Hydrogen sensitive material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of detection, in particular to a hydrogen-sensitive material as well as a preparation method and application thereof. The preparation method of the hydrogen-sensitive material comprises the following steps: S1, mixing cerium salt, gadolinium salt and water to obtain a metal salt solution; s2, adding the metal salt solution into a complexing reagent to obtain a mixed solution; s3, heating the mixed solution until excessive water is evaporated to obtain a colloidal precursor; s4, drying the colloidal precursor to obtain a loose porous solid; then grinding the loose porous solid into powder, and then carrying out first calcination treatment to obtain a Gd1-xCexO2 material; wherein x ranges from 0.8 to 0.9. According to the invention, a certain proportion of Gd metal cations are introduced into a CeO2 metal oxide lattice through a sol-gel method, and the prepared Gd1-xCexO2 material has the advantages of wide range, stability and quick response.

Description

Technical Field

[0001] The present invention relates to the field of detection technology, and in particular to a hydrogen-sensitive material and a preparation method and application thereof. Background Art

[0002] As a renewable energy carrier with abundant sources, high energy density, and various forms of storage and utilization, hydrogen has become the focus of energy development. For a new energy system to be promoted and applied, its safety is the first concern. Hydrogen is volatile, flammable, explosive, and brittle, which makes hydrogen have certain safety hazards during use. How to foresee the occurrence of hydrogen leakage and possible dangers is a very challenging problem. Hydrogen sensors are one of the important means to locate hydrogen leaks, with the characteristics of fast response speed and high sensitivity. However, hydrogen sensors currently have prominent problems such as narrow monitoring range and poor selectivity for CO, hydrocarbons, etc. There is still huge room for improvement in practical applications.

[0003] Cerium dioxide (CeO2) has attracted attention in the field of gas sensors due to its strong oxygen absorption / release ability and high carrier mobility. However, single-component CeO2 materials have shortcomings such as low sensitivity and poor selectivity in gas sensing applications, which affect their application.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The present invention provides a hydrogen-sensitive material and a preparation method and application thereof, so as to solve the above-mentioned defects in the prior art and improve the hydrogen-sensitive performance of the sensitive material.

[0006] In a first aspect, the present invention first provides a method for preparing a hydrogen-sensitive material, comprising: S1: mixing cerium salt, gadolinium salt and water to obtain a metal salt solution; S2: adding the metal salt solution to a complexing agent to obtain a mixed solution; S3: heating the mixed solution until excess water is evaporated to obtain a colloidal precursor; S4: drying the colloidal precursor to obtain a loose porous solid; then grinding the loose porous solid into powder, and then performing a first calcination treatment to obtain Gd 1-x Ce x O2 materials; The range of x is 0.8~0.9.

[0007] The present invention introduces a certain proportion of Gd metal cations into the CeO2 metal oxide lattice by a sol-gel method to prepare the Gd 1-x Ce x O2 materials have the advantages of wide range, stability and rapid response.

[0008] Preferably, the cerium salt includes Ce(NO3)3·6H2O and / or Ce(NO3)3; and / or, the gadolinium salt includes Gd(NO3)3·6H2O, Gd(NO3)3.

[0009] More preferably, the cerium salt comprises Ce(NO3)3·6H2O; and / or, the gadolinium salt comprises Gd(NO3)3·6H2O.

[0010] Preferably, the molar ratio of the total molar amount of gadolinium and cerium atoms to the molar amount of gadolinium atoms is (5-10):1.

[0011] Preferably, in the metal salt solution, the concentration of the cerium salt is 0.16M-0.18M; and / or the concentration of the gadolinium salt is 0.02M-0.04M.

[0012] Preferably, the complexing agent comprises citric acid and / or polyvinyl pyrrolidone.

[0013] More preferably, the complexing agent comprises citric acid.

[0014] Preferably, the method for preparing the hydrogen sensitive material further comprises S5: loading Pd onto the Gd 1-x Ce x In the O2 material, the impregnated sample was dried at room temperature and then subjected to a second calcination treatment to obtain Pd-Gd 1- x Ce x O2 hydrogen sensitive material.

