Pump-probe tap instrument
By improving the structure and materials of the TAP instrument, problems such as unstable pulse valve connection, easy damage to the reactor, low vacuum degree and high noise were solved, realizing high-temperature heating and automatic continuous pulse experiment to obtain key information of catalytic reaction.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- SHANGHAI TECH UNIV
- Filing Date
- 2025-04-07
- Publication Date
- 2026-06-04
AI Technical Summary
Existing TAP instruments suffer from problems such as unstable connection between pulse valve and micro-reaction tube, easy damage to reactor in high-temperature environment, low vacuum degree, large noise in mass spectrometry signal, and easy contamination of vacuum system, making it difficult to achieve high-temperature heating and automatic continuous pulse experiment.
A pump-probe TAP instrument was designed, including a sample introduction pulse system, a microreactor, a liquid nitrogen cooling system, a mass spectrometry system, and a vacuum system. The reactor is made of stainless steel with a quartz coating on the inner wall. A spiral groove heating coil is set up, and a three-pump series vacuum pump group is used. An electromagnetic signal shielding mesh is used in the annular liquid nitrogen chamber to achieve stable control of gas pulses and high vacuum, and reduce noise interference.
It enables continuous or intermittent pulsed experiments of gas molecules, obtains surface chemistry and microdynamic information related to elementary steps, improves the thermal stability of the reactor and the clarity of mass spectrometry signals, reduces the system failure rate, and supports high-temperature heating and high-vacuum environments.
Smart Images
Figure CN2025087629_04062026_PF_FP_ABST
Abstract
Description
A pump-probe TAP instrument Technical Field
[0001] This invention relates to the field of transient dynamics and catalytic interface research, and in particular to a pump detection (TAP) instrument. Background Technology
[0002] Early understanding of catalytic reaction processes was primarily based on the analysis and simulation of apparent reaction kinetics. This approach struggled to reveal the reaction mechanisms, establish a quantitative relationship between active sites and catalytic performance, and obtain information on reaction intermediates related to elementary reactions. Intrinsic reaction kinetics analysis, grounded in elementary reactions, studies the interfacial chemistry related to catalytic reactions at the microscopic level. It establishes the relationship between the chemical properties and reactivity of catalysts, identifies key factors influencing catalytic performance, and thus guides catalyst design and development.
[0003] Catalytic reactions involve catalysts undergoing dynamic changes. The complexity of the catalyst surface structure, the diversity of active sites, the adsorption of gas molecules on the catalyst surface, and mass and heat transfer during the reaction all directly influence our understanding of the laws governing catalytic chemical reactions. Conventional steady-state experimental analysis struggles to obtain information related to elementary reactions, thus hindering theoretical support for catalyst design. Transient experiments, however, can provide more mechanistic information about reaction intermediates and pathways in elementary steps. Temporal Analysis of Products (TAP) involves pulsed injection of minute amounts of reactant gas (e.g., as small as 0.01 nmol) into a micro-reaction tube containing the catalyst. High-time-resolution mass spectrometry at the end of the micro-reaction tube is used to monitor the transient response of gases (including reactants and products) leaving the catalyst bed in real time. TAP technology, utilizing high-frequency pulsed solenoid valves, can reduce pulse widths to below 10 microseconds, thereby obtaining information such as the sequence of elementary reaction steps and their kinetic constants.
[0004] Currently, commercial TAP instruments suffer from a series of problems, such as: excessive dead volume and high diffusion resistance between the pulse valve and the micro-reaction tube; easy leakage at the connection between the pulse flange and the pulse valve; and unstable gas pulse volume. When operating in high-temperature environments, problems frequently arise, including quartz reactor breakage, damage to the connected O-ring coils, chemical inertness of stainless steel reactors, short lifespan and easy breakage of heating coils, or difficulty in achieving heating above 600°C. Mass spectrometry signal noise is also significant. Excessive O-ring coil design leads to high system failure rate and low vacuum. The method of using a diffusion pump and manual liquid nitrogen injection for cooling to achieve high vacuum can easily cause contamination of the vacuum chamber and the second-stage electron multiplier tube of the mass spectrometer by oil droplets from the diffusion pump, thereby damaging the mass spectrometry performance. Due to the manual addition of liquid nitrogen, pulse experiments cannot be performed automatically for extended periods.
[0005] In summary, there is an urgent need for a pump-probe TAP instrument that simultaneously features a gas channel, a small size, a stable connection, a chemically inert and thermally stable reactor, a clear mass spectrometry response signal, and a high vacuum. Summary of the Invention
[0006] To address the aforementioned problems, this invention provides a pump-probe TAP instrument capable of performing experiments involving continuous or intermittent pulses, or pump-probe pulses, of one or two gas molecules, thereby obtaining surface chemistry and microdynamic information related to the elementary steps.
