In-situ Mössbauer spectroscopy and in-situ X-ray absorption spectroscopy test sample cell and method thereof

Abstract

The present invention belongs to the technical field of phase change testing, and particularly relates to an in-situ Mössbauer spectrum and in-situ X-ray absorption spectrum testing sample pool and method thereof. The testing sample pool comprises a sample pool tray, a heating device, a perspective window I and a perspective window II, wherein a central through hole is provided on the sample pool tray, and perspective windows I and II are arranged in parallel in the central through hole of the sample pool tray, and a sample slot is formed between perspective windows I and II; a heating device and a gas path connected to the sample slot are provided on the sample pool tray. The sample pool of the present invention can withstand high temperature and high pressure, is suitable for various atmosphere reactions, can test the Mössbauer spectrum effect of samples under in-situ conditions, and utilizes high resolution of Mössbauer spectrum nuclides to analyze the phase composition, structure, adsorption, and coordination environment of samples in-situ with high precision; it can also test the X-ray absorption spectrum of samples under in-situ conditions to characterize the material structure.

Description

Technical Field

[0001] The invention belongs to the technical field of phase change testing, and particularly relates to an in-situ Mössbauer spectrum and in-situ X-ray absorption spectrum testing sample pool and a method thereof. Background Art

[0002] The Mössbauer effect is a science that studies the behavior of electrons outside the nucleus by observing the resonance absorption of gamma rays by the atomic nucleus. It is widely used in many chemical fields such as material structure, chemical bonding, and in-situ state analysis. The Mössbauer effect has a very high energy sensitivity, and the energy difference it detects can reach 10 -8 eV; Mössbauer spectroscopy (Mössbauer spectroscopy) uses keV-level gamma rays, which have low attenuation in air and do not require a high vacuum environment, so Mössbauer spectroscopy can detect samples at normal pressure or even high pressure. Therefore, Mössbauer spectroscopy can provide in-situ detection under the real conditions of the reaction and its fine structure for the chemical, structural and magnetic changes of Mössbauer elements.

[0003] Most of the existing in-situ Mössbauer spectroscopy testing technologies for high-temperature, high-pressure, and atmospheric reactions in China are quasi-in-situ Mössbauer spectroscopy tests, which terminate the reaction at different stages of the reaction, remove the sample from the in-situ environment, and perform Mössbauer spectroscopy testing at room temperature, pressure, and air. The test results can show the phase change law of the sample at different reaction stages to a certain extent, but even if the sampling method is used with inert gas protection, the influence of the sample when the temperature and pressure are reduced cannot be avoided, and the phase change of the sample in the in-situ environment cannot be truly reflected. The existing technology cannot achieve in-situ Mössbauer spectroscopy testing. Summary of the invention

[0004] In view of the above problems, the object of the present invention is to provide an in-situ Mössbauer spectroscopy and in-situ X-ray absorption spectroscopy test sample cell and method thereof, which can perform in-situ Mössbauer spectroscopy and in-situ X-ray absorption spectroscopy tests of atmosphere reactions from room temperature to high temperature and from normal pressure to high pressure, so that the tests can be performed under in-situ conditions.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] An in-situ Mössbauer spectroscopy and in-situ X-ray absorption spectroscopy test sample cell comprises a sample cell disc, a heating device, a perspective window I and a perspective window II, wherein the sample cell disc is provided with a central through hole, the perspective window I and the perspective window II are arranged in parallel in the central through hole of the sample cell disc, and a sample slot is formed between the perspective window I and the perspective window II; the sample cell disc is provided with a heating device and a gas path connected to the sample slot.

[0007] The sample pool body comprises a sample pool bottom plate and a sample pool cover plate, wherein the sample pool cover plate is arranged above the sample pool bottom plate and is sealed and connected to the sample pool bottom plate;

[0008] The central through hole of the sample pool plate body includes a central through hole I arranged on the sample pool bottom plate and a central through hole II arranged on the sample pool cover plate, and the central through hole I and the central through hole II are coaxial; the perspective window I and the perspective window II are arranged in the central through hole II.

