A human exhaled breath detection method based on high-performance gas sensing materials

Abstract

The present invention discloses a method for detecting human exhaled breath based on high-performance gas sensing materials. The gas sensing material has a periodic cavity micro-nano structure, which is used for detecting human exhaled breath. The periodic cavity micro-nano structure produces a vortex effect in human exhaled breath. The micro-nano structure induces the gas to produce spontaneous airflow vibrations, accelerates the homogenization of the gas phase fluid, causes more target molecules to diffuse to the surface of the material, and reduces the movement speed of gas molecules, prolongs the molecular residence time, enhances the molecular adsorption efficiency, and improves the detection sensitivity of trace gas molecules. Based on this principle, a variety of high-performance gas sensing materials for human exhaled breath analysis are prepared, and a variety of oxide semiconductor gas sensing materials with periodic cavity micro-nano structures are integrated on a sensor chip to achieve simultaneous detection of multiple gas molecules in real exhaled breath samples, which is expected to be applied in the field of disease exhaled breath monitoring.

Description

Technical Field

[0001] The present invention relates to the field of biological testing technology, and in particular to a method for detecting human exhaled breath based on high-performance gas sensing materials. Background Art

[0002] Gas sensors have important applications in the field of instant detection of exhaled breath due to their advantages such as miniaturization and easy integration. It can detect the types and concentrations of gas markers in exhaled breath to reflect the metabolic state of the human body, and has great application value in life and health monitoring. Previous research on gas sensors has mainly focused on the design and manufacture of sensing materials, without fully considering gas mass transfer including gas molecule diffusion and adsorption, which is also very important in molecular detection. Typically, molecular detection relies on the selective interaction between gas molecules and gas sensing materials, including cycles of diffusion, adsorption, reaction, product desorption and diffusion.

[0003] Most gas sensors use planar membranes, such as Figure 1 As shown. The airflow is mainly laminar, and the diffusion of target gas molecules to the surface of the sensing material depends only on slow molecular diffusion. In addition, dominated by molecular thermal motion, the average speed of gas molecules at room temperature can reach several hundred meters per second. According to the Maxwell model, gas molecules can easily escape after elastic collision with the planar membrane, resulting in a decrease in adsorption efficiency. These two points are especially true for target gases at the part per billion (ppb) level, while the concentration of gas markers in exhaled breath is often at the ppb level. Therefore, most of these planar membrane-based gas sensors face the problem of insufficient sensitivity to low-concentration molecules and are unable to perform the task of exhaled breath detection. Summary of the invention

[0004] In view of the above-mentioned defects or deficiencies in the prior art, it is desired to provide a method for detecting human exhaled breath based on high-performance gas sensing materials, introducing periodic cavity micro-nano structures into oxide semiconductors. Such periodic cavity micro-nano structures generate embedded vortices in human exhaled breath, that is, the micro-nano structures induce vortices, thereby enhancing the molecular diffusion and adsorption efficiency and improving the detection sensitivity of gas molecules.

[0005] The present invention provides a method for detecting human exhaled breath based on a high-performance gas sensing material, wherein the gas sensing material has a periodic cavity micro-nano structure, the cavity diameter of the periodic cavity micro-nano structure is 0.1 μm to 8 mm, the center spacing between adjacent cavities is 1.1 to 2 times the cavity diameter, and the cavity depth is 0.5 to 3 times the cavity diameter;

[0006] The gas sensing material is used to detect human exhaled breath, and the gas flow rate of human exhaled breath is 10 mL / min~2000 mL / min; the periodic cavity micro-nanostructure generates gas vortex in human exhaled breath;

[0007] The periodic cavity micro-nano structure is prepared and formed by a forming template, and the forming template is a butterfly wing template, a honeycomb template or an anodic porous alumina template, which is cut into a rectangle of 1-4 cm×1-4 cm;

[0008] The gas sensing material is one of palladium-modified zinc oxide, tungsten oxide, cerium-doped cobalt tetraoxide and gold-modified indium oxide;

[0009] The preparation process of gas sensing materials includes the following steps:

[0010] The oxide precursor and metal ion mixture are loaded onto the molding template by ion or molecular adsorption method, and the sample is washed with deionized water and dried to obtain the sample; the oxide precursor is ZIF-8, ZIF-67, InCl 3 or WCl 6 ; The metal ion is palladium ion, gold ion or cerium ion;

[0011] The sample is calcined at high temperature in an air atmosphere to obtain an oxide gas sensing material with a periodic cavity micro-nano structure.