[0007] The first aspect of this invention provides a pump-probe TAP instrument, comprising an injection pulse system, a microreactor, a liquid nitrogen cooling system, a mass spectrometry system, and a vacuum system; the vacuum system includes a first vacuum chamber, a second vacuum chamber, and a vacuum pump assembly connected in sequence; a vacuum gauge with its working end extending into the inner cavity is provided on the side wall of the first vacuum chamber; the liquid nitrogen cooling system includes an annular liquid nitrogen chamber disposed within the first vacuum chamber; the injection pulse system includes a pulse flange disposed at the top of the first vacuum chamber, and the pulse flange is provided with a first pulse valve and a second pulse valve, the first pulse valve and the second pulse valve being... An included angle α is formed between the pulse valves; the pulse flange is also provided with a condensate pipe channel for loading condensate pipes; the microreactor is located at the bottom of the pulse flange, and the pulse flange is also provided with a pulse channel, the first pulse valve and the second pulse valve are connected to the top of the microreactor through the pulse channel, and the microreactor is suitable for loading samples; the mass spectrometry system includes a mass spectrometer, the mass spectrometer is located on the side wall of the first vacuum chamber, and the mass spectrometer filament extends to the center of the first vacuum chamber; the bottom of the microreactor is also provided with an extension tube extending towards the mass spectrometer filament and located above the mass spectrometer filament.
[0008] In one feasible embodiment, the microreactor includes an insulation layer and a reactor body disposed inside the insulation layer. The reactor body has a reaction channel that runs vertically through it, and the reaction channel is suitable for loading samples. A first pulse valve and a second pulse valve are connected to the air inlet of the reaction channel through a pulse channel, and the air outlet of the reaction channel is connected to an expansion pipe. A spiral groove is provided on the outer wall of the reactor body, and a heating coil is disposed in the spiral groove.
[0009] In one feasible embodiment, the pulse channel includes a first branch channel, a second branch channel, and a converging channel; the air inlet of the first branch channel is connected to a first pulse valve, and the air inlet of the second branch channel is connected to a second pulse valve; the air outlets of the first branch channel and the second branch channel are both connected to the air inlet of the converging channel, and the air outlet of the converging channel is connected to the air inlet of the reaction channel; an angle β is formed between the first branch channel and the second branch channel.
[0010] In one feasible embodiment, the included angle α is 30 to 150°; and / or, the included angle β is 30 to 150°; and / or, the included angle α and the included angle β are the same.
[0011] In one feasible embodiment, the liquid nitrogen cooling system further includes an upper liquid level temperature sensor located on the upper part of the outer wall of the annular liquid nitrogen cavity and a lower liquid level temperature sensor located on the lower part of the outer wall of the annular liquid nitrogen cavity, wherein the sensing ends of the upper liquid level temperature sensor and the lower liquid level temperature sensor are both located in the inner cavity of the annular liquid nitrogen cavity.
[0012] In one feasible embodiment, a control module is also included, which is connected via circuitry to the sample injection pulse system, the microreactor, the liquid nitrogen cooling system, the mass spectrometry system, and the vacuum system.
[0013] In some feasible embodiments, the top of the annular liquid nitrogen chamber is provided with an electromagnetic signal shielding mesh; and / or, the vacuum pump assembly includes a first molecular pump, a second molecular pump and a mechanical pump connected in sequence; and / or, a vacuum valve is provided between the first vacuum chamber and the second vacuum chamber; and / or, a seal is provided between the pulse flange and the microreactor; and / or, the mass spectrometer is a quadrupole mass spectrometer; and / or, a vacuum gauge with its working end extending into the inner cavity is also provided on the side wall of the second vacuum chamber.
[0014] In one feasible embodiment, the inner diameter of the first vacuum chamber is 200–1000 mm, the height is 50–1500 mm, and the wall thickness is 1–200 mm; and / or, the inner diameter of the second vacuum chamber is 20–1000 mm, the height is 50–500 mm, and the wall thickness is 1–100 mm; and / or, the inner ring diameter of the annular liquid nitrogen chamber is 100–1000 mm, the outer ring diameter is 120–1200 mm, the height is 50–1000 mm, and the wall thickness is 1–100 mm; and / or, the vacuum level of both the first and second vacuum chambers is 10. -7 ~10 -10 mbar; and / or, the pulse width of the first pulse valve and the second pulse valve are both 5 to 500 μs; and / or, the pulse frequency of the first pulse valve and the second pulse valve is 1 to 50 times / s; and / or, the length of the first bifurcation channel and the second bifurcation channel are both 2 to 20 mm, and the inner diameter is both 0.05 to 2 mm.
[0015] In one feasible embodiment, the reactor body is made of stainless steel; and / or, the inner diameter of the reactor body is 2 to 50 mm; and / or, the inner wall of the reactor body is coated with a quartz coating with a thickness of 10 to 500 nm; and / or, the depth of the spiral groove 22.2 is 0.1 to 5 mm; and / or, the heating temperature range of the heating coil is 25 to 1000 °C; and / or, the length of the expansion tube is 5 to 200 mm, and the inner diameter is 2 to 100 mm.
