Characterization method, apparatus and storage medium for material adsorption amount and structural response

Abstract

The application discloses a material adsorption amount and structure response characterization analysis method, equipment and storage medium. By combining a cantilever beam with a Fourier transform infrared spectrometer, the gas adsorption behavior of an adsorption material and micro-molecular vibration information thereof are synchronously detected by using the super-sensitive mass detection function of the cantilever beam and the in-situ infrared spectrum technology. The application can test trace adsorption materials, is favorable for the research on the adsorption mechanism, can synchronously monitor the structure change of the adsorption material in an in-situ mode, is higher in accuracy, realizes full-scale analysis from a macroscopic adsorption amount to a micro-bonding mechanism, and provides a deep analysis tool for the design and application of porous materials.

Description

Technical Field

[0001] This invention belongs to the field of detection and characterization, and particularly relates to a method, device and storage medium for characterizing and analyzing the adsorption amount and structural response of a material. Background Technology

[0002] The study of gas adsorption testing in materials has attracted much attention in recent years, mainly due to their significant application potential in environmental remediation, clean energy storage, and industrial separation. For example, the gas adsorption behavior of covalent organic frameworks (COFs) stems from their unique structural designability and high specific surface area. Gravimetric analysis of COF gas adsorption helps to quantitatively explain the adsorption mechanism, playing a crucial role in the optimization and application of COFs. However, gravimetric analysis cannot observe changes in material structure and functional groups during adsorption, which is precisely where infrared spectroscopy excels. On the other hand, infrared spectroscopy is a qualitative analysis and cannot quantitatively characterize the amount of gas adsorbed by the material, thus complementing gravimetric adsorption testing. Therefore, combining gravimetric adsorption and infrared spectroscopy for in-situ joint characterization has the potential to become a core means of elucidating adsorption mechanisms and optimizing material performance, promoting the research and characterization of various COFs, and their applications in gas sensing, gas separation and storage, and gas capture.

[0003] However, traditional gravimetric adsorption testing methods and instruments, such as the IGA (Intelligent Gravimetric Analysis System) from Hyde Technology in the UK, require measurement using a balance in a closed environment. On the one hand, the required sample volume is relatively large (several grams), making it impossible to test trace samples, which is detrimental to the study of adsorption mechanisms. On the other hand, the closed environment prevents it from being directly coupled to an infrared spectrometer in situ; it can only be measured using a non-in-situ method by testing the infrared spectrum of the escaped gas, which results in measurement lag and decreased accuracy. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a method, apparatus, and storage medium for characterizing and analyzing the adsorption capacity and structural response of materials. This invention can test trace amounts (pg-level, ng-level) of adsorbent materials, which is beneficial for studying adsorption mechanisms. It also enables simultaneous, in-situ monitoring of structural changes in adsorbent materials with higher accuracy. Furthermore, it achieves full-scale analysis from macroscopic adsorption capacity to microscopic bonding mechanisms, providing a deep analytical tool for the design and application of porous materials.

[0005] The present invention solves the above-mentioned technical problems through the following technical solution:

[0006] On one hand, the present invention provides a method for characterizing and analyzing the adsorption capacity and structural response of a material, comprising the following steps: S1, placing a blank cantilever chip in a test chamber under an inert atmosphere, performing a baseline test, and recording the intrinsic frequency of the blank cantilever chip; S2, placing a cantilever chip coated with adsorbent material in the test chamber of step S1, and recording the resonant frequency of the cantilever chip under the same test environment as in step S1; then switching the inert atmosphere in the test chamber to the adsorbed gas, performing a gas adsorption test, and monitoring the change in resonant frequency in real time; S3, starting a Fourier transform infrared spectrometer to acquire the transmission and reflection spectra of the adsorbent material in real time; S4, calculating the relationship curve between the adsorbed mass percentage and time based on the intrinsic frequency in step S1, the resonant frequency of the cantilever chip in step S2, and the change in the resonant frequency; simultaneously, generating an infrared spectrum showing the change with adsorption time based on the transmission and reflection spectra in step S3.

