Rod-shaped hollow tube MoO3atNiMoO4 bionic structure, preparation method and application of rod-shaped hollow tube MoO3atNiMoO4 bionic structure as triethylamine sensor

Abstract

The invention discloses a rod-shaped hollow tube MoO3-coated NiMoO4 bionic structure, a preparation method and application as a triethylamine sensor, the rod-shaped hollow tube MoO3-coated NiMoO4 bionic structure is prepared by adopting a hydrothermal method, a molybdenum source is added for hydrothermal synthesis of MoO3 nanorods, then the MoO3 nanorods are dispersed in a water-alcohol solution, a nickel source is added, the reaction rate of Kirkendall can be accurately regulated and controlled by accurately controlling the concentration of the nickel source, and thus the rod-shaped hollow tube MoO3-coated NiMoO4 bionic structure is obtained. The preparation method comprises the following steps: firstly, preparing a hollow nanorod, further optimizing the outward diffusion rate of Mo ions and the inward diffusion rate of Ni ions to obtain a one-dimensional contact heterostructure of the hollow nanorod with MoO3 as a core and NiMoO4 as a shell layer, and finally calcining in an argon atmosphere to obtain the rod-like hollow tube MoO3-NiMoO4 bionic structure. According to the strategy, the complementary advantages of strong adsorbability of the NiMoO4 shell layer and high sensitivity of the MoO3 core are fused, and the complex requirements of advanced sensing materials are met. The TEA gas sensor constructed based on the bionic structure shows a high response value and extremely fast response / recovery time to triethylamine at 210 DEG C.

Description

Technical Field

[0001] This invention belongs to the field of inorganic porous material synthesis technology, specifically relating to a rod-shaped hollow tube material, its preparation method, and its application. Background Technology

[0002] Many triethylamine sensors based on traditional semiconductor materials have been developed. Most triethylamine sensors are composed of traditional semiconductors or semiconductor heterostructures, but their fabrication methods are cumbersome, require high operating temperatures, suffer from poor stability, and have low sensitivity. CN 110082406 A discloses a triethylamine gas sensor based on MoO3 nanorod sensitive material and its fabrication method, belonging to the field of semiconductor oxide gas sensor technology. It consists of a ceramic tube substrate with two parallel, ring-shaped, and discrete gold electrodes on its outer surface, MoO3 nanorod sensitive material coated on the outer surface of the ceramic tube and the gold electrodes, and a nickel-chromium alloy heating wire placed inside the ceramic tube. The sensor based on MoO3 nanorod sensitive material exhibits excellent sensitivity (102.1–100 ppm) and response value (101.74) for triethylamine.

[0003] CN 109085210 A relates to an n-type heterostructure gas-sensitive material and its preparation method, specifically a TiO2@MoO3 core-shell structure gas-sensitive material with n-type nano-MoO3 as the core and n-type nano-TiO2 as the shell, and its preparation method. Compared with pure MoO3 sensors, the depletion layer formed at the n-type heterojunction in the gas-sensitive material of this invention significantly increases the change in resistance in air and TEA gases, thereby leading to a high response to TEA gases. This theoretical model can also be used to explain the characteristics of other n-type heterojunctions in sensor applications. This work provides a reasonable method for designing high-performance gas sensors.

[0004] Bionic materials, inspired by the unique structural and functional properties of organisms in nature, have attracted considerable attention due to their potential to enhance advanced technologies. By mimicking complex systems in nature, such as the hierarchical structure of plant stems or the efficient protection mechanisms of vascular bundles, biomimetic materials aim to improve the performance and efficiency of material systems. These materials typically possess superior properties, including self-supporting structures, high specific surface areas, and optimized ion transport pathways, making them ideal candidates for energy storage and sensing applications. Cleverly designed hollow structures inspired by plant stems have significantly improved gas sensing performance. These structures provide abundant active sites and efficient gas diffusion pathways, thereby promoting efficient catalytic and sensing reactions. However, the resulting surface heterogeneous structures are often randomly distributed. This leads to inhomogeneous interfacial contact between the second phase and the host matrix, lacking a well-defined and controllable structure. Therefore, randomly distributed heterogeneous structures often result in inconsistent and difficult-to-control interfacial properties, low charge separation and transport efficiency, and limited synergistic effects, thus hindering further improvements in catalytic and sensing performance. Strategically designing novel microstructures with multifunctional integration and precisely controlling structurally defined heterogeneous structures with highly reactive contact interfaces provides a feasible approach to overcoming these challenges. Summary of the Invention