[0012] Compared with the prior art, the beneficial effects of the present invention are:

[0013] The periodic cavity micro-nano structure of the present invention generates embedded vortices in the exhaled breath of the human body, that is, the micro-nano structure induces vortices, such as Figure 2 As shown. The functions of micro-nanostructure induced vortex in gas sensing include: first, as a mixer, it generates spontaneous air flow vibration, accelerates the homogenization of gas phase fluid, is more efficient than molecular diffusion, breaks the limitation of laminar mass transfer, and causes more target molecules to diffuse to the sensing surface; second, as a micro air roller bearing, it enhances the interaction between gas sensing materials and air flow, reduces the movement speed of gas molecules, prolongs the molecular residence time, and enhances the molecular adsorption efficiency. The detection sensitivity of gas molecules is improved from the aspects of enhancing diffusion and adsorption capacity.

[0014] This sensitivity enhancement strategy is different from the traditional method of optimizing the physical and chemical properties of the material itself (such as specific surface area, energy band and defect regulation, etc.). It is not only applicable to chemical resistance sensors, but also to other types of gas sensors, such as electrochemical and optical gas sensors. It has excellent performance improvement for gas sensors and a wide range of applications.

[0015] The present invention constructs a four-channel gas sensor for detecting actual exhaled breath samples, such as drinking, eating vinegar, eating fruit, drinking tea and smoking, proving that this four-channel sensor prototype can detect the metabolic process of human exhaled breath and has potential application value in the field of life and health detection.

[0016] It should be understood that the contents described in the summary of the invention are not intended to limit the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Other features, objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0018] Figure 1 It is a schematic diagram of the surface gas flow characteristics and gas response value based on the planar membrane structure;

[0019] Figure 2 Schematic diagram of surface gas flow characteristics and gas response values ​​based on periodic cavity micro-nanostructures;

[0020] Figure 3 Flowchart of preparing nanomaterials using butterfly wings as templates;

[0021] Figure 4 Flowchart of preparing nanomaterials using dragonfly wings as templates;

[0022] Figure 5 It is a schematic diagram of the experimental results of dynamic gas sensing properties of Pd / ZnO nanomaterials to ethanol gas molecules;

[0023] Figure 6 Schematic diagram of the experimental results of the dynamic gas-sensing properties of Pd / ZnO nanomaterials with periodic cavity micro-nanostructures to ethanol gas molecules;

[0024] Figure 7 Schematic diagram of the experimental results of sensitivity and selectivity of tungsten oxide with periodic cavity micro-nanostructure to acetone gas molecules;

[0025] Figure 8 Schematic diagram of the experimental results of the sensitivity and selectivity of cerium-doped cobalt tetroxide to toluene gas molecules in periodic cavity micro-nanostructures;

[0026] Fig. 9 Schematic diagram of the experimental results of the sensitivity and selectivity of gold-modified indium oxide with periodic cavity micro-nanostructure to formaldehyde gas molecules;

[0027] Fig.10This is the schlieren imaging of the carbon dioxide airflow on the plane membrane structure of the dragonfly wing;

[0028] Fig.11 This is the Schlieren imaging of carbon dioxide airflow in the periodic cavity micro-nanostructure of butterfly wings;

[0029] Fig.12 Figure i is a schematic diagram of the theoretical simulation results of gas flow in a planar membrane structure unit, and figure ii is a schematic diagram of the experimental results of smoke flow in a planar membrane structure unit;

[0030] Fig.13 Figure i is a schematic diagram of the theoretical simulation results of gas flow in the cavity structure unit, and figure ii is a schematic diagram of the experimental results of smoke flow in the cavity structure unit;

[0031] Fig.14 This is a diagram of the periodic cavity micro-nanostructure of the honeycomb;

