Preparation method and application of peptide microtubu / SnO2 / Au composite gas-sensitive material

Abstract

The invention discloses a preparation method and application of a peptide microtube / SnO2 / Au composite gas-sensitive material. The three-dimensional network structure of the peptide microtube is utilized to effectively adsorb SnO2 and Au nanoparticles, so that the SnO2 and Au nanoparticles form a complete connection path on the surface of the peptide microtube, and electron transfer is facilitated; and gas diffusion is also facilitated. The localized surface plasmon resonance (LSPR) effect of Au nanoparticles can enhance visible light absorption and surface reaction activity, so that the gas-sensitive property is improved, and rapid adsorption and desorption reaction can be carried out at room temperature. The prepared sensor exerts the synergistic effect of the three materials, realizes efficient detection of NO2 at room temperature, has very high selectivity to NO2, and has relatively high response to low-concentration NO2, so that trace detection can be carried out.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas-sensitive materials, and relates to a preparation method of a peptide microtube / SnO2 / Au composite gas-sensitive material and its application in a light-enhanced NO2 gas sensor. Background Art

[0002] With the development of industry and technology, air pollution has become a global problem. It is well known that nitrogen dioxide (NO2) not only causes acid rain and photochemical smog but is also the primary component of ozone formation. This toxic gas not only causes severe damage to the environment but also poses a potential threat to human health. When NO2 concentrations exceed 1 ppm, the human body will experience noticeable discomfort. Given the importance of NO2 detection, the development of efficient NO2 sensors with low detection limits, high selectivity, and low power consumption is of great scientific significance and application value.

[0003] Air pollution has placed higher demands on environmental monitoring technology and also imposed stricter standards on the performance indicators and operating conditions of gas sensors. Traditional metal oxide gas sensors, due to inherent drawbacks such as high operating temperatures and high energy consumption, have significantly limited their application. Against this backdrop, photoexcited resistive gas sensors offer unique advantages, employing a photoexcitation mechanism instead of traditional heating methods to successfully achieve efficient gas detection at room temperature. This technological breakthrough not only significantly reduces energy consumption but also significantly simplifies the sensor structure by eliminating temperature limitations, facilitating device miniaturization and system integration. These outstanding advantages give photoexcited resistive gas sensors broad application prospects in areas such as environmental monitoring and human respiration detection.

[0004] Due to inherent drawbacks of conventional semiconductor metal oxide (SMO) sensors, such as high operating temperatures (200-450°C) and poor selectivity, the development of novel room-temperature sensing materials is urgently needed. In recent years, sustainable sensing materials that combine environmental friendliness, low-cost manufacturing, and scalable synthesis processes have attracted widespread attention. Among these materials, bioinspired supramolecular nanostructures (particularly self-assembled aromatic peptides) have attracted considerable attention due to their intrinsic semiconductor properties imparted by ordered non-covalent interactions such as π-π stacking and hydrogen-bonding networks. One-dimensional self-assembled peptide microtubes, with their unique structural and functional properties such as high aspect ratios and tunable surface chemistry, can be used to construct efficient, environmentally friendly gas sensors operating under photoexcitation. Studies have shown that the incorporation of peptide microtubes can significantly enhance gas sensor performance. Peptide microtube / SnO2 binary composite gas sensors utilize ultraviolet light excitation, effectively reducing the sensor temperature. However, ultraviolet light sources are difficult to obtain, and the high photon energy can easily damage the components. Furthermore, gas sensors based on peptide microtube / SnO2 binary composite gas sensors perform poorly at low concentrations.

[0005] Therefore, the present invention prepares a peptide microtube / SnO2 / Au composite gas-sensitive material and applies it to a light-enhanced NO2 gas sensor, which enhances the effect of low-concentration detection and improves the response speed; and uses cheap and environmentally friendly visible light instead of ultraviolet light for excitation. Summary of the Invention

[0006] The purpose of the present invention is to provide a preparation method of peptide microtube / SnO2 / Au composite gas-sensitive material and its application in light-enhanced NO2 gas sensors, and introduce precious metal nanoparticles (Au). Because gold nanoparticles (Au) have a significant localized surface plasmon resonance (LSPR) effect, they can enhance visible light absorption and surface reaction activity, and can effectively improve photocatalytic and sensing performance.