[0016] A second aspect of the present invention provides a method of using a pump-probe TAP instrument as provided in the first aspect of the present invention, characterized in that it includes at least the following steps:
[0017] S1): The first vacuum chamber and the second vacuum chamber are evacuated using a vacuum pump set, and the vacuum level of the first vacuum chamber 51 is detected by a vacuum gauge 54.
[0018] S2): Heat the microreactor to the reaction temperature;
[0019] S3): The first pulse valve and the second pulse valve sequentially pulse different reaction gases into the microreactor, where they react with the sample;
[0020] S4): The gas reacting with the sample enters the first vacuum chamber surrounded by the annular liquid nitrogen chamber through the expansion tube, is ionized by the mass spectrometer filament, and is finally detected by mass spectrometry.
[0021] The pump-probe TAP instrument provided by this invention has the following beneficial effects:
[0022] 1) This invention achieves experiments with continuous or intermittent pulses, or pump-probe pulses, of one or two gas molecules by setting up a sample introduction pulse system, a microreactor, a liquid nitrogen cooling system, a mass spectrometry system, and a vacuum system, thereby obtaining surface chemistry and micro-dynamic information related to the elementary steps.
[0023] 2) By setting a first pulse valve and a second pulse valve, and forming an angle α between the first pulse valve and the second pulse valve, the present invention achieves independent control of two gas pulses, while shortening the gas passage volume, reducing the dead volume of the gas path, and ensuring a stable connection.
[0024] 3) The microreactor of this invention can achieve heating from room temperature to 1000℃. By setting spiral grooves and heating coils on the outer wall of the reactor, the heating coils can fit more tightly with the reactor during heating and expansion, which can improve heat utilization efficiency, reduce power output, and enhance the thermal stability of the reactor. This solves the problem of low heat utilization rate under high temperature conditions caused by the gradual increase in the distance between the heating wire and the reactor in currently commercially available TAP instruments during heating.
[0025] 4) The liquid nitrogen cooling system of the present invention can cool the area surrounded by the annular liquid nitrogen cavity in the first vacuum cavity. By setting an upper liquid level temperature sensor and a lower liquid level temperature sensor on the annular liquid nitrogen cavity, the temperature inside the annular liquid nitrogen cavity can be detected in real time, which can also indirectly detect the liquid level in the above-mentioned area. Then, by controlling the pump to pump in liquid nitrogen, the temperature of the above-mentioned area can be cooled.
[0026] 5) The reactor of the present invention is made of stainless steel and is coated with a quartz coating on the inner wall of the reactor, which solves the problem of non-inertia of stainless steel reactors at high temperatures.
[0027] 6) The present invention sets an electromagnetic signal shielding mesh at the top of the annular liquid nitrogen chamber, which can isolate the electromagnetic signal generated during heating from the influence of mass spectrometry data acquisition, reduce background noise, and thus achieve a clear mass spectrometry response signal at the minimum current amplification factor.
[0028] 7) The vacuum pump set of the present invention adopts three pumps in series, which can increase the compression ratio of small molecule gas while ensuring pumping speed and vacuum degree. At the same time, the use of two molecular pumps can avoid the risk of vacuum silicone oil contamination caused by using diffusion pumps, which affects the life of mass spectrometer. Attached Figure Description
[0029] Figure 1 is a schematic diagram of the overall structure of the present invention and a partially enlarged cross-sectional view thereof.
[0030] Figure 2 is a cross-sectional view of the microreactor and sample injection pulse system of the present invention.
[0031] Figure 3 is a cross-sectional view of the first vacuum chamber, microreactor, and sample injection pulse system of the present invention.
[0032] Figure 4 is a schematic diagram of the structure of the annular liquid nitrogen cavity of the present invention.
[0033] Figure 5 is a cross-sectional schematic diagram of the annular liquid nitrogen cavity of the present invention.
[0034] Figure 6 is a schematic diagram of the pulse flange and condensate pipeline channel of the present invention.
[0035] Figure 7 is a top view of the pulse flange and condensate pipe passage of the present invention.
[0036] The attached diagram shows the sample injection pulse system: 1. Pulse flange; 11. Pulse channel; 12. First branch channel; 12.1 Second branch channel; 12.2 Converging channel; 12.3 First pulse valve; 13. Second pulse valve; 14. Condensate pipeline channel; 15. Microreactor; 2. Insulation layer; 21. Reactor body; 22. Reaction channel; 22.1 Spiral groove; 22.2 Heating coil.3 Expansion tube 24 Liquid nitrogen cooling system 3 Annular liquid nitrogen chamber 31 Upper liquid level temperature sensor 32 Lower liquid level temperature sensor 33 Liquid nitrogen pipeline 34 Mass spectrometer quadrupole through hole 35 Mass spectrometry system 4 Mass spectrometer 41 Mass spectrometer filament 42 Electromagnetic signal shielding mesh 43 Vacuum system 5 First vacuum chamber 51 Second vacuum chamber 52 Vacuum pump assembly 53 First molecular pump 53.1 Second molecular pump 53.2 Mechanical pump 53.3 Vacuum gauge 54. Detailed Implementation
[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. In the description of the present invention, it should be noted that the terms "left side", "right side", "upper side", "lower side", "above", "below", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0038] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0039] Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.
