Liquid sample temperature-controlled test cell for synchrotron radiation x-ray absorption spectroscopy

Abstract

The utility model belongs to the technical field of synchrotron X -ray absorption spectrum test, concretely is a kind of synchrotron X -ray absorption spectrum liquid sample temperature control test cell, including the upper layer heating pool body, upper layer gasket, upper layer cover plate, film, lower layer cover plate, lower layer gasket, lower layer heating pool body that are sealed connection in turn, the utility model can accurately control the thickness and temperature of liquid sample;Conical frustum's observation window is set in the both ends of test cell, supports transmission mode and fluorescence mode test;Different temperature liquid medium is realized to the accurate temperature control of sample by annular flow channel circulation;Diamond window is embedded in the center of cover plate, liquid sample is directly dropped on diamond surface, diamond window can guarantee the controllable thickness of sample liquid layer in the temperature change / heating process being tested.The utility model has important significance to the structure change of liquid sample under different temperature conditions, reaction kinetics and catalytic mechanism.

Description

Technical Field

[0001] This invention belongs to the field of synchrotron radiation X-ray absorption spectroscopy testing technology, specifically a synchrotron radiation X-ray absorption spectroscopy liquid sample temperature control testing cell. Background Technology

[0002] Synchrotron radiation is a high-brightness, highly collimated X-ray source widely used for structural characterization in materials science, biology, chemistry, and other fields. X-ray absorption spectroscopy (XAS) is an important technique for studying the local atomic structure and electronic states of matter using synchrotron X-rays, including both transmission and fluorescence modes. XAS testing of liquid samples is of great significance in studying solution structure, reaction mechanisms, and phase transition processes.

[0003] Currently, XAS testing of liquid samples faces the following main technical challenges: First, the thickness of the liquid sample is difficult to control precisely, affecting the accuracy of quantitative analysis using absorption spectra; second, the temperature control precision is insufficient, failing to meet the needs of studying sample structural changes under different temperature conditions; third, the thickness of the liquid sample layer is prone to change during temperature variations, affecting the comparability of test results; fourth, the sealing performance of the test cell is limited, making liquid leakage easy; fifth, existing test cells mostly support only a single test mode, unable to simultaneously meet the needs of transmission and fluorescence mode testing; sixth, the lack of continuous sample flow capability prevents in-situ real-time studies of reaction kinetics and catalytic mechanisms; and seventh, the inability to achieve online mixing of multiple solutions limits the study of complex chemical reaction processes.

[0004] Traditional liquid sample cells typically employ a simple flat plate structure, holding the liquid sample between two transparent windows. This design suffers from problems such as uneven sample thickness, difficulty in temperature control, and poor sealing performance. Particularly in XAS experiments requiring precise temperature control, traditional designs cannot provide a stable temperature environment, nor can they guarantee the stability of the liquid sample layer thickness during temperature changes, severely impacting the accuracy of quantitative analysis in XAS spectra. Furthermore, static sample cells cannot meet the requirements for in-situ monitoring of dynamic reaction processes, limiting their application in fields such as catalysis, electrochemistry, and biochemistry. Utility Model Content

[0005] To address the aforementioned problems of traditional liquid sample cell XAS testing, the present invention aims to provide a synchrotron X-ray absorption spectroscopy liquid sample temperature-controlled testing cell. This liquid sample temperature-controlled testing cell can precisely control the thickness and temperature of the liquid sample, supports both transmission and fluorescence XAS testing modes, has excellent sealing performance, and can maintain the stability of the liquid sample layer thickness during temperature changes; it can also integrate microfluidic functions to realize continuous flow, online mixing, and in-situ monitoring of dynamic reaction processes of the liquid sample.

[0006] The objective of this utility model is achieved through the following technical solution:

[0007] This utility model includes, from top to bottom, a sealed upper heating pool, an upper gasket, an upper cover plate, a thin film, a lower cover plate, a lower gasket, and a lower heating pool, all connected in sequence. The upper and lower heating pools each have observation windows supporting X-ray absorption spectroscopy transmission mode and fluorescence mode testing. The inward-facing surfaces of the upper and lower heating pools have annular flow channels surrounding the observation windows. The sidewalls of the annular flow channels each have an inlet and an outlet, extending to the outer surfaces of the upper and lower heating pools. The upper and lower cover plates each have diamond windows embedded for holding liquid samples. The thin film is located between the upper and lower cover plates, and the thickness of the liquid sample can be controlled by changing the film to different thicknesses. The upper gasket, the thin film, and the lower gasket each have through holes.