[0007] A preparation method of a peptide microtube / SnO2 / Au composite gas-sensitive material is as follows: Step 1: Preparation of peptide microtubes using solution self-assembly method: First, 20mg to 60mg of phenylalanine dipeptide FF was dissolved in 1ml to 3ml of organic solvent and stirred continuously for 4h to 10h to ensure full dissolution of the phenylalanine dipeptide. Next, an appropriate amount of deionized water was added to the phenylalanine dipeptide solution to dilute it to a final concentration of 4mg / ml. The solution was then allowed to stand for 1h to 4h to allow the phenylalanine dipeptide to self-assemble into peptide microtubes.

[0008] After self-assembly, the peptide microtube solution was dried by freeze-drying (freeze-drying conditions: temperature -40°C to -70°C, reaction time 30 h to 60 h) to obtain peptide microtubes with complete structure and stable chemical composition. Furthermore, the organic solvent is ethanol, acetone or dimethyl sulfoxide (DMSO).

[0009] Furthermore, the solvent, concentration, and time of phenylalanine dipeptide self-assembly, as well as the temperature and time of the suspension during freeze-drying, are crucial. A uniform phenylalanine dipeptide suspension is a key step in preparing three-dimensional network peptide microtubes, as it affects the structure and morphology of the self-assembled microtubes, and thus their gas-sensing properties. The porous three-dimensional network formed by the peptide microtubes prepared in this step facilitates the adsorption of SnO2 and Au nanoparticles, providing more reactive sites and promoting the diffusion of the target gas.

[0010] Step 2: Prepare ternary composite materials using a double-particle co-adsorption method: 36mg-54mg of SnO2 nanoparticles and 12mg of the peptide microtubes prepared in step 1 were added to 2ml-10ml of deionized water and ultrasonicated (ultrasonication time: 50 min-100 min, ultrasonication power: 50%-100%) to ensure the homogeneity of the binary mixture to obtain a peptide microtube / SnO2 binary composite gas-sensitive material; Then, a solution of 0.05 mg / mL to 0.5 mg / mL gold nanoparticles (Au NPs) was added to the above binary mixture, and ultrasonic treatment was continued (ultrasonic time was 40 min to 100 min, ultrasonic power was 50% to 100%) to form a uniform peptide microtube / SnO2 / Au ternary composite material suspension.

[0011] Preferably, in the peptide microtube / SnO2 / Au composite gas-sensitive material, the mass ratio of peptide microtube and SnO2 is 1:4, and the concentration of Au nanoparticles is 0.1 mg / mL.

[0012] The application of the peptide microtube / SnO2 / Au composite gas-sensitive material prepared by the above method in a room temperature NO2 gas sensor under visible light excitation is as follows: Using a rubber-tipped pipette, a suspension of the peptide microtube / SnO2 / Au composite gas-sensing material was dripped onto an interdigitated electrode sheet. The interdigitated electrode sheet was then dried in an oven (drying conditions: 30°C–80°C, 12–24 hours). This yielded a peptide microtube / SnO2 / Au gas sensor. This sensor was then placed in a gas testing system and tested for gas detection under visible light excitation. Optimal gas-sensing performance was achieved by varying the visible light intensity.

[0013] Preferably, the visible light intensity is 4.7 mW / cm 2 The gas-sensitive performance is optimal.

[0014] This invention utilizes peptide microtubes in gas sensing. Their three-dimensional network structure offers a large surface area, effectively adsorbing SnO2 and Au nanoparticles. This allows for a complete connection between the SnO2 and Au nanoparticles on the peptide microtube surface, facilitating electron transfer. The porous network structure facilitates gas diffusion. The localized surface plasmon resonance (LSPR) effect of the Au nanoparticles enhances visible light absorption and surface reactivity, improving gas sensing performance and enabling rapid adsorption and desorption reactions at room temperature. The peptide microtube / SnO2 / Au composite gas-sensing material leverages the synergistic effects of the three materials, exhibiting high selectivity for NO2 and enabling efficient NO2 detection at room temperature. The sensor also exhibits a high response to low NO2 concentrations, enabling trace detection.