[0007] In this invention, preferably, in step S1, the test chamber is provided with a window to allow the infrared beam of the Fourier transform infrared spectrometer to pass through.

[0008] In this invention, preferably, in step S1, the inert atmosphere includes an argon atmosphere.

[0009] In step S2 of the present invention, the same test environment as in step S1 includes the type and flow rate of the inert atmosphere.

[0010] In this invention, preferably, in step S2, the switching device for the adsorbed gas includes a gas control system.

[0011] In this invention, preferably, in step S2, the device for monitoring the change of resonant frequency includes a resonant frequency detection circuit.

[0012] In this invention, preferably, in step S2, the coating method of the adsorbent material includes: dispersing the adsorbent material in a solvent to prepare a liquid sample; adsorbing the liquid sample using a hydraulic spotting instrument and a capillary glass needle; and spotting the sample in the sample area of ​​the cantilever beam chip under a microscope by moving the tip of the capillary glass needle.

[0013] Preferably, the solvent includes anhydrous ethanol.

[0014] In this invention, the adsorbent material may include microporous material, mesoporous material or macroporous material.

[0015] Preferably, the adsorbent material includes COFs (covalent organic frameworks) or MOFs (gold metal-organic frameworks); more preferably, the COFs include LZU-111 or COF-V.

[0016] In this invention, preferably, in step S2, the gas adsorption test is performed in an airflow containing the adsorbed gas.

[0017] In this invention, preferably, in step S2, the adsorbed gas includes air, nitrogen dioxide, or ammonia; the adsorbed gas may be referred to as the adsorbate.

[0018] In this invention, preferably, in step S2, the flow rate fluctuation range of the adsorbed gas is 10-100 sccm.

[0019] In this invention, preferably, in step S4, the calculation expression for the relationship curve between the adsorption mass percentage of the adsorbent material and time is:

[0020] The percentage of adsorbed mass of the adsorbent material = (f-f0) / (f0-f1);

[0021] Where f0 is the intrinsic resonant frequency of the blank cantilever beam chip in step S1; f1 is the resonant frequency of the cantilever beam in step S2; and f is the real-time resonant frequency monitored in step S2.

[0022] In this invention, preferably, in step S4, the infrared spectrum is used to detect changes in the vibrational frequency of chemical bonds in the framework of the adsorbent material; the changes in vibrational frequency are manifested as changes in the shift or intensity of infrared characteristic peaks.

[0023] In this invention, preferably, the characterization and analysis method is performed in a testing device, which includes a testing chamber containing a cantilever beam and a Fourier transform infrared spectrometer; the testing chamber includes a sealed chamber with a diamond window; the testing chamber is located below the Fourier transform infrared spectrometer, and the infrared light emitter of the Fourier transform infrared spectrometer is directly opposite the diamond window, so that the infrared light beam emitted by the infrared light emitter passes through the diamond window and irradiates the sample area of ​​the cantilever beam chip.

[0024] In this invention, preferably, in step S2, the placement process includes: placing the cantilever chip in the test chamber and aligning the sample area of ​​the cantilever chip with the diamond window so that the infrared beam emitted by the infrared emitter passes through the diamond window and irradiates the adsorbed material of the cantilever chip; and measuring the mass change of the adsorbed material in real time according to the change of the resonant frequency.

[0025] The test chamber allows for adjustment of the gas type and flow rate.

[0026] On the other hand, the present invention also provides an electronic device, including a memory, a processor, and a computing program stored in the memory and executable on the processor, wherein the processor executes the computing program to implement the characterization analysis method as described above.

[0027] In another aspect, the present invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the characterization analysis method as described above.

[0028] Compared with the prior art, the present invention has the following advantages and technical effects:

[0029] 1. This invention combines the ultrasensitive mass detection function of a cantilever beam with in-situ infrared spectroscopy to simultaneously detect the adsorption behavior and microscopic molecular vibration information of adsorbent materials (such as covalent organic frameworks (COFs)). This is a highly innovative multimodal characterization technique. The two are triggered synchronously at the millisecond level, realizing for the first time the real-time correlation analysis between adsorption mass change and chemical bonding kinetics, solving the problem of dynamic process mismatch in traditional stepwise detection.