[0008] Wherein: the observation window extends through the upper heating pool and the lower heating pool, and the observation window is in the shape of a frustum cone, that is, the diameter of the observation window gradually decreases from the outside to the inside.

[0009] The cone angle of the observation window, which is shaped like a frustum, is 25° to 155°.

[0010] Microfluidic channels are formed on the inward-facing surfaces of the upper cover plate and / or the lower cover plate. These microfluidic channels are used to enable continuous flow of liquid samples and online reaction monitoring.

[0011] One end of the microfluidic channel is connected to the diamond window, and the other end of the microfluidic channel extends to the outer side of the upper cover plate and / or the lower cover plate.

[0012] The diameter of the through hole is larger than the diameter of the diamond window and the observation window.

[0013] The film thickness is 5 to 100 micrometers, preferably 10 to 50 micrometers.

[0014] The advantages and positive effects of this utility model are as follows:

[0015] 1. This utility model, through its replaceable membrane design, can precisely control the thickness of liquid samples, adjustable from 5 micrometers to 100 micrometers, to meet different XAS testing requirements and improve the accuracy of quantitative analysis.

[0016] 2. This invention employs an annular flow channel temperature control system, which can accurately control the sample temperature within the range of -50℃ to 200℃, with good temperature uniformity, providing an ideal platform for studying the temperature-dependent structural changes of liquid samples.

[0017] 3. The observation window design of this utility model in the shape of a truncated cone supports both X-ray absorption spectrum transmission mode and fluorescence mode testing, thus improving the versatility and testing efficiency of the equipment.

[0018] 4. The high thermal conductivity and low coefficient of thermal expansion of the diamond window of this invention can maintain the controllability and stability of the liquid layer thickness of the tested sample during temperature changes / heating. This is a key advantage of XAS quantitative analysis and ensures the comparability of test results at different temperatures.

[0019] 5. This utility model adds microfluidic channels to the inward-facing surfaces of the upper cover plate and / or the lower cover plate, which enables continuous flow and online monitoring of liquid samples. It can study dynamic reaction processes, catalytic mechanisms and reaction kinetics, and provides extended functionality for applications that require dynamic testing.

[0020] 6. The six-layer sealing structure design of this utility model, combined with high-performance gasket material, has excellent sealing performance, effectively preventing liquid leakage, and is suitable for XAS testing of various liquid samples.

[0021] 7. The present invention has a reasonable structural design, and each component is easy to disassemble and replace, making it easy to clean and maintain, thus improving the service life of the equipment; both the annular flow channel and the microfluidic flow channel are modular designs, which can be flexibly configured according to experimental needs. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments of this utility model will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is an exploded view of the present invention;

[0024] Figure 2 This is a three-dimensional structural diagram of one side of the upper / lower heating tank body of this utility model;

[0025] Figure 3 This is a three-dimensional structural diagram of the other side of the upper / lower heating tank body of this utility model;

[0026] Figure 4 This is a three-dimensional structural diagram of one side of the upper / lower cover plate of this utility model;

[0027] Figure 5 This is a front view of the structure on the other side of the upper / lower cover plate of this utility model;

[0028] Figure 6To test 1.6M VOC using the temperature-controlled test cell of this utility model 2+ / VO2 + Figure showing the results of VK-edge XANES testing of mixed vanadium electrolyte;

[0029] Wherein: 1 is the upper heating tank, 2 is the upper gasket, 3 is the upper cover plate, 4 is the lower cover plate, 5 is the lower gasket, 6 is the lower heating tank, 7 is the observation window, 8 is the annular flow channel, 9 is the diamond window, 10 is the thin film, 11 is the liquid inlet, 12 is the liquid outlet, 13 is the bolt hole, 14 is the microfluidic channel, and 15 is the through hole. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this utility model clearer, the following detailed description is provided through specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this utility model.

[0031] like Figure 1 As shown, this utility model includes, from top to bottom, a sealed upper heating tank 1, an upper gasket 2, an upper cover plate 3, a thin film 10, a lower cover plate 4, a lower gasket 5, and a lower heating tank 6. The upper heating tank 1 and the lower heating tank 6 are respectively provided with observation windows 7 supporting X-ray absorption spectroscopy transmission mode and fluorescence mode testing. The inward-facing surfaces of the upper heating tank 1 and the lower heating tank 6 have annular flow channels 8 surrounding the observation windows 7. The side walls are respectively provided with water inlet 11 and water outlet 12, which extend to the outer side of the upper heating pool 1 and the lower heating pool 6; the upper cover plate 3 and the lower cover plate 4 are respectively embedded with diamond windows 9 for holding liquid samples; the film 10 is located between the upper cover plate 3 and the lower cover plate 4; the thickness of the liquid sample is controlled by changing the film 10 of different thicknesses; the upper gasket 2, the film 10 and the lower gasket 5 are respectively provided with through holes 15.