[0032] Fig.15 This is a diagram of the periodic cavity micro-nanostructure of anodic porous alumina;

[0033] Fig.16 This is a schematic diagram of the detection results of gas molecules in exhaled breath by the four-channel gas sensor prototype;

[0034] Fig.17 This is a schematic diagram of the detection results of the four-channel gas sensor prototype on the gas molecules to be tested in the exhaled breath after consuming vinegar;

[0035] Fig.18 This is a schematic diagram of the detection results of the four-channel gas sensor prototype on the gas molecules to be tested in the exhaled breath after eating fruit;

[0036] Fig.19 This is a schematic diagram of the detection results of the four-channel gas sensor prototype on the gas molecules to be tested in the exhaled breath after drinking.

[0037] Fig. 20 It is a four-channel gas sensor prototype.

[0038] Numbers in the figure: 1, display screen; 2, packaging shell. DETAILED DESCRIPTION

[0039] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It should also be noted that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0040] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0041] The embodiment of the present invention provides a method for detecting human exhaled breath based on a high-performance gas sensing material, wherein the gas sensing material has a periodic cavity micro-nano structure, the cavity diameter of the periodic cavity micro-nano structure is 0.1 μm~8 mm, the center spacing between adjacent cavities is 1.1~2 times the cavity diameter, and the cavity depth is 0.5~3 times the cavity diameter; the gas sensing material is used for detecting human exhaled breath, and the gas flow rate of human exhaled breath is 10 mL / min~2000 mL / min; the periodic cavity micro-nano structure generates gas vortices in human exhaled breath;

[0042] The periodic cavity micro-nanostructure is prepared and formed by a forming template, and the forming template is a 1-4 cm×1-4 cm rectangle cut from a butterfly wing template, a honeycomb template or an anodic porous alumina template;

[0043] The gas sensing material is one of palladium-modified zinc oxide, tungsten oxide, cerium-doped cobalt tetraoxide and gold-modified indium oxide;

[0044] The preparation process of gas sensing materials includes the following steps:

[0045] The oxide precursor and metal ion mixture are loaded onto the molding template by ion or molecular adsorption method, and the sample is washed with deionized water and dried to obtain the sample; the oxide precursor is ZIF-8, ZIF-67, InCl 3 or WCl 6 ; The metal ion is palladium ion, gold ion or cerium ion;

[0046] The sample is calcined at high temperature in an air atmosphere to obtain an oxide gas sensing material with a periodic cavity micro-nano structure.

[0047] Different experimental techniques are used to verify the vortices induced by periodic cavity micro-nanostructures and their enhancing effect on the diffusion and adsorption of gas molecules. The experimental techniques include schlieren imaging experiments, smoke flow experiments and theoretical calculations.

[0048] On the other hand, a sensor for use in the above-mentioned detection method is provided, including a sensor chip, wherein the sensor chip contains palladium-modified zinc oxide gas sensor material, tungsten oxide gas sensor material, cerium-doped cobalt tetroxide gas sensor material and gold-modified indium oxide gas sensor material, which respectively detect ethanol, acetone, formaldehyde and toluene molecules in exhaled breath, thereby realizing real-time monitoring of exhaled breath molecules.

[0049] In this embodiment, a periodic cavity micro-nano structure is introduced into an oxide semiconductor and used as a gas sensing material of a gas sensor. This periodic cavity micro-nano structure can generate embedded vortices in human exhaled air, that is, the micro-nano structure induces vortices, thereby improving the molecular diffusion and adsorption efficiency and the detection sensitivity of gas molecules.