[0015] This invention utilizes peptide microtubes, SnO2, and Au nanoparticles to create a ternary composite gas-sensitive material. This peptide microtube / SnO2 / Au ternary composite material is used to fabricate a NO2 sensor. Under visible light excitation, this sensor can achieve low detection limits, effective, and highly selective detection of NO2 gas at room temperature, providing a new approach for room-temperature NO2 gas detection. The raw materials are readily available and inexpensive, requiring minimal equipment investment and enabling a simple process.

[0016] Description of the accompanying drawings.

[0017] Figure 1 This is a scanning electron microscope image of the peptide microtube / SnO2 / Au ternary composite gas-sensing material in the embodiment; Figure 2 This is a transmission electron micrograph of the peptide microtube / SnO2 / Au ternary composite gas-sensing material in the embodiment; Figure 3 Figure 2 shows the gas-sensitive response of the peptide microtube / SnO2 gas sensor and the peptide microtube / SnO2 / Au in the embodiment at different NO2 concentrations (100 ppb to 20 ppm). The inset is an amplified response at low concentrations. Figure 4 Response recovery time test results of the NO2 gas sensor prepared in the embodiment when the NO2 concentration is 10 ppm; Figure 5 The selectivity test results of the NO2 gas sensor prepared in the embodiment for different gases are shown. DETAILED DESCRIPTION

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0019] A preparation method of a peptide microtube / SnO2 / Au ternary composite gas-sensitive material is as follows: 12 mg of peptide microtubes and 48 mg of SnO2 were added to deionized water and ultrasonicated for 1 hour. 100 μl of Au nanoparticles were added and ultrasonicated for another 1 hour to obtain a peptide microtube / SnO2 / Au ternary composite gas-sensitive material suspension. After drying, a peptide microtube / SnO2 / Au ternary composite gas-sensitive material was obtained. The scanning electron micrograph of the peptide microtube / SnO2 / Au ternary composite gas-sensitive material is shown in FIG. Figure 1 shown.

[0020] At the same time, in order to better distinguish SnO2 and Au nanoparticles adsorbed on the peptide microtubes, the peptide microtube / SnO2 / Au ternary composite gas-sensitive material was subjected to transmission electron microscopy scanning, and the lattice sizes of SnO2 and Au were measured to distinguish them; the transmission electron microscopy image of the peptide microtube / SnO2 / Au ternary is shown in Figure 2. Figure 2As shown, the uniform dispersion of SnO2 and Au on the peptide microtubes can provide more adsorption sites for the detection gas.

[0021] The specific application method of the obtained peptide microtube / SnO2 / Au ternary composite gas-sensitive material is as follows: after ultrasonically cleaning the interdigitated electrode sheet with acetone, anhydrous ethanol and deionized water for 3 minutes in sequence to remove surface stains, 80 μl of the peptide microtube / SnO2 / Au ternary composite gas-sensitive material suspension is dropped onto the interdigitated electrode sheet using a rubber-tipped dropper, and after drying at 50°C for 10 hours, a NO2 gas sensor capable of detecting at room temperature under visible light excitation is obtained.

[0022] The NO2 gas sensor was tested for its gas sensing performance at room temperature (test temperature was about 26 ℃, white light irradiation (wavelength 400-700nm, light intensity 4.7mW / cm 2 ), dynamic loading gas), target gas and carrier gas of different concentrations are mixed and injected into the test chamber at a total rate of 500 sccm. The specific concentration of the required gas is controlled by adjusting the gas flow meter, and the change of resistance value during the test is recorded using a source meter.

[0023] The gas sensing characteristics of the NO2 gas sensor at different NO2 concentrations (100 ppb ~ 20 ppm) are shown in the figure below. Figure 3 As shown. Figure 3 As can be seen, at a concentration of 20 ppm, the response of the ternary peptide microtube / SnO2 / Au sensor prepared using the method described in this invention was 68.78% higher than that of the binary peptide microtube / SnO2 sensor. Furthermore, as can be seen from the inset, the sensor exhibited a high response to low concentrations of NO2, reaching a response value of 5.28 at 100 ppb, making it highly suitable for low-concentration detection.

