palladium chloride and copper chloride. After stirring for 10 min, centrifuge and dry the resulting precipitate. Step 5: Place the dried sample from Step 4 into a crucible and heat-treat it under an inert gas atmosphere. The heat treatment gas atmosphere is nitrogen. Heat treatment at 700 °C for 2 hours with a heating rate of 3 °C / min. After cooling to room temperature, Pd-Cu co-modified ZnO composite nanomaterials based on biomimetic structure are obtained.

5. The method for preparing Pd-Cu co-modified ZnO composite nanomaterials based on biomimetic structures according to any one of claims 1 to 2, characterized in that, Prepare according to the following steps: Step 1: Take fresh petals, rinse them with clean water, and then freeze-dry them at -80 °C; Step 2: Deposit a ZnO nanolayer on the dried petal surface using atomic layer deposition (ALD) technology, following the procedure below: Raise the temperature of the ALD system chamber to 100°C, open the chamber, and place the sample into the sample cell; reduce the pressure inside the chamber to below 50 hPa, and purge the reaction chamber with inert gas; introduce diethylzinc into the reaction chamber with a pulse duration of 10 s, followed by purging unreacted precursors with inert gas for a pulse duration of 50 s. Then, an oxygen precursor is introduced with a pulse duration of 10 s; after that, the unreacted oxygen precursor is cleaned with an inert gas to complete one cycle of zinc oxide deposition; this process is repeated to deposit a ZnO layer on the substrate surface for 1500 cycles. Step 3: Take 0.5 g of the sample obtained in Step 2 and place it in a methanol solution of 2-methylimidazole with a molar concentration of 0.5 M and a methanol volume of 80 mL. Place it in a reaction vessel to carry out a hydrothermal reaction to obtain sample A. The hydrothermal reaction temperature is 150°C and the reaction time is 3 hours. Step 4: Take 0.1 g of the sample obtained in Step 3 and place it in deionized water. After sonicating for 10 min, add palladium chloride and copper chloride. The mass ratio of palladium chloride, copper chloride and sample A is 0.1:0.05:

1. Add ammonia water to adjust the pH value to 10. While stirring, add an aqueous solution of sodium borohydride with a molar concentration of 0.1 M. The molar amount of sodium borohydride is 3 times the total molar amount of palladium chloride and copper chloride. After stirring for 10 min, centrifuge and dry the resulting precipitate. Step 5: Place the dried sample from Step 4 into a crucible and heat-treat it under an inert gas atmosphere. The heat treatment gas atmosphere is nitrogen or argon. The heat treatment temperature is 750 °C, the time is 4 hours, the heating rate is 3 °C / min, and after cooling to room temperature, Pd-Cu co-modified ZnO composite nanomaterials based on biomimetic structure are obtained.

6. A Pd-Cu co-modified ZnO composite nanomaterial based on a biomimetic structure, characterized in that... Prepared by the method according to any one of claims 1-5.

7. An application of the biomimetic Pd-Cu co-modified ZnO composite nanomaterial according to claim 6 in gas detection, achieving highly sensitive detection of triethylamine.

8. The application according to claim 7, characterized in that: The prepared nanomaterials are then fabricated into MEMS devices. The specific steps are as follows: A MEMS device with Pt interdigitated electrodes was ultrasonically cleaned with deionized water and ethanol, and dried with a nitrogen gun. The resulting Pd-Cu co-modified ZnO composite nanomaterial sample based on the biomimetic structure was then made into a slurry and uniformly coated onto the surface of the MEMS device. After drying, the device was placed in a muffle furnace for heat treatment at a temperature of 400°C for 1 h and a heating rate of 2°C / min. After the chamber cooled to room temperature, the device was removed to obtain a MEMS gas sensor.