[0040] This invention provides a pump-probe TAP instrument, referring to Figure 1, comprising a sample introduction pulse system 1, a microreactor 2, a liquid nitrogen cooling system 3, a mass spectrometry system 4, and a vacuum system 5. The vacuum system 5 includes a first vacuum chamber 51, a second vacuum chamber 52, and a vacuum pump assembly 53 connected in sequence. A vacuum gauge 54 with its working end extending into its inner cavity is provided on the side wall of the first vacuum chamber 51. The second vacuum chamber 52 may or may not have a vacuum gauge 54 installed on its side wall, depending on the actual situation. The working end of the vacuum gauge 54 is its vacuum detection probe. The body of the vacuum gauge 54 is located on the side wall of the first vacuum chamber 51, and the vacuum detection probe passes through the side wall of the first vacuum chamber 51 to enter its inner cavity. Therefore, the vacuum gauge 54 can detect the vacuum level of the first vacuum chamber 51. The second vacuum chamber 52 is similarly constructed. The liquid nitrogen cooling system 3 includes an annular liquid nitrogen chamber 31 located within the first vacuum chamber 51. The sample introduction pulse system 1 includes a pulse flange 11 located at the top of the first vacuum chamber 51. The pulse flange 11 houses a first pulse valve 13 and a second pulse valve 14, forming an angle α between them. The pulse flange 11 also includes a condensate pipe channel 15 for loading a condensate pipe. During the use of the first pulse valve 13 and the second pulse valve 14, the temperature of the pulse flange 11 rises sharply, and the condensate pipe helps to cool the pulse flange 11. The microreactor 2 is located at the bottom of the pulse flange 11. The pulse flange 11 also includes a pulse channel 12. The first pulse valve 13 and the second pulse valve 14 are connected to the top of the microreactor 2 through the pulse channel 12. The microreactor 2 is suitable for loading samples. The mass spectrometry system 4 includes a mass spectrometer 41 located on the side wall of the first vacuum chamber 51. The mass spectrometer filament 42 extends to the center of the first vacuum chamber 51. The bottom of the microreactor 2 is also provided with an extension tube 24 extending towards and above the mass spectrometer filament 42, typically located a few millimeters vertically above the filament. For illustration, the first vacuum chamber 51 and the second vacuum chamber 52 are usually connected by a flange, and a vacuum valve is provided between them. During the sample removal process after a test, the first vacuum chamber 51 and the second vacuum chamber 52 will inevitably be evacuated, requiring re-evacuation for the next experiment. The vacuum valve can be closed after a test, isolating the first vacuum chamber 51 and the second vacuum chamber 52, thus preventing the second vacuum chamber 52 from being evacuated, effectively reducing the evacuation time for the next test, and improving the efficiency of continuous sample testing with this device.Through the above-described configuration, this invention enables experiments involving continuous or intermittent pulses, or pump-probe pulses, of one or two types of gas molecules, thereby obtaining surface chemistry and microdynamic information related to the elementary steps. As a supplementary explanation, both the first vacuum chamber 51 and the second vacuum chamber 52 are equipped with vacuum gauges 54 extending into the inner cavity from their working ends. These vacuum gauges 54 can detect whether the vacuum level in the first vacuum chamber 51 and the second vacuum chamber 52 meets the required standard.
[0041] In the pump-probe TAP instrument provided by this invention, referring to Figure 2, the included angle α between the first pulse valve 13 and the second pulse valve 14 is 30–150°, preferably 60–120°. Further, the first pulse valve 13 and the second pulse valve 14 are arranged symmetrically in a V-shape, and the first pulse valve 13, the second pulse valve 14, and the pulse channel 12 are arranged in a Y-shape. Through the above arrangement, this invention achieves independent control of two gas pulses, while simultaneously shortening the gas flow volume, reducing the dead volume of the gas path, and ensuring a stable connection.
[0042] In the pump detection TAP instrument provided by the present invention, a sealing element is provided between the pulse flange 11 and the microreactor 2, and the sealing element can be an O-ring.
[0043] The pump-probe TAP instrument provided by the present invention also includes a control module, which is connected to the sample injection pulse system 1, the microreactor 2, the liquid nitrogen cooling system 3, the mass spectrometry system 4 and the vacuum system 5 via circuits.