[0015] More preferably, S5 includes: taking M1g sensitive material Gd 1-x Ce x Soak O2 in deionized water and drain it. Record the mass of the sensitive material at this moment as M2g. The water absorption rate of the sensitive material is W = (M2-M1) / M1×100%. Weigh the sensitive material Gd that needs to be loaded with Pd. 1-x Ce x O2 mass M3, calculate the mass of Pd salt required, add it to deionized water to prepare a salt solution with a mass of (M3·W), and mix the prepared salt solution with the sensitive material Gd 1-x Ce x O2 was fully mixed, allowed to stand for a period of time and then dried at room temperature, and then a second calcination treatment was performed to obtain Pd-Gd 1-x Ce x O2 hydrogen sensitive material.

[0016] The present invention adopts the equal volume impregnation method to load Pd on Gd 1-x Cex The surface of O2 materials can greatly improve the response sensitivity of sensitive materials to hydrogen.

[0017] More preferably, the Pd-Gd 1-x Ce x In O2 hydrogen-sensitive materials, the Pd loading is 0.5~1.5wt%.

[0018] Preferably, the calcination temperature of the first calcination treatment is 500-700°C.

[0019] And / or, the calcination temperature of the second calcination treatment is 400-500°C.

[0020] In a second aspect, the present invention provides a hydrogen-sensitive material, which is prepared by the method for preparing the hydrogen-sensitive material.

[0021] In a third aspect, the present invention provides an application of the hydrogen-sensitive material in preparing a hydrogen-sensitive element; preferably, the hydrogen-sensitive element is a hydrogen sensor.

[0022] Preferably, the method for preparing the hydrogen sensitive element comprises: S1': The Pd-Gd 1-x Ce x The O2 hydrogen-sensitive material is ground, and ethanol is added to prepare a slurry-like hydrogen-sensitive material; S2': drying and consolidating the ceramic substrate coated with the slurry-like hydrogen-sensitive material on the outer surface, and then welding the obtained ceramic substrate coated with the slurry-like hydrogen-sensitive material onto the tube seat to package the welded sensor.

[0023] In a fourth aspect, the present invention provides a hydrogen sensitive element, which contains the hydrogen sensitive material.

[0024] In a fifth aspect, the present invention provides a method for hydrogen sensitivity testing, which tests the response sensitivity of hydrogen sensitive elements to hydrogen, carbon monoxide, methane and other gases under the condition of a test temperature of 200°C to 500°C, comprehensively considering the response ability and anti-interference performance of the hydrogen sensitive element to hydrogen, and preferably selecting the optimal temperature as the operating temperature of the hydrogen sensitive element.

[0025] The hydrogen sensitive material provided by the present invention and its preparation method and application are prepared by introducing a certain proportion of Gd metal cations into the CeO2 metal oxide lattice through a sol-gel method. 1-x Ce x O2 material, and Pd was loaded on Gd by equal volume impregnation method. 1-x Ce x O2 material surface, Pd-Gd with wide range, stability and fast response advantages 1-x Ce xO2 material hydrogen-sensitive material; and coated it on the micro heat pipe, and designed a voltage-adjustable circuit to adjust the temperature of the micro heat pipe, thereby improving the selectivity of the hydrogen sensor. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Unless otherwise specified, all raw materials used in the examples are commercially available conventional raw materials, and the technical means used are conventional means well known to those skilled in the art.

[0028] In the following examples, the equal volume impregnation method used includes: taking 0.50g of sensitive material Gd 0.2 Ce 0.8 Soak O2 in deionized water, drain it, wipe off the free water on the surface, and record the mass of the sensitive material at this moment as 0.15g. The water absorption rate of the sensitive material is W=30%.