[0030] 2. This invention combines dynamic monitoring of adsorption behavior with molecular-level structural response analysis, enabling a comprehensive understanding of the adsorption mechanism and structure-function relationship of adsorbent materials from macroscopic to microscopic levels. The cantilever beam provides quantitative data on adsorption, while in-situ infrared spectroscopy reveals the evolution of the interaction between the adsorbate and the adsorbent material at different stages (e.g., physical adsorption dominates in the initial stage, followed by chemical bonding). This effectively solves the problem that existing technologies are limited by minute-level time resolution, making it difficult to capture the initial stage of rapid adsorption of adsorbent materials (e.g., the adsorption process within the first 30 seconds).

[0031] 3. In this invention, the picogram-level mass detection of the cantilever beam and the molecular vibrational information from infrared spectroscopy complement each other, covering a full-scale analysis from macroscopic adsorption capacity to microscopic bonding mechanisms. This combined technique, through the synergy of the cantilever beam and infrared spectroscopy, achieves in-situ, dynamic, and full-scale characterization of the adsorption behavior and microstructural response of adsorbent materials, providing a deep analytical tool for the design and application of porous materials. Its core value lies in directly linking macroscopic performance with molecular mechanisms, driving the leap from "empirical optimization" to "mechanism-driven design" of adsorbent materials. Attached Figure Description

[0032] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0033] Figure 1 This is a schematic diagram of the adsorption curve of LZU-111 for NO2 in Example 1 of the present invention;

[0034] Figure 2 The infrared spectrum of LZU-111 during the adsorption of NO2 in Example 1 of this invention is shown.

[0035] Figure 3 This is a schematic diagram of the adsorption curve of COF-V on NH3 after treatment in Example 2 of the present invention;

[0036] Figure 4 This is an infrared spectrum of the COF-V after treatment in Example 2 of the present invention during the adsorption process of NH3. Detailed Implementation

[0037] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0038] In the embodiments of this application, the characterization and analysis method for the material adsorption amount and structural response includes the following steps:

[0039] S1. Place the blank cantilever chip in a test chamber under an inert atmosphere, perform baseline testing, and record the intrinsic frequency of the blank cantilever chip.

[0040] S2. Coat the sample to be tested onto the sample area at the free end of the cantilever beam chip;

[0041] The cantilever beam coated with the sample was placed in the same test environment as the baseline test, and the resonant frequency of the cantilever beam coated with the sample was recorded. The atmosphere in the test chamber was switched to the target gas through the gas control system. Throughout the test, the resonant frequency change was monitored in real time through the resonant frequency detection circuit.

[0042] S3. Start the Fourier transform infrared spectrometer. The infrared beam generated by it passes through the diamond window on the test chamber and is focused on the sample surface to collect the transmission and reflection spectra.

[0043] S4. Based on the intrinsic frequency, the resonant frequency of the cantilever beam, and the change of the resonant frequency, calculate the sample adsorption mass percentage-time curve; generate an infrared spectrum that changes with adsorption time based on the transmission and reflection spectra.

[0044] In the embodiments of this application, a combination of cantilever beam and Fourier transform infrared spectrometer (FT-IR) is used to achieve gas adsorption-structure response infrared characterization of materials by combining the cantilever beam with ultra-sensitive mass detection capability and in-situ infrared spectroscopy.

[0045] Example 1

[0046] This embodiment discloses a method for characterizing and analyzing the adsorption amount and structural response of a material, the specific technical solution of which is as follows:

[0047] In this embodiment, the testing environment includes: placing the cantilever beam chip in a sealed chamber with a diamond window, the chamber being connected to a gas flow control device, which can introduce a certain amount of the required test gas (such as argon or air) to keep the cantilever beam chip in a stable test gas flow.