[0050] Example 1 Preparation of Pd / ZnO sensing material with periodic cavity micro-nanostructure for ethanol molecules in human exhaled breath

[0051] Combination Figure 3 To illustrate, butterfly wings were first cut into 2 cm × 2 cm slices and then immersed in a polyvinyl pyrrolidone aqueous solution (50 mg mL -1 ) and stirred at 25 °C for 24 h. After washing with deionized water, the butterfly wings were placed in 20 mL of Zn(NO 3 ) 2 6H 2 O (25 mmol·L -1 ) and K 2 PdCl 4 The solution was placed in water for 2 h, and then 20 mL of 2-methylimidazole aqueous solution (1.5 mol·L -1 ) for 2 h. After repeating these two steps 4 times, Pd / ZIF-8 particles were densely loaded on the butterfly wing surface, and the sample was washed with deionized water and dried at 60°C overnight. Pd / ZnO nanomaterials with periodic cavity micro-nanostructures were prepared by calcination. The calcination conditions were 2°C min at 25°C. -1 The heating rate was raised to 325 °C, maintained at 325 °C for 1 h, and then increased at 10 °C min -1 The heating rate was increased to 425 °C and maintained at 425 °C for 1 h.

[0052] Combination Figure 4 For illustration, the preparation process of the control sample Pd / ZnO nanomaterial is similar to the above process, except that the butterfly wings are replaced with dragonfly wings.

[0053] The control sample Pd / ZnO nanomaterials and the periodic cavity micro-nanostructured Pd / ZnO nanomaterials were prepared into gas sensing elements. The sensing characteristics of ethanol gas in the temperature range of 40℃~350℃ and the gas flow rate of 10 mL / min~2000 mL / min were studied using the CGS-MT intelligent sensing analysis system. Figure 5 As the control group, Pd / ZnO nanomaterials prepared from dragonfly wings were selected. Figure 6 As an experimental example, Pd / ZnO nanomaterials with periodic cavity micro-nanostructures synthesized from butterfly wings were selected. The morphologies of the two materials were characterized by scanning electron microscopy. Figure 3 and Figure 4 , with specific surface areas of 23.0 and 11.7 m 2 g -1 , and the pore volumes are 0.11 and 0.25 cm 3 g -1 .Depend on Figure 5 and Figure 6 It can be seen from the comparison that the ethanol sensitivity (Ra / Rg) of the experimental example is better than that of the control example.

[0054] Example 2 Tungsten oxide, cerium-doped cobalt tetroxide and gold-modified indium oxide sensing materials with periodic cavity micro-nanostructures for detecting acetone, toluene and formaldehyde gas molecules in human exhaled breath

[0055] The synthesis process of periodic cavity micro-nanostructured tungsten oxide, cerium-doped cobalt oxide and gold-modified indium oxide sensing materials mainly includes two steps: the required oxide precursors (ZIF-67, InCl 3 or WCl 6 ) and metal ions (palladium ions or cerium ions) for enhancing gas selectivity are fully loaded onto the butterfly wing template; calcination is performed to prepare periodic cavity micro-nanostructured oxide semiconductor sensing materials: tungsten oxide, cerium-doped cobalt oxide and gold-modified indium oxide.

[0056] During the preparation of control samples for the above three samples, butterfly wings were replaced with dragonfly wings.

[0057] The control sample and the sample with periodic cavity micro-nanostructure were prepared into gas sensing elements, and the sensing characteristics of acetone, toluene and formaldehyde gases were studied in the temperature range of 40℃~350℃ and the gas flow rate was 10 mL / min~2000 mL / min. Figure 7 , Figure 8 and Fig. 9 The results of dynamic gas sensing properties experiments are shown in Figure 2. Each group has a control example and an experimental example. The control example uses conventional nanomaterials prepared from dragonfly wings, while the experimental example uses tungsten oxide, cerium-doped cobalt oxide, and gold-modified indium oxide nanomaterials with periodic cavity micro-nano structures synthesized from butterfly wings. Figure 7 , Figure 8 and Fig. 9 It can be seen that the gas sensitivities (Ra / Rg or Rg / Ra) of acetone, toluene and formaldehyde of the experimental examples are better than those of the control examples.

