Button cell in-situ cell for high temperature in-situ x-ray diffraction characterization

Abstract

The application relates to a button type in-situ cell for high-temperature in-situ X-ray diffraction characterization, which comprises an in-situ cell body, a top cover, a bottom cover and a ceramic heating sheet, wherein a prefabricated through hole is arranged in the middle of the in-situ cell body, first and second circular grooves are arranged on the two sides of the in-situ cell body, and an air inlet channel and an air outlet channel are arranged on the in-situ cell body; the top cover can be fixed on the in-situ cell body and covers the first circular groove, a window sheet is arranged on the top cover; the bottom cover can be fixed on the in-situ cell body and covers the second circular groove; the ceramic heating sheet is arranged in the second circular groove and is clamped between the bottom cover and the top cover. Compared with the prior art, the button type in-situ cell has the advantages of small cavity volume, low average gas residence time, accurate temperature control, wide temperature control range and the like, and can be directly placed on an original off-line sample table of an X-ray diffractometer for in-situ testing.

Description

Technical Field

[0001] This invention relates to the field of instrumental analysis technology, and in particular to a button-shaped in-situ cell for high-temperature in-situ X-ray diffraction characterization. Background Technology

[0002] Heterogeneous catalysts have important applications in industrial production, especially in gas-solid phase catalytic reactions. Under reaction conditions, the adsorption, reaction, and desorption of gases on solid catalysts are crucial steps in gas-solid phase catalytic reactions. At the same time, the structure of the solid catalyst itself dynamically changes with time and external conditions, giving rise to a series of key scientific questions such as the evolution of catalyst structure and dynamic structure-activity relationships.

[0003] Compared to non-in-situ XRD, which can only characterize the structural changes of catalysts before and after the reaction, in-situ XRD can detect the evolution of the catalyst structure in real-time during actual reactions, including changes in crystal form, particle size, peak intensity, and unit cell parameters. Therefore, in-situ XRD technology has extremely important applications in studying the transformation of the active phase of a catalyst and characterizing catalyst deactivation.

[0004] Unlike traditional laboratory test reaction cells, although new in-situ XRD cells can be designed, they are large in size and difficult to perfectly match with X-ray diffractometers. Therefore, when using new commercial in-situ cells, it is usually necessary to replace the entire setup. This results in problems such as large equipment, high cost, cumbersome operation, and easy jamming. Therefore, it is necessary to design them reasonably.

[0005] Therefore, it is particularly important to design an XRD in-situ reaction cell that is resistant to high temperatures, small and compact in size, and compatible with offline sample stages. Summary of the Invention

[0006] The purpose of this invention is to overcome the defects of the prior art and provide a button-shaped in-situ cell for high-temperature in-situ X-ray diffraction characterization. The button-shaped in-situ cell in this technical solution has a small internal volume, a low average gas residence time, accurate temperature control, and a large temperature control range. It can be directly placed on the offline sample stage of the X-ray diffractometer for in-situ testing.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] The purpose of this invention is to provide a button-shaped in-situ cell for high-temperature in-situ X-ray diffraction characterization, comprising an in-situ cell body, a top cover, a bottom cover, and a ceramic heating element, wherein specifically:

[0009] The in-situ pool body has a prefabricated through hole in the middle, and the two sides of the in-situ pool body are respectively provided with a first circular groove and a second circular groove. The in-situ pool body is provided with an air inlet channel and an air outlet channel.

[0010] The top cover can be fixed to the in-situ pool body and cover the first circular groove, and the top cover is provided with a window;

[0011] The bottom cover can be fixed to the main body of the in-situ pool and cover the second circular groove;

[0012] A ceramic heating element is disposed in the second circular groove and sandwiched between the bottom cover and the top cover. The surface of the ceramic heating element and the pre-made through hole form a loading groove, and the target test catalyst is placed in the loading groove.

[0013] Furthermore, the main body of the in-situ pool is a circular sheet structure.

[0014] Furthermore, the first circular groove and the second circular groove are coaxial with the pre-fabricated through hole.

[0015] Furthermore, an O-ring is provided between the top cover and the in-situ pool body.

[0016] Furthermore, the top cover is provided with an annular groove, and the O-ring is placed in the annular groove.

[0017] Furthermore, the inner wall of the first circular groove, the lower surface of the top cover, and the surface of the ceramic heating element together constitute a sealed reaction space.

[0018] Furthermore, one end of both the air inlet channel and the air outlet channel is connected to the sealed reaction space, and the other end is connected to the outside of the in-situ pool body.

[0019] Furthermore, the in-situ cell body is provided with a circumferential groove, thereby allowing the in-situ cell body to be button-shaped and confined on the X-ray diffractometer.

