A samarium ferrite-based gas sensitive material for detecting hydrogen sulfide in pyrolysis gas, a preparation method and application thereof

Abstract

The application discloses a kind of for pyrolysis gas hydrogen sulfide detection SmFeO3-based gas sensitive material and its preparation method and application, it is related to gas sensitive material technical field.The application uses Sm (NO3) 3·6H2O, Fe (NO3) 3·9H2O, PtCl4, PdCl2 as raw material, by hydrothermal method preparation for pyrolysis gas hydrogen sulfide detection SmFeO3-based gas sensitive material.The application uses Pt and Pd and so on noble metal to SmFeO3 material is doped.By the doping of two kinds of elements, not only can SmFeO3-based gas sensitive material in high humidity environment to pyrolysis gas H2S gas maintains high sensitivity, also reduce the working temperature of SmFeO3-based gas sensitive material, improve temperature stability.Specifically, the SmFeO3-based gas sensitive material for pyrolysis gas hydrogen sulfide detection prepared in the application, when relative humidity is less than 60%, response value change rate is less than 10%.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas sensitive materials, in particular to a SmFeO3-based gas sensitive material for detecting hydrogen sulfide in pyrolysis gas, a preparation method and application thereof. BACKGROUND

[0002] Pyrolysis gas refers to a mixture of gases produced by the thermal chemical decomposition of biomass, plastics, garbage and other organic matter under oxygen-free or oxygen-deficient conditions, which is widely used in the fields of energy conversion, chemical raw material preparation and waste treatment. As a kind of gas mixture, pyrolysis gas includes non-combustible gases (CO2, N2), combustible gases (H2, CO), volatile organic compounds and impurities, and the impurities include sulfur-containing compounds H2S.

[0003] H2S gas in pyrolysis gas is highly toxic and flammable, which may pose a great threat to the life safety of on-site operators during real-time detection, and H2S dissolved in water forms hydrogen sulfide acid, which can cause serious chemical corrosion to metal equipment such as pipelines, valves, gas storage tanks and burners, thereby increasing the risk of leakage and equipment maintenance costs. In addition, under the background of carbon peak and carbon neutral, monitoring H2S in pyrolysis gas can evaluate the situation of emission sources and provide a basis for optimizing measures such as biochar return to reduce emissions, thereby supporting the implementation of emission reduction policies and promoting low-carbon transformation, which further highlights the urgency of monitoring H2S in pyrolysis gas. However, the temperature of pyrolysis gas outlet is usually very high (300-800℃ or even higher), and direct discharge will result in huge energy waste, and it is extremely difficult to directly detect the gas content in high-temperature pyrolysis gas, accompanied by significant operational risks. Therefore, heat exchangers are usually used to recover heat from pyrolysis gas for preheating raw materials, generating steam or power generation, and the temperature of pyrolysis gas after heat recovery is generally about 120-130℃.

[0004] Gas sensitive sensors have great application potential in the field of pyrolysis gas H2S detection due to their high sensitivity, simple operation, low cost and portability. Among them, SmFeO3, as a p-type semiconductor perovskite material, has attracted much attention in the field of gas sensitive materials due to its stable structure. Although SmFeO3 has slightly larger Sm radius and better structural stability and carrier transport characteristics at higher working temperature intervals, its response strength to H2S and humidity resistance still need to be improved. 3+ Therefore, it is particularly necessary to optimize SmFeO3 material to obtain a gas sensitive material that is more suitable for the detection of H2S in pyrolysis gas, so as to realize efficient detection of H2S gas in pyrolysis gas.

[0005] Therefore, it is particularly necessary to optimize SmFeO3 material to obtain a gas sensitive material that is more suitable for the detection of H2S in pyrolysis gas, so as to realize efficient detection of H2S gas in pyrolysis gas. SUMMARY

[0006] In view of the prior art, the purpose of the present application is to provide a SmFeO3-based gas sensitive material for detecting hydrogen sulfide in pyrolysis gas, and a preparation method and application thereof. The SmFeO3-based gas sensitive material for detecting hydrogen sulfide in pyrolysis gas is prepared by a hydrothermal method using Sm(NO3)3·6H2O, Fe(NO3)3·9H2O, PtCl4 and PdCl2 as raw materials. The SmFeO3 material is doped with noble metals such as Pt and Pd. Through the doping of the two elements, not only the working temperature of the SmFeO3-based gas sensitive material is reduced, and the temperature stability is improved, but also the humidity resistance is significantly enhanced.

