Preparation and application method of a UV-assisted sensitized MOF-derived AuRu-In2O3 gas-sensitive material

Abstract

This invention discloses a method for preparing and using a UV-assisted sensitized MOF-derived AuRu-In2O3 gas-sensitive material. The gas-sensitive material is prepared using a metal-organic framework (MOF) formed by In-BTC / DOBDC as the matrix. After calcination, pure indium oxide is obtained. Subsequently, Au and Ru are modified onto the surface of the indium oxide using in-situ redox technology, controlling parameters such as the loading ratio and reaction time, to obtain the AuRu-In2O3 gas-sensitive material. The gas-sensitive element obtained using this AuRu-In2O3 material overcomes the problems of existing triethylamine gas sensors, such as high operating temperature, high detection limit, low sensitivity, and poor selectivity. Furthermore, the UV irradiation during gas detection not only improves the sensor's gas-sensitive performance for triethylamine detection at low temperatures but also enables high-performance detection of triethylamine at room temperature, making the sensor particularly suitable for detecting triethylamine in relatively humid room-temperature environments. The AuRu-In2O3 gas-sensitive material prepared by this invention exhibits excellent performance and has significant application value in the detection of triethylamine gas.

Description

Technical Field

[0001] This invention belongs to the field of oxide semiconductor gas sensor technology, specifically relating to the preparation and use of a UV-assisted sensitized MOF-derived AuRu-In2O3 gas-sensitive material. Background Technology

[0002] Triethylamine (TEA) is an important chemical raw material, mainly used as a catalyst, preservative, and synthetic dye. TEA has a strong fishy odor and is a volatile organic compound (VOC). Its concentration is commonly used as a chemical indicator to assess the quality of marine organisms. However, high concentrations of TEA can seriously cause discomfort and health hazards in humans, such as respiratory irritation, vomiting, headaches, and even death. Furthermore, its flammability and explosiveness pose a threat to environmental safety when exposed to open flames, high temperatures, and environments with strong oxidizers. The National Institute for Occupational Safety and Health recommends a safe upper limit for TEA concentration of 10 ppm, while the American Conference of American Industrial Hygienes (ACGIH) has set a threshold of 1 ppm. Therefore, the development of TEA gas sensors with high selectivity, low detection limits, fast detection speeds, and low operating temperatures is urgently needed.

[0003] Currently, methods for detecting TEA include gas chromatography, catalytic combustion gas sensors, electrochemical sensors, photoionization detectors, and photoionization gas sensors. While these methods can detect certain concentrations of TEA, they have drawbacks such as long detection times, high costs, and complex operating procedures. Metal oxide semiconductor gas sensors, due to their low manufacturing cost, high sensitivity, and ability to quickly and accurately detect target gases, have attracted widespread attention from researchers.

[0004] Indium oxide (In₂O₃), a typical n-type semiconductor metal oxide, has attracted widespread attention in the field of gas detection due to its wide bandgap (3.55-3.75 eV), low resistivity, excellent thermal stability, and superior physicochemical properties. Although single indium oxide materials respond to TEA gases, they still suffer from problems such as high operating temperature, low selectivity between gases, and high detection limits, which hinder the implementation of practical applications. Summary of the Invention

[0005] This invention addresses the shortcomings of current indium oxide-based triethylamine gas sensors, such as high operating temperature, high detection limit, low sensitivity, poor moisture resistance, and difficulty in recovering from room temperature detection. It provides a method for preparing and using a UV-assisted sensitized MOF-derived AuRu-In2O3 gas-sensitive material. The gas-sensitive material prepared by this method is suitable for low-temperature and room-temperature detection of triethylamine gas. The preparation of this gas-sensitive material uses a metal-organic framework (MOF) formed by In-BTC / DOBDC as the matrix. After calcination, pure indium oxide is obtained. Subsequently, Au and Ru are modified onto the surface of the indium oxide using in-situ redox technology, controlling parameters such as the loading ratio and reaction time, to obtain the AuRu-In2O3 gas-sensitive material. The gas-sensitive element is then fabricated through subsequent coating and welding processes. The resulting gas-sensitive element overcomes the problems of high operating temperature, high detection limit, low sensitivity, and poor selectivity of existing triethylamine gas sensors. Meanwhile, the irradiation of ultraviolet lamps (UV) during gas detection not only improves the gas-sensing performance of the sensor in detecting triethylamine at low temperatures, but also enables the gas sensor to achieve high-performance detection of triethylamine at room temperature, making the sensor more suitable for detecting triethylamine in relatively humid room temperature environments.

[0006] The present invention adopts the following technical solution: a method for preparing a UV-assisted sensitized MOF-derived AuRu-In2O3 gas-sensitive material, characterized in that the method includes the following steps:

[0007] Step 1: At room temperature, dissolve 0.8-1.5 mmol / L indium nitrate in 20-40 mL of N,N dimethylformamide and stir magnetically until completely dissolved to obtain an indium nitrate solution;

[0008] Step 2: Under magnetic stirring, add 0.5-1.5 mmol / L of terephthalic acid and 0.5-1.5 mmol / L of trimellitic acid to the above indium nitrate solution, and stir magnetically at room temperature for 20-40 minutes at a stirring speed of 800-1000 rpm to obtain a mixed solution. In this mixed solution, the molar ratio of indium nitrate, terephthalic acid, and trimellitic acid is 1:0.5~1.5:0.5~1.5.

[0009] Step 3: Place the above mixed solution in an oven and react at 100-140℃ for 0.5-1.5 h. After the reaction is complete, cool the mixed solution for 10-15 h, then centrifuge it, take the precipitate and wash it alternately with deionized water and anhydrous ethanol 5-7 times. Then place the washed precipitate in an oven at 60-80℃ and dry it for 5-10 hours.

[0010] Step 4: Place the dried precipitate from Step 3 into a muffle furnace and anneal it at 400-600℃ for 2-3 hours. The heating rate of the annealing process is 1-3℃ / min. Then, allow it to cool naturally to room temperature and collect the yellow indium oxide powder material.

[0011] Step 5: Take 10-30 mg of the yellow indium oxide powder material from Step 4 and place it in 20 mL of deionized water. Sonicate for 5-10 min and stir magnetically until the mixture is homogeneous to obtain an indium oxide suspension.

[0012] Step 6: At room temperature, prepare a RuCl3 solution with a concentration of 0.5 mg / mL, a HAuCl4·4H2O solution with a concentration of 20 mg / mL, and a NaBH4 solution with a concentration of 0.05 mmol / mL.

