A high-performance room-temperature gas sensor based on rapeseed pollen-derived carbon material generated by regulating pyrolysis temperature and a preparation method thereof

Abstract

This invention relates to a method for preparing a high-performance room-temperature gas sensor based on rapeseed pollen-derived carbon materials generated by controlling the pyrolysis temperature. During the experiment, CRFP-5 was prepared at the optimal temperature by optimizing and controlling the pyrolysis temperature. At room temperature (25 °C), the CRFP-5 sensor exhibited unique selective sensitivity, particularly for C2H6O2, in gas sensitivity tests of five gas analytes (C2H6O2, NH3, C2H8N2, C3H9N, C5H9NO, and CH2O) at 500 ppm, with a response value reaching 3420. The CRFP-5 successfully prepared under the controlled pyrolysis temperature strategy achieved high response performance and excellent selectivity for C2H6O2 gas at room temperature, effectively expanding the research boundaries and application scenarios of biomass-derived carbon materials in the field of gas sensing. Furthermore, the preparation process of this material combines low cost, simplicity, and ease of control, providing not only novel functional material support for the development of high-performance gas sensors but also innovative research ideas for breakthroughs in low-cost sensing technology. This technology has the potential to be applied to scenarios such as real-time early warning of C2H6O2 leaks in chemical production, and has broad research and development and market prospects. It is expected to be applied in core areas such as chemical safety production protection, electronic industry process control, and laboratory hazardous chemical safety supervision, with promising future research and development and market prospects.

Description

Technical Field

[0001] This invention relates to the field of gas sensor technology, specifically to a high-performance room-temperature gas sensor prepared from rapeseed pollen-derived carbon material generated by controlling the pyrolysis temperature. This sensor can be applied to the detection of ethylene glycol gas in various fields such as industrial production, atmospheric environment, and warehousing and logistics. Background Technology

[0002] Gas sensors have been widely used in recent years in fields such as air quality monitoring, industrial gas detection, national defense and security, food quality control, and disease diagnosis, becoming a key technological tool for ensuring safety and health. Ethylene glycol, an important chemical raw material, is widely used in polyester production and automotive antifreeze applications. It is a colorless, odorless, sweet-tasting viscous liquid. However, it has a certain degree of toxicity and can be metabolized in the human body into harmful substances such as glycolaldehyde and oxalic acid. Oral ingestion may cause coma and acute renal failure. Skin contact or inhalation of high concentrations of vapor can irritate the skin and respiratory tract, and long-term exposure may lead to chronic damage. Therefore, there is an urgent need to develop a high-performance ethylene glycol gas sensor.

[0003] In recent years, biomass-derived carbon gas-sensitive materials have attracted widespread attention from researchers. Biomass, as a widely available green and renewable resource, is an important alternative to traditional fossil fuels. Through in-depth research and development, the production of functional materials from waste biomass not only reduces the ecological burden caused by its indiscriminate disposal but also demonstrates significant application potential in energy storage and environmental governance. Therefore, biomass carbon materials are also widely used in the field of gas sensors. Current research shows that biomass carbon gas sensors have advantages such as good selectivity, high sensitivity, and good stability. Furthermore, their raw materials are derived from natural waste, combining environmental friendliness and low cost, and they can operate at room temperature with extremely low energy consumption.