[0058] Example 3 Principle of sensitivity enhancement based on gas eddy effect induced by micro-nanostructures

[0059] By using an improved Schlieren imaging device and utilizing the change in light refractive index caused by gas phase fluid flow, the invisible airflow is visualized to study the flow characteristics of carbon dioxide in the planar membrane structure of dragonfly wings and the periodic cavity micro-nanostructure of butterfly wings, with a gas flow rate of 10 mL / min~2000 mL / min. Fig.10 This shows that when the airflow passes through the flat structure of the dragonfly's wings, the airflow is relatively stable and no vibration occurs. Fig.11 This shows that when the airflow passes through the concave-convex structure of butterfly wings, the airflow undergoes obvious periodic vibrations, which are caused by gas vortices. This periodic vibration shows that the vortices act as mixers, generating spontaneous airflow vibrations, strengthening material mixing, making the fluid more uniform, and leading to more effective gas diffusion.

[0060] Based on the finite element method numerical simulation software, the gas flow state of the plane membrane structure unit and the cavity structure unit is simulated. Fig.12 i and 13 i. The velocity field simulation shows that the velocity streamlines of the plane model are parallel to the surface, that is, laminar flow, in which mass transfer depends only on molecular diffusion driven by concentration gradient. The gas molecules have a fast passing time and a short residence time, resulting in limited diffusion of molecules to the surface. When the airflow passes through the cavity, a gas vortex is formed due to the collision of the shear layer. The velocity streamlines are perpendicular to the surface, which means that the vortex acts as a mixer to enhance the molecular diffusion sensing surface. When the time is 20.5 seconds, the gas concentration of the cavity model is higher than that of the plane model, proving that the embedded vortex prolongs the residence time of the airflow due to the drag effect on the airflow, which is conducive to the adsorption of the gas molecules to be measured. It also proves that there is no gas flow and the vortex effect does not exist, so this cavity structure is designed for the detection of flowing gas (exhaled breath). When the diameter of the cavity and the spacing between the cavities remain unchanged, the cavity depth is reduced to 1 / 3 of the diameter. This cavity cannot generate air vortices at the center, so to generate vortices in the flowing gas, the cavity structure needs to have reasonable structural parameters.

[0061] At the same time, smoke flow experiments are carried out to provide further evidence for the simulation results, such as Fig.12 ii and Fig.13 ii. First, put the printed 3D bionic butterfly wing structure model into the quartz in-situ pool, then put the lit cigarette into the conical flask, and then use the air tube to connect the peristaltic pump, conical flask and quartz in-situ pool. Use air as the carrier gas, use the peristaltic pump to pass air into the conical flask at a certain flow rate, and use the air flow to form a flue gas flow, with a gas flow rate of 10 mL / min~2000mL / min. When the flue gas passes through the quartz in-situ pool, use a high-speed camera to shoot the flue gas flow process. Combined with Fig.12 ii. The smoke experiment confirms that the cavity structure model produces vortices, and also proves that there is no gas flow and the vortex effect does not exist.

[0062] Therefore, the vortex induced by the microstructure has multiple functions in the field of gas sensing. First, as a mixer, it generates spontaneous airflow vibrations, tends to homogenize the gas phase fluid, is more efficient than molecular diffusion, breaks the limitations of laminar mass transfer, and thus causes more target molecules to diffuse to the sensing surface; secondly, as a micro air roller bearing, it enhances the interaction between the sensing material and the airflow, reduces the movement speed of gas molecules, prolongs the molecular residence time, and enhances the gas molecule adsorption efficiency. Therefore, the cavity model can improve the sensitivity of gas molecules.

[0063] Example 4 Honeycomb and anode porous alumina

[0064] Combination Fig.14 and Fig.15 It is shown that the honeycomb is a hexagonal column with a flat hexagonal surface, a pore diameter of about 5 mm, a distance between two adjacent pores of about 5.6 mm, and a pore depth of about 10 mm. The anodic aluminum oxide film has a highly ordered pore structure and uniform pore size. The pore diameter of the anodic porous aluminum oxide film is about 270 nm, the distance between two adjacent pores is about 460 nm, and the pore depth is about 400 nm. It can be used as a sensing material for preparing periodic cavity micro-nanostructures.

