Pd-doped WO3 nanoparticle material as well as preparation method and application thereof

Abstract

The invention discloses a Pd-doped WO3 nanoparticle material as well as a preparation method and application thereof, and relates to the technical field of sensing material preparation. The preparation method comprises the following steps: (1) dissolving palladium chloride nanoparticles in absolute ethyl alcohol, stirring at room temperature for 20 minutes, then adding tungsten trioxide, then adding hydrazine hydrate, stirring at room temperature for 4 hours for precipitation reaction, centrifuging, washing and drying to obtain an intermediate product; and (2) heating the intermediate product obtained in the step (1) to 400 DEG C, sintering for 2 hours, and naturally cooling to room temperature to obtain the Pd-doped WO3 nanoparticle material. The Pd-doped WO3 nano-particle material provided by the invention has a relatively good detection capability on toluene gas.

Description

Technical Field

[0001] The present invention relates to the technical field of sensor material preparation, and in particular to a Pd-doped WO3 nanoparticle material and a preparation method and application thereof. Background Art

[0002] Gas sensing technology has attracted widespread attention due to its ability to detect gases quickly and sensitively. It plays a vital role in food quality testing, breath analysis, environmental monitoring, and industrial safety. Sensing materials are the basis for the development of smart sensors and determine the performance and application range of sensors. In the field of sensing materials, metal oxide semiconductors are widely favored by researchers due to their high sensitivity, fast response, low cost and good stability, and have become one of the most widely used materials. Common metal oxide semiconductor materials include SnO2, WO3, In2O3, Co3O4, etc. These materials occupy a core position in sensor technology due to their excellent properties. Under certain conditions, the interaction between semiconductor sensing materials and target gas molecules will trigger a chemical reaction. This process is accompanied by charge transfer, which in turn leads to a change in the resistance value of the semiconductor material, and ultimately achieves accurate detection of the target gas molecules. This detection mechanism based on semiconductor materials can convert the chemical signals of gas molecules into electrical signals, providing an effective technical means for gas detection. Toluene, as a typical aromatic volatile organic compound, is highly toxic and carcinogenic, posing a serious threat to human health and environmental safety. Therefore, the development of efficient toluene gas sensing materials is crucial for the advancement of gas sensor technology.

[0003] When evaluating the performance of sensing materials, key indicators such as sensitivity, selectivity, stability, response speed and recovery speed are usually focused on. However, most sensing materials cannot achieve excellent performance in all these aspects, so material modification is needed to improve their performance. Common modification strategies include element doping, heterojunction design and surface modification. Among these methods, element doping stands out due to its high efficiency. By introducing a small amount of impurity elements into the sensing material, the electronic structure and chemical properties of the material can be changed, thereby adjusting its adsorption capacity for target gas molecules, thereby enhancing the sensing performance. However, these studies are lacking in terms of which element doping can effectively improve the performance of WO3 sensing materials. Therefore, it is necessary to find a suitable element to change the sensing performance of WO3 sensing materials to toluene gas molecules. Summary of the invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a Pd-doped WO3 nanoparticle material and a preparation method and application thereof, wherein the material has a good detection capability for toluene gas.

[0005] The technical solution of the present invention to solve the above technical problem is as follows: a method for preparing a Pd-doped WO3 nanoparticle material is provided, comprising the following steps: (1) Dissolve palladium chloride nanoparticles in anhydrous ethanol, stir at room temperature for 20 min, then add tungsten trioxide, then add hydrazine hydrate, stir at room temperature for 4 h for precipitation reaction, centrifuge, wash and dry to obtain an intermediate product; (2) The intermediate product obtained in step (1) is heated to 400°C and sintered for 2 h, and then naturally cooled to room temperature to obtain Pd-doped WO3 nanoparticle material.

[0006] Furthermore, in step (1), the mass volume ratio of palladium chloride nanoparticles, tungsten trioxide, anhydrous ethanol and hydrazine hydrate is 0.04-0.06 g: 0.4-0.6 g: 10 mL: 100 µL.

[0007] Furthermore, in step (1), the mass volume ratio of palladium chloride nanoparticles, tungsten trioxide, anhydrous ethanol and hydrazine hydrate is 0.05 g: 0.495 g: 10 mL: 100 µL.

[0008] Furthermore, in step (1), the product is centrifuged and washed with deionized water and ethanol, and dried at 60°C for 12 h.

[0009] Furthermore, in step (2), the heating rate during heating is 1 °C / min.

[0010] The present invention also provides a Pd-doped WO3 nano-particle material prepared by the preparation method of the Pd-doped WO3 nano-particle material.

