Sample cup compensation ring for in-situ variable-temperature diffuse reflection infrared spectrum test

Abstract

The utility model discloses a sample cup compensation ring for an in-situ variable-temperature diffuse reflection infrared spectrum test. The compensation ring provided by the utility model comprises an annular part and a barrel part sleeved on a sample cup, wherein the barrel part is an inverted circular truncated cone-shaped barrel part or a cylindrical barrel part; the upper end of the inverted-truncated-cone-shaped cylinder part is connected with an outer ring of the annular part, and the outer diameter of the upper end face of the inverted-truncated-cone-shaped cylinder part is the same as that of the annular part. The cylindrical barrel part is connected with an inner ring of the annular part, and the inner diameter of the cylindrical barrel part is the same as that of the annular part; and the compensation ring is made of an unpolished metal material. The compensation ring is simple in structure and easy to manufacture, and can well solve the technical problem that the diffuse reflection signal of the sample cannot be detected or the diffuse reflection signal of the sample is attenuated due to the fact that the position of the sample deviates from a light spot irradiation area caused by deformation of an infrared test sample cup at high temperature in the prior art.

Description

Technical Field

[0001] This utility model relates to a sample cup compensation ring for in-situ variable temperature diffuse reflectance infrared spectroscopy testing, belonging to the field of infrared spectroscopy detection technology. Background Technology

[0002] Infrared diffuse reflectance technology, due to its advantages such as low sample preparation requirements and the ability to directly analyze solid and powder samples without complex pretreatment, has wide application value in many fields such as materials science, chemistry, and life sciences. Commercially available diffuse reflectance testing accessories consist of a reflective optical path, a reaction cell, inlet and outlet gas lines, and a temperature control system. The reflective optical path comprises four plane mirrors and two off-axis parabolic mirrors; the reaction cell is made of stainless steel, with the sample placed inside a cylindrical sample cup and sealed by a saucer-shaped cover with three transparent windows; the inlet and outlet gas lines are located on one side of the reaction cell, allowing the reaction atmosphere to enter the sample cell and the exhaust gas to exit; the temperature control system keeps the sample in the reaction cell at a continuously increasing temperature environment, which can enhance the rate of chemical reaction. These advantages have led to the widespread application of this type of testing accessory in high-temperature in-situ infrared spectroscopy monitoring technology for gas-solid two-phase catalytic reactions. It can monitor key information such as the evolution of species on the catalyst surface and the transformation of reaction intermediates in real time, providing powerful characterization information for catalyst performance optimization and reaction mechanism elucidation. Theoretically, when the test temperature exceeds 500 degrees Celsius, the background thermal radiation signal will severely interfere with the characteristic infrared absorption signal of the sample, thus limiting the upper limit of the detection temperature of the in-situ cell. However, in the actual use of the equipment to monitor the infrared spectrum of a gas-solid two-phase catalytic reaction, the following phenomenon was repeatedly observed: after heating to approximately 400 degrees Celsius, the signal-to-noise ratio of the sample's infrared spectrum decreased significantly, and the baseline drifted significantly, making it difficult to continuously assess the temperature dependence of the sample's infrared characteristic signal; while when the temperature dropped back below 400 degrees Celsius, the sample's infrared characteristic spectrum suddenly recovered. The following troubleshooting steps were attempted: changing different samples, adjusting the longitudinal position of the reaction in the reflected light path at high temperatures, replacing the sample cell window with one of different materials (barium fluoride and zinc selenide), or not installing the window at all, but the abnormal phenomenon persisted. Therefore, after ruling out factors such as sample differences, longitudinal offset of the reaction cell, and the sample cell window, this common problem was considered to originate from the high-temperature deformation of the sample cup within the sample cell, which caused the sample position to deviate from the light spot irradiation area, thus making it impossible to detect the diffuse reflection signal of the sample. (Appendix) Figure 4The high-temperature deformation of the sample cup can be attributed to the following three factors: a. The sample cup is made of stainless steel, commonly 316L, with an embrittlement temperature range of 380-420 degrees Celsius. Its peak Vickers hardness during embrittlement is more than twice that at room temperature. b. The thermal expansion of the catalyst powder sample is significantly lower than that of the sample cup made of stainless steel. c. The structural design of the reaction chamber: for ease of operation, the inlet and outlet ports for the cooling water and reaction gas phase are located on the side of the sample cup closest to the spectrometer sample chamber opening. During heating, a temperature difference forms on both sides of the sample cup. As the stainless steel expands due to heat, the side with the distributed ports deforms towards the center of the cup, while the other side expands outwards. Based on this deformation, the influence of the sample cup's high-temperature deformation becomes particularly noticeable in infrared diffuse reflectance testing, especially when the initial incident infrared beam is positioned near the edge of the sample cup. When the temperature rises to approximately 400 degrees Celsius, the converging light spot hits the edge of the sample cup that deforms towards the center, reducing the amount of infrared light illuminating the sample, weakening the sample's characteristic absorption signal, and lowering the signal-to-noise ratio of the spectrum. Furthermore, after repeated high-temperature oxidizing gas experiments, the steel of the sample cup exhibits corrosion and blackening on its surface, and the resulting substances absorb the infrared light illuminating it, causing a significant upward shift in the spectrum baseline. However, the cell body is typically only movable vertically and is not easily removed at high temperatures. Therefore, it is impossible to adjust the optical path in real time at high temperatures by translating the cell body or reusing a reflective standard plate. Considering all these factors, it is necessary to provide a compensation device for the deformation of the infrared diffuse reflection in-situ sample cup at high temperatures. Summary of the Invention