[0029] Weighing sensitive material Gd that needs to be loaded with Pd 0.2 Ce 0.8 O2 mass 10g, weigh 0.1g Pd salt, add deionized water to prepare a salt solution with a mass of 3g, and mix the prepared salt solution with the sensitive material Gd 0.2 Ce 0.8 O2 is fully mixed and allowed to stand for the next step.

[0030] Example 1

[0031] This embodiment provides a Pd-Gd 0.2 Ce 0.8 O2 hydrogen sensitive material, the preparation method thereof comprises the following steps: 1. Dissolve 15.875g Ce(NO3)3·6H2O and 4.125g Gd(NO3)3·6H2O in 457ml deionized water to obtain a metal salt solution; the concentration of Ce(NO3)3·6H2O in the metal salt solution is 0.16M; the concentration of Gd(NO3)3·6H2O is 0.04M.

[0032] 2. Add 13.16 g of citric acid (C6H8O7) to the metal salt solution under vigorous stirring.

[0033] 3. The solution was heated in a water bath at 75°C with vigorous stirring until excess water was evaporated to obtain a clear and transparent colloidal precursor.

[0034] 4. The colloidal precursor was transferred to an oven and dried at 120 °C for 12 h. The colloidal precursor expanded into a loose porous solid under the heat. The solid was gently ground into powder and calcined in a muffle furnace at 600 °C for 2 h to obtain Gd 0.2 Ce 0.8 O2 material.

[0035] 5. Use equal volume impregnation method to load the above Gd 0.2 Ce 0.8 In the O2 material, the salt used was Pd(NO3)2 with a loading of 1.0%wt.

[0036] 6. The impregnated sample was dried at room temperature for 12 h, and then kept at 500 °C in an atmosphere furnace for 5 h to obtain Pd-Gd 0.2 Ce 0.8 O2 hydrogen sensitive material.

[0037] This embodiment further provides a hydrogen gas sensing element, the preparation method of which includes the following steps: 1. The Pd-Gd 0.2 Ce 0.8 The O2 hydrogen-sensitive material is fully ground and ethanol is added at a ratio of 1:5 to prepare a slurry.

[0038] 2. The slurry hydrogen-sensitive material is evenly coated on the outer surface of the micro heat pipe, and then the ceramic substrate coated with the sensitive material is placed in an atmosphere furnace for drying and consolidation. The atmosphere furnace is heated to 400°C at a heating rate of 40°C / h, and calcined at 400°C for 3h, and then naturally cooled to room temperature.

[0039] 3. Weld the ceramic substrate onto the tube socket, package the welded sensor, and age the sensor for 7 days.

[0040] Example 2

[0041] This embodiment provides a Pd-Gd 1-x Ce x The preparation method of the O2 hydrogen-sensitive material is different from that of Example 1 only in that Ce(NO3)3·6H2O is replaced by an equal amount of Ce(NO3)3; and Gd(NO3)3·6H2O is replaced by an equal amount of Gd(NO3)3.

[0042] This embodiment further provides a hydrogen sensing element, and its preparation method is the same as that of embodiment 1.

[0043] Example 3

[0044] This embodiment provides a Pd-Gd 1-x Ce x The preparation method of the O2 hydrogen-sensitive material is different from that of Example 1 only in that citric acid is replaced by polyvinyl pyrrolidone.

[0045] This embodiment further provides a hydrogen sensing element, and its preparation method is the same as that of embodiment 1.

[0046] Example 4

[0047] This embodiment provides a Pd-Gd 1-x Ce x The preparation method of the O2 hydrogen-sensitive material is different from that of Example 1 only in that steps 5 to 6 are not included.

[0048] This embodiment further provides a hydrogen sensing element, and its preparation method is the same as that of embodiment 1.

[0049] Comparative Example 1

[0050] This embodiment provides a Pd-Gd 1-x Ce x The preparation method of the O2 hydrogen-sensitive material is different from that of Example 1 only in that Gd(NO3)3·6H2O is replaced by an equal amount of ZrO (NO3)2·2H2O.

