Catalytic luminescence detection method for carbon monoxide

Abstract

The invention belongs to the technical field of catalytic luminescence detection, and discloses a carbon monoxide catalytic luminescence detection method which comprises the following steps: respectively preparing alpha-Fe2O3 nanoparticles and an alpha-Fe2O3 / reduced graphene oxide composite material based on ferric chloride hexahydrate, urea, an anhydrous hydrazine solution and graphene oxide powder; respectively carrying out material characterization on the prepared alpha-Fe2O3 nanoparticles and the alpha-Fe2O3 / reduced graphene oxide composite material so as to analyze the structural performance of the alpha-Fe2O3 nanoparticles and the structural performance of the alpha-Fe2O3 / reduced graphene oxide composite material; the prepared alpha-Fe2O3 nanoparticles and the alpha-Fe2O3 / reduced graphene oxide composite material are used as catalytic luminescence gas sensitive materials, and catalytic luminescence detection is carried out on carbon monoxide under preset conditions. The response strength of the composite material to CO is improved by several times under the same condition, the response time and the recovery time can reach the second level respectively, and rapid detection in the true sense is achieved.

Description

Technical Field

[0001] This invention relates to the field of catalytic luminescence detection technology, and in particular to a method for detecting carbon monoxide catalytic luminescence. Background Technology

[0002] Currently, common technologies for online carbon monoxide (CO) monitoring include electrochemical sensors, infrared spectroscopy, and semiconductor resistive sensors. Electrochemical sensors are susceptible to interference from electrochemically active gases such as NO, SO2, and H2 in CO detection, and changes in humidity can cause baseline drift and decreased sensitivity. Infrared spectroscopy is sensitive to gases with overlapping infrared absorption, such as H2O and CO2, and is prone to false signals or quantitative errors in high CO2 environments. Semiconductor resistive sensors exhibit significant cross-response in the presence of multiple volatile organic gases, and their recovery speed is slow.

[0003] Therefore, how to provide a method for detecting carbon monoxide through catalytic luminescence is an urgent problem to be solved. Summary of the Invention

[0004] This invention provides a method for detecting carbon monoxide catalytic luminescence to solve the problems mentioned above in the prior art.

[0005] To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general commentary, nor is it intended to identify key / important components or to describe the scope of protection of these embodiments. Its sole purpose is to present some concepts in a simple form as a prelude to the detailed description that follows.

[0006] According to a first aspect of the present invention, a method for detecting carbon monoxide catalytic luminescence is provided.

[0007] In one embodiment, the carbon monoxide catalytic luminescence detection method includes: α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite materials were prepared based on ferric chloride hexahydrate, urea, anhydrous hydrazine solution and graphene oxide powder, respectively. The prepared α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composites were characterized to analyze their structural properties. The prepared α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite materials were used as catalytic luminescence gas-sensitive materials, and carbon monoxide was detected by catalytic luminescence under preset conditions.

[0008] In one embodiment, the preparation of α-Fe₂O₃ nanoparticles and α-Fe₂O₃ / reduced graphene oxide composite materials based on ferric chloride hexahydrate, urea, anhydrous hydrazine solution, and graphene oxide powder includes: α-Fe2O3 nanoparticles with uniform particle size distribution were prepared by using ferric chloride hexahydrate, urea, and anhydrous hydrazine solution. α-Fe2O3 / reduced graphene oxide composite material was prepared using ferric chloride hexahydrate, urea, anhydrous hydrazine solution and graphene oxide powder.

[0009] In one embodiment, the preparation of α-Fe2O3 nanoparticles with uniform particle size distribution using ferric chloride hexahydrate, urea, and anhydrous hydrazine solution comprises: Ferric chloride hexahydrate and urea were dissolved in deionized water, anhydrous hydrazine solution was added, and after stirring evenly, the mixture was transferred to a reaction vessel to react and obtain a precipitate. The precipitate was separated by centrifugation and then washed alternately with deionized water and anhydrous ethanol. It was then dried under vacuum to obtain α-Fe2O3 nanoparticles with uniform particle size distribution.

[0010] In one embodiment, the preparation of the α-Fe2O3 / reduced graphene oxide composite material using ferric chloride hexahydrate, urea, anhydrous hydrazine solution, and graphene oxide powder includes: Graphene oxide powder was dispersed in deionized water and subjected to ultrasonic treatment to obtain a graphene oxide solution. Ferric chloride hexahydrate and urea were added sequentially to the graphene oxide solution and stirred until homogeneous. Then anhydrous hydrazine solution was added dropwise as a reducing agent and stirred until homogeneous to obtain a mixed solution. The mixed solution was transferred to a pre-set reaction vessel and placed in an oven for hydrothermal reaction. After the reaction was completed, it was naturally cooled to room temperature to obtain the precipitated product. The precipitated product was separated by centrifugation and then washed alternately with deionized water and anhydrous ethanol, followed by vacuum drying to obtain α-Fe2O3 / reduced graphene oxide composite material.