[0032] In this embodiment, the upper heating tank 1, upper gasket 2, upper cover 3, membrane 10, lower cover 4, lower gasket 5, and lower heating tank 6 are all rectangular. Regarding material selection, considering that the test tank needs to contact various types of liquid samples (including electrolytes, organic solvents, acid and alkali solutions, etc.), and the special requirements of precise temperature control and XAS testing, this embodiment fully considers factors such as corrosion resistance, thermal conductivity, and mechanical strength in material selection. Especially for highly corrosive liquid samples, nickel-based alloys such as Hastelloy provide excellent corrosion protection.

[0033] like Figures 1-3As shown, in this embodiment, observation windows 7 are respectively opened at the center of the upper heating pool 1 and the lower heating pool 6. The observation windows 7 penetrate through the upper heating pool 1 and the lower heating pool 6. The observation windows 7 are truncated cones, meaning that the diameter of the observation windows 7 gradually decreases from the outside to the inside. The cone angle of the truncated cone-shaped observation windows 7 is 25° to 155°, which meets the vertical incidence requirements of the transmission mode, and at the same time provides sufficient space for the 30° to 60° incidence and 90° to 150° exit of the fluorescence mode, ensuring flexible testing under different geometric configurations. The upper heating pool 1 and the lower heating pool 6 are made of one of the following materials: 316 stainless steel, 316L stainless steel, 317 stainless steel, titanium alloy, TA1 titanium, aluminum alloy, Monel alloy, Hastelloy alloy, or copper alloy. They have good corrosion resistance and thermal conductivity, ensuring long-term stability in various liquid media environments. In this embodiment, both the upper heating pool 1 and the lower heating pool 6 are made of 316 stainless steel.

[0034] In this embodiment, the annular flow channel 8 is collinear with the axial centerline of the observation window 7. The annular flow channel 8 is C-shaped, with a width of 5 mm and a depth of 3 mm. The inlet 11 and outlet 12 are respectively located on the two closed end sidewalls of the C-shape. They are connected to an external thermostatic circulator through the inlet 11 and outlet 12 to achieve circulation of the heating or cooling liquid medium. The design of the annular flow channel 8 ensures uniform temperature distribution and avoids temperature gradients in the sample area. The liquid medium in this embodiment is one of ethylene glycol aqueous solution, silicone oil, thermal oil, fluorinated liquid, or propylene glycol, with a temperature control range of -50℃ to 200℃. The annular flow channel 8 can circulate liquid media such as ethylene glycol aqueous solution, silicone oil, thermal oil, fluorinated liquid, and propylene glycol to achieve temperature control from -50℃ to 200℃. Different media are selected for different temperature ranges: 50% propylene glycol aqueous solution (freezing point about -59℃) or fluorinated liquid is used in the low temperature range (-50℃~0℃), ethylene glycol aqueous solution or propylene glycol is used in the medium temperature range (0℃~100℃), and silicone oil (operating temperature range -50℃~250℃) or heat transfer oil is used in the high temperature range (100℃~200℃).

[0035] like Figure 1 and Figure 4 , Figure 5As shown, in this embodiment, both the upper cover plate 3 and the lower cover plate 4 have diamond windows 9 embedded in their middle. The diamond windows 9 not only possess excellent X-ray transmittance, extremely high thermal conductivity, excellent chemical inertness, and vacuum sealing, but are also key components in X-ray absorption spectroscopy research involving harsh conditions such as X-ray exposure, in-situ conditions, and corrosive environments. Liquid samples are directly dripped onto the surface of the diamond windows 9, ensuring the accuracy of the test signal. In this embodiment, the diamond windows 9 are made of optical-grade diamond with a thickness of 0.2–2 mm, exhibiting excellent X-ray transmittance and chemical stability. While ensuring mechanical strength, they maximize X-ray transmittance and maintain the stability of the liquid sample layer thickness during temperature changes. The upper cover plate 3 and the lower cover plate 4 are made of Monel alloy, Hastelloy, nickel-based alloy, copper alloy, titanium alloy, 316 stainless steel, Incol nickel alloy, or other metallic materials, or polymeric materials such as polyetheretherketone (PEEK) and polyimide. These materials possess excellent corrosion resistance, thermal conductivity, and mechanical strength. Since the upper cover plate 3 and the lower cover plate 4 may directly contact various electrolytes or corrosive solutions, the excellent corrosion resistance and thermal conductivity of metallic materials are beneficial for the accuracy and uniformity of temperature control. Nickel-based alloys such as Hastelloy perform particularly well in highly corrosive environments. In this embodiment, both the upper cover plate 3 and the lower cover plate 4 are made of Monel alloy. Because the upper cover plate 3 and the lower cover plate 4 may directly contact corrosive liquids such as electrolytes, the high corrosion resistance of Monel alloy ensures the long-term stable operation of the equipment, while its good thermal conductivity facilitates uniform temperature transfer. Both the upper cover plate 3 and the lower cover plate 4 have optical-grade diamond windows 9 with a diameter of 5 mm and a thickness of 200 micrometers embedded in their centers. The diamond windows 9 are fixed with epoxy resin adhesive. The diamond windows 9 have high thermal conductivity (approximately 2000 W / m·K) and extremely low coefficient of thermal expansion (approximately 1 × 10⁻⁶). -6 / K) Ensuring the stability of the liquid sample layer thickness during temperature changes is crucial for XAS quantitative analysis.

