A peptide microtube / In2O3 / Au composite gas-sensitive material: its preparation method and application
By assembling a peptide microtube/In2O3/Au composite material, a highly sensitive and selective detection of ethanol gas at room temperature under visible light excitation was achieved, solving the problem of high-temperature operation of traditional sensors and providing a low-cost and efficient detection solution.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HANGZHOU POLYTECHNIC
- Filing Date
- 2026-04-13
- Publication Date
- 2026-05-29
AI Technical Summary
Traditional In2O3-based gas sensors require high temperatures to operate, which leads to increased power consumption, safety hazards, and shortened lifespan. They also have poor selectivity and high detection limits, making it difficult to achieve a synergistic optimization of high sensitivity and high selectivity at room temperature.
A ternary composite system is formed by using a self-assembled peptide microtube/In2O3/Au composite material. The peptide microtube serves as a three-dimensional support framework, In2O3 nanoparticles are uniformly dispersed, and Au nanoparticles are loaded on the surface. Room temperature detection is achieved by visible light excitation.
It achieves highly sensitive and selective detection of ethanol gas at room temperature, with a detection limit as low as 1 ppm. The materials are readily available and inexpensive, requiring minimal equipment investment and a simple process.
Smart Images
Figure CN122108949A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of gas-sensitive materials technology, and relates to a peptide microtube / In2O3 / Au composite gas-sensitive material, its preparation method, and its application in a photoexcited ethanol gas sensor. Background Technology
[0002] Ethanol, a widely distributed volatile organic compound (VOC), is not only a common environmental pollutant, but its concentration changes can also serve as respiratory biomarkers for specific diseases. Rapid and highly sensitive detection of ethanol is of great significance for environmental protection and human health. Semiconductor metal oxide-based gas sensors have been extensively studied in the field of ethanol detection due to their advantages such as simple fabrication and low cost. Among them, indium oxide (In₂O₃), as a typical n-type semiconductor, possesses a wide bandgap, low resistivity, and outstanding catalytic activity, making it one of the ideal sensitive materials for ethanol sensing.
[0003] However, traditional In2O3-based gas sensors have significant technical drawbacks: to ensure sufficient sensitivity, they need to operate at high temperatures of 200℃ to 450℃, leading to increased power consumption, safety hazards, and shortened device lifespan; they also suffer from poor selectivity and high detection limits, restricting the expansion of practical applications. Existing improvement methods, such as noble metal functionalization, heterostructure construction, and photoexcitation, can improve performance to some extent, but a single method cannot simultaneously achieve synergistic optimization of room-temperature operation, high sensitivity, and high selectivity. In particular, ultraviolet light excitation schemes suffer from difficulties in obtaining the light source and the high photon energy easily damages components, while visible light excitation has become a research hotspot due to its environmentally friendly and inexpensive advantages.
[0004] Self-assembled peptide microtubes (SPMTs), as bio-inspired supramolecular nanostructures, possess high aspect ratios, three-dimensional porous network structures, and excellent mechanical properties, providing a stable dispersion carrier for nanoparticles and promoting gas diffusion. The localized surface plasmon resonance (LSPR) effect of gold nanoparticles (Au NPs) enhances visible light absorption and surface reactivity, significantly improving sensing sensitivity. Based on this, this invention combines SPMTs, In₂O₃, and Au NPs to construct a ternary composite system, achieving highly efficient detection of ethanol at room temperature under visible light excitation, filling a gap in related technologies. Summary of the Invention
[0005] The purpose of this invention is to provide a peptide microtube / In2O3 / Au composite gas-sensitive material, its preparation method, and its application in a light-enhanced ethanol gas sensor. Through the synergistic effect of the SPMTs / In2O3 / Au ternary composite material, it achieves high sensitivity, high selectivity, and rapid detection of ethanol gas at room temperature under visible light excitation, solving the problems of high operating temperature and poor detection effect at low concentrations in traditional sensors.