[0007] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0008] In the first aspect of the present application, a preparation method of a SmFeO3-based gas sensitive material is provided, comprising the following steps:

[0009] (1) Sm(NO3)3·6H2O and Fe(NO3)3·9H2O are mixed with citric acid and then added to water, and NaOH solution is added for reaction; after the reaction is completed, filtration, washing and drying are performed to obtain a SmFeO3 precursor;

[0010] (2) The SmFeO3 precursor is dispersed in water to obtain a SmFeO3 solution; PtCl4 and PdCl2 are added to the SmFeO3 solution for reaction, and the solid after reaction is collected, washed, dried and calcined to obtain the SmFeO3-based gas sensitive material for detecting hydrogen sulfide in pyrolysis gas;

[0011] In the first aspect of the present application, a preparation method of a SmFeO3-based gas sensitive material is provided, comprising the following steps:

[0012] Preferably, in step (1), the adding amount ratio of Sm(NO3)3·6H2O, water and NaOH solution is (0.01-0.05) mol: 100 mL: (50-70) mL.

[0013] Preferably, in step (1), the concentration of the NaOH solution is 1-2 mol / L, and the reaction time is 1-2 h.

[0014] Preferably, in step (1), the washing operation is that the solid is washed with deionized water and ethanol for 3-5 times in sequence.

[0015] Preferably, in step (1), the drying method is vacuum drying, the drying temperature is 70-90°C, and the drying time is 6-12 h.

[0016] Preferably, in step (2), the ratio of the SmFeO3 precursor to water is 1 g to (25-35) mL.

[0017] Preferably, in step (2), the reaction temperature is 60-80°C and the reaction time is 2-4 h.

[0018] Preferably, in step (2), the drying method is vacuum drying, the drying temperature is 70-90°C, and the drying time is 6-12 h.

[0019] Preferably, in step (2), the calcination temperature is 400-600°C, the calcination time is 2.5-3.5 h, and the calcination atmosphere is air.

[0020] In a second aspect, the present application provides a SmFeO3-based gas sensitive material prepared by the above method.

[0021] Preferably, the SmFeO3-based gas sensitive material for detecting hydrogen sulfide in pyrolysis gas has the chemical formula Xwt%Pt-Ywt%Pd-SmFeO3, wherein X and Y are the doping amounts of Pt and Pd in the SmFeO3-based gas sensitive material, and 0X≤5 and 0Y≤5.

[0022] In a third aspect, the present application provides the use of the above SmFeO3-based gas sensitive material in detecting H2S gas in pyrolysis gas.

[0023] Preferably, the specific operation of detecting H2S gas in pyrolysis gas using the SmFeO3-based gas sensitive material is as follows:

[0024] The SmFeO3-based gas sensitive material, deionized water, and terpineol are mixed in a ratio of (1-3) g to (5-10) mL to (1-3) mL to obtain a slurry; the slurry is spin-coated on an alumina ceramic substrate to form a gas sensitive film with a thickness of 50-200 μm; the gas sensitive film is aged at 180-200°C for 12-24 h to obtain a hydrogen sulfide gas sensor; and the hydrogen sulfide gas sensor is used to detect H2S gas in pyrolysis gas in real time.

[0025] Preferably, when the hydrogen sulfide gas sensitive material detects H2S gas in pyrolysis gas, the working temperature is 110-130°C and the working humidity is 20-60%.

[0026] The present application has the following advantages:

[0027] 1.The SmFeO3-based gas sensing material for detecting hydrogen sulfide in pyrolysis gas is prepared by a hydrothermal method using Sm(NO3)3·6H2O, Fe(NO3)3·9H2O, PtCl4 and PdCl2 as raw materials. The SmFeO3 material is doped with noble metals such as Pt and Pd. The doping of the two elements not only improves the humidity resistance of the SmFeO3-based gas sensing material, but also realizes high sensitivity of the SmFeO3-based gas sensing material to H2S gas in pyrolysis gas in a high humidity environment, and reduces the working temperature of the SmFeO3-based gas sensing material and improves the temperature stability.

[0028] Specifically, the SmFeO3-based gas sensing material for detecting hydrogen sulfide in pyrolysis gas prepared by the present application has a response change rate of <10% in the temperature range of 110-130℃; when the relative humidity is <60%, the response value change rate is <10%. In addition, long-term use (response value change <5% within one month) shows excellent stability, and is suitable for environmental monitoring and industrial emission detection.

