An adaptive method for preparing powder samples for x-ray photoelectron spectrometer without adding
By selecting suitable substrate materials and conductive carbon double-sided adhesive, and combining them with a moldless tableting process, the problems of loose powder samples and interference from foreign elements were solved, thus achieving stability and accuracy in X-ray photoelectron spectroscopy testing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- OCEAN UNIV OF CHINA
- Filing Date
- 2026-04-02
- Publication Date
- 2026-07-14
AI Technical Summary
In existing powder sample preparation methods, sample loosening affects test stability, the addition of spectrally pure materials introduces additional elemental signals that interfere with qualitative and quantitative analysis, and the supporting substrate may change the chemical environment of the sample surface, leading to inaccurate test results.
An adaptive, additive-free method is adopted, which uses a suitable substrate and conductive carbon double-sided adhesive, combined with a moldless tableting process to fix the powder sample, avoid interference from foreign substances, and ensure sample stability and test accuracy.
It achieves stable fixation of samples during transfer and testing, avoids interference from foreign element signals, improves the accuracy and reliability of test results, simplifies the preparation process, and is suitable for the efficient preparation of batch samples.
Smart Images
Figure CN122385657A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of X-ray photoelectron spectrometer sample preparation technology, specifically to a method for preparing additive-free powder samples for X-ray photoelectron spectrometers. Background Technology
[0002] X-ray photoelectron spectroscopy (XPS) is an advanced surface analysis technique capable of qualitative and quantitative analysis of all elements except H and He. It obtains photoelectron spectra by measuring the kinetic energy of emitted electrons within a 1-10 nm range on the sample surface, thus providing crucial information such as elemental composition, relative abundance, and chemical state for materials research. It has wide applications in materials science, environmental science, and information science. The quality of powder sample preparation directly determines the accuracy of XPS test results. Existing powder sample preparation methods are mainly divided into two categories: film preparation and pellet preparation.
[0003] CN116337906A discloses a method for preparing powder samples for X-ray photoelectron spectrometers. This method uses a film-forming method, with aluminum foil or copper foil as the substrate, and a film layer of fixed thickness is prepared by a four-sided film-forming device to reduce cross-contamination. CN120685701A discloses another method for preparing powder samples for X-ray photoelectron spectrometers. This method uses a pelleting method, which improves sample stability by adding spectral purity to the sample and pressing it into a pellet in a mold.
[0004] However, the samples prepared by the aforementioned film-forming method are loosely bonded to the foil, making them prone to loosening during transfer and testing, thus affecting test stability. The aforementioned pelleting method requires the addition of spectrally pure materials, introducing additional elemental signals that interfere with the qualitative and quantitative analysis of the sample itself. Furthermore, these materials may interact with the sample, altering the sample surface chemical environment and leading to deviations in chemical state judgment, thereby affecting the accuracy of the final detection results. Therefore, this application proposes an additive-free X-ray photoelectron spectroscopy powder sample preparation method that solves the sample loosening problem, avoids interference from foreign substances, and mitigates background interference from the supporting substrate, further improving the accuracy of the test results. Summary of the Invention
[0005] To address the shortcomings of existing technologies, this invention provides a method for preparing powder samples for additive-free X-ray photoelectron spectrometry. By selecting a suitable substrate for the powder sample, attaching conductive carbon double-sided adhesive to the substrate, and combining this with a moldless tableting process using a tablet press, stable sample fixation is achieved. This method is compatible with both aluminum-containing and aluminum-free powder samples, improving the accuracy and reliability of test results. Specifically, it includes the following steps: S1: Place the powder sample to be tested into an agate mortar and grind it thoroughly until it is homogeneous. Weigh it and divide it into equal portions for later use. S2: Determine whether the powder sample to be tested contains aluminum; if the powder sample to be tested does not contain aluminum, aluminum foil is selected as the carrier substrate; if the powder sample to be tested contains aluminum, weighing paper is selected as the carrier substrate. S3: Take a rectangular piece of aluminum foil or weighing paper and lay it flat on a clean test bench. Wipe the surface of the aluminum foil or weighing paper clean. Fold the aluminum foil or weighing paper in half and then unfold it to leave clear creases on its surface. S4: Evenly apply a layer of conductive carbon double-sided tape to one side of the fold line on the surface of the aluminum foil or weighing paper, press the conductive carbon double-sided tape to make it adhere tightly to the aluminum foil or weighing paper, and ensure that there are no air bubbles or lifting. S5: Remove the protective paper from the top of the conductive carbon double-sided adhesive, and spread the powder sample prepared in step S1 evenly on the surface of the conductive carbon double-sided adhesive, ensuring that the sample completely covers the conductive carbon double-sided adhesive, while avoiding sample accumulation. S6: Fold the aluminum foil or weighing paper with the sample attached along the crease, press gently to initially fix the sample, then transfer it to the tablet press, pressurize to the set pressure value and hold the pressure for a period of time; S7: Remove the pressure from the tablet press, take out the compressed powder sample, peel off the aluminum foil or weighing paper, and the powder sample is pressed into a flat and dense sheet. Use a syringe to blow away the loose powder on the sample surface to obtain a sample for X-ray photoelectron spectroscopy testing.