[0036] According to application requirements, this embodiment has a microfluidic channel 14 formed on the inward-facing surface of the upper cover plate 3 and / or the lower cover plate 4. The microfluidic channel 14 is used to realize continuous flow of liquid samples and online reaction monitoring. The microfluidic function supports one or more test modes among static mode, continuous flow mode, stop flow mode, and reaction mixing mode, providing extended functions for dynamic reaction process research. One end of the microfluidic channel 14 is connected to the diamond window 9, and the other end of the microfluidic channel 14 extends to the outer surface of the upper cover plate 3 and / or the lower cover plate 4.

[0037] A replaceable, corrosion-resistant, inert film 10 is provided between the upper cover plate 3 and the lower cover plate 4. The thickness of the film 10 is 5-100 micrometers (preferably 10-50 micrometers), and the material can be a chemically stable polymer material such as polyimide or polyethylene terephthalate. By replacing the film 10 with different thicknesses, the thickness of the liquid sample can be controlled to meet different experimental requirements. In this embodiment, the film 10 can be a polyimide film with a thickness of 5 micrometers, 10 micrometers, 25 micrometers, 50 micrometers, or 100 micrometers.

[0038] The upper gasket 2 and the lower gasket 5 are made of polytetrafluoroethylene, polyimide or silicone, which have good chemical stability and sealing performance. In this embodiment, the upper gasket 2 and the lower gasket 5 are both made of polytetrafluoroethylene with a thickness of 1mm. The upper gasket 2 and the lower gasket 5 are tightly attached to each layer of the components to prevent leakage of liquid medium.

[0039] In this embodiment, the diameter of the through holes 15 on the upper gasket 2, the thin film 10, and the lower cover plate 4 is larger than the diameter of the diamond window 9 and the observation window 7.

[0040] The upper heating tank body 1, upper gasket 2, upper cover plate 3, membrane 10, lower cover plate 4, lower gasket 5, and lower heating tank body 6 can be fixed by one of the following methods: bolt connection, snap ring connection, or compression connection, which facilitates disassembly and replacement. In this embodiment, bolt holes 13 are respectively opened at the four corners of the upper heating tank body 1, upper gasket 2, upper cover plate 3, membrane 10, lower cover plate 4, lower gasket 5, and lower heating tank body 6, and fixed by bolts and nuts; when the membrane 10 needs to be replaced, simply remove the bolts and nuts and separate the upper cover plate 3 and lower cover plate 4.

[0041] Experimental Example 1: XAS Test of Electrolyte Temperature Control in Vanadium Redox Flow Battery

[0042] The temperature-controlled test cell of this invention was used to test 1.6M VOC. 2+ / VO2 + XANES analysis of the VK edge was performed using a mixed vanadium electrolyte. The film thickness was 25 μm, and the temperature ranged from 20 °C to 40 °C in 10 °C increments. The results showed that the intensity of the white line peak at the VK edge (located at 5486 eV) gradually decreased from 1.156 at 20 °C to 1.125 at 50 °C, a decrease of approximately 2.7%. Simultaneously, the oscillation intensity of the subsequent fine structure (5485-5540 eV) also weakened with increasing temperature, indicating that temperature has a significant impact on the coordination environment and local structure of vanadium ions. The vanadium ion coordination structure was most ordered at 20 °C; with increasing temperature, thermal vibrations led to a broadening of the coordination bond length distribution and a decrease in structural order. The test results are as follows: Figure 6 As shown.