[0004] This invention addresses the aforementioned problems by proposing a solution for preparing high-performance room-temperature gas sensors based on rapeseed pollen-derived carbon materials generated through controlled pyrolysis temperature. By controlling the pyrolysis temperature, a porous, olive-kernel-like gas-sensitive material was successfully prepared. Scanning electron microscopy (SEM) characterization results clearly show a dense and uniform porous structure with distinct pore size details. Further analysis reveals that CRFP-5 possesses a nanoscale fine pore network with interconnected pores and continuous pore wall morphology. Structurally, the porous spherical structure provides abundant adsorption sites for gas molecules, enabling the sensor to effectively capture target molecules even in low-concentration gas environments, thereby improving the detection sensitivity of the target gas and shortening the response time. Transmission electron microscopy (TEM) characterization results show that the material exhibits an irregular, multi-level layered structure; the uniformly distributed white dots in the image represent pore cross-sections, perfectly consistent with the porous characteristics observed in SEM. SAED images show a continuous halo, confirming the material's amorphous structure. These findings, along with XRD results, demonstrate the amorphous nature of the material. Furthermore, the diffraction peak positions in samples CRFP-4, CRFP-5, and CRFP-6 are 20.859°, 26.64°, 36.546°, 42.452°, 50.14°, 59.96°, and 68.143°, respectively, which correspond to the characteristic peaks of SiO2 and the (100), (011), (110), (200), (112), (211), and (203) crystal planes, respectively. This is related to the Si content inherent in the biomass itself. The presence of distinct diffraction peaks indicates that the SiO2 in CRFPs is definite. Moreover, it has been reported that the presence of SiO2 is beneficial to gas-sensing performance. KCl was also detected in the sample, with diffraction peaks of 28.414°, 40.619°, 58.794°, 66.569°, and 73.908°, corresponding to the (200), (220), (400), (420), and (422) crystal planes, respectively. To further investigate the surface functional groups of the materials, Fourier transform infrared spectroscopy analysis was performed on CRFP-4, CRFP-5, and CRFP-6. The broad peak near 3330.56 cm⁻¹ was attributed to the stretching vibration of the hydroxyl group (-OH), the peak at 1842.34 cm⁻¹ was attributed to the stretching vibration of the carbonyl group (C=O), and the peak at 1081.79 cm⁻¹ was attributed to the stretching vibration of the carbonyl group (C=O). -1 Nearby and 1025.23 cm -1 The characteristic peaks in the vicinity are related to the stretching vibration of the CO bond. The peak near 1547.56 cm⁻¹ belongs to the C=C stretching vibration, and the peak near 868.56 cm⁻¹ is attributed to the bending vibration of the CH bond. The peak at 502.43 cm⁻¹ corresponds to the damping vibration of the Si-O-Si group.

[0005] Experimental data demonstrate the outstanding selectivity of the CRFP-5 sensor. At room temperature (25 ℃), in gas sensing performance tests of six gases (500 ppm C2H6O2, NH3, C2H8N2, C3H9N, C5H9NO, and CH2O), it exhibits exceptional selective sensing capability for C2H6O2. The CRFP-5 sensor achieves a response value of 3420 for 500 ppm C2H6O2 at room temperature, with a response / recovery time of 7.85 / 83.73 s, a linear range covering 10-80 ppm, and a fitting equation of y=0.055x+1.825, R0. 2 =0.99. The excellent gas-sensing performance of CRFP-5 is attributed to the synergistic effect of carrier concentration and defect structure, surface adsorbed oxygen content, the porous structure of SiO2 itself, and the provision of more active sites, which together promote the excellent gas-sensing performance of CRFP-5 sensing material for ethylene glycol at room temperature.

[0006] In view of this, the present invention proposes an innovative solution. A CRFP-5 material with a porous olive-kernel-like structure was successfully prepared by controlled pyrolysis, and its gas-sensing performance was tested. This invention applies biomass-derived carbon materials as gas-sensing materials to the field of gas sensing, broadening the research scope and extending the research direction of this type of material. It also fills the technical gap in high-performance room-temperature C2H6O2 gas detection, possessing considerable and broad practical application prospects. In industrial production and storage safety, this sensor can monitor leaks in ethylene glycol production units, storage tanks, and pipelines to prevent gas accumulation that could lead to explosions or poisoning risks. In the automotive and transportation sector, it can detect leaks in automotive antifreeze (containing C2H6O2), particularly suitable for early warning of cooling system failures in new energy vehicles, trucks, and other large vehicles. In environmental protection and exhaust gas monitoring, it can monitor the volatilization and emission of C2H6O2 during industrial exhaust gas and wastewater treatment processes to ensure compliance with environmental emission standards. Its performance breakthrough provides an efficient technical path for accurate room-temperature monitoring of toxic gases, possessing multiple values ​​including safety production protection, environmental risk management, and personnel health protection. Summary of the Invention