[0013] Step 7: Take 3-10 μL of the above-mentioned HAuCl4·4H2O solution and 5-15 μL of RuCl3 solution and slowly add them dropwise to the indium oxide suspension in Step 5, and stir magnetically for 10-20 min; then slowly add 40-60 μL of the above-mentioned NaBH4 solution, and stir magnetically for 10-30 min at a stirring rate of 800-1000 rpm; then let stand for 3-5 h, then centrifuge, take the precipitate and wash it alternately with ethanol and deionized water 5-7 times, and then place the precipitate in an oven and dry for 5-10 h to obtain the metal-organic framework-derived AuRu-In2O3 gas-sensitive material.

[0014] Furthermore, the present invention provides a method for using a UV-assisted sensitized MOF-derived AuRu-In2O3 gas-sensitive material, characterized in that the AuRu-In2O3 gas-sensitive material is obtained by the preparation method described above, and the method of using it includes the following steps:

[0015] Step 1) Use the above AuRu-In2O3 gas-sensitive material as the gas-sensitive material of the gas-sensitive element to fabricate a side-heated gas-sensitive element.

[0016] Step 2) Connect the gas-sensitive element to the circuit. Apply a working voltage to both ends of its resistance wire to heat the wire and allow the gas-sensitive element to achieve different operating temperatures. Connect the two ring-shaped metal electrodes in series with a load resistor through their terminals to form a series resistor circuit. Supply a test voltage V across this series resistor circuit. c The voltage across the load resistor is the output voltage V. out The resistance value of the detection resistor is R1 = V. c / V out (1-R0), where R0 is the resistance value of the load resistor; at the test voltage V cIf the resistance remains constant, the resistance value of the detection resistor changes with the ambient temperature and the type and concentration of the target gas.

[0017] Step 3) Place the gas-sensitive element in a 1L air bottle and wait for the resistance value of the gas-sensitive element to stabilize at the operating temperature; then place the gas-sensitive element in a 1L glass container containing the target gas and wait for the resistance value of its detection resistor to stabilize, recording the resistance value as R at this time. g ;

[0018] Step 4) Transfer the gas-sensitive element to a 1L quartz glass bottle that is transparent to ultraviolet light. Turn on an ultraviolet lamp with a wavelength of 300-400 nm, with the quartz glass bottle facing the ultraviolet lamp at a horizontal distance of 5-10 cm. This promotes the desorption of gas molecules on the surface of the gas-sensitive material until the resistance value of the gas-sensitive material stabilizes. Record the resistance value R of the gas-sensitive element after desorption. UV Turn off the UV lamp;

[0019] Step 5) Using the obtained R UV R g The sensitivity S=R was calculated. UV / R g Based on the sensitivity of target gas at different concentrations, plot the correlation curve between target gas concentration and sensitivity.

[0020] Step 6) Place the gas-sensitive element in a 1L glass container containing a target gas of unknown concentration, wait for the resistance value of its detection resistor to stabilize, and record the resistance value at this time; then repeat the operation of step 4) and record the resistance value of the detection resistor of the gas-sensitive element after desorption; based on the above two resistance values, obtain the sensitivity value of the target gas of unknown concentration; substitute the sensitivity value into the correlation curve in step 5) to obtain the concentration value of the target gas of unknown concentration.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] (1) This invention innovatively uses N,N-dimethylformamide as a solvent and indium nitrate, terephthalic acid, and trimesic acid as precursors to synthesize an indium oxide metal-organic framework (In-BTC / DOBDC) in the liquid phase at room temperature. After annealing, porous clustered indium oxide is obtained. Using this as a matrix, Au and Ru are modified onto the surface using in-situ redox technology. The resulting product is an AuRu-In₂O₃ gas-sensitive material. The gas-sensitive element prepared from this material exhibits high response (350-750) to 50 ppm triethylamine at a relatively low operating temperature (175°C), with a detection limit as low as 10 ppb and a response time of only 1 s. The gas-sensitive element obtained by the method of this invention has broad application prospects in the field of low-temperature detection of trace triethylamine gas.

[0023] (2) In the gas detection process, the present invention utilizes an ultraviolet lamp device to irradiate the gas-sensitive element during recovery, shortening the recovery time of the gas-sensitive element in detecting triethylamine at low temperature (175°C) and improving the response (835). Simultaneously, it achieves high-performance detection of triethylamine at room temperature. Specifically, under ultraviolet light irradiation, the baseline resistance of the gas-sensitive element is significantly increased, thereby greatly enhancing the response to 50 ppm triethylamine (250), promoting rapid desorption of triethylamine on the sensor, and allowing the sensor to recover quickly in air. More importantly, the addition of the ultraviolet lamp device overcomes the problem of poor moisture resistance in previous triethylamine gas sensors, even making the sensor more suitable for detecting triethylamine in relatively humid (80 RH%) environments, with a response as high as 2332. It has broad application prospects in detecting triethylamine gas in humid room temperature environments.

[0024] (3) The AuRu-In2O3 gas-sensitive material prepared by the present invention has a simple preparation process, short cycle, low cost, and high selectivity for triethylamine gas, making it suitable for mass production. Attached Figure Description

[0025] Figure 1 The diagram shows the structure of a side-heated gas-sensitive element; where A is a resistance wire, B is an insulating ceramic tube, C is the first annular metal electrode, D is the second annular metal electrode, and E is the gas-sensitive material coating; 1 and 6 are the connecting pins connected to the two ends of the resistance wire, 2 and 3 are the connecting pins connected to the two ends of the first metal electrode, and 4 and 5 are the connecting pins connected to the two ends of the second metal electrode.

[0026] Figure 2 The diagram shows the packaging state of a side-heated gas-sensitive element.

[0027] Figure 3 The image shown is a scanning electron microscope (SEM) image of the indium oxide (In2O3) gas-sensitive material obtained in Comparative Example 1 of the present invention at a magnification of 20k.

[0028] Figure 4 The image shown is a scanning electron microscope (SEM) image of the AuRu-In2O3 gas-sensitive material obtained in Example 2 of this invention at a magnification of 20k.

[0029] Figure 5 The figure shows the response curves of the gas-sensitive elements prepared from the gas-sensitive materials of Examples 1, 2, 3, Comparative Examples 1, 2, and 3 of the present invention as a function of operating temperature.

[0030] Figure 6The figure shows the response of the gas-sensitive element prepared from the indium oxide gas-sensitive material in Comparative Example 1 of the present invention to 50 ppm triethylamine and 100 ppm of other different gases at 175°C.