[0029] 2.The Pt and Pd complex doping has a synergistic effect on improving the temperature stability of the SmFeO3-based gas sensing material for detecting hydrogen sulfide in pyrolysis gas. Specifically, the SmFeO3 modified by the double noble metals Pt and Pd prepared by the present application has a response value of 57.43 to 1ppm H2S gas at a working temperature of 120℃. The H2S gas sensor prepared by the present application has low working temperature, low energy consumption, and is easy to integrate into portable devices, and has a broad application prospect.

[0030] From the principle analysis: the present application realizes the synergy of "electronic sensitization + chemical sensitization" by constructing a Pt / Pd nano heterojunction interface on the surface of p-type SmFeO3. The high work function and d-orbital characteristics of Pt make it easy to adsorb and dissociate O2, form high-coverage activated oxygen, and establish a stable Schottky barrier at the interface, significantly amplify the energy band bending and surface potential change under the disturbance of reducing gas; Pd has a lower S-H bond breaking barrier for sulfur-containing molecules, and preferentially undergoes transient sulfuration / oxidation process, forming a chemical reaction-gated work function and barrier dynamic modulation. The maximum interface perimeter density and "chemical→electronic" cascade amplification effect can be obtained near the 2wt%Pt-3wt%Pd load. Further, the noble metal-induced electronic local redistribution reduces the SmFeO3 surface / near-surface oxygen vacancy formation energy, making lattice oxygen participate in H2S oxidation (Mars-van Krevelen path), and Fe 3+ / Fe 4+Reversible valence coordination ensures high response, strong selectivity and good reversibility in high humidity complex working conditions. In a high humidity environment, water molecules are easy to occupy oxygen vacancy / hydroxyl sites and compete with surface oxygen. Pt / Pd-SmFeO3 heterojunction interface realizes humidity resistance: Pt improves the coverage of activated oxygen and continuously "overflow" oxygen, making it difficult for water to exhaust O3d2; Pd has higher adsorption energy and affinity with H2S than H2O, which preferentially triggers S-H rupture and subsequent oxidation, and water is more likely to be weakly adsorbed / molecularly short-stayed, which is difficult to "poison" active sites; In the working temperature zone above 100°C, the surface water desorbs quickly, leaving only sparse hydroxyl groups, which can act as proton shuttles to reduce S-H rupture and SO x The generated apparent energy barrier; the interface work function / barrier induced by noble metal is not sensitive to the dipole disturbance of water, but highly sensitive to sulfur-containing reducing species, which shows that ΔΦ_H2S>>ΔΦ_H2O, resulting in clear band bending changes and distinguishable resistance response under high humidity; The oxygen vacancy-lattice oxygen (Mars-van Krevelen) cycle of SmFeO3 can still be carried out in the presence of water, and the water generated by the reaction is quickly desorbed, and the interface is quickly regenerated, ensuring long-term stable operation.

[0031] 3. The SmFeO3-based gas sensitive material for detecting hydrogen sulfide in pyrolysis gas prepared by the hydrothermal method has a nanoparticle structure with a particle size of 60-180 nm, a large specific surface area, and can provide more adsorption and reaction sites for H2S molecules, further improving the sensitivity and response speed. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 : XRD pattern of the SmFeO3-based gas sensitive material for detecting hydrogen sulfide in pyrolysis gas prepared in Example 1;

[0033] Figure 2 : SEM images of the SmFeO3-based gas sensitive material for detecting hydrogen sulfide in pyrolysis gas prepared in Example 1 at different scales, wherein (a) is the SEM image at a scale of 5 μm, (b) is the SEM image at a scale of 2 μm, (c) is the SEM image at a scale of 1 μm, and (d) is the SEM image at a scale of 500 nm;

[0034] Figure 3 : EDS Mapping images of Pt element, Pd element, Sm element and Fe element in the SmFeO3-based gas sensitive material for detecting hydrogen sulfide in pyrolysis gas prepared in Example 1;

[0035] Figure 4 : Relationship between gas sensitive performance and temperature of the SmFeO3-based gas sensitive material for detecting hydrogen sulfide in pyrolysis gas prepared in Example 1 and Comparative Examples 1-3 to 1 ppm H2S gas;

[0036] Figure 5 : The relationship between humidity and the gas sensing performance of the SmFe03-based gas sensing material for detecting hydrogen sulfide in pyrolysis gas prepared in Example 1 and Comparative Examples 1-3 to 1 ppm H2S gas;

[0037] Figure 6 : The long-term gas sensing stability of the SmFe03-based gas sensing material for detecting hydrogen sulfide in pyrolysis gas prepared in Example 1 to 1 ppm H2S gas. DETAILED DESCRIPTION

[0038] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0039] In order to enable a person skilled in the art to more clearly understand the technical solutions of the present application, the technical solutions of the present application will be described in detail below in conjunction with specific examples.