[0007] This invention discloses a method for preparing a high-performance room-temperature gas sensor based on rapeseed pollen-derived carbon material generated by controlling the pyrolysis temperature. By controlling the pyrolysis temperature, a porous olive-kernel-like structure, CRFP-5, was prepared. According to gas-sensing test results, the CRFP-5 sensor exhibits excellent selectivity for C2H6O2 gas among six gas analytes at room temperature. Its response intensity to 500 ppm C2H6O2 gas reaches 3420, with response and recovery times of 7.85 s and 83.73 s, respectively, and a detection linear range of 10–80 ppm.

[0008] To achieve the above objectives, the present invention provides the following technical solution: Preparation methods of gas-sensitive materials and sensors: a. Weigh out 15 g of rapeseed pollen (RFP) and put 5 g into three porcelain boats; b. Place the RFP in the ceramic boat into a three-zone tube furnace, introduce N2, and set the calcination temperatures to 400℃, 500℃, and 600℃ respectively, with a heating rate of 5℃ per minute, and hold at that temperature for two hours; c. After the reaction is complete and the temperature drops to room temperature, collect the black powder product and name the carbonized samples CRFP-4, CRFP-5 and CRFP-6 respectively.

[0009] This invention application provides a method for preparing a high-performance room temperature gas sensor and a method thereof using rapeseed pollen-derived carbon material generated by regulating pyrolysis temperature. The sensor is prepared according to the above method. Beneficial technical effects of the present invention

[0010] (1) This invention achieves a breakthrough in the technology of C2H6O2 gas sensor based on CRFP-5 through material design and process innovation. By controlling the pyrolysis temperature, CRFP-5 with a porous olive-kernel structure was prepared, and a gas-sensitive material with uniform size, rough surface and multi-level pore structure distribution and excellent gas sensing performance was prepared, realizing high-performance response to C2H6O2 gas at room temperature.

[0011] (2) The CRFP-5 material prepared by micro-tuning the pyrolysis temperature in this invention exhibits a clear, dense, and uniform porous structure with a nanoscale fine pore network, interconnected pores, and continuous pore wall morphology. These characteristics provide abundant adsorption sites for C2H6O2 gas molecules and also promote the diffusion of gas molecules within the material structure. First, in terms of selectivity, the CRFP-5 sensor exhibits a very significant selective response to C2H6O2 gas at room temperature (25 ℃), far exceeding the response values ​​for five other gases: NH3, C2H8N2, C3H9N, C5H9NO, and CH2O. The CRFP-5 sensor achieves a response value of 3420 for 500 ppm C2H6O2 gas at room temperature (25 ℃), with response and recovery times of 7.85 s and 83.73 s, respectively. Meanwhile, the CRFP-5 sensor exhibits excellent linear response to HCl gas in the range of 10-80 ppm, with a fitting equation of y=0.055x+1.825, R0 2=0.99. The sensor's excellent performance at room temperature allows it to be integrated into portable detection terminals and industrial online monitoring systems to monitor leaks in ethylene glycol production units, storage tanks, and pipelines, preventing the risk of explosions or poisoning due to gas accumulation. It can also detect leaks in automotive antifreeze (containing C2H6O2) and monitor the volatilization emissions of C2H6O2 during industrial exhaust gas and wastewater treatment processes, ensuring compliance with environmental emission standards. Attached Figure Description