[0031] Figure 7 The graph shows the response of the gas-sensitive element prepared from the gas-sensitive material of Example 2 to 50 ppm triethylamine and 100 ppm of other different gases at the optimal operating temperature of 175°C.

[0032] Figure 8 The figure shows line graphs illustrating the change in sensitivity of gas-sensitive elements prepared from the gas-sensitive materials in Comparative Examples 1-3 and Examples 1-3 of the present invention as a function of concentration in the range of 10 ppb-50 ppm triethylamine.

[0033] Figure 9 The figure shows line graphs illustrating the change in sensitivity of gas-sensitive elements prepared from the gas-sensitive materials in Comparative Examples 1-3 and Examples 1-3 of the present invention as a function of concentration in the range of 10 ppb-1 ppm triethylamine.

[0034] Figure 10 The figure shows the sensitivity curve of the gas-sensitive element prepared by the gas-sensitive material of Example 2 of the present invention as a function of concentration at the optimal operating temperature of 175°C.

[0035] Figure 11 The image shows a comparison of the recovery time of the gas-sensitive element prepared from the gas-sensitive material of Example 2 of the present invention in air and under ultraviolet light irradiation; the gray shaded area represents the data under ultraviolet light irradiation.

[0036] Figure 12 The figure shown is a test graph of the response of the gas-sensitive element prepared by the gas-sensitive material of Example 2 of the present invention to 50 ppm triethylamine and 100 ppm other gases under ultraviolet light irradiation at room temperature.

[0037] Figure 13 The figure shows the curves of the sensitivity of the gas-sensitive element prepared by the gas-sensitive material of Example 2 of the present invention as a function of different concentrations of triethylamine under the influence of ultraviolet light at room temperature.

[0038] Figure 14 The figure shows a line graph of the sensitivity of a gas-sensitive element prepared from the gas-sensitive material of Example 2 of the present invention as a function of triethylamine concentration, which is restored at room temperature by irradiation with ultraviolet light.

[0039] Figure 15 The results shown are repeatability test results of the gas-sensitive element prepared by the gas-sensitive material of Example 2 of the present invention under the condition of recovery by ultraviolet lamp irradiation at room temperature.

[0040] Figure 16The figure shows the resistance value of the gas-sensitive element prepared by the gas-sensitive material of Embodiment 2 of the present invention as a function of humidity under the condition of room temperature recovery by ultraviolet lamp irradiation.

[0041] Figure 17 The figure shows a line graph of the sensitivity of a gas-sensitive element prepared from the gas-sensitive material of Example 2 of the present invention as a function of humidity, which is restored at room temperature by irradiation with an ultraviolet lamp. Detailed Implementation

[0042] The technical solution of the present invention will be further described below with reference to specific implementation examples and accompanying drawings.

[0043] This invention provides a method for preparing a UV-assisted sensitized MOF-derived AuRu-In2O3 gas-sensitive material, the method comprising the following steps:

[0044] Step 1: At room temperature, dissolve 0.8-1.5 mmol / L indium nitrate in 20-40 mL of N,N dimethylformamide and stir magnetically until completely dissolved to obtain an indium nitrate solution;

[0045] Step 2: Under magnetic stirring, add 0.5-1.5 mmol / L of terephthalic acid and 0.5-1.5 mmol / L of trimellitic acid to the above indium nitrate solution, and stir magnetically at room temperature for 20-40 minutes at a stirring speed of 800-1000 rpm to obtain a mixed solution. In this mixed solution, the molar ratio of indium nitrate, terephthalic acid, and trimellitic acid is 1:0.5~1.5:0.5~1.5.

[0046] Step 3: Place the above mixed solution in an oven and react at 100-140℃ for 0.5-1.5 h. After the reaction is complete, cool the mixed solution for 10-15 h, then centrifuge it, take the precipitate and wash it alternately with deionized water and anhydrous ethanol 5-7 times. Then place the washed precipitate in an oven at 60-80℃ and dry it for 5-10 hours.

[0047] Step 4: Place the dried precipitate from Step 3 into a muffle furnace and anneal it at 400-600℃ for 2-3 hours. The heating rate of the annealing process is 1-3℃ / min. Then, allow it to cool naturally to room temperature and collect the yellow indium oxide powder material.

[0048] Step 5: Take 10-30 mg of the yellow indium oxide powder material from Step 4 and place it in 20 mL of deionized water. Sonicate for 5-10 min and stir magnetically until the mixture is homogeneous to obtain an indium oxide suspension.

[0049] Step 6: At room temperature, prepare a RuCl3 solution with a concentration of 0.5 mg / mL, a HAuCl4·4H2O solution with a concentration of 20 mg / mL, and a NaBH4 solution with a concentration of 0.05 mmol / mL.

[0050] Step 7: Take 3-10 μL of the above-mentioned HAuCl4·4H2O solution and 5-15 μL of RuCl3 solution and slowly add them dropwise to the indium oxide suspension in Step 5, and stir magnetically for 10-20 min; then slowly add 40-60 μL of the above-mentioned NaBH4 solution, and stir magnetically for 10-30 min at a stirring rate of 800-1000 rpm; then let stand for 3-5 h, then centrifuge, take the precipitate and wash it alternately with ethanol and deionized water 5-7 times, and then place the precipitate in an oven and dry for 5-10 h to obtain the metal-organic framework-derived AuRu-In2O3 gas-sensitive material.

[0051] In the AuRu-In2O3 gas-sensitive material, the molar ratio of its components is In2O3: Au: Ru = 100: 0.5~1.5: 0.5~1.5.

[0052] The dripping rate for the above-mentioned slow addition is 0.5-1 μL / s.

[0053] Furthermore, the present invention provides a method for using a UV-assisted sensitized MOF-derived AuRu-In2O3 gas-sensitive material, which is obtained by the above preparation method, and the method of use includes the following steps:

[0054] Step 1) Using the above AuRu-In2O3 gas-sensitive material as the gas-sensitive element, a side-heated gas-sensitive element is fabricated. This specifically includes the following steps:

[0055] Step 1.1: Take 1-3 mg of the AuRu-In2O3 gas-sensitive material as described above, mix it with 1-3 mL of deionized water to make a paste, and then use a brush to evenly coat the paste on the surface of the ceramic tube between the two annular and parallel metal electrodes of the side-heated gas-sensitive element. The thickness of the paste is 5-15 μm.

