Synthesis process of humidity-interference-resistant nitrogen-doped porous carbon heterojunction gas-sensitive material
By introducing magnetic ion doping and oxygen vacancy engineering on SnO2/ZnO substrates, combined with nitrogen-doped porous carbon tight heterojunctions and black magnetic phase nanophotothermal desorption, the problems of weak response, slow recovery and poor anti-interference of traditional gas-sensitive materials in NO2 detection are solved, and efficient and stable NO2 detection is achieved.
Patent Information
- Application Number
- CN202511762445.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-27
- Publication Date
- 2026-02-27
AI Technical Summary
Traditional metal oxide gas-sensitive materials such as SnO2 and ZnO have weak response signals, slow recovery speed, sensitivity to humidity, and poor anti-interference ability in NO2 detection. Moreover, their performance degrades significantly after long-term use. Existing modification methods cannot solve these problems simultaneously.
Using SnO2/ZnO as the substrate, and combining three major modification mechanisms—magnetic ion doping and oxygen vacancy engineering, magnetically doped oxide-nitrogen-doped porous carbon tight heterojunction, and black magnetic phase nanophotothermal-assisted desorption—a humidity-resistant nitrogen-doped porous carbon heterojunction gas-sensitive material is formed.
It achieves strong response, rapid recovery, and high stability at room temperature, reduces humidity interference, improves the selectivity and responsiveness of NO2 detection, and is suitable for large-scale production.
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Figure CN121571102A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of gas-sensitive materials technology, specifically to the synthesis process of nitrogen-doped porous carbon heterojunction gas-sensitive materials resistant to humidity interference. Background Technology
[0002] NO2, a typical toxic and harmful gas, is widely generated in industrial emissions, vehicle exhaust, and other scenarios, posing a serious threat to human health and the ecological environment. Therefore, the development of efficient NO2 gas detection technology is of great significance. Gas sensors have become the mainstream choice for gas detection due to their advantages such as ease of operation and low cost. The performance of gas-sensitive materials directly determines the detection effect of the sensor.
[0003] Traditional metal oxide gas-sensitive materials such as SnO2 and ZnO have significant drawbacks in NO2 detection: weak response signals at room temperature, usually requiring high-temperature heating to obtain an effective response, increasing energy consumption; slow recovery speed after gas adsorption, prone to signal drift; sensitive to environmental factors such as humidity, with poor anti-interference ability; poor cycle stability, with significant performance degradation after long-term use. Although existing technologies modify them through doping, compositing, and other methods, a single modification method cannot simultaneously solve the above multiple problems and cannot meet the comprehensive requirements of actual detection for high response, fast recovery, strong stability, and anti-interference. Summary of the Invention
[0004] To address the shortcomings of existing technologies, this invention provides a synthesis process for humidity-resistant nitrogen-doped porous carbon heterojunction gas-sensitive materials. This process solves the significant defects of traditional metal oxide gas-sensitive materials such as SnO2 and ZnO in NO2 detection: weak response signals at room temperature, often requiring high-temperature heating to obtain an effective response, increasing energy consumption; slow recovery speed after gas adsorption, prone to signal drift; sensitivity to environmental factors such as humidity, poor anti-interference ability; and poor cycle stability, with significant performance degradation after long-term use. Although existing technologies modify these materials through doping, compositing, etc., a single modification method cannot simultaneously solve the above multiple problems and cannot meet the comprehensive requirements of practical detection for high response, fast recovery, strong stability, and anti-interference.
[0005] To achieve the above objectives, the present invention provides the following technical solution: a high-performance carbon nitride-based NO2 gas-sensitive material, based on SnO2 / ZnO, integrating three core modification mechanisms: magnetic ion doping and oxygen vacancy engineering, magnetically doped oxide-nitrogen-doped porous carbon tight heterojunction, and black magnetic phase nanophotothermal-assisted desorption.