[0005] The technical problem this invention aims to solve is to address the shortcomings of triethylamine sensors, such as low sensitivity, slow response recovery, and poor stability. This invention provides a rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure with high sensitivity, low power consumption, and excellent selectivity for triethylamine, along with its preparation method and its application in triethylamine sensors. Inspired by the structure and function of plant stems, this invention constructs a rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure by precisely controlling the ion diffusion rate in the Kirkendall effect process. This strategy combines the complementary advantages of the strong adsorption of the NiMoO4 shell and the high sensitivity of the MoO3 core, meeting the complex requirements of advanced sensing materials.

[0006] To solve the above technical problems, the present invention adopts the following technical solution: The rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure of the present invention is synthesized by a hydrothermal strategy. The rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure consists of a NiMoO4 shell composed of stacked nanosheets rich in adsorption sites and a MoO3 sensitive core that has both support and sensing functions.

[0007] This invention also provides a method for preparing a rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure: First, a molybdenum source is dissolved in deionized water, nitric acid or hydrochloric acid is added and stirred to disperse the solution; then, the solution is placed in a reaction vessel for hydrothermal reaction, and the resulting mixture is centrifuged and dried to obtain MoO3 nanorods; the MoO3 nanorods are dispersed in an aqueous alcohol solution, a nickel source is added and stirred; then, the solution is placed in a reaction vessel for hydrothermal reaction, and the resulting mixture is centrifuged and dried, and then calcined in argon to obtain the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure. Specifically, the method includes the following steps: (1) Preparation of MoO3 nanorods: Dissolve molybdenum source in water, add nitric acid or hydrochloric acid and stir until transparent and clear, place in a reaction vessel for hydrothermal reaction, and centrifuge and dry the mixed solution after reaction to obtain MoO3 nanorods; (2) Preparation of rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure: The MoO3 nanorods obtained in step (1) are dispersed in a mixed solution of deionized water and ethanol, a nickel source is added, and the mixture is ultrasonically stirred until it is completely dispersed. The mixed solution is placed in a reaction vessel for hydrothermal reaction. After the reaction is completed, the mixture is centrifuged and dried, and then calcined in argon to obtain the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure.

[0008] Furthermore, the molybdenum source in step (1) is any one of ammonium molybdate, sodium molybdate, or calcium molybdate, and the acid solution is a 0.1M ~ 0.6M nitric acid solution or a 0.1M ~ 0.6M hydrochloric acid solution; the ratio of molybdenum source to acid solution is (1-2) g : (20-40) mL.

[0009] Furthermore, the hydrothermal reaction temperature in step (1) is 160-200℃, and the reaction time is 12-18h.

[0010] Furthermore, in step (2), the volume ratio of deionized water to ethanol in the mixed solution composed of deionized water and ethanol is 1:1 to 1:3.

[0011] Furthermore, in step (2), the nickel source can be any one of nickel acetate, nickel chloride, nickel sulfate, or nickel nitrate.

[0012] Furthermore, in step (2), the mass ratio of MoO3 nanorods to nickel source is 1:1.5 to 1:6, the hydrothermal temperature is 60-90℃, and the hydrothermal time is 3-8h. By precisely controlling the nickel source concentration and reaction time, the Kirkendall reaction rate can be precisely controlled, thereby optimizing the outward diffusion rate of Mo ions and the inward diffusion rate of Ni ions, resulting in a heterostructure with one-dimensional contact of hollow nanorods with MoO3 as the core and NiMoO4 as the shell.