[0056] Step 1.2: Place the ceramic tube coated with the paste under a rapid drying lamp and bake for 5-10 minutes to form a coating; then weld the ceramic tube onto a hexagonal base, with a resistance wire placed inside the ceramic tube to heat it. The two ends of the resistance wire are connected to pins 1 and 6 respectively via platinum wire. Each of the two annular metal electrodes has a connection point at both ends of its outer diameter passing through the center. The four connection points are connected to pins 2, 3, 4, and 5 respectively via platinum wire, thus obtaining a gas-sensitive element containing AuRu-In2O3 gas-sensitive material.

[0057] The gas-sensitive element is connected to the circuit through its pins 1-6. Pins 1 and 6 connect the resistance wire in parallel to the circuit, so that the resistance wire receives the working voltage and generates heat. The two pins on each ring metal electrode are connected in parallel to form a terminal. The coating between the two ring metal electrodes is the detection resistor, and the two terminals connect the detection resistor to the circuit.

[0058] The working principle of a gas-sensitive element is based on the change in resistance caused by the oxidation and reduction reactions of gas on the surface of a semiconductor coating. When the semiconductor coating is heated to a stable state, the gas comes into contact with the surface of the semiconductor coating, and the adsorbed molecules react with the semiconductor coating, causing a change in the charge layer on the surface of the semiconductor coating. This changes the carrier concentration of the semiconductor coating, which is ultimately reflected in a change in the resistance value of the detection resistor, i.e., a change in the resistance value of the gas-sensitive element.

[0059] The gas-sensing characteristics of gas-sensitive elements are usually characterized by sensitivity. In the technical solution of this invention, when the gas-sensitive element is not enhanced by an ultraviolet device, the sensitivity is defined as the stable resistance value R of the gas-sensitive element in an atmospheric atmosphere. a The stable resistance value R of the gas-sensitive element in the measured gas atmosphere g The ratio:

[0060] S=R a / R g

[0061] When a gas-sensitive element is irradiated with ultraviolet light to promote the desorption of gas molecules and the recovery of the resistance of the gas-sensitive material, the sensitivity is defined as the stable resistance value R of the gas-sensitive element after irradiation with ultraviolet light in an atmospheric atmosphere. UV The stable resistance value R of the gas-sensitive element in the measured gas atmosphere g The ratio:

[0062] S=R UV / R g

[0063] Response time is the time required for the resistance of a sensor to change by 90% when it is transferred from an air atmosphere to a target gas.

[0064] Step 2) Connect the gas-sensitive element to the circuit. Apply a working voltage to both ends of its resistance wire to heat the wire and allow the gas-sensitive element to achieve different operating temperatures. Connect the two ring-shaped metal electrodes in series with a load resistor through their terminals to form a series resistor circuit. Supply a test voltage V across this series resistor circuit. c The voltage across the load resistor is the output voltage V. out The resistance value of the detection resistor is R1 = V. c / V out (1-R0), where R0 is the resistance value of the load resistor; at the test voltage V c If the resistance remains constant, the resistance value of the detection resistor changes with the ambient temperature and the type and concentration of the target gas.

[0065] Step 3) Place the gas-sensitive element in a 1L air bottle and wait for the resistance value of the gas-sensitive element to stabilize at the operating temperature (room temperature: 25℃ or low temperature: 175℃-225℃). Then place the gas-sensitive element in a 1L glass container containing the target gas and wait for the resistance value of its detection resistor to stabilize. Record the resistance value as R. g .

[0066] Step 4) Transfer the gas-sensitive element to a 1L quartz glass bottle that is transparent to ultraviolet light. Turn on an ultraviolet lamp with a wavelength of 300-400 nm, with the quartz glass bottle facing the ultraviolet lamp at a horizontal distance of 5-10 cm. This promotes the desorption of gas molecules on the surface of the gas-sensitive material until the resistance value of the gas-sensitive material stabilizes. Record the resistance value R of the gas-sensitive element after desorption. UV Turn off the UV lamp.

[0067] Step 5) Using the obtained R UV R g The sensitivity S=R was calculated. UV / R g Based on the sensitivity of target gas at different concentrations, a correlation curve between the concentration of the target gas and the sensitivity was plotted.

[0068] Step 6) Place the gas-sensitive element in a 1L glass container containing a target gas of unknown concentration, wait for the resistance value of its detection resistor to stabilize, and record the resistance value at this time. Then repeat the operation of step 4), and record the resistance value of the detection resistor of the gas-sensitive element after desorption; based on the above two resistance values, obtain the sensitivity value of the target gas of unknown concentration; substitute this sensitivity value into the correlation curve in step 5), and obtain the concentration value of the target gas of unknown concentration.

[0069] Example 1

[0070] This embodiment provides a method for preparing a UV-assisted sensitized MOF-derived AuRu-In2O3 gas-sensitive material, which includes the following steps:

[0071] Step 1: At room temperature, dissolve 1 mmol / L of indium nitrate in 30 mL of N,N dimethylformamide and stir magnetically until completely dissolved to obtain an indium nitrate solution;

[0072] Step 2: Under magnetic stirring, add 1 mmol / L of terephthalic acid and 1 mmol / L of trimellitic acid to the above indium nitrate solution, and stir magnetically for 30 minutes at room temperature at a stirring speed of 900 rpm to obtain a mixed solution. In this mixed solution, the molar ratio of indium nitrate, terephthalic acid, and trimellitic acid is 1:1:1.

[0073] Step 3: Place the above mixed solution in an oven and react at 120°C for 1 h. After the reaction is complete, cool the mixed solution for 12 h, then centrifuge it, take the precipitate and wash it 6 times alternately with deionized water and anhydrous ethanol. Then place the washed precipitate in an oven at 60°C and dry it for 8 hours.

[0074] Step 4: Place the dried precipitate from Step 3 into a muffle furnace and anneal it at 500°C for 2 hours. The heating rate of the annealing process is 2°C / min. Then, allow it to cool naturally to room temperature and collect the yellow indium oxide powder material.

[0075] Step 5: Take 10 mg of the yellow indium oxide powder material from Step 4 and place it in 20 mL of deionized water. Sonicate for 5 min and stir magnetically until the mixture is homogeneous to obtain an indium oxide suspension.

[0076] Step 6: At room temperature, prepare a RuCl3 solution with a concentration of 0.5 mg / mL, a HAuCl4·4H2O solution with a concentration of 20 mg / mL, and a NaBH4 solution with a concentration of 0.05 mmol / mL.