[0003] The purpose of this invention is to solve the problems mentioned in the background art. This invention provides a sample cup compensation ring for in-situ temperature-varying diffuse reflectance infrared spectroscopy testing. The compensation ring is used to directly fit onto the sample cup. Without replacing the sample cup, it can diffusely reflect the infrared beam irradiating the edge of the sample cup into the optical path. After multiple reflections and refractions, part of the beam irradiates the sample, thereby allowing the diffuse reflectance signal of the sample to be detected.

[0004] To achieve the above objectives, this utility model provides a sample cup compensation ring for in-situ variable temperature diffuse reflectance infrared spectroscopy testing. The compensation ring includes an annular portion and a cylindrical portion for fitting onto the sample cup. The cylindrical portion is either an inverted frustum-shaped cylindrical portion or a cylindrical cylindrical portion.

[0005] The upper end of the inverted frustum-shaped cylindrical part is connected to the outer ring of the annular part, and the outer diameter of its upper end face is the same as the outer diameter of the annular part.

[0006] The cylindrical section is connected to the inner ring of the annular section, and its inner diameter is the same as that of the annular section.

[0007] The compensation ring is made of unpolished metal.

[0008] Optionally, the compensation ring is made of a metal material with a gold-plated film.

[0009] Optionally, the surface of the compensation ring is a surface with roughness or microstructure.

[0010] Optionally, the metal material is molybdenum, copper, tungsten, nickel-based alloy, or gold.

[0011] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0012] The compensation ring provided by this invention is used to directly fit onto the sample cup during in-situ diffuse reflectance infrared spectroscopy testing. It can diffusely reflect the infrared beam irradiating the edge of the sample cup into the optical path without replacing the sample cup. After multiple reflections and refractions, part of the beam irradiates the sample, thereby enabling the diffuse reflectance signal of the sample to be detected. The compensation ring has a simple structure and is easy to manufacture. It can effectively solve the technical problem in the prior art where the infrared test sample cup deforms at high temperatures, causing the sample position to deviate from the irradiation area of ​​the light spot, thus making it impossible to detect the diffuse reflectance signal of the sample or causing the diffuse reflectance signal of the sample to attenuate. Attached Figure Description

[0013] Figure 1 This is a three-dimensional schematic diagram of an outer-shroud type compensation ring provided in the embodiment.