[0044] In the pump detection TAP instrument provided by this invention, referring to Figures 1, 4, and 5, the annular liquid nitrogen chamber 31 is filled with liquid nitrogen to condense water molecules entering the first vacuum chamber 51. The liquid nitrogen cooling system 3 also includes an upper liquid level temperature sensor 32 located on the upper part of the outer wall of the annular liquid nitrogen chamber 31 and a lower liquid level temperature sensor 33 located on the lower part of the outer wall of the annular liquid nitrogen chamber 31. The sensing ends of the upper liquid level temperature sensor 32 and the lower liquid level temperature sensor 33 are both located inside the annular liquid nitrogen chamber 31. For illustration, the upper liquid level temperature sensor 32 is used to detect the temperature at the upper part of the annular liquid nitrogen chamber 31, and the lower liquid level temperature sensor 33 is used to detect the temperature at the lower part of the annular liquid nitrogen chamber 31. Typically, the upper liquid level temperature sensor 32, the lower liquid level temperature sensor 33, and the pump are all connected to a control module or host computer via circuitry. During use, the host computer or control module can acquire the temperature T1 fed back by the upper liquid level temperature sensor 32 and the temperature T2 fed back by the lower liquid level temperature sensor 33 in real time, and obtain the temperature difference ΔT, wherein the temperature difference ΔT = T2 - T1. When the temperature difference ΔT exceeds the temperature threshold T... θWhen the host computer or control module sends a start signal to the pump body, the pump body receives the signal and continuously pumps liquid nitrogen into the annular liquid nitrogen chamber 31 through the liquid nitrogen pipeline 34, causing the temperature in the annular liquid nitrogen chamber 31 to drop; until the temperature difference ΔT is lower than the temperature threshold T. θ When the pump stops, the host computer or control module sends a stop signal to the pump body, and the pump body stops pumping liquid nitrogen.
[0045] In the pump-probe TAP instrument provided by this invention, referring to Figure 3, the top of the annular liquid nitrogen chamber 31 is provided with an electromagnetic signal shielding mesh 43. The electromagnetic signal shielding mesh 43 can isolate the background noise affecting the mass spectrometer 41 data acquisition caused by the electromagnetic signal generated during heating, and can achieve a clear mass spectrometer 41 response signal at the minimum current amplification factor. For illustration, the mass spectrometry system 4 also includes a mass spectrometry data acquisition system capable of receiving and processing the data acquired by the mass spectrometer 41, wherein the mass spectrometer 41 is preferably a quadrupole mass spectrometer. Further, the annular liquid nitrogen chamber 31 is also provided with a quadrupole mass spectrometer through-hole 35, allowing the quadrupole of the mass spectrometer 4 to pass through the quadrupole mass spectrometer through-hole 35 into the first vacuum chamber 51, and ensuring that the mass spectrometer filament 42 located at the front end of the quadrupole is at the center of the first vacuum chamber 51 and surrounded by the annular liquid nitrogen chamber 31.
[0046] In the pump-probe TAP instrument provided by this invention, the expansion tube 24, as the outlet pipe for the reactant gas, typically needs to have a suitable length and inner diameter. The length of the expansion tube 24 is 10–200 mm, preferably 10–100 mm, and the inner diameter is 2–100 mm, preferably 5–20 mm. The first pulse valve 13 and the second pulse valve 14, when providing gas pulse signals, typically need to have suitable pulse widths and pulse frequencies. The pulse widths of both the first pulse valve 13 and the second pulse valve 14 are 5–500 μs, preferably 10–150 μs, and the pulse frequencies are both 1–50 times / s. The first vacuum chamber 51, the second vacuum chamber 52, and the annular liquid nitrogen chamber 31 typically need to have suitable height, inner diameter, and wall thickness. The inner diameter of the first vacuum chamber 51 is 200–1000 mm, preferably 100–500 mm; its height is 50–1500 mm, preferably 200–1000 mm; and its wall thickness is 1–200 mm, preferably 5–50 mm. The inner diameter of the second vacuum chamber 52 is 20–1000 mm, preferably 100–500 mm. The height is 50-1000mm, preferably 100-500mm, and the wall thickness is 1-200mm, preferably 5-50mm; the inner ring diameter of the annular liquid nitrogen cavity 31 is 100-1000mm, preferably 100-500mm, the outer ring diameter is 120-1200mm, preferably 150-600mm, the height is 50-1000mm, preferably 100-300mm, and the wall thickness of both the outer and inner rings is 1-100mm, preferably 5-50mm.