[0006] Furthermore, in step S1, the weight of the powder sample to be tested is 0.6 g, with an error range of ±0.1 g, and the ground sample is divided into 3 portions, each weighing 0.2 g, with an error range of ±0.1 g.
[0007] Furthermore, in step S2, the weighing paper is powder-free weighing paper.
[0008] Furthermore, in step S3, the aluminum foil and weighing paper are both 2 cm × 4 cm in size, and are wiped with degreased cotton soaked in ethanol.
[0009] Furthermore, in step S4, the conductive carbon double-sided adhesive has a size of 5 mm × 5 mm and a conductivity range of 10. -4 ~10 -3 S / cm.
[0010] Furthermore, in step S5, tweezers or spatulas should be avoided from touching the spread sample during the powder spreading process.
[0011] Furthermore, in step S6, a suitable pressure and holding time are selected according to the material type to obtain a compact and uniform test sample.
[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention eliminates the need to add spectrally pure or other foreign additives to the sample, thereby avoiding the problem of foreign additives introducing additional elemental signals and interfering with the qualitative and quantitative analysis of the sample. At the same time, it eliminates the risk of foreign additives interacting with the sample and changing the surface chemical environment, ensuring that the test results can truly reflect the original state of the sample. 2. This invention utilizes the adhesive properties of conductive carbon double-sided adhesive to firmly fix the powder sample onto the substrate. Combined with a moldless pressing process, it significantly improves the bonding stability between the sample and the substrate, effectively preventing the sample from loosening or falling off during transfer and testing, thus ensuring the smooth progress of the testing process. 3. This invention innovatively designs a differentiated carrier substrate selection scheme. For samples without aluminum, aluminum foil with excellent conductivity is selected as the carrier substrate, while for samples containing aluminum, weighing paper without aluminum interference is selected as the carrier substrate, effectively avoiding background interference from the carrier substrate to the sample test. 4. The preparation process of this invention is simple. The steps such as sample pretreatment, selection of substrate, and sample fixation are easy to standardize, which can reduce the risk of cross-contamination when multiple samples are prepared at the same time. Moreover, the preparation cycle is short and there is no need for complicated mold disassembly and assembly process. It is suitable for the efficient preparation of batch samples, and it takes into account both preparation efficiency and testing effect. Attached Figure Description
[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.
[0014] Figure 1 This is a flowchart of the method for preparing powder samples for an additive-free X-ray photoelectron spectrometer adapted to this invention; Figure 2 XPS full spectrum of SiO2 sample using aluminum foil as substrate; Figure 3 XPS full spectrum of Al2O3 sample using powderless weighing paper as substrate; Figure 4 XPS full spectrum of Al2O3 sample with aluminum foil as substrate; Figure 5 XPS full spectrum comparison images of powder-free weighed paper substrate, aluminum foil substrate, and Al2O3 samples prepared using the two substrates respectively. Detailed Implementation
[0015] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.