[0077] Step 7: Take 4 μL of the above-mentioned HAuCl4·4H2O solution and 15 μL of RuCl3 solution and slowly add them dropwise to the indium oxide suspension in Step 5, and stir magnetically for 10 min; then slowly add 40 μL of the above-mentioned NaBH4 solution, and stir magnetically for 10 min at a stirring rate of 900 rpm; then let stand for 4 h, then centrifuge, take the precipitate and wash it with ethanol and deionized water alternately 6 times, and then place the precipitate in an oven and dry for 8 h to obtain the metal-organic framework-derived AuRu-In2O3 gas-sensitive material.

[0078] In the AuRu-In2O3 gas-sensitive material, the molar ratio of its components is In2O3: Au: Ru = 100: 0.5: 1.

[0079] Example 2

[0080] This embodiment provides a method for preparing a UV-assisted sensitized MOF-derived AuRu-In2O3 gas-sensitive material, which includes the following steps:

[0081] Step 1: At room temperature, dissolve 1 mmol / L of indium nitrate in 30 mL of N,N dimethylformamide and stir magnetically until completely dissolved to obtain an indium nitrate solution;

[0082] Step 2: Under magnetic stirring, add 1 mmol / L of terephthalic acid and 1 mmol / L of trimellitic acid to the above indium nitrate solution, and stir magnetically for 30 minutes at room temperature at a stirring speed of 900 rpm to obtain a mixed solution. In this mixed solution, the molar ratio of indium nitrate, terephthalic acid, and trimellitic acid is 1:1:1.

[0083] Step 3: Place the above mixed solution in an oven and react at 120°C for 1 h. After the reaction is complete, cool the mixed solution for 12 h, then centrifuge it, take the precipitate and wash it 6 times alternately with deionized water and anhydrous ethanol. Then place the washed precipitate in an oven at 60°C and dry it for 8 hours.

[0084] Step 4: Place the dried precipitate from Step 3 into a muffle furnace and anneal it at 500°C for 2 hours. The heating rate of the annealing process is 2°C / min. Then, allow it to cool naturally to room temperature and collect the yellow indium oxide powder material.

[0085] Step 5: Take 10 mg of the yellow indium oxide powder material from Step 4 and place it in 20 mL of deionized water. Sonicate for 5 min and stir magnetically until the mixture is homogeneous to obtain an indium oxide suspension.

[0086] Step 6: At room temperature, prepare a RuCl3 solution with a concentration of 0.5 mg / mL, a HAuCl4·4H2O solution with a concentration of 20 mg / mL, and a NaBH4 solution with a concentration of 0.05 mmol / mL.

[0087] Step 7: Take 5.5 μL of the above-mentioned HAuCl4·4H2O solution and 11.5 μL of RuCl3 solution and slowly add them dropwise to the indium oxide suspension in Step 5, and stir magnetically for 10 min; then slowly add 40 μL of the above-mentioned NaBH4 solution, and stir magnetically for 10 min at a stirring rate of 900 rpm; then let stand for 4 h, then centrifuge, take the precipitate and wash it with ethanol and deionized water alternately 6 times, and then place the precipitate in an oven and dry for 8 h to obtain the metal-organic framework-derived AuRu-In2O3 gas-sensitive material.

[0088] In the AuRu-In2O3 gas-sensitive material, the molar ratio of its components is In2O3: Au: Ru = 100: 0.75: 0.75.

[0089] The Au prepared in this embodiment 0.75 Ru 0.75SEM images of In2O3 materials are shown below. Figure 4 As shown, its morphology can be observed to be porous nanoclusters with a particle size of 100-200 nm.

[0090] Example 3

[0091] This embodiment provides a method for preparing a UV-assisted sensitized MOF-derived AuRu-In2O3 gas-sensitive material, which includes the following steps:

[0092] Step 1: At room temperature, dissolve 1 mmol / L of indium nitrate in 30 mL of N,N dimethylformamide and stir magnetically until completely dissolved to obtain an indium nitrate solution;

[0093] Step 2: Under magnetic stirring, add 1 mmol / L of terephthalic acid and 1 mmol / L of trimellitic acid to the above indium nitrate solution, and stir magnetically for 30 minutes at room temperature at a stirring speed of 900 rpm to obtain a mixed solution. In this mixed solution, the molar ratio of indium nitrate, terephthalic acid, and trimellitic acid is 1:1:1.

[0094] Step 3: Place the above mixed solution in an oven and react at 120°C for 1 h. After the reaction is complete, cool the mixed solution for 12 h, then centrifuge it, take the precipitate and wash it 6 times alternately with deionized water and anhydrous ethanol. Then place the washed precipitate in an oven at 60°C and dry it for 8 hours.

[0095] Step 4: Place the dried precipitate from Step 3 into a muffle furnace and anneal it at 500°C for 2 hours. The heating rate of the annealing process is 2°C / min. Then, allow it to cool naturally to room temperature and collect the yellow indium oxide powder material.

[0096] Step 5: Take 10 mg of the yellow indium oxide powder material from Step 4 and place it in 20 mL of deionized water. Sonicate for 5 min and stir magnetically until the mixture is homogeneous to obtain an indium oxide suspension.

[0097] Step 6: At room temperature, prepare a RuCl3 solution with a concentration of 0.5 mg / mL, a HAuCl4·4H2O solution with a concentration of 20 mg / mL, and a NaBH4 solution with a concentration of 0.05 mmol / mL.

[0098] Step 7: Take 7.5 μL of the above-mentioned HAuCl4·4H2O solution and 7.5 μL of RuCl3 solution and slowly add them dropwise to the indium oxide suspension in Step 5, and stir magnetically for 10 min; then slowly add 40 μL of the above-mentioned NaBH4 solution, and stir magnetically for 10 min at a stirring rate of 900 rpm; then let stand for 4 h, then centrifuge, take the precipitate and wash it with ethanol and deionized water alternately 6 times, and then place the precipitate in an oven and dry for 8 h to obtain the metal-organic framework-derived AuRu-In2O3 gas-sensitive material.

[0099] In the AuRu-In2O3 gas-sensitive material, the molar ratio of its components is In2O3: Au: Ru = 100: 1: 0.5.

[0100] Comparative Example 1

[0101] This comparative example provides a gas-sensitive material, which is prepared by the following steps:

[0102] Step 1: At room temperature, dissolve 1 mmol / L of indium nitrate in 30 mL of N,N dimethylformamide and stir magnetically until completely dissolved to obtain an indium nitrate solution;

[0103] Step 2: Under magnetic stirring, add 1 mmol / L of terephthalic acid and 1 mmol / L of trimellitic acid to the above indium nitrate solution, and stir magnetically for 30 minutes at room temperature at a stirring speed of 900 rpm to obtain a mixed solution. In this mixed solution, the molar ratio of indium nitrate, terephthalic acid, and trimellitic acid is 1:1:1.