[0013] Furthermore, in step (2), the calcination temperature is 400-600℃, preferably 400-500℃, the heating rate is 2℃ / min ~ 5℃ / min, and the calcination time is 1-2h.

[0014] Furthermore, the drying temperature in steps (1) to (2) is 60-80°C and the drying time is 4-6h.

[0015] The key innovation of this invention lies in the preparation of a rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure and the successful construction of a hierarchical catalytic sensing platform based on the MoO3@NiMoO4 composite rod-shaped hollow tube structure. The rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure of this invention provides abundant active sites and efficient gas diffusion pathways, thereby promoting efficient catalytic and sensing reactions. For example, metal oxide heterostructure gas sensors with hollow structures have shown high efficiency in this regard. However, the resulting surface heterostructures are usually randomly distributed. This leads to inhomogeneous interfacial contact between the second phase and the host matrix, lacking a well-defined and controllable structure. Therefore, randomly distributed heterostructures often result in inconsistent and difficult-to-control interfacial properties, low charge separation and transport efficiency, and limited synergistic effects, thus hindering further improvements in catalytic and sensing performance. This invention provides a method for forming a heterostructure of MoO3 and NiMoO4 through one-dimensional linear contact, exhibiting a well-defined and highly ordered heterostructure interface with significant curvature.

[0016] This invention also provides the application of the above-described rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure as a gas-sensitive element in a fast-response triethylamine sensor. The gas-sensitive performance of the element was tested at different temperatures, and its gas-sensitive performance exhibited a typical "volcano-like" pattern with respect to operating temperature. Figure 3 It can be clearly observed that 210°C is the optimal operating temperature. Therefore, when the operating temperature is 210°C, the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure, as a gas-sensitive element, has good selectivity for triethylamine and a response time of only 7 seconds to 50 ppm of triethylamine.

[0017] The beneficial effects of this invention are as follows: This invention utilizes the different ion diffusion rates during the Kirkendall effect process at different concentrations to construct a heterostructure. By optimizing the outward diffusion rate of Mo ions and the inward diffusion rate of Ni ions, a one-dimensional contact heterostructure with a MoO3 core and a NiMoO4 shell is obtained, ultimately forming rod-shaped hollow tubes of MoO3@NiMoO4 during the calcination stage. The NiMoO4 shell, rich in adsorption sites, acts as a nanoreactor, promoting the hierarchical catalytic reaction from NiMoO4 to MoO3. The heterostructure at the core-shell interface enables directional charge transfer from NiMoO4 to MoO3, while the highly ordered, high-curvature heterostructure interface effectively enhances the O2-to-O3 catalytic reaction. ads The reactivity of O⁻ and O₂⁻ accelerates the oxidation of the intermediate product glycidol. This further validates the concept of staged catalysis. Figure 4 As can be seen, the response / recovery time of this invention to 50 ppm triethylamine reaches 7 s / 51 s at an operating temperature of 210°C, which is lower than the operating temperature of existing triethylamine sensors. The method of this invention is innovative in synthesis, with high yield and low preparation cost; the material has uniform morphology and size; it responds quickly to triethylamine, and is easy to industrialize. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is the XRD pattern of the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure prepared in Example 8.

[0020] Figure 2 This is a transmission electron microscope (TEM) image of the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure prepared in Example 8.

[0021] Figure 3 The response value of the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure prepared in Example 8 to 50 ppm triethylamine at 110-230°C.

[0022] Figure 4 The figure shows the long-term stability test curve of the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure prepared in Example 8 against 50ppm triethylamine for 30 days at 110-230°C.

[0023] Figure 5The response / recovery amplification curves of the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure and MoO3 nanorods prepared in Example 8 to 50 ppm triethylamine at 210°C are shown.

[0024] Figure 6 This is a transmission electron microscope (TEM) image of the MoO3@NiMoO4 heterostructure prepared in Comparative Example 1. Figure 7 This is a transmission electron microscope (TEM) image of the MoO3@NiMoO4 heterostructure prepared in Comparative Example 2.