[0040] The experimental materials used in the embodiments of the present application are all conventional experimental materials in the art and can be purchased through commercial channels.

[0041] Example 1:

[0042] (1) 4.589 g of Sm(N03)3-6H20, 4.040 g of Fe(N03)3-9H20 and 10 g of citric acid were mixed and then added to 100 mL of deionized water. After adding 60 mL of 1 mol / L NaOH solution, the mixture was reacted for 1.5 h. After the reaction was completed, the precipitate was collected by filtration, washed with deionized water and ethanol for 3 times respectively, and then vacuum dried at 80°C for 8 h to obtain a SmFe03 precursor;

[0043] (2) The SmFe03 precursor prepared in step (1) was dispersed in 50 mL of deionized water to obtain a SmFe03 solution. After adding 0.093 g of PtCl4 and 0.134 g of PdCl2 to the SmFe03 solution, in-situ deposition reaction was carried out at 70°C for 3 h. The solid after reaction was collected, washed, vacuum dried at 80°C for 8 h, and then calcined at 500°C for 3 h to obtain a SmFe03-based gas sensing material 2 wt% Pt-3 wt% Pd-SmFe03 for detecting hydrogen sulfide in pyrolysis gas, which is denoted as Pt-Pd-SFO.

[0044] Example 2:

[0045] (1) 4.589 g Sm(N03)3-6H20, 4.040 g Fe(N03)3-9H20 and 15 g citric acid were mixed, then added into 100 mL deionized water, 55 mL of 1 mol / L NaOH solution was added, and the reaction was carried out for 2 h. After the reaction was completed, the precipitate was collected by filtration, washed with deionized water and ethanol for 4 times respectively, and then vacuum dried at 70°C for 12 h to obtain a SmFe03 precursor;

[0046] (2) The SmFe03 precursor prepared in step (1) was dispersed in 50 mL deionized water to obtain a SmFe03 solution. After 0.046 g PtCl4 and 0.134 g PdCl2 were added into the SmFe03 solution, in-situ deposition reaction was carried out at 80°C for 2 h. The solid after reaction was collected, washed, vacuum dried at 70°C for 12 h, and then calcined at 600°C for 2.5 h to obtain a SmFe03-based gas sensitive material 1 wt% Pt-3 wt% Pd-SmFe03 for detecting hydrogen sulfide in pyrolysis gas.

[0047] Example 3:

[0048] (1) 4.589 g Sm(N03)3-6H20, 4.040 g Fe(N03)3-9H20 and 15 g citric acid were mixed, then added into 100 mL deionized water, 55 mL of 1 mol / L NaOH solution was added, and the reaction was carried out for 2 h. After the reaction was completed, the precipitate was collected by filtration, washed with deionized water and ethanol for 4 times respectively, and then vacuum dried at 70°C for 12 h to obtain a SmFe03 precursor;

[0049] (2) The SmFe03 precursor prepared in step (1) was dispersed in 50 mL deionized water to obtain a SmFe03 solution. After 0.046 g PtCl4 and 0.134 g PdCl2 were added into the SmFe03 solution, in-situ deposition reaction was carried out at 80°C for 2 h. The solid after reaction was collected, washed, vacuum dried at 70°C for 12 h, and then calcined at 600°C for 2.5 h to obtain a SmFe03-based gas sensitive material 1 wt% Pt-3 wt% Pd-SmFe03 for detecting hydrogen sulfide in pyrolysis gas.

[0050] Comparative Example 1:

[0051] The difference between this comparative example and Example 1 is that Pt and Pd are not used to dope the SmFe03 material. The specific preparation method is as follows:

[0052] SmFe03 precursor was prepared by mixing 4.589 g of Sm(N03)3-6H20, 4.040 g of Fe(N03)3-9H20 and 10 g of citric acid, adding them into 100 mL of deionized water, adding 60 mL of 1 mol / L NaOH solution, and then reacting for 1.5 h. After the reaction was completed, the precipitate was collected by filtration, washed with deionized water and ethanol for 3 times respectively, and then dried at 80°C for 8 h under vacuum to obtain the SmFe03 precursor.