[0016] Example 1 (Sample without aluminum: SiO2 powder) A method for preparing powder samples for an additive-free X-ray photoelectron spectrometer includes the following steps: S1: Weigh the SiO2 powder sample to be tested to an accuracy of 0.6 g ± 0.1 g, grind it thoroughly in an agate mortar until it is uniform, weigh it and divide it into 3 portions, each weighing 0.2 g ± 0.1 g, for later use; The parameters in this step are determined based on detection accuracy and operational feasibility, meeting the testing requirements of the powder samples: To ensure complete coverage of the double-sided tape and avoid material waste, the single sample loading is determined to be approximately 0.2 g, with a total sample weight of 0.6 g, and the samples are divided into 3 parallel tests; different materials have significantly different compressibility, requiring less pressure for fine, soft, and sticky powders, while requiring relatively higher pressure for metals and hard powders. Appropriate pressure is selected according to the material type to obtain a compacted sample; the conductivity of different brands and models of conductive carbon double-sided tape varies slightly, with general-purpose conductive carbon double-sided tape having a conductivity of around 10. -4 ~10 -3 Within the S / cm range, all testing requirements can be met.
[0017] S2: Elemental analysis determined that the SiO2 powder sample did not contain aluminum, so aluminum foil was selected as the substrate. It should be noted that the SiO2 powder sample does not contain aluminum, which can be directly determined from the composition of the raw materials used in the sample synthesis. If the raw material information is unclear, scanning electron microscopy energy dispersive spectroscopy (EDS) or X-ray diffraction (XRD) can be used to quickly determine whether the sample contains aluminum, thus providing a basis for correctly selecting the substrate in this step.
[0018] S3: Cut the aluminum foil into 2 cm × 4 cm pieces, lay them flat on a clean test bench, fold them in half and then unfold them to leave clear creases on the surface of the aluminum foil; S4: Evenly adhere a layer of conductive carbon double-sided adhesive to one side of the fold line on the surface of the aluminum foil. The conductive carbon double-sided adhesive should be 5 mm × 5 mm in size and have a conductivity of 5 × 10⁻⁶. -4 S / cm, after pasting, use clean tweezers to gently press the entire surface of the conductive carbon double-sided adhesive to ensure that it adheres tightly to the aluminum foil without bubbles or lifting. S5: Remove the protective paper from the top of the conductive carbon double-sided adhesive. Take a sample of SiO2 powder prepared in step S1 and spread it evenly on the surface of the conductive carbon double-sided adhesive. Ensure that the sample completely covers the conductive carbon double-sided adhesive and there is no obvious accumulation. Avoid touching the sample with a spatula or tweezers during the powder spreading process. S6: Fold the aluminum foil with the SiO2 powder sample along the crease, press gently to initially fix the sample, transfer it to the tablet press, pressurize to 10 t, and hold the pressure for 10 s; S7: Remove the pressure from the tablet press, take out the tableted SiO2 powder sample, slowly peel off the aluminum foil, and the SiO2 powder sample is pressed into a flat and dense sheet. Use a rubber bulb to blow away the loose SiO2 powder on the surface to obtain a SiO2 sample that can be tested by X-ray photoelectron spectroscopy. Example 2 (Sample containing aluminum: Al2O3 powder) A method for preparing powder samples for X-ray photoelectron spectrometry includes the following steps: S1: Weigh the Al2O3 powder sample to be tested to an accuracy of 0.6 g ± 0.1 g, grind it thoroughly in an agate mortar until it is uniform, weigh it and divide it into 3 portions, each weighing 0.2 g ± 0.1 g, for later use; S2: Elemental analysis was used to determine that the Al2O3 powder sample contained aluminum, and powder-free weighing paper was selected as the substrate. S3: Cut the powder-free weighing paper into 2 cm × 4 cm sizes, lay it flat on a clean test bench, fold it in half and then unfold it so that clear creases are left on the surface of the weighing paper; S4: Evenly apply a layer of conductive carbon double-sided adhesive to one side of the fold line on the surface of the weighing paper. The conductive carbon double-sided adhesive should be 5 mm × 5 mm in size and have a conductivity of 5 × 10⁻⁶. -4 S / cm, after pasting, use clean tweezers to gently press the entire surface of the conductive carbon double-sided tape to ensure that it adheres tightly to the weighing paper without any air bubbles or lifting. S5: Remove the protective paper from the top of the conductive carbon double-sided tape, take a sample of Al2O3 powder prepared in step S1, and spread it evenly on the surface of the conductive carbon double-sided tape. Ensure that the sample completely covers the conductive carbon double-sided tape and there is no obvious accumulation. Avoid touching the sample with a spatula or tweezers during the powder spreading process. S6: Fold the weighing paper with the Al2O3 powder sample attached along the crease, press gently to initially fix the sample, transfer it to the tablet press, pressurize to 5 t, and hold the pressure for 10 s; S7: Remove the pressure from the tablet press, take out the compressed powder sample, slowly peel off the weighing paper, and the Al2O3 powder sample is pressed into a flat and dense sheet. Use a syringe to blow away the loose Al2O3 powder on the surface to obtain an Al2O3 sample that can be tested by X-ray photoelectron spectroscopy.