[0014] Figure 2 This is a three-dimensional schematic diagram of an embedded compensation ring provided in the embodiment.

[0015] Figure 3 This is a top view of the compensation ring in the embodiment.

[0016] Figure 4 This is a schematic diagram of the position of the light spot under high-temperature deformation of the sample cup.

[0017] Figure 5 A schematic diagram of the beam with a compensation ring added to the sample cup.

[0018] Figure 6 The infrared spectrum of the sample during the heating process in the original sample cup (without the compensation ring).

[0019] Figure 7 Infrared spectrum of sample during heating of sample cup with compensation ring installed. Detailed Implementation

[0020] To make this utility model more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings.

[0021] Example 1

[0022] This embodiment provides a sample cup compensation ring for in-situ variable-temperature diffuse reflectance infrared spectroscopy testing. The compensation ring must be shape-fitting to the sample cup without affecting sample loading. The sample cup is typically cylindrical. The compensation ring is used to fit over the sample cup (inside or outside the cup), and its specific structure is as follows... Figures 1-3 As shown, the compensation ring includes an annular portion 1 and a cylindrical portion 2 for fitting onto the sample cup. Depending on the fitting method, this compensation ring is classified as an outer cover type compensation ring. Figure 1 , 3 ) and embedded compensation ring ( Figure 2 , 3 );in:

[0023] like Figure 1 As shown, the outer cover type compensation ring is designed with an upper annular part 1 as an annular surface and a lower cylindrical part 2 as an inverted frustum shape. The upper end of the inverted frustum cylindrical part 2 is connected to the outer ring of the annular part 1 and the outer diameter of its upper end face is the same as the outer diameter of the annular part 1. The outer cover type compensation ring can be directly covered on the upper outer wall of the sample cup.

[0024] like Figure 2 As shown, the embedded compensation ring is designed with an upper annular part 1 as an annular surface and a lower cylindrical part 2 as a cylinder. The cylindrical part 2 is connected to the inner ring of the annular part 1 and its inner diameter is the same as that of the annular part. The embedded compensation ring can be inserted into the sample cup.

[0025] The design of the compensation ring material is as follows: 1. The chemical stability temperature of the material must be higher than the actual operating temperature, such as molybdenum, copper, tungsten, nickel-based alloys, and gold; 2. The surface does not need to be polished to maintain its good diffuse reflection characteristics to infrared beams; or, based on the diffuse reflection optical path, a surface with adjustable roughness or microstructure can be designed to facilitate diffuse reflection of infrared beams and their return to the sample; 3. To avoid infrared signal interference from the compensation ring and to reduce costs, copper can be used to make the compensation ring in reducing and inert gas atmospheres (such as hydrogen, carbon monoxide, nitrogen, and argon) or vacuum environments; in oxidizing gas and other organic gas atmospheres (such as oxygen, nitric oxide, methanol, ethylene, and alkanes), a gold-plated metal (including but not limited to copper) should be used to make the compensation ring.

[0026] The adjustable roughness or microstructure includes, for example: 1) designing a non-periodic pit / protrusion array on the upper surface of the compensation ring to enhance the multi-directional diffuse reflection path of the infrared beam through scattering effect, allowing more beams to be reflected back to the sample; 2) designing a fractal geometric structure (such as dendritic microgrooves) on the upper surface of the compensation ring to expand the scattering dimension of the light path using its self-similarity, thereby improving the diffuse reflection efficiency of the surface for infrared light of different wavelengths; 3) preparing a porous alumina template on the upper surface of the compensation ring using electrochemical anodizing, and forming a nanoscale rough surface by voltage-controlled pore size to meet the diffuse reflection requirements of specific infrared bands (such as mid-infrared 2.5-25μm); 4) using abrasives of different particle sizes (such as steel shot and glass beads) to impact the upper surface of the compensation ring to form a uniform pit structure; the larger the abrasive particle size and the higher the jetting pressure, the greater the roughness Ra value.