[0006] Using peptide microtubes (SPMFs) as a three-dimensional support framework, Au nanoparticles with a concentration of 0.1 mg / mL were added to a solution of peptide microtubes and In2O3 binary composite gas-sensitive materials with a mass ratio of 1:2.3-1:9. After ultrasonic treatment, the In2O3 nanoparticles were uniformly dispersed and the Au nanoparticles were loaded on the surface, forming a peptide microtube / In2O3 / Au ternary composite material suspension.
[0007] The specific preparation method of the aforementioned peptide microtube / In2O3 / Au composite gas-sensitive material is as follows:
[0008] Step 1: Prepare peptide microtubes using a solution self-assembly method:
[0009] First, 20 mg–60 mg of phenylalanine dipeptide (FF) was dissolved in 1 ml–3 ml of organic solvent and stirred continuously for 4 h–10 h to ensure complete dissolution of the phenylalanine dipeptide. Next, deionized water was added to the solution to dilute it to a final concentration of 4 mg / ml of phenylalanine dipeptide. After standing for 2 h–6 h, the phenylalanine dipeptide self-assembled to form peptide microtubes (SPMTs).
[0010] After self-assembly, the peptide microtube solution is dried by freeze-drying (preferably, the freeze-drying conditions are: temperature -40 ℃ to -70 ℃, reaction time 30 h to 60 h) to obtain peptide microtubes with complete structure and stable chemical composition.
[0011] Preferably, the organic solvent is acetone or dimethyl sulfoxide (DMSO).
[0012] During the preparation process, the solvent, concentration, and time during the self-assembly of the phenylalanine dipeptide, as well as the temperature and time during the freeze-drying of the suspension, are crucial. In the preparation of three-dimensional network peptide microtubes, the preparation of a uniform phenylalanine dipeptide suspension is a key step, as it affects the structure and morphology of the microtubes' self-assembly, thus influencing the gas-sensing performance. The porous three-dimensional network structure formed by the peptide microtubes prepared in this step facilitates the adsorption of In₂O₃ and Au nanoparticles, provides more reactive sites, and promotes the diffusion of the target gas.
[0013] Step 2: Prepare ternary composite materials using a two-particle co-adsorption method:
[0014] Add 42 mg to 54 mg of In2O3 nanoparticles and 6 mg to 18 mg of peptide microtubes prepared in step one to 8 ml to 10 ml of deionized water and sonicate for 60 min to 120 min to ensure uniform dispersion of the peptide microtube / In2O3 binary mixture, and obtain peptide microtube / In2O3 binary composite gas-sensitive material.
[0015] Next, 80–100 µL of a solution of 0.1 mg / mL gold nanoparticles (AuNPs) was added to the binary mixture, and the mixture was sonicated for 60–120 min to form a uniform peptide microtube / In2O3 / Au ternary composite material suspension.
[0016] Preferably, the power of the ultrasonic treatment is 300 W to 350 W.
[0017] On the other hand, the prepared peptide microtube / In2O3 / Au composite gas-sensitive material was applied to a room-temperature ethanol gas sensor under visible light excitation to detect ethanol gas. The specific process is as follows:
[0018] After dropwise application of a peptide microtube / In₂O₃ / Au composite gas-sensitive material suspension onto a finger electrode plate using a pipette, the finger electrode plate was placed in an oven for drying (oven drying conditions: drying temperature 50 ℃~80 ℃, drying time 12 h~24 h) to obtain the peptide microtube / In₂O₃ / Au gas sensor. This sensor was then placed in a gas detection system for gas detection under visible light excitation. Furthermore, the optimal gas-sensing performance was obtained by optimizing the mass ratio of peptide microtubes to In₂O₃.
[0019] Preferably, the wavelength of visible light is 400 nm to 700 nm, and the illuminance is 4.7 mW / cm². 2 It has the best time-sensitive performance.