[0009] The in-situ Mössbauer spectroscopy and in-situ X-ray absorption spectroscopy test sample cell further comprises a compression screw with a hollow structure, wherein the compression screw is threadedly connected in the central through hole II and is used for compressing the perspective window II.

[0010] A gasket I for sealing is provided between the perspective window I and the bottom plate of the sample pool, and a gasket II for sealing is provided between the perspective window II and the clamping screw.

[0011] An inner pressure washer is provided between the clamping screw and the perspective window II.

[0012] A convex structure is arranged on the top of the sample pool bottom plate, and a groove which is engaged with the convex structure is arranged on the bottom of the sample pool cover plate.

[0013] The gas path comprises a reaction gas inlet channel and a reaction gas outlet channel which are arranged on the sample pool cover plate, and the reaction gas inlet channel and the reaction gas outlet channel are arranged on both sides of the sample slot.

[0014] The heating device comprises a plurality of heating rods; a plurality of heating rod insertion holes are arranged on the sample pool disc along the circumferential direction, and the plurality of heating rods are respectively inserted into the heating rod insertion holes.

[0015] The in-situ Mössbauer spectroscopy and in-situ X-ray absorption spectroscopy test sample cell further comprises a protective insulating water cooling jacket, wherein the protective insulating water cooling jacket comprises an insulating base and an insulating cover;

[0016] The sample pool disc is embedded in the heat-insulating base; a ring-shaped cooling medium cavity is provided in the side wall of the heat-insulating base, and a through hole for the light source to pass through is provided at the bottom;

[0017] The heat-insulating cover is arranged above the sample pool disc body; a cooling medium cavity is arranged inside the cover body of the heat-insulating cover, and a perspective window III for the light source to pass through is arranged on the heat-insulating cover.

[0018] A method for testing a sample cell using in-situ Mössbauer spectroscopy and in-situ X-ray absorption spectroscopy as described above comprises the following steps:

[0019] 1) Connect the sample pool cover and the sample pool bottom plate with bolts;

[0020] 2) Install perspective window I in the central through hole II of the sample pool cover, place the sample to be tested on perspective window I, and then install perspective window II;

[0021] 3) Screw the clamping screw into the central through hole Ⅱ of the sample pool cover and press the perspective window Ⅱ;

[0022] 4) Pass gas into the sample tank and check for air tightness;

[0023] 5) Install the heating device and perform heating;

[0024] 6) Start the water cooling cycle of the protective insulation water cooling jacket;

[0025] 7) Place the test sample cell on the sample stage of the Mössbauer spectrometer, allow the gamma rays to pass through the sample cell window, and collect signals.

[0026] The advantages and beneficial effects of the present invention are as follows: the sample cell of the present invention can withstand high temperature and high pressure, is suitable for various atmosphere reactions, can test the Mössbauer spectroscopy effect of samples under in-situ conditions, and utilizes high resolution of Mössbauer spectroscopy nuclides to analyze the phase composition, structure, adsorption and coordination environment of the samples in-situ with high precision. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the structure of the sample cell for in-situ Mössbauer spectroscopy and in-situ X-ray absorption spectroscopy testing of the present invention;

[0028] Figure 2 A top view of the sample pool disc of the present invention;

[0029] Figure 3 for Figure 2 AA section view;

[0030] Figure 4 It is a schematic structural diagram of the heat insulation base in the present invention;

[0031] Figure 5 for Figure 4 A top view of

[0032] Figure 6 It is a schematic diagram of the structure of the heat insulation cover in the present invention;

[0033] Figure 7 for Figure 6 A top view of

[0034] FIG8 is a Moos spectrum obtained in an embodiment of the present invention: (a) is a Moos spectrum obtained by measuring the prepared catalyst at room temperature; (b) is a Moos spectrum obtained by measuring the prepared catalyst at room temperature; o (c) is the Mus spectrum after CH2 gas reduction; (c) is the Mus spectrum after hydrogenation reaction for 10 hours.