[0065] Example 5 Construction of a four-channel gas sensor for human exhaled breath analysis and detection results of real exhaled breath samples

[0066] The four-channel gas sensor includes a sensor chip, an electronic circuit, a display screen 1, and a packaging shell 2. Fig. 20 As shown. The sensor chip includes four sensing materials, including palladium-modified zinc oxide, tungsten oxide, cerium-doped cobalt tetraoxide and gold-modified indium oxide gas sensing materials, which are used to detect ethanol, acetone, toluene and formaldehyde gas molecules in exhaled breath respectively. The sensor chip is connected to the electronic circuit, which is used to convert chemical signals into electrical signals and amplify and output electrical signals. The display screen provides users with a convenient operation interface and easy-to-understand test results.

[0067] Combination Fig.16 , Fig.17 , Fig.18 and Fig.19 It is explained that the four-channel gas sensor can accurately distinguish four different gas molecules, ethanol, toluene, formaldehyde and acetone, through principal component analysis (PCA), indicating its ability to identify gas mixtures. The results are as follows Fig.16 By collecting exhaled breath samples after specific diet or activities (such as drinking alcohol, drinking vinegar, and eating fruit), the four-channel gas sensor is used to detect and evaluate its ability to detect actual breath samples. Fig.17 , Fig.18 and Fig.19These are the test results of exhaled breath samples under the conditions of eating vinegar, eating fruit, and drinking alcohol, where sensor one indicates ethanol, sensor two indicates acetone, sensor three indicates toluene, and sensor four indicates formaldehyde. Fig.18 It shows that the signal of formaldehyde molecules in the exhaled breath is the strongest after eating fruit. Fig.19 It shows that the signal of ethanol molecules in exhaled breath after drinking is the strongest, which indicates that different diets will cause obvious changes in the content of the gas molecules to be tested in exhaled breath.

[0068] According to the exhaled breath markers of respiratory inflammation, diabetes, lung cancer and other diseases such as nitric oxide, acetone, formaldehyde, benzaldehyde gas molecules, the corresponding gas sensing materials can be selected and integrated on the sensor chip to achieve the simultaneous detection of multiple gas molecules and the detection of multiple diseases. When the number of types of gas molecules to be detected in the exhaled gas increases, the design of the sensor chip and electronic circuit can be adjusted according to actual needs.

[0069] The four-channel gas sensor of this embodiment ( Fig. 20 ) is small in size and light in weight, making it convenient for home testing. When in use, blow air into the sensor, and the exhaled air is transmitted to the sensor chip in the gas sensor for detection. The palladium-modified zinc oxide, tungsten oxide, cerium-doped cobalt tetroxide, and gold-modified indium oxide sensing materials integrated on the sensor chip detect the gas molecules to be tested in the exhaled air. The display screen displays the detection data, and the data can be transmitted to the mobile terminal via Bluetooth connection.

[0070] In the description of this specification, the description of the terms "one embodiment", "some embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0071] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for detecting human exhaled breath based on high-performance gas sensing materials, characterized in that: The gas sensing material has a periodic cavity micro-nano structure, the cavity diameter of the periodic cavity micro-nano structure is 0.1 μm to 8 mm, the center spacing between adjacent cavities is 1.1 to 2 times the cavity diameter, and the cavity depth is 0.5 to 3 times the cavity diameter; The gas sensing material is used for detecting human exhaled air, the gas flow rate of the human exhaled air is 10 mL / min~2000 mL / min; the periodic cavity micro-nano structure generates gas vortices in the human exhaled air; The periodic cavity micro-nano structure is prepared and formed by a forming template, wherein the forming template is a butterfly wing template, a honeycomb template or an anodic porous alumina template cut into a rectangle of 1-4 cm×1-4 cm; The gas sensing material is one of palladium-modified zinc oxide, tungsten oxide, cerium-doped cobalt tetroxide and gold-modified indium oxide; The preparation process of the gas sensing material comprises the following steps: The oxide precursor and the metal ion mixture are loaded onto the molding template by an ion or molecule adsorption method, and the sample is washed with deionized water and dried to obtain the sample; the oxide precursor is ZIF-8, ZIF-67, InCl3 or WCl6; the metal ion is palladium ion, gold ion or cerium ion; The sample is calcined at high temperature in an air atmosphere to obtain an oxide gas sensing material having the periodic cavity micro-nano structure.

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