[0011] In one embodiment, the mass of graphene oxide powder is 10-40 mg, the volume of deionized water is 30-120 mL, and the ultrasonic treatment time is 20-40 min.

[0012] In one embodiment, the mass of ferric chloride hexahydrate is 0.317~1.268g, the mass of urea is 0.3~1.2g, the volume of anhydrous hydrazine solution is 25~100μL, and the weight percentage of anhydrous hydrazine solution is 70~80wt%, and the stirring time is 10~20min.

[0013] In one embodiment, the reactor is a stainless steel reactor lined with 150 mL of polytetrafluoroethylene, the hydrothermal reaction temperature is 170~200℃, and the reaction time is 10~15 h.

[0014] In one embodiment, the washing is repeated 3 times, and the vacuum drying process is carried out at a temperature of 60~80℃ for 10~12 hours.

[0015] In one embodiment, the material characterization of the prepared α-Fe₂O₃ nanoparticles and the α-Fe₂O₃ / reduced graphene oxide composite material, respectively, to analyze the structural properties of the α-Fe₂O₃ nanoparticles and the α-Fe₂O₃ / reduced graphene oxide composite material includes: X-ray diffraction patterns of α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite materials were obtained by X-ray diffraction. Transmission electron microscopy (TEM) images of α-Fe₂O₃ nanoparticles and α-Fe₂O₃ / reduced graphene oxide composites were obtained. The structural properties of α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composites were analyzed by combining X-ray diffraction patterns and transmission electron microscopy images.

[0016] In one embodiment, the preset conditions for the catalytic luminescence detection of carbon monoxide include: a detection wavelength of 475 nm, an operating temperature of 223 °C, a carrier gas flow rate of 550 mL / min, and a carbon monoxide concentration of 150 mg / m³. 3 .

[0017] In one embodiment, using the prepared α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite material as a catalytic luminescence gas-sensitive material, and performing catalytic luminescence detection of carbon monoxide under preset conditions, further includes: Under the conditions of a detection wavelength of 475 nm and an operating temperature of 223 °C, the concentration of 150 mg / m³ was determined by changing the carrier gas flow rate. 3 The response of carbon monoxide on the surface of α-Fe2O3 / reduced graphene oxide composite material was studied to determine the target carrier gas flow rate.

[0018] In one embodiment, using the prepared α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite material as a catalytic luminescence gas-sensitive material, and performing catalytic luminescence detection of carbon monoxide under preset conditions, further includes: Under the conditions of a detection wavelength of 475 nm and a carrier gas flow rate of 550 mL / min, the concentration of 150 mg / m³ was determined by varying the operating temperature. 3The response of carbon monoxide on the surface of α-Fe2O3 / reduced graphene oxide composite material was investigated to determine the target operating temperature.

[0019] In one embodiment, using the prepared α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite material as a catalytic luminescence gas-sensitive material, and performing catalytic luminescence detection of carbon monoxide under preset conditions, further includes: Under operating conditions of 223℃ and a carrier gas flow rate of 550 mL / min, 150 mg / m³ was determined by changing the detection wavelength. 3 The response of carbon monoxide on the surface of α-Fe2O3 / reduced graphene oxide composite material was studied to determine the target detection wavelength.

[0020] In one embodiment, using the prepared α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite material as a catalytic luminescence gas-sensitive material, and performing catalytic luminescence detection of carbon monoxide under preset conditions, further includes: Under the conditions of detection wavelength of 475 nm, operating temperature of 223 °C, and carrier gas flow rate of 550 mL / min, dynamic response curves of carbon monoxide at different concentrations were plotted to examine the response / recovery speed of the sensor.

[0021] In one embodiment, using the prepared α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite material as a catalytic luminescence gas-sensitive material, and performing catalytic luminescence detection of carbon monoxide under preset conditions, further includes: Under the conditions of a detection wavelength of 475 nm, an operating temperature of 223 °C, and a carrier gas flow rate of 550 mL / min, 24 parallel detections were performed to obtain a concentration of 150 mg / m³. 3 The carbon monoxide was measured to verify the reproducibility of carbon monoxide determination in α-Fe2O3 / reduced graphene oxide composite materials.

[0022] In one embodiment, using the prepared α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite material as a catalytic luminescence gas-sensitive material, and performing catalytic luminescence detection of carbon monoxide under preset conditions, further includes: Under the conditions of detection wavelength of 475 nm, operating temperature of 223 °C, and carrier gas flow rate of 550 mL / min, concentrations ranging from 80 to 1125 mg / m³ were detected. 3 The catalytic reflective signal of carbon monoxide within a certain range was obtained, and a linear regression equation between the catalytic luminescence signal and the carbon monoxide concentration was plotted to achieve the detection of carbon monoxide concentration. The expression for the linear regression equation is as follows: S =10.21 c-1219; In the formula, S It is a light-emitting signal. c This represents the concentration of carbon monoxide.