[0020] This invention applies peptide microtubes (SPMFs) to the field of gas sensors. The material uses self-assembled SPMFs as a three-dimensional support framework. Through solution mixing and functionalization modification, In2O3 nanoparticles are uniformly dispersed and Au nanoparticles are loaded onto the surface, forming a ternary composite system. The three-dimensional network structure has a large specific area, which can effectively adsorb In2O3 and Au NPs, allowing In2O3 and Au NPs to form complete connection pathways on the surface of the SPMFs, which is beneficial for electron transfer.
[0021] The porous structure of SPMFs provides a stable loading platform for nanoparticles and accelerates gas diffusion. The localized surface plasmon resonance (LSPR) effect of Au nanoparticles enhances visible light absorption and surface reactivity, thereby improving gas sensing performance and enabling rapid adsorption-desorption reactions at room temperature. The heterojunction formed by In2O3 and SPMFs regulates electron transport. The peptide microtube / In2O3 / Au composite gas-sensitive material leverages the synergistic effect of the three materials. This material can efficiently detect ethanol at room temperature and under visible light excitation, exhibiting high selectivity, high sensitivity, and rapid adsorption-desorption characteristics. It demonstrates high selectivity for ethanol, achieving efficient detection of ethanol at room temperature. Furthermore, this sensor exhibits high response to low concentrations of ethanol, with a detection limit as low as 1 ppm, meeting the needs for real-time monitoring of trace ethanol.
[0022] An ethanol sensor was fabricated using a peptide microtube / In₂O₃ / Au ternary composite material. Under visible light excitation, it achieves low detection limit, high efficiency, and high selectivity for ethanol gas detection at room temperature, providing a new approach for ethanol gas detection at room temperature. Furthermore, the raw materials are readily available and inexpensive, requiring minimal equipment investment and a simple process. Attached Figure Description
[0023] Figure 1 The image shown is a scanning electron microscope image of the peptide microtube / In2O3 / Au ternary composite gas-sensitive material in the example.
[0024] Figure 2 This is a projection electron microscope image of the peptide microtube in the embodiment;
[0025] Figure 3 The image shows the EDX elemental distribution of the peptide microtube / In2O3 / Au ternary composite gas-sensitive material in the examples.
[0026] Figure 4 The images show the gas response of the peptide microtube / In2O3 gas sensor and the peptide microtube / In2O3 / Au in the examples at different ethanol concentrations (1-50 ppm).
[0027] Figure 5 The response recovery time test results of the ethanol gas sensor prepared in the example at an ethanol concentration of 10 ppm are shown.
[0028] Figure 6 The results show the selectivity test results of the ethanol gas sensor prepared in the examples for different gases. Detailed Implementation
[0029] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.
[0030] A method for preparing a peptide microtube / In2O3 / Au ternary composite gas-sensitive material is as follows:
[0031] Three groups of peptide microtubes and In2O3 nanoparticles were weighed separately, with the following specific ratios: 6 mg peptide microtubes + 54 mg In2O3, 12 mg peptide microtubes + 48 mg In2O3, and 18 mg peptide microtubes + 42 mg In2O3. These three groups of materials were added to deionized water and ultrasonically dispersed for 1 h to obtain three binary composite gas-sensitive material suspensions, which were labeled SPMFs / In2O3-1, SPMFs / In2O3-2, and SPMFs / In2O3-3, respectively.
[0032] 100 μL of Au nanoparticle solution was added to each of the SPMFs / In2O3-1, SPMFs / In2O3-2, and SPMFs / In2O3-3 suspensions, and the mixture was ultrasonically dispersed for 1 h to obtain peptide microtube / In2O3 / Au ternary composite gas-sensitive material suspensions, labeled as SPMFs / In2O3-1 / Au, SPMFs / In2O3-2 / Au, and SPMFs / In2O3-3 / Au. These ternary suspensions were then freeze-dried at -60 ℃ for 48 h to obtain the peptide microtube / In2O3 / Au ternary composite gas-sensitive material. (Scanning electron microscope image of the peptide microtube / In2O3 / Au ternary composite gas-sensitive material is shown below.) Figure 1 As shown.