[0020] Furthermore, both the top cover and the bottom cover are connected to the in-situ pool body via fasteners.

[0021] Furthermore, the bottom cover is provided with wiring through holes, through which thermocouples, air inlet pipes, air outlet pipes, and power supply lines for ceramic heating elements are all connected.

[0022] Compared with the prior art, the present invention has the following technical advantages:

[0023] (1) The in-situ cell in this technical solution is small in size and does not require an additional in-situ stage when in use. Due to its miniaturized and button-shaped design, it can be directly fixed on the original offline sample stage through the circumferential slot, and can be quickly placed on the X-ray diffractometer. Therefore, there is no situation where the in-situ cell gets stuck during the rotation process of the measurement.

[0024] (2) The instrument cavity in this technical solution has a small volume and a low average residence time of the gas, which can quickly respond to changes in the environment of the catalyst.

[0025] (3) In this technical solution, the thermocouples and ceramic heating elements used in the in-situ pool are directly connected to the DCS temperature control system, which makes the temperature control more accurate and the temperature control range wider. Attached Figure Description

[0026] Figure 1 This is a physical disassembled view of the high-temperature button in-situ cell suitable for high-temperature in-situ XRD characterization in this invention.

[0027] Figure 2 This is a photograph of the ceramic heating element and the main body of the in-situ pool in this invention.

[0028] Figure 3 This is a schematic diagram of the top cover structure in this invention;

[0029] Figure 4 This is a schematic diagram of the structure of the in-situ pool body in this invention;

[0030] Figure 5 This is a schematic diagram of the bottom cover structure in this invention;

[0031] Figure 6 This is a schematic diagram of the temperature control structure of the thermocouple and ceramic heating element in conjunction with the DCS temperature control system in this invention;

[0032] 1. Top cover, 2. In-situ pool body, 3. Bottom cover, 4. O-ring seal, 5. Ceramic heating element, 6. Thermocouple, 7. DCS temperature control system, 8. Gas inlet, 9. Gas outlet, 10. Window. Implementation

[0033] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms, and other features not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0034] The button-shaped in-situ cell for high-temperature in-situ X-ray diffraction characterization in this invention includes an in-situ cell body 2, a top cover 1, a bottom cover 3, and a ceramic heating element 5, as detailed below. Figures 1 to 5 .

[0035] In specific implementation, the in-situ pool body 2 has a pre-fabricated through hole in the middle, and the two sides of the in-situ pool body 2 are respectively provided with a first circular groove and a second circular groove. The in-situ pool body 2 is provided with an air inlet channel and an air outlet channel. The top cover 1 can be fixed to the in-situ pool body 2 and covers the first circular groove. The top cover 1 is provided with a window 10. The bottom cover 3 can be fixed to the in-situ pool body 2 and covers the second circular groove. The top cover 1 and the bottom cover 3 are both connected to the in-situ pool body 2 by fasteners.

[0036] In specific implementation, the ceramic heating element 5 is disposed in the second circular groove and sandwiched between the bottom cover 3 and the top cover 1. The surface of the ceramic heating element 5 and the pre-fabricated through hole form a loading groove, and the target test catalyst is placed in the loading groove. The first circular groove and the second circular groove are coaxial with the pre-fabricated through hole.

[0037] In practice, the in-situ cell body 2 is a circular sheet structure, i.e., a button-like structure. The in-situ cell body 2 has a circumferential groove, which allows the in-situ cell body 2 to be button-likely confined on the X-ray diffractometer.

[0038] In specific implementation, an O-ring 4 is provided between the top cover 1 and the in-situ pool body 2. The top cover 1 has an annular groove, and the O-ring 4 is placed in the annular groove.

[0039] In practice, the inner wall of the first circular groove, the lower surface of the top cover 1, and the surface of the ceramic heating element 5 together form a sealed reaction space. One end of both the air inlet channel and the air outlet channel is connected to the sealed reaction space, and the other end is connected to the outside of the in-situ pool body 2.

[0040] In practice, the in-situ cell body has two channels, connected to the reactant inlet and reactant outlet respectively. The ceramic heating element 5 is connected to the in-situ cell body by high-temperature adhesive or welding, naturally forming a small groove for filling the catalyst requiring in-situ high-temperature atmosphere XRD characterization. A sealed gas chamber is formed between the top cover and the in-situ cell body. Gaseous reactants enter through the gaseous reactant inlet channel on the in-situ cell body and exit through the gaseous reaction product outlet channel.

[0041] In practice, the bottom cover 3 is provided with a wiring through hole, through which the thermocouple 7, the air inlet pipe, the air outlet pipe, and the power supply line for the ceramic heating element are all connected.