[0035] In the figure: 1. Sample pool bottom plate; 2. Sample pool cover plate; 3. Gasket I; 4. Perspective window I; 5. Sample slot; 6. Perspective window II; 7. Gasket II; 8. Reaction gas inlet channel; 9. Heating rod socket II; 10. Threaded hole; 11. Pressing screw; 12. Internal pressure washer; 13. Screw socket; 14. Heating rod socket I; 15. Bolt; 16. Insulation base; 161 is the base water inlet; 162 is the annular cooling medium cavity; 163 is the base water outlet; 164 is the through hole; 17. Insulation cover; 171 is the cover body water inlet; 172 is the cover body water outlet; 173 is the perspective window III; 19 is the reaction gas outlet channel. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] like Figure 1 As shown, the present invention provides an in-situ Mössbauer spectroscopy and in-situ X-ray absorption spectroscopy test sample cell, comprising a sample cell plate, a heating device, a perspective window I4 and a perspective window II6, wherein a central through hole is provided on the sample cell plate, the perspective window I4 and the perspective window II6 are arranged in parallel in the central through hole of the sample cell plate, and a sample slot 5 is formed between the perspective window I4 and the perspective window II6; the sample cell plate is provided with a heating device and a gas path connected to the sample slot 5.

[0038] In the embodiment of the present invention, the sample cell body comprises a sample cell bottom plate 1 and a sample cell cover plate 2. The sample cell cover plate 2 is disposed above the sample cell bottom plate 1 and is sealed and connected to the sample cell bottom plate 1 via bolts.

[0039] Specifically, Figure 2-3 As shown, a plurality of screw insertion holes 13 are circumferentially arranged on the sample pool bottom plate 1 , and a plurality of threaded holes 10 are circumferentially arranged on the sample pool cover plate 2 . The plurality of threaded holes 10 correspond to the plurality of screw insertion holes 13 one by one and are connected by bolts 15 .

[0040] The central through hole of the sample pool body includes a central through hole I arranged on the sample pool bottom plate 1 and a central through hole II arranged on the sample pool cover plate 2, and the central through hole I and the central through hole II are coaxial; the perspective window I4 and the perspective window II6 are arranged in the central through hole II.

[0041] The in-situ Mössbauer spectroscopy and in-situ X-ray absorption spectroscopy test sample cell of the present invention also includes a compression screw 11 with a hollow structure, which is threadedly connected in the central through hole II and is used to compress the perspective window II 6. An inner pressure washer 12 is provided between the compression screw 11 and the perspective window II 6 to avoid damaging the perspective window II 6.

[0042] Furthermore, a gasket I3 for sealing is provided between the perspective window I4 and the sample pool bottom plate 1 , and a gasket II7 for sealing is provided between the perspective window II6 and the clamping screw 11 .

[0043] Specifically, the center of the clamping screw 11 has a cylindrical structure with a hexagonal hole and a thread on the outside; the inner pressure washer 12 is used to buffer the pressure and friction between the inner pressure screw 11 and the perspective window II 6. The lower surface of the inner pressure washer 12 has a circular groove, which can be placed with a rubber O-ring, which is used to seal between the sample tank 5 and the perspective window II 6 during in-situ reaction at room temperature.

[0044] In an embodiment of the present invention, a protruding structure is provided on the top of the sample pool bottom plate 1, and a groove is provided on the bottom of the sample pool cover plate 2. The sample pool bottom plate 1 is clamped with the groove at the bottom of the sample pool cover plate 2 through the protruding structure, which is convenient for installation and disassembly.

[0045] In the embodiment of the present invention, the gas circuit includes a reaction gas inlet channel 8 and a reaction gas outlet channel 19 disposed in the sample pool cover plate 2, and the reaction gas inlet channel 8 and the reaction gas outlet channel 19 are both L-shaped structures and are respectively disposed on both sides of the sample slot 5. Gas is introduced into the sample slot 5 through the reaction gas inlet channel 8, and the gas in the sample slot 5 is discharged through the reaction gas outlet channel 19.