[0047] In the pump-probe TAP instrument provided by this invention, referring to Figure 2, the microreactor 2 body includes an insulation layer 21 and a reactor body 22 disposed inside the insulation layer 21. The insulation layer 21 prevents significant temperature loss during the reaction process, while the reactor body 22 serves as the reaction site for the gas. The reactor body 22 has a vertically penetrating reaction channel 22.1, suitable for loading samples. A first pulse valve 13 and a second pulse valve 14 are connected to the inlet of the reaction channel 22.1 via a pulse channel. The outlet of the reaction channel 22.1 is equipped with an expansion tube 24. Multiple spiral grooves 22.2 are provided on the outer wall of the reactor body 22. Heating coils 22.3 are installed in the spiral grooves 22.2, which can heat the reactor body 22. Currently, in commercially available TAP instruments, the distance between the heating wire and the reactor body 22 gradually increases during heating, resulting in low heat utilization efficiency under high-temperature conditions. The aforementioned design allows the heating coil 22.3 to fit more tightly against the reactor body 22 during heating and expansion, improving heat utilization efficiency, reducing power output, and enhancing the thermal stability of the reactor body 22. For illustration, the microreactor 2 typically includes a heating program that can raise the temperature of the microreactor to 1000°C via the heating coil 22.3. The heating rate and mode can be determined by the operator based on actual conditions. For illustration, the reactor body 22 has an inner diameter of 2–50 mm, preferably 2–10 mm, an outer diameter of 20–500 mm, preferably 20–100 mm, and a height of 20–500 mm, preferably 50–100 mm.
[0048] Furthermore, a catalyst is also provided in the reaction channel 22.1, with a catalyst loading range of 5–500 mg. The reactor can be made of stainless steel, and the inner wall of the reactor is coated with a quartz coating. The stainless steel material increases the stability of the reactor, while the quartz coating solves the problem of non-inertia of the stainless steel reactor at high temperatures. The thickness of the quartz coating is 10–500 nm. The insulation layer 21 can be a hollow cylinder made of stainless steel. Generally, the spiral groove 22.2 needs to be deep enough to accommodate the heating coil 22.3, and the depth of the spiral groove 22.2 is 0.1–5 mm. The heating coil 22.3 typically needs a certain heating capacity to ensure that the sample in the reaction channel 22.1 is heated to the reaction temperature, and the heating temperature range of the heating coil 22.3 is 25–1000 °C.
[0049] In the pump-probe TAP instrument provided by this invention, referring to Figure 2, the pulse channel 12 includes a first branch channel 12.1, a second branch channel 12.2, and a converging channel 12.3. The air inlet of the first branch channel 12.1 is connected to the first pulse valve 13, and the air inlet of the second branch channel 12.2 is connected to the second pulse valve 14. Further, the air outlets of the first branch channel 12.1 and the second branch channel 12.2 are both connected to the air inlet of the converging channel 12.3, and the air outlet of the converging channel 12.3 is connected to the air inlet of the reaction channel 22.1. An angle β is formed between the first branch channel 12.1 and the second branch channel 12.2, with an angle β of 30–150°, preferably 60–120°. Generally, the angles α and β are the same. The overall shape of the pulse channel 12 is Y-shaped.
[0050] Furthermore, the first branching channel 12.1, the second branching channel 12.2, and the converging channel 12.3 typically need to have sufficient length. The lengths of the first branching channel 12.1 and the second branching channel 12.2 can be 2–20 mm, preferably 5–10 mm; the inner diameters of the first branching channel 12.1 and the second branching channel 12.2 can be 0.05–2 mm, preferably 0.1–1 mm; the length of the converging channel 12.3 can be 0.1–10 mm, preferably 0.5–3 mm; the inner diameter of the converging channel 12.3 can be 0.05–5 mm, preferably 0.1–3 mm.
[0051] The pump detection TAP instrument provided by this invention, referring to Figure 1, includes a vacuum pump assembly 53 comprising a first molecular pump 53.1, a second molecular pump 53.2, and a mechanical pump 53.3 connected in sequence. The first molecular pump 53.1, the second molecular pump 53.2, and the mechanical pump 53.3 are all connected via vacuum flanges and vacuum bellows. Generally, the first molecular pump 53.1 has a higher pumping speed than the second molecular pump 53.2, while the second molecular pump 53.2 has a lower pumping speed but a higher rotational speed than the first molecular pump 53.1. The mechanical pump 53 is a dry pump. The vacuum pump assembly 53 ensures both pumping speed and vacuum level while increasing the compressibility of small molecule gases, and avoids the risk of vacuum silicone oil contamination caused by diffusion pumps, which could affect the lifespan of the mass spectrometer 41. Furthermore, the first molecular pump 53.1 can be a Pfaff 2300, Pfaff 700, or Pfaff 300, etc., and the second molecular pump 53.2 can be a Pfaff 30 or Pfaff 80, etc. When the vacuum pump assembly 53 is working, it can maintain the vacuum level of the first vacuum chamber 51 and the second vacuum chamber 52 at 10. -7 ~10 -10 mbar.
[0052] The present invention also provides a method for using a pump-probe TAP instrument, as detailed below:
[0053] S1): Vacuum pump assembly 53 is used to evacuate the first vacuum chamber 51 and the second vacuum chamber 52. Vacuum gauge 54 is used to detect the vacuum level in the first vacuum chamber 51. If a vacuum gauge 54 is also installed in the second vacuum chamber 52, the vacuum level in the second vacuum chamber 52 is also detected simultaneously. Further, the first vacuum chamber 51 and / or the second vacuum chamber 52 are evacuated by connecting the first molecular pump 53.1, the second molecular pump 53.2, and the mechanical pump 53.3 in series, and the vacuum level is maintained at 10. -7 ~10 -10 mbar.