[0023] The technical solutions provided by the embodiments of the present invention may include the following beneficial effects: This invention constructs an α-Fe₂O₃ / G composite material and applies it to the catalytic luminescence detection of carbon monoxide. Compared with single α-Fe₂O₃ material, this composite material exhibits a several-fold increase in response intensity to CO under the same conditions, with response and recovery times reaching the second level, achieving truly rapid detection. Simultaneously, this material maintains high selectivity for CO under complex atmospheres and significantly suppresses interference from common coexisting gases and high concentrations of organic vapors, ensuring detection accuracy. This invention demonstrates good linearity over a wide concentration range, with a low detection limit and excellent repeatability, providing a solution for online CO monitoring that combines high sensitivity, rapid response, and anti-interference capabilities.

[0024] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0025] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0026] Figure 1 This is a flowchart illustrating a carbon monoxide catalytic luminescence detection method according to an exemplary embodiment; Figure 2 This is an XRD pattern illustrated according to an exemplary embodiment; Figure 3 This is a TEM image of α-Fe2O3 and α-Fe2O3 / G composite materials according to an exemplary embodiment; Figure 4 This is a graph showing the luminescence intensity of CO on different material surfaces, according to an exemplary embodiment. Figure 5 This is a diagram illustrating the wavelength optimization results according to an exemplary embodiment; Figure 6 This is a diagram illustrating the optimized operating temperature according to an exemplary embodiment; Figure 7 This is a diagram illustrating the optimized carrier gas flow rate according to an exemplary embodiment; Figure 8 This is a diagram illustrating the response of different gases to an α-Fe2O3 / G catalytic luminescence sensor according to an exemplary embodiment; Figure 9This is a dynamic response curve of CO illustrated according to an exemplary embodiment; Figure 10 The parallel 24 detections according to an exemplary embodiment show a concentration of 120 mg / m³. 3 CO results graph; Figure 11 This is a CO standard curve diagram illustrated according to an exemplary embodiment. Detailed Implementation

[0027] The following description and accompanying drawings fully illustrate specific embodiments described herein to enable those skilled in the art to practice them. Some embodiments may include or substitute parts and features of other embodiments. The scope of the embodiments herein encompasses the entire scope of the claims and all available equivalents thereof. Throughout this document, the terms “first,” “second,” etc., are used only to distinguish one element from another without requiring or implying any actual relationship or order between the elements. Indeed, a first element can also be referred to as a second element, and vice versa. Furthermore, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a structure, apparatus, or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a structure, apparatus, or device. Without further limitation, an element defined by the phrase “comprising one…” does not exclude the presence of other identical elements in the structure, apparatus, or device that includes said element. The various embodiments described herein are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments; similar or identical parts between embodiments can be referred to interchangeably.

[0028] It should be understood that although the steps in the flowchart are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order constraint on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the diagram may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the sub-steps or stages of other steps.

[0029] The modules in the apparatus or system of this application can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device in hardware form, or stored in the memory of a computer device in software form, so that the processor can call and execute the operations corresponding to each module.

[0030] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0031] Figure 1 An embodiment of a carbon monoxide catalytic luminescence detection method of the present invention is shown.

[0032] In this optional embodiment, the carbon monoxide catalytic luminescence detection method includes: Step S101: Based on ferric chloride hexahydrate, urea, anhydrous hydrazine solution and graphene oxide powder, α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite materials are prepared respectively. Step S102: The prepared α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite materials are characterized to analyze their structural properties. Step S103: The prepared α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite material are used as catalytic luminescence gas-sensitive materials, and carbon monoxide is detected by catalytic luminescence under preset conditions.

[0033] In this optional embodiment, the preparation of α-Fe₂O₃ nanoparticles and α-Fe₂O₃ / reduced graphene oxide composite materials based on ferric chloride hexahydrate, urea, anhydrous hydrazine solution, and graphene oxide powder includes: α-Fe2O3 nanoparticles with uniform particle size distribution were prepared by using ferric chloride hexahydrate, urea, and anhydrous hydrazine solution. α-Fe2O3 / reduced graphene oxide composite material was prepared using ferric chloride hexahydrate, urea, anhydrous hydrazine solution and graphene oxide powder.

[0034] In this optional embodiment, the preparation of α-Fe2O3 nanoparticles with uniform particle size distribution using ferric chloride hexahydrate, urea, and anhydrous hydrazine solution includes: Ferric chloride hexahydrate and urea were dissolved in deionized water, anhydrous hydrazine solution was added, and after stirring evenly, the mixture was transferred to a reaction vessel to react and obtain a precipitate. The precipitate was separated by centrifugation and then washed alternately with deionized water and anhydrous ethanol. It was then dried under vacuum to obtain α-Fe2O3 nanoparticles with uniform particle size distribution.