[0025] Figure 8 The impedance curves are those of the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure and MoO3 nanorods prepared in Example 8. Detailed Implementation

[0026] The present invention will be further described below with reference to specific embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make some non-essential improvements and adjustments based on the above-described invention.

[0027] Example 1 The preparation method of the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure in this embodiment is as follows: (1) Dissolve 2g of tetrahydrate and ammonium molybdate in 20ml of water, stir for 10min, add 20mL of 0.22M nitric acid solution and stir until transparent and clear to obtain a mixed solution; place the solution in a 100ml reaction vessel and perform hydrothermal reaction at 180℃ for 12h, centrifuge the mixed solution after reaction, and dry the product at 70℃ for 4h to obtain MoO3 nanorods.

[0028] (2) 0.1 g MoO3 nanorods were dispersed in 40 mL of water-ethanol solution with a volume ratio of 1:1. 0.5 g nickel acetate was added and ultrasonically stirred until completely dispersed to obtain a mixed solution. The solution was placed in a 100 mL reactor and subjected to hydrothermal reaction at 90 °C for 6 h. After centrifugation, the solution was dried at 80 °C for 4 h and then calcined in a muffle furnace at 500 °C for 1 h with a heating rate of 5 °C / min to obtain a rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure.

[0029] Example 2 The preparation method of the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure in this embodiment is as follows: (1) Dissolve 1g of sodium molybdate in 20ml of water, stir for 10min, add 20mL of 0.22M nitric acid solution and stir until transparent and clear to obtain a mixed solution; place the solution in a 100ml reaction vessel and perform hydrothermal reaction at 200℃ for 12h, centrifuge the mixed solution after reaction, and dry the product at 70℃ for 4h to obtain MoO3 nanorods.

[0030] (2) 0.1 g MoO3 nanorods were dispersed in 40 mL of water-ethanol solution with a volume ratio of 1:3. 0.5 g nickel acetate was added and ultrasonically stirred until completely dispersed to obtain a mixed solution. The solution was placed in a 100 mL reactor and subjected to hydrothermal reaction at 90 °C for 3 h. After centrifugation, the solution was dried at 60 °C for 4 h and then calcined in a muffle furnace at 500 °C for 1 h with a heating rate of 5 °C / min to obtain a rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure.

[0031] Example 3 The preparation method of the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure in this embodiment is as follows: (1) Dissolve 2g of calcium molybdate in 20ml of water, stir for 10min, add 20mL of 0.22M nitric acid solution and stir until transparent and clear to obtain a mixed solution; place the solution in a 100ml reaction vessel and perform hydrothermal reaction at 160℃ for 12h, centrifuge the mixed solution after reaction, and dry the product at 70℃ for 4h to obtain MoO3 nanorods.

[0032] (2) 0.1 g MoO3 nanorods were dispersed in 40 mL of water-ethanol solution with a volume ratio of 1:1 (deionized water:ethanol). 0.6 g nickel acetate was added and ultrasonically stirred until completely dispersed to obtain a mixed solution. The solution was placed in a 100 mL reactor and subjected to hydrothermal reaction at 90 °C for 6 h. After centrifugation, the solution was dried at 60 °C for 4 h and then calcined in a muffle furnace at 500 °C for 1 h with a heating rate of 5 °C / min to obtain a rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure.

[0033] Example 4 The preparation method of the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure in this embodiment is as follows: (1) Take 2g of tetrahydrate and ammonium molybdate and dissolve them in 20ml of water. After stirring for 10min, add 30mL of 0.6M hydrochloric acid solution and stir until transparent and clear to obtain a mixed solution. Place the solution in a 100ml reaction vessel and carry out hydrothermal reaction at 180℃ for 18h. Centrifuge the mixed solution after reaction and dry the product at 60℃ for 5h to obtain MoO3 nanorods.