[0012] Figure 1 Scanning electron microscope (SEM) image of CRFP-5 prepared for this invention; Figure 2 Transmission electron microscope (TEM) image of CRFP-5 prepared for this invention; Figure 3 X-ray diffraction (XRD) patterns of CRFP-4, CRFP-5 and CRFP-6 prepared for this invention; Figure 4 Fourier transform infrared (FT-IR) spectra of CRFP-4, CRFP-5 and CRFP-6 prepared for this invention; Figure 5 The CRFP-4, CRFP-5 and CRFP-6 sensors prepared for this invention exhibit selective dynamic response curves to 500 ppm of six common polar gases (C2H6O2, NH3, C2H8N2, C3H9N, C5H9NO, CH2O) at room temperature (25 °C). Figure 6 The response time and recovery time of the CRFP-4, CRFP-5 and CRFP-6 sensors prepared for this invention to 500 ppm C2H6O2 at room temperature (25 °C); Figure 7 The dynamic response curves of the CRFP-5 sensor prepared for this invention to 10-500 ppm C2H6O2 gas at room temperature (25 °C); Figure 8 The concentration-response fitting curves of the CRFP-5 sensor prepared for this invention for 10-80 ppm C2H6O2 gas at room temperature (25 °C). Detailed Implementation

[0013] The following is a detailed description of various exemplary embodiments of this invention. This description illustrates alternative embodiments of this invention; however, it is more clearly stated that this invention can be implemented in various forms and is not intended to limit the invention. Rather, these specific embodiments are provided to increase the completeness and thoroughness of the invention and to clearly and fully convey the scope of this invention to those skilled in the art.

[0014] The terminology used in this application is not intended to limit the scope of the application, but is merely for describing the embodiments. The singular forms “a,” “the,” etc., used in this application and the claims are intended to represent more than one form, but to encompass multiple forms. Open-ended terms such as “having,” “comprising,” etc., used herein mean including but not limited to, unless specifically stated otherwise.

[0015] The numerical ranges used herein do not specifically refer to or represent any particular intermediate value, but rather encompass every intermediate value within that specific range. Any stated value or every smaller range within a stated range is also included in this application.

[0016] Unless otherwise specified herein, all technical and scientific terms used herein have the same meaning as understood by one of ordinary skill in the art. While only preferred materials and embodiments have been described herein, any methods and materials similar to or equivalent to those described herein may be used in the implementation or testing of this invention.

[0017] The following is a detailed description, with reference to the accompanying drawings, of a method for preparing a high-performance room-temperature gas sensor based on rapeseed pollen-derived carbon material generated by controlling pyrolysis temperature, as described in this invention: Example 1 This invention discloses a method for preparing a high-performance room-temperature gas sensor based on rapeseed pollen-derived carbon material generated by controlling pyrolysis temperature, comprising: a. Weigh out 15 g of rapeseed pollen (RFP) and put 5 g into three porcelain boats; b. Place the RFP in the ceramic boat into a three-zone tube furnace, introduce N2, and set the calcination temperatures to 400℃, 500℃, and 600℃ respectively, with a heating rate of 5℃ per minute, and hold at that temperature for two hours; c. After the reaction is complete and the temperature drops to room temperature, collect the black powder product and name the carbonized samples CRFP-4, CRFP-5 and CRFP-6 respectively.

[0018] Example 2 Figure 1 SEM images for CRFP-5. From Figure 1 It can be seen that CRFP-5 has a porous spherical structure, and its surface structure can be further magnified (a) Figure 1 (b) Clearly presents a dense and uniform porous structure on the surface, with distinct layers of pore size details. Figure 1Further analysis reveals that CRFP-5 possesses a nanoscale fine pore network with interconnected pores and continuous pore wall morphology. Structurally, the porous spherical structure provides abundant adsorption sites for gas molecules. This characteristic enables the sensor to effectively capture target molecules even in low-concentration gas environments, thereby improving the detection sensitivity of target gases and shortening the response time.

[0019] Example 3 The microstructure of CRFP-5 was further observed using TEM. Figure 2 (ac) At different magnifications, the material exhibits an irregular multi-level layered structure. The uniformly distributed white dots in the figure represent the pore cross-section, which is completely consistent with the porous features observed by SEM. Figure 2 The SAED image of d shows a continuous halo, confirming that the material has an amorphous structure.