[0048] The testing apparatus includes a testing chamber containing a cantilever beam and a Fourier transform infrared spectrometer; the testing chamber includes a sealed chamber with a diamond window; the testing chamber is located below the Fourier transform infrared spectrometer, and the infrared light emitter of the Fourier transform infrared spectrometer is directly opposite the diamond window, so that the infrared light beam emitted by the infrared light emitter passes through the diamond window and irradiates the sample area of ​​the cantilever beam chip.

[0049] The gas adsorption test procedure includes: placing the cantilever chip in the test chamber and aligning the sample area of ​​the cantilever chip with the diamond window so that the infrared beam emitted by the infrared emitter passes through the diamond window and irradiates the adsorbed material of the cantilever chip; measuring the mass change of the adsorbed material in real time according to the change of the resonant frequency, while the infrared spectrometer collects the spectrum of the sample in real time.

[0050] The steps of the method for co-measuring adsorption behavior and structural changes include:

[0051] Step 1, Baseline Test: Place the blank cantilever beam chip in the test chamber and first record the intrinsic frequency f0 of the blank cantilever beam chip under an inert atmosphere (such as argon).

[0052] A time reference can be used to ensure the consistency between the adsorption signal and the infrared signal;

[0053] Step 2, Loading the sample: Coat the sample area at the free end of the cantilever chip with the LZU-111 to be tested (picometer to nanogram level).

[0054] The process of coating the LZU-111 to be tested (picometer to nanogram level) onto the sample area at the free end of the cantilever chip specifically includes: dispersing the LZU-111 to be tested in anhydrous ethanol, preparing the liquid sample, adsorbing a certain amount of the liquid sample using a hydraulic spotting instrument and a capillary glass needle, and then spotting the sample area of ​​the cantilever chip under a microscope by moving the tip of the capillary glass needle. Because ethanol is highly volatile, the remaining LZU-111 to be tested in the conductivity sample area easily evaporates.

[0055] Step 3, Adsorption capacity – Infrared spectroscopy characterization:

[0056] Adsorption capacity test: The cantilever beam coated with the sample is placed in the same test environment as the baseline test. The resonant frequency f1 of the cantilever beam coated with the sample is recorded. After a period of time, the atmosphere in the test chamber is switched to the target gas (e.g., NO2) through the gas control system. Throughout the test, the real-time resonant frequency f is monitored by the resonant frequency detection circuit. (The inert gas and the target gas can be controlled at the same flow rate by preset parameters corresponding to different gases.)

[0057] Infrared spectral acquisition: During the test, FT-IR is initiated, and an infrared beam is focused onto the sample surface through a diamond window. Transmission / reflection spectra are acquired at a rate of 1–10 times per second, with a spectral range of 400–4000 cm⁻¹. -1 Resolution ≤ 4cm -1 .

[0058] Step 4, Data Processing:

[0059] Adsorption data processing: Based on f and intrinsic frequency f0, the relationship curve of sample adsorption mass percentage - time can be calculated using the following formula, and parameters such as gas molecule adsorption amount and adsorption time can be extracted;

[0060] The percentage of gas adsorption can be calculated by the frequency difference before and after real-time adsorption / the frequency difference before and after spotting, which will eventually result in a curve of adsorption percentage versus time.

[0061] Since Δf∝Δm; the percentage of adsorbed mass of the sample is (f-f0) / (f0-f1);

[0062] Where f0 is the intrinsic resonant frequency of the cantilever beam in an inert atmosphere; f1 is the resonant frequency of the cantilever beam coated with the sample; and f is the real-time resonant frequency of the cantilever beam during the gas adsorption test. Δf is the difference between the real-time resonant frequency and the intrinsic resonant frequency f0 of the cantilever beam.

[0063] Infrared data: Infrared spectroscopy detects changes in chemical bond vibrations caused by adsorption, generating infrared spectra that change with adsorption time. When gas molecules adsorb onto the pores or surface of LZU-111, it may cause changes in the vibrational frequencies of chemical bonds (such as CN, N=O, etc.) in the LZU-111 framework, which manifests as shifts or intensities of infrared characteristic peaks.

