Preparation method of Pd-modified SnO2 hydrogen sensor sensitive material

Abstract

The invention discloses a Pd modification-based SnO2 hydrogen sensor sensitive material preparation method, which comprises: dissolving stannous chloride dihydrate and polyvinylpyrrolidone in a solvent according to a certain ratio to obtain a uniform mixed solution; carrying out solvothermal reaction, washing, drying and calcining treatment on the mixed solution to prepare pure SnO2 nano powder; and ultrasonically dispersing the prepared nano SnO2 powder in ethanol, adding a PdCl2 solution, uniformly dispersing, drying, and calcining at high temperature, thereby obtaining the catalyst. The hydrogen sensor sensitive material has good response to low-concentration hydrogen and can be used for leakage detection of low-concentration hydrogen.

Description

Technical Field

[0001] This invention relates to the field of gas sensor technology, and more specifically, to a method for preparing and applying a Pd-modified SnO2 hydrogen sensor sensitive material. Background Technology

[0002] As a new generation of clean energy, hydrogen energy has significant advantages and wide applications. However, hydrogen molecules are small, have low ignition energy, and a wide flammability range, making them highly susceptible to leakage and deflagration during production, transportation, storage, and application, leading to casualties and property damage. Therefore, developing fast, sensitive, and reliable hydrogen sensors for real-time monitoring of leaked hydrogen in the environment is crucial for ensuring the safety of hydrogen-related industries. Semiconductor hydrogen sensors offer high sensitivity, good stability, and low cost, but their excessively high operating temperatures limit their practical application in the field of hydrogen safety.

[0003] Noble metal doping is a very effective way to improve the gas-sensing performance of semiconductor hydrogen sensors. Traditional noble metal loading methods mostly use reducing agents such as traps and sodium borohydride for reduction, which is a complicated and time-consuming process. Therefore, there is an urgent need for a simple and easy noble metal modification method to improve the gas-sensing performance of semiconductor hydrogen sensors. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing a Pd-modified SnO2 hydrogen sensor sensitive material. This invention has certain universality for the modification of metal oxide sensor sensitive materials.

[0005] This invention provides a method for preparing a Pd-modified SnO2 hydrogen sensor sensitive material, comprising the following steps:

[0006] a) Stannous chloride dihydrate and polyvinylpyrrolidone were dissolved in a solvent to obtain a mixed solution. This solution was then transferred to a reaction vessel for hydrothermal reaction. The resulting precipitate was washed, dried, and calcined to obtain pure SnO2 powder.

[0007] b) Disperse the SnO2 obtained in the previous step into ethanol by ultrasonication, add a quantitative amount of PdCl2 solution, mix well and then dry.

[0008] c) The dried product was calcined in a muffle furnace to obtain Pd-modified SnO2 hydrogen sensor sensitive material.

[0009] In the preferred step a), the mass ratio of stannous chloride dihydrate to polyvinylpyrrolidone is 3:7, and the dissolution is a mixed solution of ethanol and DMF, wherein the volume ratio of ethanol to DMF is 1:1.

[0010] The preferred step a) involves a hydrothermal reaction temperature of 150°C and a reaction time of 12 hours, with the resulting precipitate being calcined at 400°C for 2 hours.

[0011] In the preferred step b), the amount of PdCl2 solution added is 0.75 wt.% Pd / SnO2, and the drying temperature of the mixed solution is 80°C.

[0012] The preferred step c) involves calcining the product at a temperature of 400°C for 2 hours.

[0013] This invention provides a method for preparing a Pd-modified SnO2 hydrogen sensor sensitive material, which can be obtained by using the above-described scheme.

[0014] Compared with existing technologies, this invention provides a method for preparing a Pd-modified SnO2 hydrogen sensor sensitive material, comprising the following steps: a) dissolving stannous chloride dihydrate and polyvinylpyrrolidone in a solvent to obtain a mixed solution, transferring this solution to a reaction vessel for hydrothermal reaction, and then washing, drying, and calcining the resulting precipitate to obtain pure SnO2 powder; b) ultrasonically dispersing the SnO2 obtained in the previous step in ethanol, adding a quantitative amount of PdCl2 solution, mixing evenly, and then drying; c) calcining the dried product in a muffle furnace to obtain the Pd-modified SnO2 hydrogen sensor sensitive material. The hydrogen sensor prepared from this sensitive material has an effective response to 50 ppm of hydrogen, which makes it valuable for applications in the detection of low-concentration hydrogen. Attached Figure Description

[0015] Figure 1 The images shown are SEM and EDS images of 0.75 wt.% Pd-doped SnO2 obtained in Example 1.