[0046] In an embodiment of the present invention, the heating device comprises a plurality of heating rods; a plurality of heating rod insertion holes are circumferentially arranged on the sample pool disc body, and the plurality of heating rods are respectively inserted into the heating rod insertion holes.

[0047] Specifically, Figure 2-3 As shown, a plurality of heating rod sockets Ⅰ14 are provided along the circumferential direction on the sample pool bottom plate 1, and a plurality of heating rod sockets Ⅱ9 are provided along the circumferential direction on the sample pool cover plate 2. The plurality of heating rod sockets Ⅱ9 correspond to the plurality of heating rod sockets Ⅰ14 one by one, respectively. A heating rod is inserted into the corresponding heating rod sockets Ⅰ14 and heating rod sockets Ⅱ9, and a heat source is provided for the sample slot 5 through the heating rod.

[0048] In the embodiment of the present invention, the sample pool bottom plate 1 is provided with six evenly distributed screw jacks 13 and four heating rod jacks Ⅰ14, preferably hexagon socket screws to make the sample pool more convenient to disassemble and assemble and evenly stress, thereby improving the airtightness of the sample slot; the four heating rod jacks Ⅰ14 are evenly distributed, and the sample pool heats up quickly and steadily; the raised part of the sample pool bottom plate 1 is in close and firm contact with the groove under the sample pool cover plate 2. The perspective window Ⅰ4 and the perspective window Ⅱ6 are installed in the surface groove of the central through hole Ⅱ of the sample pool cover plate 2, and have the best transmittance to gamma rays and X-rays.

[0049] like Figure 1As shown, the in-situ Mössbauer spectroscopy and in-situ X-ray absorption spectroscopy test sample cell provided by the present invention also includes a protective insulating water cooling jacket, which includes an insulating base 16 and an insulating cover 17. The sample cell tray is embedded in the insulating base 16, and the insulating base 16 reduces the thermal radiation of the high-temperature in-situ sample cell in the Mössbauer instrument through a water cooling cycle. The insulating cover 17 is arranged above the sample cell tray and is aligned with the center of the in-situ sample cell, and reduces the thermal radiation of the high-temperature in-situ sample cell in the Mössbauer instrument through a water cooling cycle.

[0050] like Figure 4-5 As shown, an annular cooling medium cavity 162 is provided in the side wall of the insulating base 16, a base water inlet 161 and a base water outlet 163 are provided on both sides of the annular cooling medium cavity 162, and a through hole 164 for the light source to pass through is provided at the bottom of the insulating base 16.

[0051] like Figure 6-7 As shown, a cooling medium cavity is provided in the cover body of the insulation cover 17, and a cover water inlet 171 and a cover water outlet 172 are respectively provided on both sides of the cooling medium cavity. A central hole for the light source to pass through is provided in the center of the insulation cover 17, and a perspective window III 173 with a conical surface is provided in the central hole, and the perspective window III 173 is located above the perspective window II 6.

[0052] Specifically, the center hole on the heat-insulating cover 17 is a tapered hole with an upper diameter larger than a lower diameter, and the perspective window III 173 is installed at the upper end of the center hole.

[0053] In the embodiment of the present invention, the perspective window I4, the perspective window II6 and the perspective window III173 are all made of special materials, such as high-purity beryllium. The special material window has the best transmittance to gamma rays and X-rays, and the surface of the special material window is coated with an aluminum oxide protective film; the material of the gasket I3 and the gasket II7 is polytetrafluoroethylene or polyimide.

[0054] A method for testing a sample cell using in-situ Mössbauer spectroscopy and in-situ X-ray absorption spectroscopy as described above comprises the following steps:

[0055] 1) Connect the sample pool cover plate 2 and the sample pool bottom plate 1 by bolts;

[0056] 2) Install a perspective window I4 in the central through hole II of the sample pool cover 2, place the sample to be tested on the perspective window I4, and then install the perspective window II6;

[0057] 3) Screw the clamping screw 11 into the central through hole Ⅱ of the sample pool cover plate 2 and press the perspective window Ⅱ6;

[0058] 4) Pass gas into the sample tank 5 and perform an airtightness check;

[0059] 5) Install the heating device and perform heating;

[0060] 6) Start the water cooling cycle of the protective insulation water cooling jacket;

[0061] 7) Place the test sample cell on the sample stage of the Mössbauer spectrometer, allow the gamma rays to pass through the sample cell window, and collect signals.