[0064] The advantages of this embodiment are: 1. The signal during adsorption can be observed in real time, and the amount of adsorption can be calculated. (This is calculated using the formula: frequency difference before and after adsorption / mass sensitivity S of the cantilever beam (which is calibrated after chip manufacturing, S = resonant frequency difference / mass change)). The second advantage is that changes in the infrared signal can be observed simultaneously with adsorption, revealing the mechanism of adsorption behavior, such as which functional group the adsorbed gas interacts with.

[0065] Figure 1 This is a schematic diagram of the adsorption curve of LZU-111 for NO2 in this embodiment; from Figure 1 The adsorption curves show that initially, in an inert argon atmosphere, the cantilever chip exhibits a stable frequency and almost no mass change. After approximately 60 seconds, diluted NO2 gas is introduced, and the material immediately begins to adsorb, with its mass increasing. The adsorption rate is rapid for the first 360 seconds, until the material reaches near saturation after 2400 seconds of testing. Ultimately, the calculated mass percentage of NO2 adsorbed by LZU-111 is approximately 9.6%.

[0066] Figure 2 This is the infrared spectrum of LZU-111 during the NO2 adsorption process in this embodiment; (The image is from...) Figure 2 Infrared spectroscopy results during the adsorption process show that the absorption peak intensities of (CN) and (N=O) groups on the material surface increase after NO2 gas is introduced, indicating that the target gas molecules NO2 undergo chemical adsorption with the material. Since the changes in the infrared spectrum are almost negligible after 360 seconds of testing, the adsorption behavior can be revealed by continuous infrared spectra within 360 seconds.

[0067] Example 2

[0068] This embodiment discloses a characterization and analysis method for the adsorption amount and structural response of a material; wherein the adsorbent material is a treated COF-V, and the adsorbed gas is a mixture of ammonia and argon; otherwise, all other conditions are the same as in Example 1.

[0069] Figure 3 This is a schematic diagram of the adsorption curve of COF-V for NH3 after treatment in this embodiment; from Figure 3 The adsorption curves show that initially, the material was in a stable argon inert atmosphere, and the sample on the cantilever chip showed almost no mass change. Around 300 seconds, the introduction of 10% NH3 / AR gas immediately triggered adsorption, and the sample mass began to increase. The adsorption curves also indicate that the adsorption rate was rapid within the first 5 minutes after the introduction of the target gas (NH3 / AR gas), and the material nearly reached adsorption saturation at 3600 seconds. Finally, the calculated mass percentage of NH3 adsorbed by the treated COF-V was approximately 5.6%.

[0070] Figure 4 This is the infrared spectrum of the COF-V after treatment in this embodiment during the adsorption process of NH3; (The image is from...) Figure 4 Infrared spectroscopy results during the adsorption process show that the absorption peak intensity of the amide group (-CONH-) on the material surface increases after NH3 gas is introduced, indicating that the target gas molecule NH3 has undergone adsorption behavior with the material, and NH3 molecules are more likely to adsorb near the amide group.

[0071] Combination Figure 1 and Figure 2 , Figure 3 and Figure 4 The material adsorption capacity and structural response characterization and analysis method of this application can effectively realize dynamic monitoring of adsorption behavior and molecular-level structural response analysis.

[0072] Compared with existing technologies, this embodiment achieves the following effects:

[0073] (1) Overcoming the limitations of single detection dimension: Traditional methods such as quartz microbalance (QCM) can only obtain changes in adsorption amount (sensitivity at the nanogram level), while in-situ infrared spectroscopy alone can only capture molecular vibrational signals, and the data of the two are not synchronized in time and space. In this embodiment, by synchronously triggering the cantilever beam (sensitivity at the picogram level) and infrared spectroscopy at the millisecond level, real-time correlation analysis of adsorption mass change and chemical bonding kinetics is realized for the first time, solving the problem of dynamic process mismatch in traditional stepwise detection.

[0074] (2) Overcoming the bottlenecks of traditional coupled technologies: Existing technologies are limited by minute-level time resolution, making it difficult to capture the initial stage of rapid adsorption of COFs materials (such as the adsorption process within the first 30 seconds). This method greatly improves the dynamic monitoring time resolution and can successfully capture rapid or weak adsorption processes.

