Characterization analysis method and device for material adsorption capacity and structural response and storage medium

Abstract

The invention discloses a characterization analysis method and device for material adsorption capacity and structural response and a storage medium. A cantilever beam is combined with a Fourier transform infrared spectrometer, and the ultra-sensitive quality detection function of the cantilever beam and an in-situ infrared spectrum technology are utilized to synchronously detect the gas adsorption behavior of the adsorption material and the microcosmic molecular vibration information of the adsorption material. According to the invention, a trace amount of adsorption material can be tested, the research on an adsorption mechanism is facilitated, the structural change of the adsorption material can be synchronously monitored in an in-situ manner, and the accuracy is higher; the full-scale analysis from the macroscopic adsorption capacity to the microcosmic bonding mechanism is realized, and a deep analysis tool is provided for the design and application of the porous material.

Description

Technical Field

[0001] The present invention belongs to the field of detection and characterization, and in particular relates to a characterization and analysis method, device and storage medium for material adsorption amount and structural response. Background Art

[0002] Research on gas adsorption testing of materials has attracted considerable attention in recent years, primarily due to their significant application potential in environmental remediation, clean energy storage, and industrial separations. For example, the gas adsorption behavior of covalent organic frameworks (COFs) stems from their unique structural designability and high specific surface area. Gravimetric gas adsorption testing of COFs helps quantitatively elucidate the adsorption mechanism and plays a crucial role in the optimization and application of COFs. However, gravimetric testing cannot observe changes in material structure and functional groups during the adsorption process, which is precisely what infrared spectroscopy excels at. On the other hand, infrared spectroscopy is a qualitative analysis that cannot quantitatively characterize the amount of gas adsorbed by a material, making it a complementary approach to gravimetric adsorption testing. Therefore, in situ characterization combining gravimetric adsorption and infrared spectroscopy has the potential to become a core tool for elucidating adsorption mechanisms and optimizing material properties, promoting the research and development, characterization, and application of various COFs in gas sensing, gas separation and storage, and gas capture.

[0003] However, traditional gravimetric adsorption testing methods and instruments, such as the UK Hyde Technology's IGA (Intelligent Gravimetric Analysis System), require measurements to be performed using a balance in a sealed environment. For one thing, the test requires a relatively large sample size (several grams), making it impossible to test trace amounts, hindering the study of adsorption mechanisms. Furthermore, the sealed environment precludes direct in-situ integration with infrared spectrometers, forcing the instrument to rely on ex-situ methods such as measuring the infrared spectrum of the outgassing gas. This results in measurement lag and reduced accuracy. Summary of the Invention

[0004] To address the above technical issues, the present invention provides a method, device, and storage medium for characterizing and analyzing the adsorption capacity and structural response of materials. This method can test trace amounts (pg and ng levels) of adsorbent materials, facilitating the study of adsorption mechanisms. It also enables in situ, simultaneous monitoring of structural changes in adsorbent materials with greater accuracy. This method enables full-scale analysis, from macroscopic adsorption capacity to microscopic bonding mechanisms, providing an in-depth analytical tool for the design and application of porous materials.

[0005] The present invention solves the above technical problems through the following technical solutions:

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

[0007] In the present 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 the present invention, preferably, in step S1, the inert atmosphere includes an argon atmosphere.

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

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

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

[0012] In the present invention, preferably, in step S2, the coating method of the adsorption material includes: dispersing the adsorption material in a solvent to prepare a liquid sample; adsorbing the liquid sample with an oil pressure spotter and a capillary glass needle; and moving the tip of the capillary glass needle to the sample area of ​​the cantilever beam chip under a microscope for spotting.

[0013] Wherein, preferably, the solvent includes anhydrous ethanol.

[0014] In the present invention, the adsorption material may include a microporous material, a mesoporous material or a macroporous material.

[0015] Among them, preferably, the adsorption material includes COFs (covalent organic framework materials) or MOFs (gold metal organic framework materials); further preferably, the COFs include LZU-111 or COF-V.

[0016] In the present invention, preferably, in step S2, the gas adsorption test is performed in a gas flow containing the adsorbed gas.

[0017] In the present invention, preferably, in step S2, the adsorbed gas includes air, nitrogen dioxide or ammonia; the adsorbed gas can be called an adsorbate.