[0019] Figure 2 This is the XPS full spectrum of the SiO2 sample on the aluminum foil substrate. Figure 3 , Figure 4 XPS full spectra of Al2O3 samples on powder-free weighing paper and aluminum foil substrates, respectively. Figure 5 The figures show a comparison of XPS full-spectrum images of powder-free weighing paper substrate, aluminum foil substrate, and Al2O3 samples prepared using the two substrates respectively. In the figures, 531.1 eV corresponds to the O1s characteristic peak of SiO2 and Al2O3, 284.8 eV corresponds to the C1s characteristic peak, 103.5 eV corresponds to the Si2p characteristic peak of SiO2, and 74.6 eV corresponds to the Al2p characteristic peak of Al2O3. The Si2p and Al2p peaks are characterized by high intensity, symmetrical peak shape, and low interference, making them suitable for quantitative analysis of the relative content of silicon and aluminum. The figures clearly show that the aluminum foil substrate has an Al2p characteristic peak, making it suitable for XPS testing of samples without aluminum components; the powder-free weighing paper substrate lacks an Al2p characteristic peak, making it more suitable for XPS testing of samples containing aluminum components. Furthermore, the intensity of the Al2p characteristic peak in the Al2O3 sample measured using the aluminum foil substrate is slightly higher than that of the powder-free weighing paper substrate (the difference in intensity is not significant because the atomic percentage of aluminum differs by only a few percentage points).
[0020] Quantitative analysis was performed on the Si2p, Al2p, and O1s high-resolution photoelectron spectral peaks of SiO2 and Al2O3 samples, respectively. The relative percentage content of each element was calculated by multiplying the high-resolution peak area by the corresponding orbital sensitivity factor. Table 1 shows the XPS quantitative analysis data of SiO2 samples on aluminum foil substrate, and Tables 2 and 3 show the XPS quantitative analysis data of Al2O3 samples on powder-free weighing paper and aluminum foil substrate, respectively.
[0021] Table 1 Table 2 Table 3 Analysis Results: Using aluminum foil as the substrate, XPS tests were performed on SiO2 samples. The percentages of silicon atoms in the three parallel experiments were 33.57%, 33.97%, and 32.89%, respectively. The calculated standard deviation (SD) was 0.55, and the relative standard deviation (RSD) was 1.63%, which is less than 5%, indicating excellent repeatability of the test. The average percentage of silicon atoms was 33.48%, and the relative error compared with the theoretical value of 33.33% was only 0.45%, which fully demonstrates that the aluminum element signal in the aluminum foil substrate does not interfere with the XPS detection results of SiO2 samples.
[0022] XPS tests were performed on Al2O3 samples using powder-free weighing paper as the substrate. The percentages of aluminum atoms in the three parallel experiments were 36.16%, 36.36%, and 35.96%, respectively, with an average of 36.16%. The standard deviation (SD) was 0.20 and the relative standard deviation (RSD) was 0.55%, which is less than 5%, indicating excellent repeatability and no interference from additional elemental signals throughout the detection process.