[0053] Comparative Example 2

[0054] The difference between the present comparative example and Example 1 is that only Pt is used to dope the SmFe03 material. The specific preparation method is as follows:

[0055] (1) SmFe03 precursor was prepared by mixing 4.589 g of Sm(N03)3-6H20, 4.040 g of Fe(N03)3-9H20 and 10 g of citric acid, adding them into 100 mL of deionized water, adding 60 mL of 1 mol / L NaOH solution, and then reacting for 1.5 h. After the reaction was completed, the precipitate was collected by filtration, washed with deionized water and ethanol for 3 times respectively, and then dried at 80°C for 8 h under vacuum to obtain the SmFe03 precursor.

[0056] (2) The SmFe03 precursor prepared in step (1) was dispersed in 50 mL of deionized water to obtain a SmFe03 solution. Then, 0.093 g of PtCl4 was added to the SmFe03 solution, and in-situ deposition reaction was carried out at 70°C for 3 h. The solid after the reaction was collected, washed, dried at 80°C for 8 h under vacuum, and then calcined at 500°C for 3 h to obtain a SmFe03-based gas sensing material 2 wt% Pt-SmFe03 for detecting hydrogen sulfide in pyrolysis gas, which is denoted as Pt-SFO.

[0057] Comparative Example 3

[0058] The difference between the present comparative example and Example 1 is that only Pd is used to dope the SmFe03 material. The specific preparation method is as follows:

[0059] (1) SmFe03 precursor was prepared by mixing 4.589 g of Sm(N03)3-6H20, 4.040 g of Fe(N03)3-9H20 and 10 g of citric acid, adding them into 100 mL of deionized water, adding 60 mL of 1 mol / L NaOH solution, and then reacting for 1.5 h. After the reaction was completed, the precipitate was collected by filtration, washed with deionized water and ethanol for 3 times respectively, and then dried at 80°C for 8 h under vacuum to obtain the SmFe03 precursor.

[0060] (2) The SmFeO3 precursor prepared in step (1) was dispersed in 50 mL of deionized water to obtain a SmFeO3 solution; 0.134 g of PdCl2 was added to the SmFeO3 solution, and in-situ deposition reaction was carried out at 70°C for 3 h; the solid after the reaction was collected, washed, vacuum dried at 80°C for 8 h, and then calcined at 500°C for 3 h to obtain a SmFeO3-based gas-sensitive material 3 wt% Pd-SmFeO3 for detecting hydrogen sulfide in pyrolysis gas, which is denoted as Pd-SFO.

[0061] Test Example 1

[0062] The SmFeO3-based gas-sensitive material for detecting hydrogen sulfide in pyrolysis gas prepared in Example 1 was subjected to structural characterization, and the results are shown in Figures 1-3

[0063] Figure 1 The XRD pattern of the SmFeO3-based gas-sensitive material for detecting hydrogen sulfide in pyrolysis gas can be seen from Figure 1 The crystalline peaks correspond to (121), (200) and (002) crystal phases of SmFeO3 (No. 39-1490), indicating that the material has a pure perovskite structure. As can be seen from Figure 2 The SmFeO3-based gas-sensitive material for detecting hydrogen sulfide in pyrolysis gas prepared has a typical nanoparticle structure, with a particle size of about 60-180 nm, a large specific surface area and porosity, providing abundant reaction sites and transport channels for gas molecules. Figure 3 The EDS Mapping patterns of Pt, Pd, Sm and Fe elements can be seen from Figure 3 It can be seen that each element is uniformly distributed, proving that the surface of the Pt and Pd modified SmFeO3.

[0064] Test Example 2

[0065] The SmFeO3-based gas-sensitive materials for detecting hydrogen sulfide in pyrolysis gas prepared in Example 1 and Comparative Examples 1-3 were coated on a gas-sensitive film, and the gas-sensitive response (Rg / Ra) of the materials to H2S gas was detected, and the results are shown in Figures 4-6 . Among them, Ra is the resistance of the sensor in air, and Rg is the resistance in the measured gas. The experimental environment is: relative humidity (RH) 20%, ambient temperature 20°C.