[0062] The present invention provides an in-situ Mössbauer spectroscopy and in-situ X-ray absorption spectroscopy test sample cell, which can withstand room temperature to high temperature, normal pressure to high pressure, and various oxidizing, reducing, and inert atmospheres. The sample cell structure is a flat cylindrical shape, and the distance between the windows is very small. The optimized sample cell structure can effectively improve the test efficiency and reduce the loss of rays. Example

[0063] Place the empty test sample cell in the Musspectr instrument and the X-ray absorption spectrometer, and test in air atmosphere at room temperature and pressure for 24 hours.

[0064] The purpose of the above test is mainly to test the influence of special material window on the test. The special material window in both instruments has no detectable blocking effect on gamma rays and X-rays. In addition, the Mu spectrum test shows that the content of Mu spectrum nuclides in special materials is low enough. No peak signal is found in the Mu spectrum after 24 hours of testing. This shows that the test record of the test sample pool can truly reflect the Mu spectrum and X-ray absorption spectrum of the sample under in-situ conditions.

[0065] The in-situ Mössbauer spectroscopy and in-situ X-ray absorption spectroscopy test sample cell provided by the present invention can be used for 57 Fe, 119 Sn, 151 In-situ Musspectrographic testing of three Eu nuclides in atmosphere reactions from room temperature to high temperature and from normal pressure to high pressure. Example

[0066] Study the phase transition of hydrogenation catalysts during the reaction process;

[0067] Nitric Acid Dissolves Metals 57 Fe Preparation 57 FeNO3 solution, replacing 40% of the precursor with 57 The catalyst was pressed into the test sample cell and H2 gas was introduced at a pressure of 1 MPa and a temperature of 340 o C, the catalyst was reduced in situ for 2 hours, and then a mixed gas of H2:CO2 = 3:1 was introduced at a pressure of 1.5 MPa and a temperature of 340 o C, start collecting spectral data after two hours of hydrogenation reaction, collect points every 2 hours, and continue the reaction for 12 hours;

[0068] The data tested above are the results of the catalytic hydrogenation test using the test sample cell. The test results are shown in Figures 8(a), 8(b) and 8(c). Figure 8(a) is the Mohs spectrum of the prepared catalyst measured at room temperature; Figure 8(b) is the Mohs spectrum of the prepared catalyst measured at room temperature; o Figure 8 (c) is the Mu spectrum after hydrogenation reaction for 10 hours. The test sample cell of the above embodiment can obtain high-quality Mu spectrum in a high-temperature and high-pressure atmosphere.

[0069] The present invention provides an in-situ Mössbauer spectrum and in-situ X-ray absorption spectrum test sample pool, which can perform in-situ Mössbauer spectrum test on solid, viscous liquid and liquid samples with Mössbauer spectrum effect nuclides; it can also perform in-situ X-ray absorption spectrum test on solid, viscous liquid and liquid samples; the protective insulating water cooling jacket reduces the influence of the in-situ sample pool thermal radiation on the Mössbauer spectrum instrument through water cooling cycle. The sample pool of the present invention can withstand high temperature and high pressure, is suitable for various atmosphere reactions, can test the Mössbauer spectrum effect of samples under in-situ conditions, and utilize high resolution of Mössbauer spectrum nuclides to analyze the phase composition, structure, adsorption and coordination environment of samples in-situ with high precision; it can also test the X-ray absorption spectrum of samples under in-situ conditions to characterize the material structure.