[0042] The DCS temperature control system 7 outputs a specific power current to the ceramic heating element based on the temperature information obtained by the thermocouple 7, and realizes the heating process based on the preset heating program.

[0043] The specific assembly method of the high-temperature button in-situ cell suitable for high-temperature in-situ X-ray diffraction characterization in this technical solution is as follows:

[0044] First, place the O-ring 4 in the groove at the bottom of the top cover 1, and use tools to connect the top cover 1, the in-situ pool body 2, and the bottom cover 3 with fasteners. The O-ring 4 will achieve a sealing effect between the top cover 1 and the in-situ pool body 2.

[0045] Then, the thermocouple 6 is fixed to the lower part of the ceramic heating element 5 through the lower circle of the bottom cover 3 with high temperature glue, and both the ceramic heating element 5 and the thermocouple 6 are connected to the DCS temperature control system 7. Then, at room temperature, a certain amount of catalyst powder is transferred to the small groove formed between the ceramic heating element 5 and the in-situ pool body 2.

[0046] Subsequently, the assembled in-situ cell is embedded into the X-ray diffractometer, and gaseous reactants are introduced through gaseous reactant inlet 8. The reaction temperature and heating rate required for the experiment are set through the DCS temperature control system. The X-ray diffractometer collects the signal of the catalytic system, thus obtaining information on the catalyst phase and lattice.

[0047] In this example, taking a copper catalyst supported on alumina as an example, after being filled into the small groove, the in-situ cell was assembled and fixed to the X-ray diffractometer for testing using a clip. During the test, the catalyst bed temperature was raised to 300 ºC using a DCS temperature control system, and 5% H2 / N2 activation gas with a flow rate of 30 mL / min was introduced for activation, with an activation time of approximately 0.5 hours. The activation gas entered the gas chamber through the main gas reactant inlet of the in-situ cell, passed through the Cu / Al2O3 catalyst placed in the reaction tube, and after complete reaction, flowed out through the gaseous reaction product outlet.

[0048] During the reaction, the catalyst was subjected to a wide-angle 10° test. o -80 o A scan takes approximately 8 minutes to obtain a spectrum, revealing the catalyst's phase and lattice information. (See [link to relevant documentation]). Figure 6 .

[0049] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A button-shaped in-situ cell for high-temperature in-situ X-ray diffraction characterization, characterized in that, include: The in-situ pool body (2) has a prefabricated through hole in the middle, and a first circular groove and a second circular groove are respectively provided on both sides of the in-situ pool body (2). The in-situ pool body (2) is provided with an air inlet channel and an air outlet channel. The top cover (1) can be fixed on the in-situ pool body (2) and covered on the first circular groove. The top cover (1) is provided with a window (10). The bottom cover (3) can be fixed on the in-situ pool body (2) and cover the second circular groove; A ceramic heating element (5) is disposed in the second circular groove and sandwiched between the bottom cover (3) and the top cover (1). The surface of the ceramic heating element (5) and the pre-made through hole form a loading groove, and the target test catalyst is placed in the loading groove. An O-ring (4) is provided between the top cover (1) and the in-situ pool body (2); The top cover (1) is provided with an annular groove, and the O-ring (4) is placed in the annular groove; The inner wall of the first circular groove, the lower surface of the top cover (1), and the surface of the ceramic heating plate (5) together form a closed reaction space; One end of the air inlet channel and the air outlet channel are connected to the sealed reaction space, and the other end is connected to the outside of the in-situ pool body (2).

2. The button-shaped in-situ cell for high-temperature in-situ X-ray diffraction characterization according to claim 1, characterized in that, The in-situ pool body (2) is a circular sheet structure.

3. The button-shaped in-situ cell for high-temperature in-situ X-ray diffraction characterization according to claim 1, characterized in that, The first and second circular grooves are coaxial with the pre-fabricated through hole.

4. A button-shaped in-situ cell for high-temperature in-situ X-ray diffraction characterization according to claim 1, characterized in that, The in-situ cell body (2) is provided with a circumferential groove so that the in-situ cell body (2) is button-shaped and limited on the X-ray diffractometer.

5. A button-shaped in-situ cell for high-temperature in-situ X-ray diffraction characterization according to claim 1, characterized in that, The top cover (1) and the bottom cover (3) are both connected to the in-situ pool body (2) by fasteners.

6. A button-shaped in-situ cell for high-temperature in-situ X-ray diffraction characterization according to claim 1, characterized in that, The bottom cover (3) is provided with a wiring through hole, through which thermocouples, air inlet pipes, air outlet pipes, and power supply lines for ceramic heating elements are all connected.

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