[0034] (2) 0.1 g MoO3 nanorods were dispersed in 40 mL of water-ethanol solution with a volume ratio of 1:1 (deionized water:ethanol). 0.5 g nickel acetate was added and ultrasonically stirred until completely dispersed to obtain a mixed solution. The solution was placed in a 100 mL reactor and subjected to hydrothermal reaction at 70 °C for 8 h. After centrifugation, the solution was dried at 60 °C for 4 h and then calcined in a muffle furnace at 500 °C for 1 h with a heating rate of 5 °C / min to obtain a rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure.

[0035] Example 5 The preparation method of the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure in this embodiment is as follows: (1) Dissolve 2g of sodium molybdate in 20ml of water, stir for 10min, add 20mL of 0.1M hydrochloric acid solution and stir until transparent and clear to obtain a mixed solution; place the solution in a 100ml reaction vessel and perform hydrothermal reaction at 180℃ for 15h, centrifuge the mixed solution after reaction, and dry the product at 70℃ for 4h to obtain MoO3 nanorods.

[0036] (2) 0.1 g MoO3 nanorods were dispersed in 40 mL of water-ethanol solution with a volume ratio of 1:1. 0.5 g nickel acetate was added and ultrasonically stirred until completely dispersed to obtain a mixed solution. The solution was placed in a 100 mL reactor and subjected to hydrothermal reaction at 90 °C for 3 h. After centrifugation, the solution was dried at 60 °C for 4 h and then calcined in a muffle furnace at 500 °C for 1 h with a heating rate of 5 °C / min to obtain a rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure.

[0037] Example 6 The preparation method of the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure in this embodiment is as follows: (1) Dissolve 1.4g tetrahydrate and ammonium molybdate in 20ml water, stir for 10min, add 20mL of 0.5M nitric acid solution and stir until transparent and clear to obtain a mixed solution; place the solution in a 100ml reaction vessel and perform hydrothermal reaction at 180℃ for 12h, centrifuge the mixed solution after reaction, and dry the product at 80℃ for 6h to obtain MoO3 nanorods.

[0038] (2) 0.1 g MoO3 nanorods were dispersed in 40 mL of water-ethanol solution with a volume ratio of 1:2. 0.3 g nickel chloride was added and ultrasonically stirred until completely dispersed to obtain a mixed solution. The solution was placed in a 100 mL reactor and subjected to hydrothermal reaction at 60 °C for 6 h. After centrifugation, the solution was dried at 60 °C for 4 h and then calcined in a muffle furnace at 500 °C for 1 h with a heating rate of 5 °C / min to obtain a rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure.

[0039] Example 7 The preparation method of the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure in this embodiment is as follows: (1) Take 2g of tetrahydrate and ammonium molybdate and dissolve them in 20ml of water. After stirring for 10min, add 20mL of 0.5M nitric acid solution and stir until transparent and clear to obtain a mixed solution. Place the solution in a 100ml reaction vessel and perform a hydrothermal reaction at 180℃ for 12h. Centrifuge the mixed solution after the reaction and dry the product at 70℃ for 6h to obtain MoO3 nanorods.

[0040] (2) 0.1 g MoO3 nanorods were dispersed in 40 mL of water-ethanol solution with a volume ratio of 1:2. 0.6 g nickel sulfate was added and ultrasonically stirred until completely dispersed to obtain a mixed solution. The solution was placed in a 100 mL reactor and subjected to hydrothermal reaction at 90 °C for 6 h. After centrifugation, the solution was dried at 60 °C for 4 h and then calcined in a muffle furnace at 500 °C for 2 h with a heating rate of 2 °C / min to obtain a rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure.

[0041] Example 8 The preparation method of the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure in this embodiment is as follows: (1) Dissolve 1.4g tetrahydrate and ammonium molybdate in 20ml water, stir for 10min, add 20mL of 0.4M nitric acid solution and stir until transparent and clear to obtain a mixed solution; place the solution in a 100ml reaction vessel and perform hydrothermal reaction at 180℃ for 12h, centrifuge the mixed solution after reaction, and dry the product at 80℃ for 4h to obtain MoO3 nanorods.