[0070] The above description is only an embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, expansion, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. An in-situ Mössbauer spectroscopy and in-situ X-ray absorption spectroscopy test sample cell, characterized in that: The invention comprises a sample pool disc, a heating device, a perspective window I (4) and a perspective window II (6), wherein the sample pool disc is provided with a central through hole, the perspective window I (4) and the perspective window II (6) are arranged in parallel in the central through hole of the sample pool disc, and a sample slot (5) is formed between the perspective window I (4) and the perspective window II (6); the sample pool disc is provided with a heating device and an air path connected to the sample slot (5); The sample pool body comprises a sample pool bottom plate (1) and a sample pool cover plate (2), wherein the sample pool cover plate (2) is arranged above the sample pool bottom plate (1) and is sealed and connected to the sample pool bottom plate (1); The central through hole of the sample pool body comprises a central through hole I arranged on the sample pool bottom plate (1) and a central through hole II arranged on the sample pool cover plate (2), wherein the central through hole I and the central through hole II are coaxial; the perspective window I (4) and the perspective window II (6) are arranged in the central through hole II; The in-situ Mössbauer spectroscopy and in-situ X-ray absorption spectroscopy test sample cell further comprises a compression screw (11) with a hollow structure, wherein the compression screw (11) is threadedly connected in the central through hole II and is used to compress the perspective window II (6); The in-situ Mössbauer spectroscopy and in-situ X-ray absorption spectroscopy test sample cell further comprises a protective insulating water cooling jacket, wherein the protective insulating water cooling jacket comprises an insulating base (16) and an insulating cover (17); The sample pool disc is embedded in the heat-insulating base (16); an annular cooling medium cavity (162) is provided in the side wall of the heat-insulating base (16), and a through hole (164) for the light source to pass through is provided at the bottom; The heat-insulating cover (17) is arranged above the sample pool disc body; a cooling medium cavity is provided in the cover body of the heat-insulating cover (17); and a perspective window III (173) for a light source to pass through is provided on the heat-insulating cover (17); The top of the sample pool bottom plate (1) is provided with a protruding structure, and the bottom of the sample pool cover plate (2) is provided with a groove that is engaged with the protruding structure; The heating device comprises a plurality of heating rods; a plurality of heating rod insertion holes are arranged on the sample pool disc along the circumferential direction, and the plurality of heating rods are respectively inserted into the heating rod insertion holes.

2. The in-situ Mössbauer spectroscopy and in-situ X-ray absorption spectroscopy test sample cell according to claim 1, characterized in that: A gasket I (3) for sealing is provided between the perspective window I (4) and the sample pool bottom plate (1), and a gasket II (7) for sealing is provided between the perspective window II (6) and the clamping screw (11).

3. The in-situ Mössbauer spectroscopy and in-situ X-ray absorption spectroscopy test sample cell according to claim 1, characterized in that: An inner pressure washer (12) is provided between the clamping screw (11) and the perspective window II (6).

4. The in-situ Mössbauer spectroscopy and in-situ X-ray absorption spectroscopy test sample cell according to claim 1, characterized in that: The gas path comprises a reaction gas inlet channel (8) and a reaction gas outlet channel (19) arranged on the sample pool cover plate (2); the reaction gas inlet channel (8) and the reaction gas outlet channel (19) are arranged on both sides of the sample slot (5).

5. A method for testing a sample cell using the in-situ Mössbauer spectroscopy and in-situ X-ray absorption spectroscopy as claimed in any one of claims 1 to 4, characterized in that: It includes the following steps: 1) Connect the sample pool cover plate (2) and the sample pool bottom plate (1) by means of bolts; 2) Installing a perspective window I (4) in the central through hole II of the sample pool cover (2), placing a sample to be tested on the perspective window I (4), and then installing the perspective window II (6); 3) Screw the clamping screw (11) into the central through hole II of the sample cell cover (2) and press the perspective window II (6); 4) Pass gas into the sample tank (5) and perform an airtightness check; 5) Install the heating device and perform heating; 6) Start the water cooling cycle of the protective insulation water cooling jacket; 7) Place the test sample cell on the sample stage of the Mössbauer spectrometer, allow the gamma rays to pass through the sample cell window, and collect signals.

Images