[0054] S2): The temperature of the microreactor 2 is heated to the reaction temperature. Further, the temperature of the reactor body 22 is heated to the reaction temperature using a heating coil 22.3. Typically, the heating program controls the heating rate and mode of the reactor body 22. While the heating coil 22.3 is heating the reactor body 22, the temperature of the sample in the reaction channel 22.1 also increases. The temperature of the reactor body 22 can be detected by embedding thermocouples in the side wall of the reactor body 22, thus ensuring that the sample is heated to the reaction temperature.
[0055] S3): The first pulse valve 13 and the second pulse valve 14 sequentially pulse different reaction gases into the microreactor 2, where they react with the sample. Further, the two pulsed gases converge into the main channel 12.3 via the first branch channel 12.1 and the second branch channel 12.2, and then enter the reaction channel 22.1 in the reactor body 22 to react with the sample. Simultaneously, the condensate pipe cools the pulse flange 11.
[0056] S4): The gas reacting with the sample enters the first vacuum chamber 31, which is surrounded by the annular liquid nitrogen chamber 31, through the expansion tube 24, and is detected by the mass spectrometer filament 42. Further, the gas carrying product molecules after reacting with the sample in step S3) contacts the mass spectrometer filament 42 through the expansion tube 24 to obtain the corresponding mass spectrometer signal 41. Water molecules that may be contained in the product molecules condense on the inner wall of the annular liquid nitrogen chamber 31, while other gas molecules that do not condense diffuse into the second vacuum chamber 52 and are extracted by the vacuum pump assembly 53.
[0057] Example 1
[0058] Pump-probe experiment
[0059] Before testing: Use vacuum pump assembly 53 to evacuate the first vacuum chamber 51 and the second vacuum chamber 52 to a vacuum level of 10. -7 ~10 -10 mbar, and then the sample is heated to the desired reaction temperature by heating coil 22.3.
[0060] During testing: The first pulse valve 13 pulses a certain amount of small gas molecules (such as H2, CO2, CO, CH4, etc.) (pump molecules) onto the sample surface, and the peak shape of the exit pulse is detected by the mass spectrometry system 4. Next, the second pulse valve 14 pulses a probe molecule (such as low-carbon alkanes) to detect the effect of the chemical changes on the sample surface induced by the pump molecule on the activation and reaction of the probe molecule. The delay between the two pulses can be adjusted by changing the time difference between them, thereby studying the dynamic changes of matter at different time scales and obtaining information about active sites and elementary reaction kinetics.
[0061] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.
Claims
1. A pump-probe TAP instrument, characterized in that: It includes a sample introduction pulse system (1), a microreactor (2), a liquid nitrogen cooling system (3), a mass spectrometry system (4), and a vacuum system (5); The vacuum system (5) includes a first vacuum chamber (51), a second vacuum chamber (52) and a vacuum pump group (53) connected in sequence. The first vacuum chamber (51) has a vacuum gauge (54) with its working end extending into its inner cavity on its side wall. The liquid nitrogen cooling system (3) includes an annular liquid nitrogen chamber (31) located in the first vacuum chamber (51). The sample injection pulse system (1) includes a pulse flange (11) located at the top of the first vacuum chamber (51), and a first pulse valve (13) and a second pulse valve (14) are provided in the pulse flange (11), with an included angle α between the first pulse valve (13) and the second pulse valve (14); the pulse flange (11) is also provided with a condensate pipe channel (15) for loading condensate pipes; The microreactor (2) is located at the bottom of the pulse flange (11), and the pulse flange (11) is also provided with a pulse channel (12). The first pulse valve (13) and the second pulse valve (14) are connected to the top of the microreactor (2) through the pulse channel (12). The microreactor (2) is suitable for loading samples. The mass spectrometry system (4) includes a mass spectrometer (41), which is located on the side wall of the first vacuum chamber (51). The mass spectrometer filament (42) of the mass spectrometer (41) extends to the center of the first vacuum chamber (51). The bottom of the microreactor (2) is also provided with an extension tube (24) extending towards the mass spectrometer filament (42) and located above the mass spectrometer filament (42).
2. The pump detection TAP instrument according to claim 1, characterized in that: The microreactor (2) includes a heat insulation layer (21) and a reactor body (22) disposed inside the heat insulation layer (21). The reactor body (22) is provided with a reaction channel (22.1) that runs vertically through it. The reaction channel (22.1) is suitable for loading the sample. The first pulse valve (13) and the second pulse valve (14) are connected to the air inlet of the reaction channel (22.1) through the pulse channel (12), and the air outlet of the reaction channel (22.1) is connected to the expansion pipe (24); a spiral groove (22.2) is provided on the outer wall of the reactor body (22), and a heating coil (22.3) is provided in the spiral groove (22.2).