[0035] In this optional embodiment, the preparation of the α-Fe2O3 / reduced graphene oxide composite material using ferric chloride hexahydrate, urea, anhydrous hydrazine solution, and graphene oxide powder includes: Graphene oxide powder was dispersed in deionized water and subjected to ultrasonic treatment to obtain a graphene oxide solution. Ferric chloride hexahydrate and urea were added sequentially to the graphene oxide solution and stirred until homogeneous. Then, anhydrous hydrazine solution was slowly added dropwise as a reducing agent and stirred until homogeneous to ensure thorough mixing, thus obtaining a mixed solution. The mixed solution was transferred to a pre-set reaction vessel and placed in an oven for hydrothermal reaction. After the reaction was completed, it was naturally cooled to room temperature to obtain the precipitated product. The precipitated product was separated by centrifugation and then washed alternately with deionized water and anhydrous ethanol, followed by vacuum drying to obtain α-Fe2O3 / reduced graphene oxide composite material.

[0036] In this optional embodiment, the mass of graphene oxide powder is 10-40 mg, the volume of deionized water is 30-120 mL, and the ultrasonic treatment time is 20-40 min.

[0037] In this optional embodiment, the mass of ferric chloride hexahydrate is 0.634 g, the mass of urea is 0.3~1.2 g, the volume of anhydrous hydrazine solution is 45~55 μL, and the weight percentage of anhydrous hydrazine solution is 70~80 wt%, and the stirring time is 10~20 min.

[0038] In this optional embodiment, the reactor is a stainless steel reactor lined with 150 mL of polytetrafluoroethylene, the hydrothermal reaction temperature is 180°C, and the reaction time is 12 h.

[0039] In this optional embodiment, the washing is repeated 3 times, and the vacuum drying process is carried out at a temperature of 60~80℃ for 10~12 hours.

[0040] In this optional embodiment, the material characterization of the prepared α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite materials to analyze their structural properties includes: X-ray diffraction patterns of α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite materials were obtained by X-ray diffraction. Transmission electron microscopy (TEM) images of α-Fe₂O₃ nanoparticles and α-Fe₂O₃ / reduced graphene oxide composites were obtained. The structural properties of α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composites were analyzed by combining X-ray diffraction patterns and transmission electron microscopy images.

[0041] In this optional embodiment, the preset conditions for the catalytic luminescence detection of carbon monoxide include: a detection wavelength of 475 nm, an operating temperature of 223 °C, a carrier gas flow rate of 550 mL / min, and a carbon monoxide concentration of 150 mg / m³. 3 .

[0042] In this optional embodiment, the step of using the prepared α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite material as a catalytic luminescence gas-sensitive material and performing catalytic luminescence detection of carbon monoxide under preset conditions further includes: Under the conditions of a detection wavelength of 475 nm and an operating temperature of 223 °C, the concentration of 150 mg / m³ was determined by changing the carrier gas flow rate. 3 The response of carbon monoxide on the surface of α-Fe2O3 / reduced graphene oxide composite material was studied to determine the target carrier gas flow rate.

[0043] In this optional embodiment, the step of using the prepared α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite material as a catalytic luminescence gas-sensitive material and performing catalytic luminescence detection of carbon monoxide under preset conditions further includes: Under the conditions of a detection wavelength of 475 nm and a carrier gas flow rate of 550 mL / min, the concentration of 150 mg / m³ was determined by varying the operating temperature. 3 The response of carbon monoxide on the surface of α-Fe2O3 / reduced graphene oxide composite material was investigated to determine the target operating temperature.

[0044] In this optional embodiment, the step of using the prepared α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite material as a catalytic luminescence gas-sensitive material and performing catalytic luminescence detection of carbon monoxide under preset conditions further includes: Under operating conditions of 223℃ and a carrier gas flow rate of 550 mL / min, 150 mg / m³ was determined by changing the detection wavelength. 3 The response of carbon monoxide on the surface of α-Fe2O3 / reduced graphene oxide composite material was studied to determine the target detection wavelength.

[0045] In this optional embodiment, the step of using the prepared α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite material as a catalytic luminescence gas-sensitive material and performing catalytic luminescence detection of carbon monoxide under preset conditions further includes: Under the conditions of detection wavelength of 475 nm, operating temperature of 223 °C, and carrier gas flow rate of 550 mL / min, dynamic response curves of carbon monoxide at different concentrations were plotted to examine the response / recovery speed of the sensor.