[0020] Example 4 Figure 3 The XRD patterns and test results collectively demonstrate the amorphous properties of this material. Furthermore, the diffraction peaks in the CRFP sample are at 20.859°, 26.64°, 36.546°, 42.452°, 50.14°, 59.96°, and 68.143°, corresponding to characteristic peaks of SiO2, and corresponding to the (100), (011), (110), (200), (112), (211), and (203) crystal planes, respectively. This is related to the Si content inherent in the biomass itself. The presence of distinct diffraction peaks indicates that the SiO2 in the CRFP is morphologically stable. Moreover, it has been reported that the presence of SiO2 is beneficial for gas-sensing performance. KCl was also detected in the CRFP sample, with diffraction peaks of 28.414°, 40.619°, 58.794°, 66.569° and 73.908°, corresponding to the (200), (220), (400), (420) and (422) crystal planes, respectively.

[0021] Example 5 Figure 4 Fourier transform infrared (FTIR) spectra of CRFP-4, CRFP-5, and CRFP-6 were obtained. FTIR analysis of CRFP-4, CRFP-5, and CRFP-6 revealed a broad peak near 3330.56 cm⁻¹ attributed to the stretching vibration of the hydroxyl group (-OH), a peak at 1842.34 cm⁻¹ attributed to the stretching vibration of the carbonyl group (C=O), and a peak at 1081.79 cm⁻¹ attributed to the stretching vibration of the carbonyl group (C=O). -1 Nearby and 1025.23 cm -1The characteristic peaks in the vicinity are related to the stretching vibration of the CO bond. The peak near 1547.56 cm⁻¹ belongs to the C=C stretching vibration, and the peak near 868.56 cm⁻¹ is attributed to the bending vibration of the CH bond. The peak at 502.43 cm⁻¹ corresponds to the damping vibration of the Si-O-Si group.

[0022] Example 6 Figure 5 To power the CGS-MT optoelectronic integrated test platform, the dynamic response curves of the CRFP-4, CRFP-5, and CRFP-6 sensors to 500 ppm of six common polar gases (C2H6O2, NH3, C2H8N2, C3H9N, C5H9NO, CH2O) were tested at room temperature (25℃) under conditions of 4 V bias, room temperature (25℃), and 30% relative humidity. The CRFP-5 gas sensor prepared in this invention was found to exhibit excellent sensitivity and outstanding selectivity to C2H6O2 gas.

[0023] Example 7 pass Figure 6 It can be seen that the CRFP-5 sensor has a response value of 3420 to 500 ppm C2H6O2 gas, with response and recovery times of 7.85 s and 83.73 s, respectively.

[0024] Example 8 pass Figure 7 The dynamic response curve of the CRFP-5 sensor to 10-500 ppm C2H6O2 gas at room temperature (25 ℃) can be seen, with a response value of 3420.

[0025] Example 9 pass Figure 8 It can be seen that the CRFP-5 sensor exhibits excellent concentration-response fitting results for 10-80 ppm C2H6O2 gas at room temperature (25 ℃), with the fitting equation being y=0.055x+1.825, R0. 2 =0.99.

Claims

1. Preparation method of gas-sensitive material CRFP: a. Weigh out 15 g of rapeseed pollen (RFP) and put 5 g into three porcelain boats; b. Place the RFP in the ceramic boat into a three-temperature zone tube furnace, introduce N2, and set the calcination temperatures to 400℃, 500℃ and 600℃ respectively, with a heating rate of 5℃ per minute, and hold for two hours. c. After the reaction is complete and the temperature drops to room temperature, collect the black powder product and name the carbonized samples CRFP-4, CRFP-5 and CRFP-6 respectively.

2. A method of preparing a silica / rape pollen derived carbon composite by regulating carbonization temperature according to claim 1, characterized in that Step b. Adjust the calcination heating rate to 5 degrees Celsius per minute and hold for two hours.

3. A method of preparing a silica / rape pollen derived carbon composite by modulating carbonization temperature, characterized in that, Prepared according to the preparation method according to any one of claims 1 to 2.

4. The method for preparing silica / rapeseed pollen-derived carbon composite material by controlling the carbonization temperature according to claim 3 realizes a high-performance gas sensor, which has the application of efficiently detecting ethylene glycol (C2H6O2) gas at room temperature.

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