[0043] Experimental Example 2: XAS Test of Electrolyte Temperature Control in Zinc-ion Batteries

[0044] Zn K-edge XAS measurements were performed on a 2M ZnSO4 electrolyte. The film thickness was 10 μm, and the temperature ranged from -10 °C to 40 °C in 10 °C increments. XAFS measurements provided information on the oxidation state of zinc ions, the coordination environment, and their interactions with surrounding atoms. The results showed that the Zn-O bond length and coordination number changed systematically with temperature.

[0045] Experimental Example 3: XAS Test of Electrolyte in Iron-Vanadium Redox Flow Battery

[0046] For Fe 3+ / Fe 2+ -V 4+ / V 5+ A two-element XAS analysis was performed on the mixed electrolyte system. The Fe K-edge (7112 eV) and VK-edge (5465 eV) were simultaneously measured at 30 °C to investigate the interaction between the two metal ions. The results show that the iron and vanadium ions maintain their respective coordination characteristics in the mixed system, but there is a slight shift in the edge energy positions.

[0047] Experiment Example 4: Study on the Influence of Additives on Lithium-ion Battery Electrolytes

[0048] The effect of adding different concentrations of FEC additives to 1M LiPF6-EC / DPC electrolyte on the Li coordination environment was investigated. The regulatory mechanism of different FEC concentrations (0%, 5%, 10%) on the lithium-ion solvation structure at 25℃ was studied by Li K-edge XAS test (55 eV).

[0049] This invention features a rational structural design, simple operation, excellent sealing performance, and high temperature control accuracy. In particular, the diamond window 9 maintains the stability of the liquid sample layer thickness during temperature changes. The microfluidic function provides expanded capabilities for special applications requiring dynamic testing. This invention provides a fully functional and technologically advanced experimental platform for XAS studies of liquid samples, playing a significant role in promoting related scientific research.

[0050] The above description is merely an embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A temperature-controlled testing cell for liquid samples subjected to synchrotron X-ray absorption spectroscopy, characterized in that: The device comprises, from top to bottom, a sealed upper heating pool (1), an upper gasket (2), an upper cover plate (3), a thin film (10), a lower cover plate (4), a lower gasket (5), and a lower heating pool (6). Observation windows (7) supporting X-ray absorption spectrum transmission mode and fluorescence mode testing are respectively provided on the upper heating pool (1) and the lower heating pool (6). Annular flow channels (8) are formed around the observation windows (7) on the inward-facing surfaces of the upper heating pool (1) and the lower heating pool (6). The sidewalls of the annular flow channels (8) are respectively provided with... It has an inlet (11) and an outlet (12), which extend to the outer side of the upper heating tank (1) and the lower heating tank (6); the upper cover plate (3) and the lower cover plate (4) are respectively embedded with diamond windows (9) for carrying liquid samples; the film (10) is located between the upper cover plate (3) and the lower cover plate (4); the thickness of the liquid sample is controlled by changing the film (10) of different thicknesses; the upper gasket (2), the film (10) and the lower gasket (5) are respectively provided with through holes (15).

2. The synchrotron X-ray absorption spectroscopy liquid sample temperature-controlled testing cell according to claim 1, characterized in that: The observation window (7) extends through the upper heating pool (1) and the lower heating pool (6). The observation window (7) is shaped like a frustum of a cone, meaning that the diameter of the observation window (7) gradually decreases from the outside to the inside.

3. The synchrotron X-ray absorption spectroscopy liquid sample temperature control test cell according to claim 2, characterized in that: The cone angle of the observation window (7) in the shape of a frustum is 25° to 155°.

4. The synchrotron X-ray absorption spectroscopy liquid sample temperature control test cell according to claim 1, characterized in that: Microfluidic channels (14) are provided on the inward-facing surfaces of the upper cover plate (3) and / or the lower cover plate (4), and the microfluidic channels (14) are used to realize continuous flow of liquid samples and online reaction monitoring.

5. The synchrotron X-ray absorption spectroscopy liquid sample temperature-controlled testing cell according to claim 4, characterized in that: One end of the microfluidic channel (14) is connected to the diamond window (9), and the other end of the microfluidic channel (14) extends to the outer side of the upper cover plate (3) and / or the lower cover plate (4).

6. The synchrotron X-ray absorption spectroscopy liquid sample temperature control test cell according to claim 1, characterized in that: The diameter of the through hole (15) is larger than the diameter of the diamond window (9) and the observation window (7).

7. The synchrotron X-ray absorption spectroscopy liquid sample temperature control test cell according to claim 1, characterized in that: The thickness of the film (10) is 5 to 100 micrometers.

8. The synchrotron X-ray absorption spectroscopy liquid sample temperature-controlled testing cell according to claim 1, characterized in that: The thickness of the film (10) is 10 to 50 micrometers.

Images