[0042] (2) 0.1 g MoO3 nanorods were dispersed in 40 mL of water-ethanol solution with a volume ratio of 1:3. 0.4 g nickel nitrate was added and ultrasonically stirred until completely dispersed to obtain a mixed solution. The solution was placed in a 100 mL reactor and subjected to hydrothermal reaction at 90 °C for 6 h. After centrifugation, the solution was dried at 60 °C for 4 h and then calcined in a muffle furnace at 600 °C for 2 h with a heating rate of 2 °C / min to obtain a rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure.

[0043] Figure 1 The image shows the XRD pattern of the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure obtained in Example 8. The product is a composite of rod-shaped hollow tubes NiMoO4 and MoO3. Figure 1 The XRD pattern clearly shows diffraction peaks of MoO3 and NiMoO4, proving the successful synthesis of the heterostructure. Figure 2 The TEM image of the material shows a distinct rod-shaped hollow tube structure. Figure 2TEM results confirmed the successful synthesis of the rod-shaped hollow tube. This unique interfacial geometry is expected to enhance the activity of the heterojunction and promote an increase in electron transport rate. Figure 8 The impedance curves of the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure and MoO3 nanorods prepared in Example 8 are shown below. Figure 8 It can be seen that the radius of the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure is much smaller than that of the MoO3 nanorod, indicating that the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure exhibits a well-defined and highly ordered heterogeneous interface with obvious curvature.

[0044] Comparative Example 1 The preparation method of the MoO3@NiMoO4 heterostructure in this comparative example is the same as that in Example 8, except that the ratio of MoO3 nanorods to nickel source in step (2) is adjusted to 1:1. The specific steps are as follows: (1) Dissolve 1.4g tetrahydrate and ammonium molybdate in 20ml water, stir for 10min, add 20mL of 0.4M nitric acid solution and stir until transparent and clear to obtain a mixed solution; place the solution in a 100ml reaction vessel and perform hydrothermal reaction at 180℃ for 12h, centrifuge the mixed solution after reaction, and dry the product at 80℃ for 4h to obtain MoO3 nanorods.

[0045] (2) 0.1 g MoO3 nanorods were dispersed in 40 mL of water-ethanol solution with a volume ratio of 1:3 (deionized water:ethanol). 0.1 g nickel nitrate was added and ultrasonically stirred until completely dispersed to obtain a mixed solution. The solution was placed in a 100 mL reactor and subjected to hydrothermal reaction at 90 °C for 6 h. After centrifugation, the solution was dried at 60 °C for 4 h and then calcined in a muffle furnace at 600 °C for 2 h with a heating rate of 2 °C / min to obtain a rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure.

[0046] Comparative Example 2 The preparation method of the MoO3@NiMoO4 heterostructure in this comparative example is the same as that in Example 8, except that the ratio of MoO3 nanorods to nickel source in step (2) is adjusted to 1:7. The specific steps are as follows: (1) Dissolve 1.4g tetrahydrate and ammonium molybdate in 20ml water, stir for 10min, add 20mL of 0.4M nitric acid solution and stir until transparent and clear to obtain a mixed solution; place the solution in a 100ml reaction vessel and perform hydrothermal reaction at 180℃ for 12h, centrifuge the mixed solution after reaction, and dry the product at 80℃ for 4h to obtain MoO3 nanorods.

[0047] (2) 0.1g of MoO3 nanorods were dispersed in 40mL of water-ethanol solution with a volume ratio of 1:3. 0.7g of nickel nitrate was added and ultrasonically stirred until completely dispersed to obtain a mixed solution. The solution was placed in a 100ml reactor and subjected to hydrothermal reaction at 90℃ for 6h. After centrifugation, the solution was dried at 60℃ for 4h and then calcined at 600℃ for 2h in a muffle furnace with a heating rate of 2℃ / min to obtain a rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure.