[0027] Combined with appendix Figure 1 , 2 The dimensional design of the above-mentioned compensation rings is explained as follows: For the outer-type compensation ring, the inner ring radius R1 of the annular portion 1 is approximately equal to the inner diameter of the sample cup. For example, if the inner radius of the sample cup is 3mm, R1 is 3mm. For the embedded compensation ring, the inner ring radius R1 of the annular portion 1 is slightly smaller than the inner diameter of the sample cup. For example, if the inner radius of the sample cup is 3mm, R1 can be 2.8mm. The outer ring radius R2 of the compensation ring annular portion 1 is slightly larger than the outer diameter of the sample cup. For example, if the outer radius of the sample cup is 5.5mm, R2 can be 6mm. The outer-type compensation ring radius R3 (outer ring...) The lower end face radius of the compensation ring cylinder 2 is slightly larger than the outer diameter of the sample cup. For example, if the outer radius of the sample cup is 5.5 mm, R3 can be 5.6 mm. The radius R4 of the embedded compensation ring (outer diameter of the embedded compensation ring cylinder 2) is slightly smaller than the inner diameter of the sample cup. For example, if the inner radius of the sample cup is 3 mm, R4 can be 2.9 mm. The height h1 is the sum of the heights of the upper annular part 1 and the lower cylinder 2 of the compensation ring. For example, if the annular part 1 is a 1 mm thick annular copper sheet, the height of the cylinder 2 is 4 mm, and the overall height h1 is 5 mm.

[0028] Figure 4 This is a schematic diagram showing the position of the light spot under high-temperature deformation of the sample cup. Figure 5 A schematic diagram of the beam after adding a compensation ring to the sample cup.

[0029] The upper part of the aforementioned outer or embedded compensation ring (made of copper) is installed on the sample cup, and heated infrared diffuse reflectance tests are performed on both the original sample cup (without the compensation ring) and the original sample cup (without the compensation ring). The sample is ZrO2 powder, and the atmosphere is nitrogen. During the heating process of the original sample cup, the infrared characteristic signal of the sample gradually changes. When the temperature rises to approximately 400 degrees Celsius, the spectral baseline suddenly jumps upward, and the noise increases significantly. Figure 6As shown; after adding a compensation ring to the sample cup, the trend of the infrared characteristic signal of the sample changing with temperature can be continuously observed as the temperature increases, and when the temperature is raised to 500 degrees Celsius, the spectral baseline and signal-to-noise ratio remain stable and good, as shown. Figure 7 As shown.

[0030] The above-described embodiments are merely preferred embodiments of this utility model and are not intended to limit this utility model in any form or substance. It should be noted that those skilled in the art can make several improvements and additions without departing from this utility model, and these improvements and additions should also be considered within the scope of protection of this utility model.

Claims

1. A sample cup compensating ring for use in in situ variable temperature diffuse reflectance infrared spectroscopy testing, the sample cup compensating ring comprising: The compensation ring includes an annular portion and a cylindrical portion for fitting onto the sample cup, wherein the cylindrical portion is an inverted frustum-shaped cylindrical portion or a cylindrical cylindrical portion; The upper end of the inverted frustum-shaped cylindrical part is connected to the outer ring of the annular part, and the outer diameter of its upper end face is the same as the outer diameter of the annular part. The cylindrical section is connected to the inner ring of the annular section, and its inner diameter is the same as that of the annular section. The compensation ring is made of unpolished metal.

2. The compensating ring of claim 1, wherein, The compensation ring is made of a gold-plated metal material.

3. The compensating ring of claim 1, wherein, The surface of the compensation ring is a surface with roughness or microstructure.

4. The compensating ring according to any one of claims 1 to 3, characterized in that The metal material is molybdenum, copper, tungsten, nickel-based alloy, or gold.

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