[0011] The present invention also provides application of the Pd-doped WO3 nanoparticle material in sensing toluene gas molecules.

[0012] The present invention has the following beneficial effects: 1. The present invention synthesizes Pd-doped WO3 nanoparticle material by precipitation method. The raw materials are easy to obtain, the production process is simple, and it is suitable for large-scale manufacturing.

[0013] 2. The Pd-doped WO3 nanoparticle material prepared in the present invention effectively promotes gas adsorption and improves the detection performance of toluene molecules.

[0014] 3. The Pd-doped WO3 nanoparticle material prepared by the present invention has good stability and selectivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a scanning electron microscope photograph of the Pd-doped WO3 nanoparticle material obtained in Example 1; Figure 2This is the X-ray diffraction pattern of the Pd-doped WO3 nanoparticle material obtained in Example 1; Figure 3 The response of the Pd-doped WO3 nanoparticle material obtained in Example 1 to 50 ppm toluene gas molecules at different working temperatures; Figure 4 The dynamic response curve of the Pd-doped WO3 nanoparticle material obtained in Example 1; Figure 5 The sensing performance of the Pd-doped WO3 nanoparticle material obtained in Example 1 in the concentration range of 5-200 ppm; Figure 6 The long-term stability of the Pd-doped WO3 nanoparticle material obtained in Example 1; Figure 7 This is the selectivity of the Pd-doped WO3 nanoparticle material obtained in Example 1. DETAILED DESCRIPTION

[0016] The principles and features of the present invention are described below, and the examples are only used to explain the present invention and are not used to limit the scope of the present invention. If no specific conditions are specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially. Example

[0017] A Pd-doped WO3 nanoparticle material, the preparation method of which comprises the following steps: (1) 0.05 g of palladium chloride nanoparticles were dissolved in 10 mL of anhydrous ethanol and stirred at room temperature for 20 min. Then, 0.495 g of tungsten trioxide was added, followed by 100 μL of hydrazine hydrate. The mixture was stirred at room temperature for 4 h for precipitation reaction. The mixture was centrifuged and washed with deionized water and ethanol, and dried at 60 °C for 12 h to obtain an intermediate product. (2) The intermediate product obtained in step (1) is heated to 400°C and sintered for 2 h, and then naturally cooled to room temperature to obtain Pd-doped WO3 nanoparticle material. Example

[0018] A Pd-doped WO3 nanoparticle material, the preparation method of which comprises the following steps: (1) 0.04 g of palladium chloride nanoparticles were dissolved in 10 mL of anhydrous ethanol and stirred at room temperature for 20 min. Then, 0.400 g of tungsten trioxide was added, followed by 100 μL of hydrazine hydrate. The mixture was stirred at room temperature for 4 h for precipitation reaction. The mixture was centrifuged and washed with deionized water and ethanol, and dried at 60 °C for 12 h to obtain an intermediate product. (2) The intermediate product obtained in step (1) is heated to 400°C and sintered for 2 h, and then naturally cooled to room temperature to obtain Pd-doped WO3 nanoparticle material. Example

[0019] A Pd-doped WO3 nanoparticle material, the preparation method of which comprises the following steps: (1) 0.06 g of palladium chloride nanoparticles were dissolved in 10 mL of anhydrous ethanol and stirred at room temperature for 20 min. Then, 0.600 g of tungsten trioxide was added, followed by 100 μL of hydrazine hydrate. The mixture was stirred at room temperature for 4 h for precipitation reaction. The mixture was centrifuged and washed with deionized water and ethanol, and dried at 60 °C for 12 h to obtain an intermediate product. (2) The intermediate product obtained in step (1) is heated to 400°C and sintered for 2 h, and then naturally cooled to room temperature to obtain Pd-doped WO3 nanoparticle material.

[0020] Experimental example 1. Obtain a scanning electron microscope photograph and an X-ray diffraction pattern of the Pd-doped WO3 nanoparticle material obtained in Example 1, as shown in FIG. Figure 1 and 2 shown.

[0021] Depend on Figure 1 It can be seen that the granular microstructure of the Pd-doped WO3 nanoparticle material of the present invention is beneficial to the interaction between gas molecules and the sensing material.

[0022] Depend on Figure 2 It can be seen that the diffraction signals at 23.14, 23.61, and 24.36° were identified as the crystal planes (002), (020), and (200) (JCPDS: 72-1465), respectively, confirming the monoclinic crystal structure of the synthesized WO3. This proves that WO3 nanomaterials have been successfully prepared.