[0046] In this optional embodiment, the step of using the prepared α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite material as a catalytic luminescence gas-sensitive material and performing catalytic luminescence detection of carbon monoxide under preset conditions further includes: Under the conditions of a detection wavelength of 475 nm, an operating temperature of 223 °C, and a carrier gas flow rate of 550 mL / min, 24 parallel detections were performed to obtain a concentration of 150 mg / m³. 3 The carbon monoxide was measured to verify the reproducibility of carbon monoxide determination in α-Fe2O3 / reduced graphene oxide composite materials.

[0047] In this optional embodiment, the step of using the prepared α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite material as a catalytic luminescence gas-sensitive material and performing catalytic luminescence detection of carbon monoxide under preset conditions further includes: Under the conditions of detection wavelength of 475 nm, operating temperature of 223 °C, and carrier gas flow rate of 550 mL / min, concentrations ranging from 80 to 1125 mg / m³ were detected. 3 The catalytic reflective signal of carbon monoxide within a certain range was obtained, and a linear regression equation between the catalytic luminescence signal and the carbon monoxide concentration was plotted to achieve the detection of carbon monoxide concentration. The expression for the linear regression equation is as follows: S =10.21 c -1219; In the formula, S It is a light-emitting signal. c This represents the concentration of carbon monoxide.

[0048] To facilitate understanding of the above technical solutions of the present invention, the following further describes the above technical solutions of the present invention from the perspectives of architecture and principle, as follows: A novel catalytic luminescence method for rapid detection of carbon monoxide based on α-Fe₂O₃ / reduced graphene oxide includes: I. Material Preparation: 20 mg of graphene oxide (GO) was dispersed in 60 mL of deionized water and sonicated for 30 min. Then, 0.317–1.268 g of ferric chloride hexahydrate (FeCl3·6H2O) and 0.3–1.2 g of urea (CO(NH2)2) were added sequentially to the GO solution and stirred until homogeneous. Next, 45–55 μL of anhydrous hydrazine solution (N2H4, 70–80 wt%) was slowly added dropwise as a reducing agent, and the mixture was stirred for another 10–20 min to ensure thorough mixing. The resulting solution was transferred to a 150 mL PTFE-lined stainless steel reactor and placed in an oven for hydrothermal reaction at 170–200°C for 10–15 h. After the reaction was completed, the mixture was naturally cooled to room temperature. The resulting precipitate was separated by centrifugation and washed three times alternately with deionized water and anhydrous ethanol. Finally, it was vacuum dried at 60-80°C for 10-12 hours to obtain the α-Fe2O3 / reduced graphene oxide (α-Fe2O3 / rGO) composite material.

[0049] In contrast, the preparation process of pure Fe₂O₃ is similar to that described above, but GO is not added to the mixed precursor solution. Specifically, 0.317–1.268 g of FeCl₃·6H₂O and 0.3–1.2 g of urea are dissolved in 60 mL of deionized water, and 45–55 μL of anhydrous hydrazine is added. After stirring thoroughly, the mixture is transferred to a reaction vessel and reacted at 170–200°C for 10–15 h. After the same washing and drying steps, α-Fe₂O₃ nanoparticles with uniform particle size distribution are obtained.

[0050] II. Material Characterization: 1) XRD: The XRD patterns (i.e., X-ray diffraction patterns) of the prepared α-Fe₂O₃ and α-Fe₂O₃ / G are as follows: Figure 2 As shown. Both exhibit distinct diffraction peaks at 2θ = 24.2°, 33.2°, 35.6°, 40.9°, 49.5°, 54.1°, 62.4°, and 64.0°, corresponding to the (012), (104), (110), (113), (024), (116), (018), and (300) crystal planes of hematite (α-Fe2O3, JCPDS No. 33-0664), respectively, indicating that the synthesized α-Fe2O3 possesses a good hematite-type crystal phase structure. In the spectrum of the α-Fe2O3 / rG composite material, a broad and weak diffraction peak appears in the range of 2θ = 24.5°–27.5°, which can be attributed to the characteristic peak of the disordered stacked reduced graphene oxide (002) crystal plane.

[0051] 2) TEM: Figure 3The images show transmission electron microscopy (TEM) images of α-Fe₂O₃ (A) and the α-Fe₂O₃ / rGO composite material (B). In Figure 3A, the pure α-Fe₂O₃ sample exhibits obvious nanoparticle aggregation. The particle size is relatively uniform, but the distribution is dense, and there is significant agglomeration between the particles, which may affect subsequent performance. Figure 3 The α-Fe₂O₃ / rGO composite material in B exhibits significantly different structural characteristics. Partially transparent reduced graphene oxide sheets can be clearly observed in the α-Fe₂O₃, acting as a carrier to support the dispersed α-Fe₂O₃ particles. This structure helps increase the specific surface area of ​​the material and improve the exposure of active sites.