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

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

[0020] Adsorption mass percentage of adsorption material = (f-f0) / (f0-f1);

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

[0022] In the present invention, preferably, in step S4, the infrared spectrum is used to detect the change in vibration frequency of chemical bonds in the skeleton of the adsorption material; the change in vibration frequency is manifested as a shift or intensity change of infrared characteristic peaks.

[0023] In the present invention, preferably, the characterization and analysis method is carried out 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 arranged below the Fourier transform infrared spectrometer, and the infrared light emitter of the Fourier transform infrared spectrometer is directly opposite to 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 the present invention, preferably, in step S2, the placement process includes: placing the cantilever beam chip in the test chamber, and aligning the sample area of ​​the cantilever beam chip with the diamond window, so that the infrared light beam emitted by the infrared light emitter passes through the diamond window and irradiates the cantilever beam chip adsorption material; according to the change of the resonant frequency, the mass change of the adsorption material is measured in real time.

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

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

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

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

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

[0030] 2. This invention combines dynamic monitoring of adsorption behavior with molecular-level structural response analysis, comprehensively revealing the adsorption mechanism and structure-function relationship of the adsorbent material from the macroscopic to the microscopic level. Cantilever beams provide quantitative adsorption data, while in situ infrared spectroscopy reveals the evolution of the interaction between the adsorbate and the adsorbent material at different stages (e.g., initial physical adsorption dominates, followed by chemical bonding). This effectively addresses the problem of existing technologies, which are limited by minute-level time resolution and have difficulty capturing the initial stages of rapid adsorption (e.g., the adsorption process within the first 30 seconds).

[0031] 3. In this invention, the picogram-level mass detection of cantilever beams complements the molecular vibration information of infrared spectroscopy, covering a full-scale analysis from macroscopic adsorption to microscopic bonding mechanisms. This combined technique, through the synergistic effect of cantilever beams and infrared spectroscopy, enables in situ, dynamic, and full-scale characterization of the adsorption behavior and microstructural response of adsorbent materials, providing an in-depth analytical tool for the design and application of porous materials. Its core value lies in directly linking macroscopic performance with molecular mechanisms, advancing the advancement of adsorbent materials from "empirical optimization" to "mechanism-driven design." BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings that constitute a part of this application are used to provide further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute improper limitations on this application.

[0033] Figure 1 Schematic diagram of the adsorption curve of NO2 by LZU-111 according to Example 1 of the present invention;

[0034] Figure 2 This is an infrared spectrum of LZU-111 during the adsorption of NO2 according to Example 1 of the present invention;

[0035] Figure 3 Schematic diagram of the adsorption curve of NH3 by COF-V after treatment in Example 2 of the present invention;

[0036] Figure 4 This is an infrared spectrum of the treated COF-V during the adsorption of NH3 in Example 2 of the present invention. DETAILED DESCRIPTION

[0037] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0038] In an embodiment of the present application, the characterization and analysis method of the material adsorption amount and structural response includes the following steps:

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

[0040] S2, applying the sample to be tested to the sample area at the free end of the cantilever beam chip;

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

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

[0043] S4. Calculating a sample adsorption mass percentage-time curve based on the eigenfrequency, the resonant frequency of the cantilever beam, and the change in the resonant frequency; and generating an infrared spectrum graph that changes with adsorption time based on the transmission and reflection spectra.

[0044] In the embodiments of the present application, a cantilever beam is combined with a Fourier transform infrared spectrometer (FT-IR) to achieve infrared combined characterization of material gas adsorption-structure response through the combination of a 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 is as follows:

[0047] In this embodiment, the test environment includes: placing the cantilever beam chip in a closed chamber with a diamond window, the chamber is connected to a gas flow control device, and a certain amount of required test gas (such as argon, air) can be introduced to place the cantilever beam chip in a stable test gas flow.

[0048] The testing device 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 arranged 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 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 light beam emitted by the infrared light emitter passes through the diamond window and illuminates the adsorbed material on the cantilever chip; based on the change in resonant frequency, the mass change of the adsorbed material is measured in real time, and the infrared spectrometer collects the spectrum of the sample in real time.