[0024] The response recovery time test curve of the NO2 gas sensor at a NO2 concentration of 10 ppm is shown in the figure below: Figure 4 As shown. Figure 4 It can be seen that the response recovery time of the ternary peptide microtube / SnO2 / Au sensor prepared by the method of the present invention is shorter than that of the binary peptide microtube / SnO2 sensor, indicating that the ternary gas sensor can quickly test the target gas.

[0025] The selectivity test results of NO2 gas sensor are as follows Figure 5 As shown. Figure 5 As can be seen, when testing different gases at the same concentration, the sensor's response to NO2 was the highest, far exceeding that of other gases. Furthermore, the response was significantly higher than that of the binary peptide microtube / SnO2 sensor, demonstrating that the NO2 gas sensor prepared using the method described in this invention has excellent selectivity.

[0026] The embodiment described above is only a preferred solution of the present invention and does not limit the present invention in any form. Other variations and modifications are possible without exceeding the technical solution described in the claims.

Claims

1. A method for preparing a peptide microtube / SnO2 / Au composite gas-sensitive material, as follows: Step 1: Preparation of peptide microtubes using solution self-assembly method: First, 20mg to 60mg of phenylalanine dipeptide FF was dissolved in 1ml to 3ml of organic solvent and stirred continuously for 4h to 10h to ensure full dissolution of the phenylalanine dipeptide. Next, an appropriate amount of deionized water was added to the phenylalanine dipeptide solution to dilute it to a final concentration of 4mg / ml. The solution was then allowed to stand for 1h to 4h to allow the phenylalanine dipeptide to self-assemble into peptide microtubes.

2. After self-assembly is completed, the peptide microtube solution is dried by freeze-drying to obtain peptide microtubes with complete structure and stable chemical composition; Step 2: Prepare ternary composite materials using a double-particle co-adsorption method: 36 mg to 54 mg of SnO2 nanoparticles and 12 mg of the peptide microtubes prepared in step 1 were added to 2 ml to 10 ml of deionized water for ultrasonic treatment to ensure the homogeneity of the binary mixture, thereby obtaining a peptide microtube / SnO2 binary composite gas-sensitive material; Then, a solution of 0.05 mg / mL to 0.5 mg / mL gold nanoparticles Au NPs was added to the above binary mixture, and ultrasonic treatment was continued to form a uniform peptide microtube / SnO2 / Au ternary composite material suspension.

3. The method for preparing the peptide microtube / SnO2 / Au composite gas-sensitive material according to claim 1, wherein: The freeze-drying conditions of the peptide microtube solution are: temperature -40°C to -70°C, and reaction time 30 h to 60 h.

4. The method for preparing the peptide microtube / SnO2 / Au composite gas-sensitive material according to claim 1, wherein: The organic solvent is ethanol, acetone or dimethyl sulfoxide.

5. The method for preparing the peptide microtube / SnO2 / Au composite gas-sensitive material according to claim 1, wherein: In the peptide microtube / SnO2 / Au composite gas-sensitive material, the mass ratio of peptide microtube and SnO2 is 1:4, and the concentration of Au nanoparticles is 0.1 mg / mL.

6. Use of the peptide microtube / SnO2 / Au composite gas-sensitive material prepared by the method of claim 1 in a room-temperature NO2 gas sensor under visible light excitation, characterized in that: Specifically: Using a rubber-tipped pipette, a suspension of the peptide microtube / SnO2 / Au composite gas-sensing material was dripped onto an interdigitated electrode sheet. The interdigitated electrode sheet was then dried in an oven to create a peptide microtube / SnO2 / Au gas sensor. This sensor was then placed in a gas testing system and tested under visible light excitation. Optimal gas-sensing performance was achieved by varying the visible light intensity.

7. The use of the peptide microtube / SnO2 / Au composite gas-sensitive material according to claim 5, characterized in that: The drying conditions are: drying temperature 30°C~80°C, and drying time 12 h~24 h.

8. The use of the peptide microtube / SnO2 / Au composite gas-sensitive material according to claim 5, characterized in that: The illumination intensity of the visible light is 4.7 mW / cm 2 .

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