[0052] In summary, the introduction of reduced graphene oxide effectively regulates the dispersion state of α-Fe2O, which helps to optimize its microstructure and improve its potential performance.

[0053] III. Evaluation of the gas-sensitive properties of the material: The prepared α-Fe₂O₃ and α-Fe₂O₃ / G composite materials, as well as three commercially available α-Fe₂O₃ materials (named α-Fe₂O₃-S1, α-Fe₂O₃-S2, and α-Fe₂O₃-S3) were used as catalytic luminescence sensing materials. The concentration of 150 mg / m³ was determined under the following conditions: detection wavelength of 475 nm, operating temperature of 223°C, and carrier gas flow rate of 550 mL / min. 3 CO. For example, Figure 4 As shown, the α-Fe₂O₃ / G composite material exhibits the strongest signal, followed by α-Fe₂O₃, while the α-Fe₂O₃-S₁ material shows a weaker signal, and α-Fe₂O₃-S₂ and α-Fe₂O₃-S₃ show no signal. Compared to α-Fe₂O₃, the α-Fe₂O₃ / G signal is enhanced by 5.5 times. The α-Fe₂O₃ signal is 5.2 times stronger than the α-Fe₂O₃-S₁ signal, while α-Fe₂O₃-S₂ and α-Fe₂O₃-S₃ show no signal. These results fully demonstrate the superior performance of the α-Fe₂O₃ prepared by this method in the catalytic luminescence detection of CO, especially after composite with graphene, where the performance is significantly improved. Therefore, the α-Fe₂O₃ / G composite material will be used in subsequent designs of catalytic luminescence sensors for CO detection.

[0054] IV. Condition Optimization: Optimization was performed on wavelength, operating temperature, and carrier gas flow rate, with the following results: Figure 5-7 As shown, based on the principle of maximizing signal-to-noise ratio, the optimal detection wavelength is 475nm, the optimal operating temperature is 223°C, and the optimal carrier gas flow rate is 550mL / min.

[0055] V. Selectivity: Under the conditions of a detection wavelength of 475 nm, an operating temperature of 223 °C, and a carrier gas flow rate of 550 mL / min, an α-Fe₂O₃ / G catalytic luminescence sensor was used to detect 150 mg / m³. 3 CO, 1339 mg / m³ 3 NO, 2053 mg / m 3 NO2, 2857 mg / m³ 3 SO2, 759 mg / m³ 3 NH3 and 15000 mg / m 3 CO2, 2-pentanone, isopropanol, methanol, ethanol, ethylene glycol, acetone, cyclopentanone, acetophenone, cyclohexanone, cycloheptanone, formic acid, acetic acid, formaldehyde, acetaldehyde, n-hexane, trichloroethylene, benzene, o-xylene, m-xylene, p-xylene. For example... Figure 8 As shown, CO can produce a significant catalytic luminescence signal at 12000 mg / m³. 3 2-Pentanone produced only a weak signal, only 3.8% of the CO signal. Other gases did not produce any signal, indicating that the method has good selectivity.

[0056] VI. Response Curve: Under the conditions of a detection wavelength of 475 nm, an operating temperature of 223 °C, and a carrier gas flow rate of 550 mL / min, 80, 150, and 225 mg / m³ were measured. 3 The dynamic response curve of CO is as follows Figure 9 As shown, the signal reaches its peak approximately 7 seconds after the sample enters and exits, and returns to the baseline in about 2.5 seconds, indicating a fast sensor response / recovery speed.

[0057] VII. Reproducibility: Under the conditions of a detection wavelength of 475 nm, an operating temperature of 223 °C, and a carrier gas flow rate of 550 mL / min, 24 parallel detections were performed at a concentration of 150 mg / mL. 3 CO, the results are as follows Figure 10 As shown, the relative standard deviation of the 24 parallel detection signals was 4.6%, indicating that the method has good reproducibility.

[0058] VIII. Method Establishment: Under the conditions of a detection wavelength of 475 nm, an operating temperature of 223 °C, and a carrier gas flow rate of 550 mL / min, the concentrations of 80, 150, 225, 300, 375, 550, 625, 750, 875, and 1125 mg / m³ were detected. 3 The CO signal was then regressed against the concentration, such as... Figure 11 As shown. The catalytic luminescence signal corresponds to the CO concentration in the range of 80-1125 mg / m³. 3 The regression equation shows a good linear relationship within the range. S=10.21 c -1219, (R) 2 =0.9925), S It is a light-emitting signal. c CO concentration (mg / m³) 3 The detection limit is 26 mg / m³. 3 (Signal-to-noise ratio = 3).