[0033] To observe the microstructure of the peptide microfibers, the prepared peptide microfibers were characterized by transmission electron microscopy (TEM). The TEM images are shown below. Figure 2 As shown in the figure. The results show that the peptide microfibers exhibit a regular tubular structure. This unique microstructure not only provides a stable and uniform support platform for the subsequent loading of In2O3 and Au nanoparticles, but also effectively avoids nanoparticle aggregation, ensuring that both form a continuous dispersion on the surface of the peptide microfibers. This provides sufficient adsorption sites for the detected gas, laying a structural foundation for improving the gas-sensing performance of the ternary composite gas-sensitive material. The elemental distribution diagram is shown in the figure. Figure 3 As shown.
[0034] The specific application method of the prepared composite gas-sensitive material as an ethanol gas sensor is as follows: After ultrasonically cleaning the interdigitated electrode sheet with deionized water for 3 min to remove surface stains and drying it, 80 μl of any kind of peptide microtube In2O3 / Au ternary composite gas-sensitive material suspension is drop-coated onto the interdigitated electrode sheet using a pipette. After drying at 50 ℃ for 10 h, an ethanol gas sensor that can detect at room temperature under visible light excitation is obtained.
[0035] The gas-sensing performance of the above-mentioned ethanol gas sensor was tested at room temperature (test temperature approximately 26 ℃, illuminated with white light (wavelength 400 nm–700 nm, light intensity 4.7 mW / cm²).2 Different concentrations of target gas and carrier gas are mixed and injected into the test chamber at a total rate of 500 sccm. The specific concentration of the gas to be introduced is controlled by adjusting the gas flow meter, and the change in resistance value during the test is recorded by a source meter.
[0036] like Figure 4 As shown, the gas-sensing characteristics of sensors prepared with three concentrations of ternary peptide microtubes / In2O3 / Au, SPMFs / In2O3-3, and In2O3 at different ethanol concentrations (1–50 ppm) in the examples are illustrated. The ratio of the resistance value (peak value) of the ethanol gas sensor in air to the resistance value (valley value) of the ethanol gas sensor in ethanol gas is used as the response value. Figure 4 As shown in Figure (f), the sensors prepared by the three concentrations of tripeptide microtubes / In2O3 / Au have higher response values at all concentrations than the ethanol gas sensor prepared by In2O3 and the sensor prepared by SPMFs / In2O3-3. Moreover, compared with the ethanol gas sensor prepared by In2O3, the ethanol gas sensor prepared by tripeptide microtubes / In2O3 / Au has almost no response to low concentrations of ethanol gas. The sensor prepared by tripeptide microtubes / In2O3 / Au is very suitable for low concentration detection. In particular, at a concentration of 20 ppm, the ethanol gas sensor prepared by SPMFs / In2O3-2 / Au has a response value as high as 12.58, and the response value for 1 ppm ethanol can reach 1.48.
[0037] like Figure 5 The figure shows the response recovery time curves of an ethanol gas sensor prepared with SPMFs / In2O3-2 / Au and an ethanol gas sensor prepared with In2O3 at an ethanol concentration of 10 ppm. From... Figure 5 It can be seen that the response recovery time of the peptide microtube / In2O3 / Au sensor is shorter than that of the In2O3 sensor, which can quickly test the target gas.
[0038] like Figure 6 The image shows the selectivity test results for an ethanol gas sensor prepared with SPMFs / In2O3-2 / Au and an ethanol gas sensor prepared with In2O3. From... Figure 6 It can be seen that, when testing different gases at the same concentration, the ethanol gas sensor prepared by SPMFs / In2O3-2 / Au has the highest response value for ethanol gas, which is much higher than that for other gases. Furthermore, its response value for ethanol gas is significantly higher than that of the ethanol gas sensor prepared by In2O3, indicating that the ethanol gas sensor prepared by SPMFs / In2O3-2 / Au has excellent ethanol gas selectivity.