[0051] This comparative example further provides a hydrogen gas sensing element, and its preparation method is the same as that of Example 1.

[0052] Test example

[0053] The present invention further tests the hydrogen-sensitive properties of the hydrogen-sensitive materials and hydrogen-sensitive elements prepared in the above-mentioned embodiments and comparative examples. The detection method is a dynamic test method, and the equipment in patent application CN215768465 U is used for detection.

[0054] The test results show that the hydrogen sensitive element in Example 1 responds to hydrogen at an operating temperature of 200-500°C. When the operating temperature is 300°C, the sensitivity to 0.5% hydrogen is the highest, which is 2.159; when the operating temperature is 350°C, the sensitivity to 0.5% hydrogen is 1.926. Under this condition, the response to the interfering gas is the smallest, and the anti-interference performance is the strongest. The test results of the hydrogen sensitive element in Examples 2-3 are equivalent to those in Example 1.

[0055] In Example 4, the hydrogen sensitive element responds to hydrogen at an operating temperature of 300°C to 450°C, and within this range, the sensitivity to 0.5% hydrogen gradually decreases with increasing temperature. When the operating temperature is 300°C, the sensitivity to 0.5% hydrogen is the highest, which is 1.20. In Comparative Example 1, the operating temperature of the hydrogen sensitive element is significantly increased, and the optimal operating temperature range is ≥500° C., which exceeds the bearing capacity of the ceramic substrate.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a hydrogen-sensitive material, characterized in that: include: S1: mixing cerium salt, gadolinium salt and water to obtain a metal salt solution; S2: adding the metal salt solution to a complexing agent to obtain a mixed solution; S3: heating the mixed solution until excess water is evaporated to obtain a colloidal precursor; S4: drying the colloidal precursor to obtain a loose porous solid; then grinding the loose porous solid into powder, and then performing a first calcination treatment to obtain Gd 1-x Ce x O2 materials; The range of x is 0.8~0.

9.

2. The method for preparing a hydrogen-sensitive material according to claim 1, wherein: The cerium salt includes Ce(NO3)3·6H2O, Ce(NO3)3; and / or the gadolinium salt includes Gd(NO3)3·6H2O, Gd(NO3)3.

3. The method for preparing the hydrogen-sensitive material according to claim 1 or 2, wherein: The ratio of the total molar amount of gadolinium and cerium atoms to the molar amount of gadolinium atoms is (5~10):

1.

4. The method for preparing the hydrogen-sensitive material according to any one of claims 1 to 3, wherein: In the metal salt solution, the concentration of cerium ions is 0.16M-0.18M; and / or the concentration of gadolinium ions is 0.02M-0.04M.

5. The method for preparing the hydrogen-sensitive material according to any one of claims 1 to 4, wherein: The complexing agent includes citric acid and / or polyvinyl pyrrolidone.

6. The method for preparing the hydrogen-sensitive material according to any one of claims 1 to 4, wherein: Also included is S5: using an equal volume impregnation method to load Pd onto the Gd 1-x Ce x In the O2 material, the sample after impregnation was dried at room temperature and then subjected to a second calcination treatment to obtain Pd-Gd 1-x Ce x O2 hydrogen sensitive material; preferably, the Pd-Gd 1-x Ce x In O2 hydrogen-sensitive materials, the Pd loading amount is 0.5~1.5wt%.

7. The method for preparing the hydrogen-sensitive material according to claim 6, wherein: The calcination temperature of the first calcination treatment is 500-700°C; And / or, the calcination temperature of the second calcination treatment is 400-500°C.

8. A hydrogen-sensitive material, characterized in that The hydrogen-sensitive material is prepared by the method for preparing the hydrogen-sensitive material according to claims 1 to 6.

9. Use of the hydrogen-sensitive material according to claim 8 in preparing a hydrogen-sensitive element; preferably, the hydrogen-sensitive element is a hydrogen sensor.

10. A hydrogen sensitive element, characterized in that: It contains the hydrogen-sensitive material according to claim 8.