[0059] IX. Anti-interference performance: CO2, NO, and SO2 are inorganic gases that commonly coexist with CO. High concentrations of 2-pentanone can generate signals on the surface of the α-Fe2O3 / G catalytic luminescence sensor. To evaluate the anti-interference capability of the α-Fe2O3 / G sensor, a mixed gas sample was prepared by mixing known concentrations of CO with certain concentrations of CO2, NO, SO2, and 2-pentanone, and then the CO recovery rate was measured. Table 1 shows that the recovery rates ranged from 103.8% to 110.1%. Despite the coexisting potential interfering gas concentration being more than 10 times the CO concentration, a relatively ideal recovery rate was still obtained, indicating that the surface method exhibits good anti-interference performance.

[0060] Table 1 Results of CO recovery rate determination

[0061] This invention constructs an α-Fe₂O₃ / G composite material and applies it to the catalytic luminescence detection of carbon monoxide. Compared with single α-Fe₂O₃ material, this composite material exhibits a several-fold increase in response intensity to CO under the same conditions, with response and recovery times both reaching the second level, achieving truly rapid detection. Simultaneously, this material maintains high selectivity for CO under complex atmospheres and demonstrates significant suppression of interference from common coexisting gases and high concentrations of organic vapors, ensuring detection accuracy. The method exhibits good linearity over a wide concentration range, with a low detection limit and excellent repeatability, providing a solution for online CO monitoring that combines high sensitivity, rapid response, and anti-interference capabilities.

[0062] This invention is not limited to the structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this invention is limited only by the appended claims.

Claims

1. A method for detecting carbon monoxide by catalytic luminescence, characterized in that, include: α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite materials were prepared based on ferric chloride hexahydrate, urea, anhydrous hydrazine solution and graphene oxide powder, respectively. The prepared α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composites were characterized to analyze their structural properties. The prepared α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite materials were used as catalytic luminescence gas-sensitive materials, and carbon monoxide was detected by catalytic luminescence under preset conditions.

2. The carbon monoxide catalytic luminescence detection method according to claim 1, characterized in that, The preparation of α-Fe₂O₃ nanoparticles and α-Fe₂O₃ / reduced graphene oxide composite materials based on ferric chloride hexahydrate, urea, anhydrous hydrazine solution, and redox graphene oxide powder includes: α-Fe2O3 nanoparticles with uniform particle size distribution were prepared by using ferric chloride hexahydrate, urea, and anhydrous hydrazine solution. α-Fe2O3 / reduced graphene oxide composite material was prepared using ferric chloride hexahydrate, urea, anhydrous hydrazine solution and graphene oxide powder.

3. The carbon monoxide catalytic luminescence detection method according to claim 2, characterized in that, The preparation of α-Fe2O3 nanoparticles with uniform particle size distribution using ferric chloride hexahydrate, urea, and anhydrous hydrazine solution includes: Ferric chloride hexahydrate and urea were dissolved in deionized water, anhydrous hydrazine solution was added, and after stirring evenly, the mixture was transferred to a reaction vessel to react and obtain a precipitate. The precipitate was separated by centrifugation and then washed alternately with deionized water and anhydrous ethanol. It was then dried under vacuum to obtain α-Fe2O3 nanoparticles with uniform particle size distribution.

4. The carbon monoxide catalytic luminescence detection method according to claim 2, characterized in that, The preparation of α-Fe2O3 / reduced graphene oxide composite material using ferric chloride hexahydrate, urea, anhydrous hydrazine solution, and graphene oxide powder includes: Graphene oxide powder was dispersed in deionized water and subjected to ultrasonic treatment to obtain a graphene oxide solution. Ferric chloride hexahydrate and urea were added sequentially to the graphene oxide solution and stirred until homogeneous. Then anhydrous hydrazine solution was added dropwise as a reducing agent and stirred until homogeneous to obtain a mixed solution. The mixed solution was transferred to a pre-set reaction vessel and placed in an oven for hydrothermal reaction. After the reaction was completed, it was naturally cooled to room temperature to obtain the precipitated product. The precipitated product was separated by centrifugation and then washed alternately with deionized water and anhydrous ethanol, followed by vacuum drying to obtain α-Fe2O3 / reduced graphene oxide composite material.

5. The carbon monoxide catalytic luminescence detection method according to claim 4, characterized in that, The mass of graphene oxide powder is 10~40mg, the volume of deionized water is 30~120mL, and the ultrasonic treatment time is 20~40min.

6. The carbon monoxide catalytic luminescence detection method according to claim 4, characterized in that, The mass of ferric chloride hexahydrate is 0.317~1.268g, the mass of urea is 0.3~1.2g, the volume of anhydrous hydrazine solution is 25~100μL and the weight percentage of anhydrous hydrazine solution is 70~80wt%, and the stirring time is 10~20min.

7. The carbon monoxide catalytic luminescence detection method according to claim 4, characterized in that, The reactor is a stainless steel reactor lined with 150 mL of polytetrafluoroethylene. The hydrothermal reaction temperature is 170~200℃ and the reaction time is 10~15h.