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

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

[0052] The consistency of adsorption signal and infrared signal can be ensured through time reference;

[0053] Step 2: Loading the sample: Apply the LZU-111 to be tested (picogram to nanogram level) to the sample area at the free end of the cantilever beam chip.

[0054] The process for applying the LZU-111 (picogram to nanogram level) to the sample area at the free end of a cantilever chip involves dispersing the LZU-111 in anhydrous ethanol, preparing the liquid sample, and using an oil pressure spotter and a capillary glass needle to absorb a predetermined amount of the liquid sample. The capillary glass needle tip is then moved to the sample area of ​​the cantilever under a microscope for spotting. Because ethanol is highly volatile, the liquid sample in the conductivity sample area easily evaporates the remaining LZU-111.

[0055] Step 3: Adsorption capacity - infrared spectroscopy characterization:

[0056] Adsorption capacity test: Place the sample-coated cantilever in the same test environment as the baseline test. Record the resonant frequency f1 of the sample-coated cantilever. After a period of time, switch the atmosphere in the test chamber to the target gas (such as NO2) through the gas control system. Throughout the test, the real-time resonant frequency f is monitored by the resonant frequency detection circuit. (By presetting the parameters corresponding to different gases, the inert gas and the target gas can be controlled at the same flow rate.)

[0057] Infrared spectrum acquisition: FT-IR is started during the test process. The infrared beam is focused on the sample surface through the diamond window and the transmission / reflection spectrum is collected at a speed of 1 to 10 times per second. The spectral range is 400 to 4000 cm -1 , resolution ≤ 4cm -1 .

[0058] Step 4: Data processing:

[0059] Adsorption data processing: According to f and the eigenfrequency f0, the relationship curve of sample adsorption mass percentage-time is calculated by 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 sampling, and finally a curve of adsorption percentage-time will be obtained.

[0061] Since Δf∝Δm; the sample adsorption mass percentage = (f-f0) / (f0-f1);

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

[0063] Infrared data: Infrared spectroscopy detects changes in chemical bond vibrations caused by adsorption, generating an infrared spectrum that changes with adsorption time. When gas molecules adsorb into the pores or surface of LZU-111, they can cause the vibrational frequencies of chemical bonds (such as CN and N=O) within the LZU-111 skeleton to shift, manifesting as shifts or changes in the intensity of characteristic infrared peaks.

[0064] The advantages of this embodiment are: 1. Real-time observation of the adsorption signal allows calculation of the adsorption amount (using the formula: frequency difference before and after adsorption / cantilever mass sensitivity S (calibrated after chip fabrication); S = resonant frequency difference / mass change). A second advantage is the ability to observe changes in the infrared signal during adsorption, revealing the mechanism of adsorption behavior, such as which functional group the adsorbed gas interacts with.

[0065] Figure 1 FIG. 1 is a schematic diagram of the adsorption curve of NO2 by LZU-111 of this embodiment; FIG. Figure 1 The adsorption curve shows that the material is initially in an inert argon atmosphere, with the cantilever chip's frequency stable and virtually no mass change. After the introduction of diluted NO₂ gas around 60 seconds, the material immediately begins to adsorb and its mass begins to increase. The adsorption rate is rapid during the first 360 seconds, until the material reaches near saturation at 2400 seconds. The final calculated NO₂ adsorption percentage by LZU-111 is approximately 9.6%.

[0066] Figure 2 FIG1 is an infrared spectrum of the LZU-111 during the adsorption of NO2 in this embodiment; ... Figure 2 The infrared spectra during the adsorption process show that after the introduction of NO₂, the absorption peak intensities of the (CN) and (N=O) groups on the material surface increase, indicating chemical adsorption of the target gas NO₂ onto the material. Since the infrared spectra barely change after 360 seconds, the adsorption behavior can be revealed by continuous infrared spectra within 360 seconds.

[0067] Example 2

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

[0069] Figure 3 Schematic diagram of the adsorption curve of NH3 by COF-V after treatment in this embodiment; Figure 3 The adsorption curve shows that the material was initially in a stable argon inert atmosphere, with virtually no mass change on the cantilever chip. Around 300 seconds later, 10% NH₃ / AR gas was introduced, and adsorption immediately began, with the sample mass increasing. The adsorption curve shows rapid adsorption within the first 5 minutes after the target gas (NH₃ / AR gas) was introduced, and near-saturation was achieved by 3600 seconds. The calculated mass percentage of NH₃ adsorbed on the treated COF-V was approximately 5.6%.