[0066] Figure 4 ​The response value of the SmFeO3-based gas sensitive material for detecting hydrogen sulfide in pyrolysis gas prepared in Example 1 and Comparative Examples 1-3 to 1 ppm H2S changes with temperature is presented. The results show that the response value of the SmFeO3-based gas sensitive material 2 wt% Pt-3 wt% Pd-SmFeO3 for detecting hydrogen sulfide in pyrolysis gas prepared in Example 1 reaches a maximum value of 57.43 at 120°C, and the working temperature is significantly lower than the optimal working temperature of unmodified SmFeO3 and single noble metal modified materials. This reflects the synergistic effect of Pt and Pd, effectively promotes surface electron transfer by reducing the H2S adsorption reaction energy barrier, significantly reduces the working temperature, and highlights the significant advantages of double noble metal doping in energy saving and low temperature detection. In addition, in terms of H2S response sensitivity, at a working temperature of 120°C, the response value of the SmFeO3-based gas sensitive material for detecting hydrogen sulfide in pyrolysis gas prepared in the application is 57.43, the response value of the SmFeO3 gas sensitive material prepared in Comparative Example 1 is 5.63, the response value of the 2 wt% Pt-SmFeO3 gas sensitive material prepared in Comparative Example 2 is 31.33, and the response value of the 3 wt% Pd-SmFeO3 gas sensitive material prepared in Comparative Example 3 is 26.61. Therefore, the double noble metal doping of Pt and Pd elements on SmFeO3 has a synergistic effect in improving the response value of the gas sensitive material to H2S.

[0067] Figure 5 The gas sensitive properties of the gas sensitive materials of Comparative Examples 1-3 and Example 1 to 1 ppm H2S gas under different humidity are shown. Figure 5 It can be seen that as the relative humidity increases, the gas sensitive properties decrease slightly, but when the relative humidity is <60%, the response value change rate is <10%, indicating that the material has good humidity resistance.

[0068] Figure 6 The long-term stability of the SmFeO3-based gas sensitive material 2 wt% Pt-3 wt% Pd-SmFeO3 for detecting hydrogen sulfide in pyrolysis gas prepared in Example 1 to 1 ppm H2S gas is shown. Figure 6 It can be seen that within one month, the response value change rate is <5%, indicating that the material has very high gas sensitive stability.

[0069] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Those skilled in the art can make various changes and modifications to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. Use of a samarium ferrite-based gas sensitive material in detecting H2S gas in pyrolysis gas, characterized in that, a preparation method of the samarium ferrite-based gas sensitive material is as follows: (1) Sm(NO3)3·6H2O, Fe(NO3)3·9H2O and citric acid are mixed and then added into water, and NaOH solution is added for reaction; after the reaction is completed, filtration, washing and drying are performed to obtain a SmFeO3 precursor; (2) the SmFeO3 precursor is dispersed in water to obtain a SmFeO3 solution; PtCl4 and PdCl2 are added into the SmFeO3 solution for reaction, and the solid after the reaction is collected, washed, dried and calcined to obtain the samarium ferrite-based gas sensitive material for detecting H2S gas in pyrolysis gas; wherein the adding amounts of Sm(NO3)3·6H2O, Fe(NO3)3·9H2O, PtCl4, PdCl2 and citric acid are (0.01-0.05) mol:(0.01-0.05) mol:(0.01-0.5) g:(0.01-0.5) g:(5-20) g, respectively; the chemical formula of the prepared samarium ferrite-based gas sensitive material is Xwt% Pt-Ywt% Pd-SmFeO3, wherein X and Y are the doping amounts of Pt and Pd in the samarium ferrite-based gas sensitive material, and 0X≤5, 0Y≤5; when the hydrogen sulfide gas sensitive material detects H2S gas in pyrolysis gas, the working temperature is 110-130℃ and the working humidity is 20-60%.

2. Use according to claim 1, wherein In step (1), the concentration of the NaOH solution is 1-2 mol / L, and the reaction time is 1-2 h; the drying method is vacuum drying, the drying temperature is 70-90℃, and the drying time is 6-12 h.

3. The use according to claim 1, wherein In step (2), the reaction temperature is 60-80℃, and the reaction time is 2-4 h.

4. The use according to claim 1, wherein In step (2), the calcination temperature is 400-600℃, the calcination time is 2.5-3.5 h, and the calcination atmosphere is air.

5. The use according to claim 1, wherein The specific operation of detecting H2S gas in pyrolysis gas is as follows: samarium ferrite-based gas sensitive material, deionized water and terpineol are mixed uniformly at a material-liquid ratio of (1-3) g:(5-10) mL:(1-3) mL to obtain a slurry; the slurry is spin-coated on an alumina ceramic substrate to form a gas sensitive film with a thickness of 50-200 μm; the gas sensitive film is aged at 180-200℃ for 12-24 h to obtain a hydrogen sulfide gas sensor; and then the hydrogen sulfide gas sensor is used to detect H2S gas in pyrolysis gas.

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