[0023] Comparative Example 1 Using the preparation method described in this invention, and with aluminum foil as the substrate, XPS comparative tests were performed on Al2O3 powder samples. The results showed that in the three parallel experiments, the percentage of aluminum atoms (the main element) was 38.37%, 38.20%, and 38.40%, with an average of 38.32%. The standard deviation (SD) was 0.11, and the relative standard deviation (RSD) was 0.29%, all less than 5%, indicating excellent repeatability. Data comparison revealed that the average percentage of aluminum atoms measured with aluminum foil as the substrate (38.32%) was 5.97% higher than the result obtained with powder-free weighing paper as the substrate (36.16%). This deviation is attributed to the interference of the detection signal introduced by the aluminum element contained in the aluminum foil substrate itself, further confirming the influence of the substrate selection on the accuracy of XPS detection.
[0024] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for preparing powder samples for an additive-free X-ray photoelectron spectroscopy system, characterized in that, Includes the following steps: S1: Place the powder sample to be tested into an agate mortar and grind it thoroughly until it is homogeneous. Weigh it and divide it into equal portions for later use. S2: Determine whether the powder sample to be tested contains aluminum; if the powder sample to be tested does not contain aluminum, aluminum foil is selected as the carrier substrate; if the powder sample to be tested contains aluminum, weighing paper is selected as the carrier substrate. S3: Take a rectangular piece of aluminum foil or weighing paper and lay it flat on a clean test bench. Wipe the surface of the aluminum foil or weighing paper clean. Fold the aluminum foil or weighing paper in half and then unfold it to leave clear creases on its surface. S4: Evenly apply a layer of conductive carbon double-sided tape to one side of the fold line on the surface of the aluminum foil or weighing paper, press the conductive carbon double-sided tape to make it adhere tightly to the aluminum foil or weighing paper, and ensure that there are no air bubbles or lifting. S5: Remove the protective paper from the top of the conductive carbon double-sided adhesive, and spread the powder sample prepared in step S1 evenly on the surface of the conductive carbon double-sided adhesive, ensuring that the sample completely covers the conductive carbon double-sided adhesive, while avoiding sample accumulation. S6: Fold the aluminum foil or weighing paper with the sample attached along the crease, press gently to initially fix the sample, then transfer it to the tablet press, pressurize to the set pressure value and hold the pressure for a period of time; S7: Remove the pressure from the tablet press, take out the compressed powder sample, peel off the aluminum foil or weighing paper, and the powder sample is pressed into a flat and dense sheet. Use a syringe to blow away the loose powder on the sample surface to obtain a sample for X-ray photoelectron spectroscopy testing.
2. The method for preparing powder samples for an additive-free X-ray photoelectron spectroscopy instrument according to claim 1, characterized in that, In step S1, the weight of the powder sample to be tested is 0.6 g, with an error range of ±0.1 g. The ground sample is divided into 3 portions, each weighing 0.2 g, with an error range of ±0.1 g.
3. The method for preparing powder samples for an additive-free X-ray photoelectron spectrometer according to claim 1, characterized in that, In step S2, the weighing paper is powder-free weighing paper.
4. The method for preparing powder samples for an additive-free X-ray photoelectron spectrometer according to claim 1, characterized in that, In step S3, the aluminum foil and weighing paper are both 2 cm × 4 cm in size, and are wiped with degreased cotton soaked in ethanol.
5. The method for preparing powder samples for an additive-free X-ray photoelectron spectrometer according to claim 1, characterized in that, In step S4, the conductive carbon double-sided adhesive has a size of 5 mm × 5 mm and a conductivity range of 10. -4 ~10 -3 S / cm.
6. The method for preparing powder samples for an additive-free X-ray photoelectron spectrometer according to claim 1, characterized in that, In step S5, avoid touching the spread sample with tweezers or a spatula during the powder spreading process.
7. The method for preparing powder samples for an additive-free X-ray photoelectron spectrometer according to claim 1, characterized in that, In step S6, appropriate pressure and holding time are selected according to the material type to obtain a compact and uniform test sample.