[0070] Figure 4 is the infrared spectrum of the COF-V treated in this embodiment during the adsorption of NH3; Figure 4 The infrared spectrum results during the adsorption process show that after the introduction of NH3 gas, the absorption peak intensity of the amide group (-CONH-) on the surface of the material increases, indicating that the target gas molecule NH3 is adsorbed on the material, and the NH3 molecule is more easily adsorbed near the amide group.

[0071] Combine Figure 1 and Figure 2 , Figure 3 and Figure 4 The characterization and analysis method of the material adsorption amount and structural response of the present application can well realize the dynamic monitoring of adsorption behavior and the structural response analysis at the molecular level.

[0072] Compared with the prior art, this embodiment achieves the following effects:

[0073] (1) Breaking through the limitations of a single detection dimension: Traditional methods such as quartz microbalance (QCM) can only detect changes in adsorption amount (nanogram-level sensitivity), while in situ infrared spectroscopy alone can only capture molecular vibration signals. The two data are subject to spatiotemporal asynchrony. This embodiment, through the synchronous triggering of a cantilever beam (picogram-level sensitivity) and infrared spectroscopy at the millisecond level, achieves for the first time the real-time correlation analysis of adsorption mass changes and chemical bonding dynamics, solving the problem of dynamic process mismatch in traditional step-by-step detection.

[0074] (2) Overcoming the bottleneck of traditional combined techniques: 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 time resolution of dynamic monitoring and can successfully capture rapid or weak adsorption processes.

[0075] The above are merely preferred embodiments of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A characterization and analysis method for material adsorption and structural response, characterized in that: It includes the following steps: S1. placing a blank cantilever beam chip in a test chamber under an inert atmosphere, performing a baseline test, and recording the eigenfrequency of the blank cantilever beam chip; S2. placing the cantilever beam chip coated with the adsorption material in the test chamber of step S1, and recording the resonant frequency of the cantilever beam chip under the same test environment as step S1; Then, the inert atmosphere in the test chamber is switched to the adsorbed gas, a gas adsorption test is performed, and the change in the resonant frequency is monitored in real time; S3, starting a Fourier transform infrared spectrometer to collect the transmission and reflection spectra of the adsorption material in real time; S4. Based on the eigenfrequency described in step S1, the resonant frequency of the cantilever beam chip described in step S2, and the change in the resonant frequency, calculate the relationship curve between the adsorption mass percentage of the adsorption material and time; at the same time, based on the transmission and reflection spectra described in step S3, generate an infrared spectrum graph 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: ① The test chamber is provided with a window to allow the infrared beam of the Fourier transform infrared spectrometer to pass through; ② The 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 adsorption material includes: dispersing the adsorption material in a solvent to prepare a liquid sample; Adsorbing the liquid sample using an oil pressure spotter and a capillary glass needle; Under a microscope, the tip of the capillary glass needle is moved to the sample area of ​​the cantilever beam chip for spotting.

4. The characterization analysis method according to claim 1, characterized in that In step S4, the calculation expression of the relationship curve between the adsorption mass percentage of the adsorption material and time is: Adsorption mass percentage of adsorption material = (f-f0) / (f0-f1); Wherein, f0 is the intrinsic resonance frequency of the blank cantilever beam chip in step S1; f1 is the resonance frequency of the cantilever beam in step S2, and f is the real-time resonance 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 the change in vibration frequency of chemical bonds in the skeleton of the adsorption material; the change in vibration frequency is manifested as a shift or intensity change 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: ① The gas adsorption test is carried out in a gas flow containing the adsorbed gas; ② The adsorbed gas includes air, nitrogen dioxide or ammonia; ③The adsorption 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 comprises a sealed chamber having a diamond window; The test chamber is arranged below the Fourier transform infrared spectrometer, and the infrared light emitter of the Fourier transform infrared spectrometer is directly opposite to 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.

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

9. An electronic device comprising a memory, a processor, and a computing program stored in the memory and executable on the processor, wherein: When the processor executes the computing program, the characterization and analysis method according to any one of claims 1 to 8 is implemented.

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

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