[0006] As a preferred technical solution of the present invention, magnetic ion doping and oxygen vacancy engineering: Fe / Co / Ni / Mn magnetic ions are introduced into SnO2 / ZnO and oxygen vacancies are controlled to form shallow energy levels and spin-related scattering, suppress charge recombination, prolong the lifetime of photogenerated carriers, and enable NO2 to obtain reversible adsorption-activation sites on the material surface, thereby achieving natural recovery at room temperature and reducing drift.
[0007] As a preferred technical solution of the present invention, the magnetically doped oxide-nitrogen-doped porous carbon compact heterojunction provides a low-resistance electron channel with a built-in electric field at the interface, which promotes the spatial separation and directional migration of electrons and holes, shortens the mass transfer path, improves the accessibility of active sites, significantly improves responsiveness and selectivity, and reduces humidity interference.
[0008] As a preferred technical solution of the present invention, black magnetic phase nanophotothermal desorption is achieved by Fe3O4 / CoFe2O4 nanoparticles serving as photothermal centers, which generate a mild localized temperature rise under ambient light, reducing the desorption energy barrier of NO2⁻ / NO3⁻ and working synergistically with photogenerated electron reduction. This shortens the recovery time without the need for external heating and ensures cycle stability.
[0009] Compared with the prior art, the present invention provides a synthesis process for nitrogen-doped porous carbon heterojunction gas-sensitive materials resistant to humidity interference, which has the following beneficial effects: 1. The synthesis process of this humidity-resistant nitrogen-doped porous carbon heterojunction gas-sensitive material not only has excellent room temperature response performance: it can generate a strong response signal to NO2 in a weak light environment without the need for external heating, solving the problem of weak room temperature response of traditional materials, but also has a fast recovery speed: photothermal desorption and reversible adsorption sites work together to significantly shorten the material recovery time and improve detection efficiency.
[0010] 2. The synthesis process of this humidity-resistant nitrogen-doped porous carbon heterojunction gas-sensitive material not only has strong anti-interference ability: the nitrogen-doped porous carbon heterojunction structure effectively reduces humidity interference and improves the selective recognition ability of NO2; but also has good stability: the response retention rate is high after multiple cycles of detection, meeting the requirements for long-term use. The preparation process is simple and controllable, the cost is moderate, it is easy to scale up production, and it has broad practical application prospects. Attached Figure Description
[0011] Figure 1 The recovery curves of the g-C3N4-NO2 sensor under different light intensities (0, 5, 10, 20, 50 mW cm⁻²) are shown, with the vertical axis representing R / R0 and the horizontal axis representing time (min). Figure 2 To show the response retention rate over five cycles, fill the bars with slashes and label the values at the top. Detailed Implementation
[0012] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0013] Example 1 Magnetic ion doping and oxygen vacancy regulation: SnCl4·5H2O, Zn(NO3)2·6H2O and FeCl3·6H2O were weighed in molar ratio Sn:Zn:Fe=1:1:0.02, added to deionized water and ultrasonically dispersed for 30 min, transferred to a hydrothermal reactor, reacted at 150℃ for 8 h, cooled and filtered and washed, the obtained precursor was calcined at 500℃ for 3 h to obtain Fe-doped-oxygen vacancy regulated SnO2 / ZnO powder; Heterogeneous structure construction: Take 1g of the above powder and 0.2g of graphene / nitrogen-doped porous carbon composite material, disperse them in 50mL of ethanol, stir for 2h, and then heat treat at 400℃ for 2h under argon atmosphere to obtain heterojunction material; Photothermal core composite: 0.1g Fe3O4 nanoparticles were added to the above heterojunction material, ultrasonically dispersed for 60min, and dried at 60℃ for 8h to obtain a high-performance carbon nitride-based NO2 gas-sensitive material.