[0016] Figure 2 This is a comparison of the responses of pure SnO2 and 1 wt.% Pd-doped SnO2 sensing materials to 50 ppm hydrogen in Example 2. Detailed Implementation

[0017] To make the implementation process of this invention clearer, a detailed description will be provided below in conjunction with the accompanying drawings.

[0018] Example 1 illustrates a method for preparing a Pd-modified SnO2 hydrogen sensor sensitive material. Pd-SnO2 nanomaterials with uniform morphology and particle size were prepared using a solution impregnation method.

[0019] In this embodiment, the main steps are as follows:

[0020] a) Dissolve 0.5g of tin dichloride dihydrate and 0.7g of polyvinylpyrrolidone in a mixture of 20ml of ethanol and 20ml of DMF, stir for 24h, transfer the above solution to an autoclave and react at 150℃ for 12h. After the hydrothermal reaction is completed, wash several times with DMF and ethanol by centrifugation, and dry in an 80℃ constant temperature drying oven for 12h. Grind the obtained precipitate and calcine it in a muffle furnace at 400℃ for 2h to obtain pure SnO2.

[0021] b) Weigh 0.27g SnO2 and ultrasonically disperse it in 40ml ethanol. Add 10.1mL PdCl2 solution, stir at room temperature for 40min, and then dry in an oven at 70℃ for 12h.

[0022] c) The precipitate obtained in the previous step was placed in a muffle furnace and calcined at 400°C for 2 hours to obtain 0.75 wt.% Pd-modified SnO2.

[0023] The samples obtained through the above experimental process are attached. Figure 1 As shown, the sample particles are uniformly dispersed and small in size. EDS analysis indicates the presence of Pd in ​​the obtained product.

[0024] Example 2 illustrates a method for preparing a Pd-modified SnO2 hydrogen sensor sensitive material, and the prepared sample was tested for hydrogen gas sensing performance.

[0025] In this embodiment, the main steps are as follows:

[0026] a) Dissolve 0.5g of tin dichloride dihydrate and 0.7g of polyvinylpyrrolidone in a mixture of 20ml of ethanol and 20ml of DMF, stir for 24h, transfer the above solution to an autoclave and react at 150℃ for 12h. After the hydrothermal reaction is completed, wash several times with DMF and ethanol by centrifugation, and dry in an 80℃ constant temperature drying oven for 12h. Grind the obtained precipitate and calcine it in a muffle furnace at 400℃ for 2h to obtain pure SnO2.

[0027] b) Weigh 0.27g SnO2 and ultrasonically disperse it in 40ml ethanol. Add 13.5mL PdCl2 solution, stir at room temperature for 40min, and then dry in an oven at 70℃ for 12h.

[0028] c) The precipitate obtained in the previous step was placed in a muffle furnace and calcined at 400°C for 2 hours to obtain 1 wt.% Pd-modified SnO2.

[0029] The samples obtained from the above experimental process were subjected to hydrogen gas sensing performance testing, and the gas sensing performance was compared with that of pure SnO2 samples, as shown in the attached figure. Figure 2 As shown, after a small amount of Pd modification, not only was the sensitivity of SnO2 to hydrogen improved, but the operating temperature of the device was also reduced.

Claims

1. A method for preparing a Pd-modified SnO2 hydrogen sensor sensitive material, comprising the following steps: a) Stannous chloride dihydrate and polyvinylpyrrolidone were dissolved in a solvent to obtain a mixed solution. This solution was then transferred to a reaction vessel for hydrothermal reaction. The resulting precipitate was washed, dried, and calcined to obtain pure SnO2 powder. b) Disperse the SnO2 obtained in the previous step into ethanol by ultrasonication, add a quantitative amount of PdCl2 solution, mix well and then dry. c) The dried product was calcined in a muffle furnace to obtain Pd-modified SnO2 hydrogen sensor sensitive material.

2. The method for preparing the hydrogen sensor sensitive material according to claim 1, characterized in that, In step a), the mass ratio of stannous chloride dihydrate to polyvinylpyrrolidone is 3:7 to 1:1, and the dissolution is a mixed solution of ethanol and DMF, wherein the volume ratio of ethanol to DMF is 1:2 to 2:

1.

3. The method for preparing the hydrogen sensor sensitive material according to claim 1, characterized in that, The hydrothermal reaction temperature in step a) is 100℃~180℃, the reaction time is 10~18 hours, and the calcination temperature of the resulting precipitate is 300℃~500℃.

4. The method for preparing the hydrogen sensor sensitive material according to claim 1, characterized in that, The amount of PdCl2 added in step b) is 0.5 wt.% to 2.0 wt.% of Pd / Sn, and the drying temperature of the mixed solution is 60℃ to 90℃.

5. The method for preparing the hydrogen sensor sensitive material according to claim 1, characterized in that, The calcination temperature of the product described in step c) is 300℃~500℃.

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