[0048] In this invention, the mass ratio of MoO3 nanorods to nickel source is particularly important. When the mass ratio is 1:1, such as... Figure 6 As shown, no hollow outer shell structure will be generated when the mass ratio is 1:7, as Figure 7 As shown, the inner rod-like structure will completely dissolve.

[0049] Application Example 1 The rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure prepared in Example 8 was used as a triethylamine sensor. Figure 3 The response values ​​of the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure obtained in Example 8 to 50ppm triethylamine at 50-350℃ are shown. It can be seen that the response value is 514.213 at 210℃. Figure 4 The long-term stability test of the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure obtained in this embodiment over 30 days shows that the response value did not change significantly, indicating that the sensor prepared from the rod-shaped hollow tube MoO3@NiMoO4 biomimetic material has good stability. Figure 5 It can be seen that the response / recovery time of the present invention to 50ppm triethylamine at an operating temperature of 210°C reaches 7 s / 51 s, which is lower than the operating temperature of existing triethylamine sensors.

[0050] The foregoing has shown and described the basic principles and main features of the present invention, as well as its advantages. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure, characterized in that: The biomimetic structure of the rod-shaped hollow tube MoO3@NiMoO4 consists of a NiMoO4 shell composed of stacked nanosheets rich in adsorption sites and a MoO3 sensitive core that has both support and sensing functions.

2. The method for preparing the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure according to claim 1, characterized in that, Includes the following steps: (1) Preparation of MoO3 nanorods: Dissolve molybdenum source in water, add nitric acid or hydrochloric acid and stir until transparent and clear, place in a reaction vessel for hydrothermal reaction, and centrifuge and dry the mixed solution after reaction to obtain MoO3 nanorods; (2) Preparation of rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure: The MoO3 nanorods obtained in step (1) are dispersed in a mixed solution of deionized water and ethanol, a nickel source is added, and the mixture is ultrasonically stirred until it is completely dispersed. The mixed solution is placed in a reaction vessel for hydrothermal reaction. After the reaction is completed, the mixture is centrifuged and dried, and then calcined in argon to obtain the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure.

3. The method for preparing MoO3 nanorods according to claim 2, characterized in that: The molybdenum source in step (1) is any one of ammonium molybdate, sodium molybdate, or calcium molybdate, and the acid solution is a 0.1M ~ 0.6M nitric acid solution or a 0.1M ~ 0.6M hydrochloric acid solution; the ratio of molybdenum source to acid solution is (1-2) g : (20-40) mL.

4. The method for preparing the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure according to claim 2, characterized in that: The hydrothermal reaction temperature in step (1) is 160-200°C and the reaction time is 12-18h. The drying temperature in steps (1) to (2) is 60-80°C and the drying time is 4-6h.

5. The method for preparing the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure according to claim 2, characterized in that: In step (2), the volume ratio of deionized water to ethanol in the mixed solution is 1:1 to 1:

3.

6. The method for preparing the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure according to claim 2, characterized in that: In step (2), the nickel source can be any one of nickel acetate, nickel chloride, nickel sulfate, or nickel nitrate.

7. The method for preparing the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure according to claim 2, characterized in that: In step (2), the mass ratio of MoO3 nanorods to nickel source is 1:1.5~1:6, the hydrothermal temperature is 60-90℃, and the hydrothermal time is 3-8h.

8. The method for preparing the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure according to claim 2, characterized in that: In step (2), the calcination temperature is 400-600℃, the heating rate is 2℃ / min ~ 5℃ / min, and the calcination time is 1-2h.

9. The application of the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure according to claim 1 as a gas-sensitive element in a fast-response triethylamine sensor.

10. The application according to claim 8, characterized in that: At an operating temperature of 210°C, the rod-shaped hollow tube MoO3@NiMoO4 biomimetic structure, as a gas-sensitive element, exhibits good selectivity for triethylamine and a response value of 514.213 for 50 ppm triethylamine. The response / recovery time for 50 ppm triethylamine at an operating temperature of 210°C reaches 7 s / 51 s.

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