8. The carbon monoxide catalytic luminescence detection method according to claim 4, characterized in that, The washing process is repeated three times, and the vacuum drying process is carried out at a temperature of 60-80℃ for 10-12 hours.

9. The carbon monoxide catalytic luminescence detection method according to claim 1, characterized in that, The material characterization of the prepared α-Fe₂O₃ nanoparticles and α-Fe₂O₃ / reduced graphene oxide composite materials, respectively, to analyze their structural properties, includes: X-ray diffraction patterns of α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite materials were obtained by X-ray diffraction. Transmission electron microscopy (TEM) images of α-Fe₂O₃ nanoparticles and α-Fe₂O₃ / reduced graphene oxide composites were obtained. The structural properties of α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composites were analyzed by combining X-ray diffraction patterns and transmission electron microscopy images.

10. The carbon monoxide catalytic luminescence detection method according to claim 1, characterized in that, The preset conditions for the catalytic luminescence detection of carbon monoxide include: a detection wavelength of 475 nm, an operating temperature of 223 °C, a carrier gas flow rate of 550 mL / min, and a carbon monoxide concentration of 150 mg / m³. 3 .

11. The carbon monoxide catalytic luminescence detection method according to claim 10, characterized in that, The method of using the prepared α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite material as catalytic luminescence gas-sensitive materials, and performing catalytic luminescence detection of carbon monoxide under preset conditions, further includes: Under the conditions of a detection wavelength of 475 nm and an operating temperature of 223 °C, the concentration of 150 mg / m³ was determined by changing the carrier gas flow rate. 3 The response of carbon monoxide on the surface of α-Fe2O3 / reduced graphene oxide composite material was studied to determine the target carrier gas flow rate.

12. The carbon monoxide catalytic luminescence detection method according to claim 10, characterized in that, The method of using the prepared α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite material as catalytic luminescence gas-sensitive materials, and performing catalytic luminescence detection of carbon monoxide under preset conditions, further includes: Under the conditions of a detection wavelength of 475 nm and a carrier gas flow rate of 550 mL / min, the concentration of 150 mg / m³ was determined by varying the operating temperature. 3 The response of carbon monoxide on the surface of α-Fe2O3 / reduced graphene oxide composite material was investigated to determine the target operating temperature.

13. The carbon monoxide catalytic luminescence detection method according to claim 10, characterized in that, The method of using the prepared α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite material as catalytic luminescence gas-sensitive materials, and performing catalytic luminescence detection of carbon monoxide under preset conditions, further includes: Under operating conditions of 223℃ and a carrier gas flow rate of 550 mL / min, 150 mg / m³ was determined by changing the detection wavelength. 3 The response of carbon monoxide on the surface of α-Fe2O3 / reduced graphene oxide composite material was studied to determine the target detection wavelength.

14. The carbon monoxide catalytic luminescence detection method according to claim 10, characterized in that, The method of using the prepared α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite material as catalytic luminescence gas-sensitive materials, and performing catalytic luminescence detection of carbon monoxide under preset conditions, further includes: Under the conditions of detection wavelength of 475 nm, operating temperature of 223 °C, and carrier gas flow rate of 550 mL / min, dynamic response curves of carbon monoxide at different concentrations were plotted to examine the response / recovery speed of the sensor.

15. The carbon monoxide catalytic luminescence detection method according to claim 10, characterized in that, The method of using the prepared α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite material as catalytic luminescence gas-sensitive materials, and performing catalytic luminescence detection of carbon monoxide under preset conditions, further includes: Under the conditions of a detection wavelength of 475 nm, an operating temperature of 223 °C, and a carrier gas flow rate of 550 mL / min, 24 parallel detections were performed to obtain a concentration of 150 mg / m³. 3 The carbon monoxide was measured to verify the reproducibility of carbon monoxide determination in α-Fe2O3 / reduced graphene oxide composite materials.

16. The carbon monoxide catalytic luminescence detection method according to claim 10, characterized in that, The method of using the prepared α-Fe2O3 nanoparticles and α-Fe2O3 / reduced graphene oxide composite material as catalytic luminescence gas-sensitive materials, and performing catalytic luminescence detection of carbon monoxide under preset conditions, further includes: Under the conditions of detection wavelength of 475 nm, operating temperature of 223 °C, and carrier gas flow rate of 550 mL / min, concentrations ranging from 80 to 1125 mg / m³ were detected. 3 The catalytic reflective signal of carbon monoxide within a certain range was obtained, and a linear regression equation between the catalytic luminescence signal and the carbon monoxide concentration was plotted to achieve the detection of carbon monoxide concentration. The expression for the linear regression equation is as follows: S =10.21 c -1219； In the formula, S It is a light-emitting signal. c This represents the concentration of carbon monoxide.

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