[0014] Example 2 Magnetic ion doping and oxygen vacancy regulation: SnSO4, ZnSO4 and CoSO4·7H2O were weighed in molar ratio Sn:Zn:Co=1:1:0.03, and ethanol was added and ultrasonically dispersed for 40 min. The mixture was then transferred to a hydrothermal reactor and reacted at 160℃ for 7 h. After cooling, the mixture was filtered and washed. The resulting precursor was calcined at 550℃ for 2.5 h to obtain Co-doped oxygen vacancy regulated SnO2 / ZnO powder. Heterogeneous structure construction: Take 1g of the above powder and 0.3g of graphene / nitrogen-doped porous carbon composite material, disperse them in 60mL of deionized water, stir for 3h, and then heat treat at 450℃ for 1.5h under nitrogen atmosphere to obtain heterojunction material; Photothermal core composite: 0.08g CoFe2O4 nanoparticles were added to the above heterojunction material, ultrasonically dispersed for 80min, and dried at 70℃ for 6h to obtain a high-performance carbon nitride-based NO2 gas-sensitive material.
[0015] The gas-sensitive materials prepared in Examples 1 and 2 were fabricated into gas-sensitive elements, and their performance was tested. The results showed that under the conditions of 25℃ and 10mWcm⁻² light intensity, the response value (R / R0) to 10ppmNO2 was greater than 0.8, and the recovery time was less than 60min; under the condition of 50% humidity, the response value decay rate was less than 10%; after five cycles of testing, the response retention rates were 92.5% and 91.6%, respectively, demonstrating excellent comprehensive gas-sensitive performance.
[0016] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A process for the synthesis of humidity interference resistant nitrogen-doped porous carbon heterojunction gas sensing material, characterized in that: It includes a substrate, a magnetic ion doping component, a nitrogen-doped porous carbon composite component, and a nanophotothermal center; the substrate is a SnO2 / ZnO composite oxide, the magnetic ion doping component is one or more of Fe / Co / Ni / Mn, the nitrogen-doped porous carbon composite component is a graphene / nitrogen-doped porous carbon composite material, and the nanophotothermal center is one or two of Fe3O4 / CoFe2O4.
2. The process for synthesis of humidity interference resistant nitrogen doped porous carbon hetero-junction gas sensing material as claimed in claim 1 wherein: The amount of magnetic ions doped in the substrate is 0.5-5 mol, and the amount of nano-photothermal centers added is 1-10% of the total mass of the gas-sensitive material.
3. The process for synthesis of humidity resistant nitrogen doped porous carbon hetero-junction gas sensing material as claimed in claim 1 wherein: Includes the following steps: S1: Magnetic ion doping and oxygen vacancy regulation. Sn source, Zn source and Fe / Co / Ni / Mn salt compound are mixed in proportion, solvent is added and ultrasonically dispersed. Magnetic ion doped SnO2 / ZnO precursor is prepared by hydrothermal reaction. The oxygen vacancy content is regulated by calcination treatment to obtain magnetic ion doped-oxygen vacancy regulated SnO2 / ZnO powder. S2: Heterogeneous structure construction, the powder obtained in step (1) is dispersed in a solvent with graphene / nitrogen-doped porous carbon composite material, stirred evenly and then heat-treated to achieve close composite, and magnetic doped oxide-nitrogen-doped porous carbon heterojunction material is obtained; S3: Photothermal center composite, Fe3O4 / CoFe2O4 nanoparticles are added to the heterojunction material obtained in step (2), ultrasonically dispersed and dried to obtain a high-performance carbon nitride-based NO2 gas-sensitive material.
4. The process for synthesis of humidity interference resistant nitrogen doped porous carbon hetero-junction gas sensing material as claimed in claim 3 wherein: The hydrothermal reaction temperature in S1 is 120-180℃, and the reaction time is 6-12h; the calcination temperature is 400-600℃, and the calcination time is 2-4h.
5. The process for synthesis of humidity resistant nitrogen doped porous carbon hetero-junction gas sensing material as claimed in claim 3 wherein: The heat treatment temperature in S2 is 300-500℃, the heat treatment time is 1-3h, and the heat treatment atmosphere is an inert gas atmosphere.
6. The synthesis process of the humidity-resistant nitrogen-doped porous carbon heterojunction gas-sensitive material according to claim 1, characterized in that: The gas-sensitive material was fabricated into a gas-sensitive element for the detection of NO2 gas at room temperature and under weak light conditions, with a detection light intensity range of 0-50 mWcm⁻².