[0075] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for characterizing and analyzing the adsorption amount and structural response of a material, characterized in that, It includes the following steps: S1. Place the blank cantilever beam chip in a test chamber under an inert atmosphere, perform baseline testing, and record the intrinsic frequency of the blank cantilever beam chip. S2. Place the cantilever beam chip coated with adsorption material into the test chamber of step S1, and record the resonant frequency of the cantilever beam chip under the same test environment as in step S1. Then, the inert atmosphere in the test chamber is switched to the adsorbed gas to conduct a gas adsorption test, and the change of resonant frequency is monitored in real time. S3. Start the Fourier transform infrared spectrometer to collect the transmission and reflection spectra of the adsorbent material in real time; S4. Based on the intrinsic frequency described in step S1, the resonant frequency of the cantilever chip described in step S2, and the change of the resonant frequency, calculate the relationship curve between the adsorption mass percentage of the adsorbent material and time; simultaneously, based on the transmission and reflection spectra described in step S3, generate an infrared spectrum that changes with adsorption time.

2. The characterization analysis method according to claim 1, characterized in that, Step S1 satisfies at least one of the following conditions: ①The test chamber is provided with a window to allow the infrared beam of the Fourier transform infrared spectrometer to pass through; ②The inert atmosphere includes an argon atmosphere.

3. The characterization analysis method according to claim 1, characterized in that, In step S2, the coating method of the adsorbent material includes: The adsorbent material is dispersed in a solvent to prepare a liquid sample; The liquid sample was adsorbed using a hydraulic spotting device and a capillary glass needle. Under a microscope, the tip of the capillary glass needle is moved to the sample area of ​​the cantilever chip for spotting.

4. The characterization analysis method according to claim 1, characterized in that, In step S4, the expression for calculating the relationship between the adsorption mass percentage of the adsorbent material and time is as follows: The percentage of adsorbed mass of the adsorbent material = (f-f0) / (f0-f1); Where f0 is the intrinsic resonant frequency of the blank cantilever beam chip in step S1; f1 is the resonant frequency of the cantilever beam in step S2; and f is the real-time resonant frequency monitored in step S2.

5. The characterization analysis method according to claim 1, characterized in that, In step S4, the infrared spectrum is used to detect changes in the vibrational frequency of chemical bonds in the framework of the adsorbent material; the changes in vibrational frequency are manifested as changes in the shift or intensity of infrared characteristic peaks.

6. The characterization analysis method according to claim 1, characterized in that, Step S2 satisfies at least one of the following conditions: ①The gas adsorption test is performed in a gas stream containing the adsorbed gas; ②The adsorbed gas includes air, nitrogen dioxide, or ammonia; ③The adsorbent material includes COFs or MOFs.

7. The characterization analysis method according to claim 1, characterized in that, The characterization and analysis method is performed in a testing device, which includes a testing chamber containing a cantilever beam and a Fourier transform infrared spectrometer. The test chamber includes a sealed chamber with a diamond window; The test chamber is located below the Fourier transform infrared spectrometer, and the infrared light emitter of the Fourier transform infrared spectrometer is directly opposite the diamond window, so that the infrared light beam emitted by the infrared light emitter passes through the diamond window and illuminates the sample area of ​​the cantilever chip.

8. The characterization analysis method according to claim 7, characterized in that, In step S2, the placement process includes: placing the cantilever chip in the test chamber and aligning the sample area of ​​the cantilever chip with the diamond window so that the infrared beam emitted by the infrared emitter passes through the diamond window and irradiates the adsorbed material of the cantilever chip; and measuring the mass change of the adsorbed material in real time according to the change of the resonant frequency.

9. An electronic device comprising a memory, a processor, and a computing program stored in the memory and executable on the processor, characterized in that, When the processor executes the calculation program, it implements the characterization analysis method according to any one of claims 1-8.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the characterization analysis method according to any one of claims 1-8.

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