[0023] 2. Prepare Pd-doped WO3 material sensor. The specific steps are as follows: 10 mg of the Pd-doped WO3 nanoparticle material obtained in Example 1 was dispersed in 200 μL of deionized water and ultrasonicated for 10 min to form a uniform solution. Then, 1.5 μL of the dispersed solution was dropped onto the surface of a 3×3 mm electrode substrate and naturally air-dried for 30 min to obtain a Pd-doped WO3 material sensor. Under an applied voltage of 0.2 V, the material was heated and aged at 300 °C for 2 h.

[0024] The response of Pd-doped WO3 sensor to 50 ppm toluene gas at different working temperatures is shown in Figure 2. Figure 3 shown.

[0025] Depend on Figure 3It can be seen that as the working temperature increases, the response of the sensing material to toluene gas increases first and then decreases. The optimal working temperature is 260 ℃, and the maximum response of the sensing material to toluene gas is about 73.4 at this time, and the performance is improved by 28 times; at the same time, it can be seen that compared with the WO3 material before modification, the Pd-doped WO3 sensing material has a higher sensing performance for toluene gas.

[0026] 3. At the above-mentioned optimal operating temperature of 260 °C, 50 ppm toluene gas is introduced into the gas sensor test system. Its dynamic response curve is as follows: Figure 4 shown.

[0027] Depend on Figure 4 It can be seen that the response time and response recovery time of WO3 sensing material are 19 and 22 s respectively, while the response time and response recovery time of Pd-doped WO3 sensing material are 4 and 16 s respectively. Compared with pure WO3 sensing material, the response time and recovery time are both reduced, the response time is reduced by 15 s, and the response recovery time is reduced by 6 s, indicating that the Pd-doped WO3 material sensor has a higher detection efficiency.

[0028] 4. At the above-mentioned optimal working temperature of 260 ℃, different concentrations of toluene gas were introduced into the gas sensor test system. The sensor performance test results are as follows: Figure 5 shown.

[0029] Depend on Figure 5 It can be seen that the toluene gas response increases with the increase of toluene concentration. Compared with the undoped WO3 sensing material, Pd-doped WO3 shows higher sensing performance for toluene gas molecules at different toluene concentrations, and has a wider concentration response range for toluene gas molecules.

[0030] 5. At the above-mentioned optimal operating temperature of 260 °C, the Pd-doped WO3 gas sensor was tested for 30 consecutive days to verify the stability of the sensor and to conduct a selectivity test. The results are as follows: Figure 6-7 As shown;.

[0031] Depend on Figure 6 It can be seen that the response of Pd-doped WO3 sensing material to 50 ppm toluene gas can maintain 82%, further confirming its good stability.

[0032] Depend on Figure 7 It can be seen that the responses of Pd-doped WO3 sensing material to toluene, acetone, ethanol, formaldehyde, methanol and ammonia gases are 73.4, 5.3, 38.0, 4.9, 7.0 and 17.6, respectively, indicating that it has excellent selectivity for toluene.

[0033] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing Pd-doped WO3 nanoparticle material, characterized in that: The following steps are involved: (1) Dissolve palladium chloride nanoparticles in anhydrous ethanol, stir at room temperature for 20 min, then add tungsten trioxide, then add hydrazine hydrate, stir at room temperature for 4 h for precipitation reaction, centrifuge, wash and dry to obtain an intermediate product; (2) The intermediate product obtained in step (1) is heated to 400°C and sintered for 2 h, and then naturally cooled to room temperature to obtain Pd-doped WO3 nanoparticle material.

2. The method for preparing the Pd-doped WO3 nanoparticle material according to claim 1, characterized in that: In step (1), the mass volume ratio of palladium chloride nanoparticles, tungsten trioxide, anhydrous ethanol and hydrazine hydrate is 0.04-0.06 g: 0.4-0.6 g: 10 mL: 100 µL.

3. The method for preparing the Pd-doped WO3 nanoparticle material according to claim 1 or 2, characterized in that: In step (1), the mass volume ratio of palladium chloride nanoparticles, tungsten trioxide, anhydrous ethanol and hydrazine hydrate is 0.05 g: 0.495 g: 10 mL: 100 µL.

4. The method for preparing the Pd-doped WO3 nanoparticle material according to claim 1, characterized in that: In step (1), the product is centrifuged and washed with deionized water and ethanol, and dried at 60 °C for 12 h.

5. The method for preparing the Pd-doped WO3 nanoparticle material according to claim 1, characterized in that: In step (2), the heating rate is 1 °C / min.

6. The Pd-doped WO3 nanoparticle material obtained by the preparation method of the Pd-doped WO3 nanoparticle material according to any one of claims 1 to 5.

7. Use of the Pd-doped WO3 nanoparticle material according to claim 6 in sensing toluene gas molecules.

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