[0104] Step 3: Place the above mixed solution in an oven and react at 120°C for 1 h. After the reaction is complete, cool the mixed solution for 12 h, then centrifuge it, take the precipitate and wash it 6 times alternately with deionized water and anhydrous ethanol. Then place the washed precipitate in an oven at 60°C and dry it for 8 hours.

[0105] Step 4: Place the dried precipitate from Step 3 into a muffle furnace and anneal it at 500°C for 2 hours. The heating rate of the annealing process is 2°C / min. Then, allow it to cool naturally to room temperature and collect the yellow powdery indium oxide gas-sensitive material.

[0106] The SEM image of the In2O3 material prepared in this comparative example is shown below. Figure 3 As shown, its morphology can be observed to be porous nanoclusters.

[0107] Comparative Example 2

[0108] This comparative example provides a gas-sensitive material, which is prepared by the following steps:

[0109] Step 1: At room temperature, dissolve 1 mmol / L of indium nitrate in 30 mL of N,N dimethylformamide and stir magnetically until completely dissolved to obtain an indium nitrate solution;

[0110] Step 2: Under magnetic stirring, add 1 mmol / L of terephthalic acid and 1 mmol / L of trimellitic acid to the above indium nitrate solution, and stir magnetically for 30 minutes at room temperature at a stirring speed of 900 rpm to obtain a mixed solution. In this mixed solution, the molar ratio of indium nitrate, terephthalic acid, and trimellitic acid is 1:1:1.

[0111] Step 3: Place the above mixed solution in an oven and react at 120°C for 1 h. After the reaction is complete, cool the mixed solution for 12 h, then centrifuge it, take the precipitate and wash it 6 times alternately with deionized water and anhydrous ethanol. Then place the washed precipitate in an oven at 60°C and dry it for 8 hours.

[0112] Step 4: Place the dried precipitate from Step 3 into a muffle furnace and anneal it at 500°C for 2 hours. The heating rate of the annealing process is 2°C / min. Then, allow it to cool naturally to room temperature and collect the yellow indium oxide powder material.

[0113] Step 5: Take 10 mg of the yellow indium oxide powder material from Step 4 and place it in 20 mL of deionized water. Sonicate for 5 min and stir magnetically until the mixture is homogeneous to obtain an indium oxide suspension.

[0114] Step 6: At room temperature, prepare a HAuCl4·4H2O solution with a concentration of 20 mg / mL and a NaBH4 solution with a concentration of 0.05 mmol / mL;

[0115] Step 7: Take 5.5 μL of the above HAuCl4·4H2O solution and slowly add it dropwise to the indium oxide suspension in Step 5, and stir magnetically for 10 min; then slowly add 40 μL of the above NaBH4 solution, and stir magnetically for 10 min at a stirring rate of 900 rpm; then let it stand for 4 h, then centrifuge, take the precipitate and wash it 6 times alternately with ethanol and deionized water, and then place the precipitate in an oven and dry for 8 h to obtain Au-In2O3 gas-sensitive material.

[0116] In the Au-In2O3 gas-sensitive material, the molar ratio of its components is In2O3: Au = 100:0.75.

[0117] Comparative Example 3

[0118] This comparative example provides a gas-sensitive material, which is prepared by the following steps:

[0119] Step 1: At room temperature, dissolve 1 mmol / L of indium nitrate in 30 mL of N,N dimethylformamide and stir magnetically until completely dissolved to obtain an indium nitrate solution;

[0120] Step 2: Under magnetic stirring, add 1 mmol / L of terephthalic acid and 1 mmol / L of trimellitic acid to the above indium nitrate solution, and stir magnetically for 30 minutes at room temperature at a stirring speed of 900 rpm to obtain a mixed solution. In this mixed solution, the molar ratio of indium nitrate, terephthalic acid, and trimellitic acid is 1:1:1.

[0121] Step 3: Place the above mixed solution in an oven and react at 120°C for 1 h. After the reaction is complete, cool the mixed solution for 12 h, then centrifuge it, take the precipitate and wash it 6 times alternately with deionized water and anhydrous ethanol. Then place the washed precipitate in an oven at 60°C and dry it for 8 hours.

[0122] Step 4: Place the dried precipitate from Step 3 into a muffle furnace and anneal it at 500°C for 2 hours. The heating rate of the annealing process is 2°C / min. Then, allow it to cool naturally to room temperature and collect the yellow indium oxide powder material.

[0123] Step 5: Take 10 mg of the yellow indium oxide powder material from Step 4 and place it in 20 mL of deionized water. Sonicate for 5 min and stir magnetically until the mixture is homogeneous to obtain an indium oxide suspension.

[0124] Step 6: Prepare a RuCl3 solution with a concentration of 0.5 mg / mL and a NaBH4 solution with a concentration of 0.05 mmol / mL at room temperature;

[0125] Step 7: Take 11.5 μL of RuCl3 solution and slowly add it dropwise to the indium oxide suspension in Step 5, and stir magnetically for 10 min; then slowly add 40 μL of the above NaBH4 solution, and stir magnetically for 10 min at a stirring rate of 900 rpm; then let it stand for 4 h, then centrifuge, take the precipitate and wash it with ethanol and deionized water alternately 6 times, and then place the precipitate in an oven and dry for 8 h to obtain Ru-In2O3 gas-sensitive material.

[0126] In the Ru-In2O3 gas-sensitive material, the molar ratio of its components is In2O3:Ru = 100:0.75.

[0127] The three AuRu-In2O3 gas-sensitive materials obtained in Examples 1, 2, and 3, as well as the indium oxide gas-sensitive material obtained in Comparative Example 1, the AuRu-In2O3 gas-sensitive material obtained in Comparative Example 2, and the Ru-In2O3 gas-sensitive material obtained in Comparative Example 3, were respectively prepared into side-heated gas-sensitive elements according to the following methods:

[0128] Step 1: Take 2 mg of the gas-sensitive material as described above, mix it with 2 mL of deionized water to make a paste, and then use a brush to evenly coat the paste on the surface of the ceramic tube between the two annular and parallel metal electrodes of the side-heated gas-sensitive element. The thickness of the paste is 10 μm.

[0129] Step 2: Place the ceramic tube coated with the paste under a rapid drying lamp and bake for 10 minutes to form a coating; then weld the ceramic tube onto a hexagonal base, and place the resistance wire inside the ceramic tube to heat it. The two ends of the resistance wire are connected to pins 1 and 6 respectively through platinum wire. Each of the two annular metal electrodes has a connection point at both ends of its outer diameter passing through the center. The four connection points are connected to pins 2, 3, 4, and 5 respectively through platinum wire, thus obtaining a gas-sensitive element containing the corresponding gas-sensitive material.