[0039] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Other variations and modifications are possible without departing from the technical solutions described in the claims.
Claims
1. A peptide microtube / In₂O₃ / Au composite gas-sensitive material, characterized in that, Using peptide microtubes (SPMFs) as a three-dimensional support framework, Au nanoparticles with a concentration of 0.1 mg / mL were added to a solution of peptide microtubes and In2O3 binary composite gas-sensitive materials with a mass ratio of 1:2.3-1:
9. After ultrasonic treatment, the In2O3 nanoparticles were uniformly dispersed and the Au nanoparticles were loaded on the surface, forming a peptide microtube / In2O3 / Au ternary composite material suspension.
2. A method for preparing the peptide microtube / In₂O₃ / Au composite gas-sensitive material according to claim 1, characterized in that, Specifically, the following steps are included: Step 1: Preparation of peptide microtubes using solution self-assembly: Dissolve 20 mg–60 mg of phenylalanine dipeptide FF in 1 ml–3 ml of organic solvent and stir continuously for 4 h–10 h to ensure complete dissolution of the phenylalanine dipeptide; add deionized water to the solution and dilute to a final concentration of 4 mg / mL of phenylalanine dipeptide; let stand for 2 h–6 h, and the phenylalanine dipeptide will self-assemble to form peptide microtubes (SPMTs); freeze-dry the self-assembled solution to obtain peptide microtubes with intact structure and stable chemical composition. Step 2: Prepare ternary composite material using a two-particle co-adsorption method: Add 42 mg–54 mg of In2O3 nanoparticles and 6–18 mg of peptide microtubes prepared in Step 1 to 8 ml–10 ml of deionized water and sonicate for 60 min–120 min to ensure the homogeneity of the peptide microtube / In2O3 binary mixture, thus obtaining a peptide microtube / In2O3 binary composite gas-sensitive material; add 80–100 µL of a 0.1 mg / mL gold nanoparticle solution to the above binary mixture and continue sonicating for 60 min–120 min to form a uniform peptide microtube / In2O3 / Au ternary composite material suspension.
3. The preparation method of the peptide microtube / In2O3 / Au composite gas-sensitive material as described in claim 2, characterized in that, The freeze-drying conditions described in step one are: temperature -40℃ to -70℃, drying time 30 h to 60 h.
4. The preparation method of the peptide microtube / In2O3 / Au composite gas-sensitive material as described in claim 2, characterized in that, The organic solvent mentioned in step one is acetone or dimethyl sulfoxide.
5. The preparation method of the peptide microtube / In2O3 / Au composite gas-sensitive material as described in claim 2, characterized in that, The power of the ultrasonic treatment in step two is 300 W to 350 W.
6. The application of the peptide microtube / In2O3 / Au composite gas-sensitive material according to claim 1 in a room temperature ethanol gas sensor under visible light excitation.
7. The application as described in claim 6, characterized in that, Specifically, the composite gas-sensitive material suspension is drop-coated onto the interdigitated electrode sheet using a pipette, and the interdigitated electrode sheet is dried in an oven to obtain a peptide microtube / In2O3 / Au gas sensor; the sensor is then placed in a gas testing system for ethanol gas detection under visible light excitation.
8. The application as described in claim 6, characterized in that, The optimal gas-sensing performance was obtained by optimizing the mass ratio of peptide microtubes and In2O3.
9. The application as described in claim 6, characterized in that, The conditions for drying the interdigitated electrode sheet in the oven are: temperature 50 ℃~80 ℃, drying time 12 h~24 h.
10. The application as described in claim 6, characterized in that, The visible light has a wavelength of 400 nm to 700 nm and an illuminance of 4.7 mW / cm². 2 .