3. The pump detection TAP instrument according to claim 1 or 2, characterized in that: The pulse channel (12) includes a first branch channel (12.1), a second branch channel (12.2), and a convergence channel (12.3); The air inlet of the first branch channel (12.1) is connected to the first pulse valve (13), and the air inlet of the second branch channel (12.2) is connected to the second pulse valve (14); the air outlets of the first branch channel (12.1) and the second branch channel (12.2) are both connected to the air inlet of the converging channel (12.3), and the air outlet of the converging channel (12.3) is connected to the air inlet of the reaction channel (22.1); an angle β is formed between the first branch channel (12.1) and the second branch channel (12.2).
4. The pump detection TAP instrument according to claim 3, characterized in that: The included angle α is 30 to 150°; and / or, the included angle β is 30 to 150°; and / or, the included angle α and the included angle β are the same.
5. The pump detection TAP instrument according to claim 1, characterized in that: The liquid nitrogen cooling system (3) further includes an upper liquid level temperature sensor (32) located on the upper part of the outer wall of the annular liquid nitrogen cavity (31) and a lower liquid level temperature sensor (33) located on the lower part of the outer wall of the annular liquid nitrogen cavity (31). The sensing ends of the upper liquid level temperature sensor (32) and the lower liquid level temperature sensor (33) are both located in the inner cavity of the annular liquid nitrogen cavity (31).
6. The pump detection TAP instrument according to claim 1, characterized in that: It also includes a control module, which is connected to the sample injection pulse system (1), the microreactor (2), the liquid nitrogen cooling system (3), the mass spectrometry system (4) and the vacuum system (5) via circuitry.
7. The pump detection TAP instrument according to claim 1, characterized in that: The top of the annular liquid nitrogen cavity (31) is provided with an electromagnetic signal shielding mesh (43); And / or, the vacuum pump assembly (53) includes a first molecular pump (53.1), a second molecular pump (53.2), and a mechanical pump (53.3) connected in sequence; And / or, a vacuum valve is provided between the first vacuum chamber (51) and the second vacuum chamber (52); And / or, a seal is provided between the pulse flange (11) and the microreactor (2); And / or, the mass spectrometer (41) is a quadrupole mass spectrometer; And / or, the second vacuum chamber (52) is also provided with a vacuum gauge (54) whose working end extends into its inner cavity.
8. The pump detection TAP instrument according to claim 4, characterized in that: The first vacuum chamber (51) has an inner diameter of 200-1000 mm, a height of 50-1500 mm, and a wall thickness of 1-200 mm; and / or, the second vacuum chamber (52) has an inner diameter of 20-1000 mm, a height of 50-500 mm, and a wall thickness of 1-100 mm. And / or, the inner ring diameter of the annular liquid nitrogen cavity (31) is 100-1000 mm, the outer ring diameter is 120-1200 mm, the height is 50-1000 mm, and the wall thickness of both the outer and inner rings is 1-100 mm. And / or, the vacuum level of both the first vacuum chamber (51) and the second vacuum chamber (52) is 10. -7 ~10 -10 mbar; And / or, the pulse widths of the first pulse valve (13) and the second pulse valve (14) are both 5 to 500 μs; And / or, the pulse frequency of the first pulse valve (13) and the second pulse valve (14) is 1 to 50 times / s; And / or, the length of the first branch channel (12.1) and the second branch channel (12.2) are both 2 to 20 mm, and the inner diameter is both 0.05 to 2 mm.
9. [Corrected according to Rule 91, 10.06.2025] The pump detection TAP instrument according to claim 2 is characterized in that: The reactor body (22) is made of stainless steel; And / or, the inner diameter of the reactor body (22) is 2 to 50 mm; And / or, the inner wall of the reactor body (22) is coated with a quartz coating, the thickness of which is 10 to 500 nm; And / or, the depth of the spiral groove (22.2) is 0.1 to 5 mm; And / or, the heating temperature range of the heating coil (22.3) is 25 to 1000°C; And / or, the length of the expansion tube (24) is 10 to 200 mm and the inner diameter is 2 to 100 mm.
10. A method of using the pump detection TAP instrument as described in claims 1 to 9, characterized in that, At least the following steps are included: S1): Vacuum pump assembly (53) is used to evacuate the first vacuum chamber (51) and the second vacuum chamber (52), and the vacuum level of the first vacuum chamber (51) is detected by vacuum gauge (54). S2): Heat the temperature of the microreactor (2) to the reaction temperature; S3): The first pulse valve (13) and the second pulse valve (14) sequentially pulse different reaction gases into the microreactor (2) and react with the sample; S4): The gas reacting with the sample enters the first vacuum chamber (51) surrounded by the annular liquid nitrogen chamber (31) through the expansion tube (24), and is ionized by the mass spectrometer filament (42) and finally detected by the mass spectrometer (41).