[0130] The above-mentioned method for preparing gas-sensitive elements is existing technology;

[0131] The gas-sensitive element described above was tested using a gas-sensitive testing system (FLUKE). The gas-sensitive testing system (FLUKE) is existing technology. During testing of the gas-sensitive element, under normal testing conditions (without UV light), the sensitivity is defined as the stable resistance value R of the gas-sensitive element in an atmospheric atmosphere. a The stable resistance value R of the gas-sensitive element in the measured gas atmosphere g The ratio: S=R a / R g Under ultraviolet irradiation conditions, the gas-sensitive element promotes the desorption of gas molecules with the help of an ultraviolet lamp. The sensitivity is defined as the stable resistance value R of the gas-sensitive element after irradiation with an ultraviolet lamp in an atmospheric atmosphere. UV The stable resistance value R of the gas-sensitive element in the measured gas atmosphere g The ratio: S=R UV / R g .

[0132] Figure 5The figures show the response curves of gas-sensitive elements prepared from the gas-sensitive materials in Examples 1, 2, 3, Comparative Examples 1, 2, and 3 as a function of operating temperature (under standard testing conditions). Specifically, the optimal operating temperature of the gas-sensitive element in Example 1 was 175°C, with a response of 371 to 50 ppm triethylamine; the optimal operating temperature of the gas-sensitive element in Example 2 was 175°C, with a response of 756 to 50 ppm triethylamine; the optimal operating temperature of the gas-sensitive element in Example 3 was 175°C, with a response of 620 to 50 ppm triethylamine; the optimal operating temperature of the gas-sensitive element in Comparative Example 1 was 200°C, with a response of 27 to 50 ppm triethylamine; the optimal operating temperature of the gas-sensitive element in Comparative Example 2 was 175°C, with a response of 106 to 50 ppm triethylamine; and the optimal operating temperature of the gas-sensitive element in Comparative Example 3 was 175°C, with a response of 206 to 50 ppm triethylamine.

[0133] Figure 8 and Figure 9 The figures show line graphs (under standard testing conditions) illustrating the sensitivity of gas-sensitive elements prepared from the gas-sensitive materials in Examples 1, 2, 3, Comparative Examples 1, 2, and 3 as a function of concentration for both high concentration (10 ppb-50 ppm) and low concentration (10 ppb-1 ppm) ranges. The results show that, except for the gas-sensitive element prepared from the gas-sensitive material in Comparative Example 1, the detection limit of the other five gas-sensitive elements is 10 ppb, and the linear relationship between concentration and response is good. Furthermore, the gas-sensitive elements corresponding to the gas-sensitive materials in Examples 1, 2, and 3 have faster responses, while the gas-sensitive element corresponding to the gas-sensitive material in Example 2 has the fastest response.

[0134] Figure 7 The response graphs of the gas-sensitive element prepared by the gas-sensitive material of Example 2 to 50 ppm triethylamine and 100 ppm of other different gases at the optimal operating temperature of 175°C (normal test conditions) show that the gas-sensitive element prepared by the gas-sensitive material of Example 2 has very good selectivity for triethylamine.

[0135] Figure 10 The graph shows the sensitivity of the gas-sensitive element prepared from the gas-sensitive material of Example 2 as a function of concentration at the optimal operating temperature of 175°C (under normal test conditions).

[0136] Figure 11 This is a comparison graph showing the recovery time of the gas-sensitive element prepared from the gas-sensitive material of Example 2 under air (conventional testing conditions) and under ultraviolet light irradiation (ultraviolet irradiation conditions). The gray shaded area represents the data under ultraviolet light irradiation. The results show that using ultraviolet light irradiation during the recovery process of this gas-sensitive element results in a faster recovery time for Au. 0.75 Ru 0.75-In2O3 showed an increased response to triethylamine to 835, and the recovery time was significantly shortened.

[0137] Figure 12 The gas-sensitive element prepared by the gas-sensitive material of Example 2 was tested to recover its response to 50 ppm triethylamine and 100 ppm other gases at room temperature by irradiation with an ultraviolet lamp. Similarly, ultraviolet lamp irradiation was only used during the recovery process of the gas-sensitive element. The results show that the gas-sensitive element has good selectivity for triethylamine under this environment.

[0138] Figure 13 The curves showing the change in sensitivity of the gas-sensitive element prepared from the gas-sensitive material of Example 2 under UV irradiation at room temperature with different concentrations of triethylamine are shown. The results indicate that the lowest detectable concentration of triethylamine is 50 ppb.

[0139] Figure 14 The line graph showing the change in sensitivity of the gas-sensitive element prepared from the gas-sensitive material of Example 2 as a function of triethylamine concentration (i.e., selection) Figure 13 A line graph was plotted between the concentration values ​​and the corresponding sensitivity, and the results showed that the two had a good linear relationship.

[0140] Figure 15 The repeatability test of the gas-sensitive element prepared by the gas-sensitive material of Example 2 under room temperature with UV lamp irradiation showed that, compared with the absence of UV lamp, its baseline resistance was significantly improved, its response was significantly improved, and it could recover quickly.

[0141] Figure 17 The graph shows the change in sensitivity of the gas-sensitive element prepared from the gas-sensitive material of Example 2 under UV irradiation at room temperature as a function of humidity. The results show that the sensitivity initially increases significantly with increasing humidity, reaching a peak value (2332) at 80% humidity, and then decreases. This indicates that the gas-sensitive element in Example 2 has high moisture resistance with the assistance of UV light, and is even more suitable for detecting triethylamine in relatively humid environments.

[0142] This invention produces an oxide semiconductor gas-sensitive material sensitive to triethylamine. With the assistance of an ultraviolet lamp, it can achieve high-performance identification of triethylamine at both room temperature and low temperature, and can detect trace amounts of triethylamine. The material preparation process is simple, and it possesses excellent properties such as low operating temperature, high sensitivity, high selectivity, and high moisture resistance.

[0143] The above embodiments are merely illustrative and not intended to be limiting. Any equivalent modifications or alterations made without departing from the spirit and scope of this invention should be included within the scope of the claims of this application.

[0144] Any aspects not covered in this invention are applicable to existing technologies.

Claims

1. A method for preparing a UV-assisted sensitized MOF-derived AuRu-In2O3 gas-sensitive material, characterized in that, The method includes the following steps: Step 1: At room temperature, dissolve 0.8-1.5 mmol / L indium nitrate in 20-40 mL of N,N dimethylformamide and stir magnetically until completely dissolved to obtain an indium nitrate solution; Step 2: Under magnetic stirring, add 0.5-1.5 mmol / L of terephthalic acid and 0.5-1.5 mmol / L of trimellitic acid to the above indium nitrate solution, and stir magnetically at room temperature for 20-40 minutes at a stirring speed of 800-1000 rpm to obtain a mixed solution; in this mixed solution, the molar ratio of indium nitrate, terephthalic acid, and trimellitic acid is 1:0.5~1.5:0.5~1.5; Step 3: Place the above mixed solution in an oven and react at 100-140℃ for 0.5-1.5 h. After the reaction is complete, cool the mixed solution for 10-15 h, then centrifuge it, take the precipitate and wash it alternately with deionized water and anhydrous ethanol 5-7 times. Then place the washed precipitate in an oven at 60-80℃ and dry it for 5-10 hours. Step 4: Place the dried precipitate from Step 3 into a muffle furnace and anneal it at 400-600℃ for 2-3 hours. The heating rate of the annealing process is 1-3℃ / min. Then, allow it to cool naturally to room temperature and collect the yellow indium oxide powder material. Step 5: Take 10-30 mg of the yellow indium oxide powder material from Step 4 and place it in 20 mL of deionized water. Sonicate for 5-10 min and stir magnetically until the mixture is homogeneous to obtain an indium oxide suspension. Step 6: At room temperature, prepare a RuCl3 solution with a concentration of 0.5 mg / mL, a HAuCl4·4H2O solution with a concentration of 20 mg / mL, and a NaBH4 solution with a concentration of 0.05 mmol / mL. Step 7: Take 3-10 μL of the above-mentioned HAuCl4·4H2O solution and 5-15 μL of RuCl3 solution and slowly add them dropwise to the indium oxide suspension in Step 5, and stir magnetically for 10-20 min; then slowly add 40-60 μL of the above-mentioned NaBH4 solution, and stir magnetically for 10-30 min at a stirring rate of 800-1000 rpm; then let stand for 3-5 h, then centrifuge, take the precipitate and wash it alternately with ethanol and deionized water 5-7 times, and then place the precipitate in an oven and dry for 5-10 h to obtain the metal-organic framework-derived AuRu-In2O3 gas-sensitive material; The AuRu-In2O3 gas-sensitive material obtained by this method has a molar ratio of In2O3: Au: Ru = 100: 0.5~1.5: 0.5~1.

5.

2. The method for preparing a UV-assisted sensitized MOF-derived AuRu-In2O3 gas-sensitive material according to claim 1, characterized in that, The slow dripping rate is 0.5-1 μL / s.

3. A method for using a UV-assisted sensitized MOF-derived AuRu-In2O3 gas-sensitive material, characterized in that, The AuRu-In2O3 gas-sensitive material is obtained by the preparation method according to any one of claims 1-2, and its usage includes the following steps: Step 1) Use the above AuRu-In2O3 gas-sensitive material as the gas-sensitive material of the gas-sensitive element to fabricate a side-heated gas-sensitive element; Step 2) Connect the gas-sensitive element to the circuit. Apply a working voltage to both ends of its resistance wire to heat the wire and allow the gas-sensitive element to achieve different operating temperatures. Connect the two ring-shaped metal electrodes in series with a load resistor through their terminals to form a series resistor circuit. Supply a test voltage V across this series resistor circuit. c The voltage across the load resistor is the output voltage V. out The resistance value of the detection resistor is R1 = V. c / V out (1-R0), where R0 is the resistance value of the load resistor; at the test voltage V c If the resistance remains constant, the resistance value of the detection resistor changes with the ambient temperature and the type and concentration of the target gas. Step 3) Place the gas-sensitive element in a 1L air bottle and wait for the resistance value of the gas-sensitive element to stabilize at the operating temperature; then place the gas-sensitive element in a 1L glass container containing the target gas and wait for the resistance value of its detection resistor to stabilize, recording the resistance value as R at this time. g ; Step 4) Transfer the gas-sensitive element to a 1L quartz glass bottle that is transparent to ultraviolet light. Turn on an ultraviolet lamp with a wavelength of 300-400 nm, with the quartz glass bottle facing the ultraviolet lamp at a horizontal distance of 5-10 cm. This promotes the desorption of gas molecules on the surface of the gas-sensitive material until the resistance value of the gas-sensitive material stabilizes. Record the resistance value R of the gas-sensitive element after desorption. UV Turn off the UV lamp; Step 5) Using the obtained R UV R g The sensitivity S=R was calculated. UV / R g Based on the sensitivity of target gas at different concentrations, plot the correlation curve between target gas concentration and sensitivity. Step 6) Place the gas-sensitive element in a 1L glass container containing a target gas of unknown concentration, wait for the resistance value of its detection resistor to stabilize, and record the resistance value at this time; then repeat the operation of step 4) and record the resistance value of the detection resistor of the gas-sensitive element after desorption; based on the above two resistance values, obtain the sensitivity value of the target gas of unknown concentration; substitute the sensitivity value into the correlation curve in step 5) to obtain the concentration value of the target gas of unknown concentration.

4. The method of using the UV-assisted sensitized MOF-derived AuRu-In2O3 gas-sensitive material according to claim 3, characterized in that, Step 1) involves the following steps in the fabrication of a side-heated gas-sensitive element: Step 1.1: Take 1-3 mg of AuRu-In2O3 gas-sensitive material and mix it with 1-3 mL of deionized water to make a paste. Then, use a brush to evenly coat the paste on the surface of the ceramic tube between the two annular and parallel metal electrodes of the side-heated gas-sensitive element. The thickness of the paste should be 5-15 μm. Step 1.2: Place the ceramic tube coated with the paste under a rapid drying lamp and bake for 5-10 minutes to form a coating; then weld the ceramic tube onto a hexagonal base. The resistance wire is placed inside the ceramic tube to heat it. The two ends of the resistance wire are connected to pins 1 and 6 respectively via platinum wire. Each of the two annular metal electrodes has a connection point at both ends of its outer diameter passing through the center. The four connection points are connected to pins 2, 3, 4, and 5 respectively via platinum wire, thus obtaining a gas-sensitive element containing AuRu-In2O3 gas-sensitive material.

5. The method of using the UV-assisted sensitized MOF-derived AuRu-In2O3 gas-sensitive material according to claim 3, characterized in that, In step 3), the operating temperature is 25℃ or 175℃-225℃.

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