Pump detection TAP instrument

Abstract

The invention provides a pumping detection TAP instrument, and relates to the field of transient dynamics and catalytic surface and interface research. The pumping detection TAP instrument provided by the invention comprises a sample injection pulse system, a micro reactor, a liquid nitrogen cooling system, a mass spectrum system and a vacuum system. Through the arrangement, the experiment of continuous pulse or intermittent pulse or pump-probe pulse of one or two gas molecules can be realized, so that surface chemistry and microdynamics information related to element steps can be obtained.

Description

Technical Field

[0001] The invention relates to the field of transient dynamics and catalytic surface interface research, in particular to a pump-probe TAP instrument. Background Art

[0002] Early understanding of catalytic reaction processes was mainly based on the analysis and simulation of apparent reaction kinetics, which made it difficult to reveal the reaction mechanism of the catalytic process, to correlate the quantitative relationship between catalyst active sites and catalytic performance, and to obtain information on reaction intermediates related to elementary reactions. Intrinsic reaction kinetics analysis is based on elementary reactions, and studies the surface and interface chemistry related to catalytic reactions at the microscopic level, establishes the relationship between the chemical properties of the catalyst and the catalyst's reaction activity, and clarifies the key factors that affect catalytic performance, thereby guiding the design and creation of catalysts.

[0003] During the catalytic reaction, the catalyst is in a dynamic change process. The complexity of the catalyst surface structure and the diversity of active sites, the adsorption of gas molecules on the catalyst surface during the reaction, and the mass transfer and heat transfer during the catalytic reaction directly affect the understanding of the laws of catalytic chemical reactions. Conventional steady-state experimental analysis is difficult to obtain information related to elementary reactions, so it is difficult to provide theoretical support for the design of catalysts. Transient experiments can provide more mechanism information about the reaction intermediates and pathways of elementary steps. Among them, the product transient analysis technology (Temporal Analysis of Products, TAP) is to inject a trace amount of reaction gas (for example, as small as 0.01nmol) into a micro-reaction tube containing a catalyst, and use a high-time-resolved mass spectrometer at the end of the micro-reaction tube to detect the transient response of the gas (including reactants and products) leaving the catalyst bed in real time. The TAP technology uses a high-frequency pulse solenoid valve to generate a pulse width that can be reduced to less than 10 microseconds, so that information such as the order of elementary reaction steps and their kinetic constants can be obtained.

[0004] At present, there are a series of major problems in commercial TAP instruments, such as: the dead volume between the pulse valve and the micro-reaction tube is too large and the diffusion resistance is large, the connection between the pulse flange and the pulse valve is prone to leakage, and the amount of gas pulse each time is unstable; when working in a high-temperature environment, the quartz reactor often breaks, the connected O-coil is damaged, or the stainless steel reactor is chemically inert, the heating coil has a short service life, is easy to break, or it is difficult to achieve heating above 600°C; the mass spectrometry signal noise is large; the design of too many O-coils leads to a high system failure rate and low vacuum degree; the use of a diffusion pump + manual injection of liquid nitrogen cooling to achieve high vacuum can easily cause the vacuum chamber and the mass spectrometry secondary electron multiplier tube to be contaminated by oil droplets in the diffusion pump, thereby destroying the mass spectrometry performance, etc.; due to the manual addition of liquid nitrogen, the pulse experiment cannot be automatically and continuously carried out for a long time.

[0005] In summary, there is an urgent need for a pulse system that has a gas channel, is small in size and can ensure stable connection, a reactor that is chemically inert and has high thermal stability, can obtain a clear mass spectrometry response signal, and a high vacuum pump-detection TAP instrument. Summary of the invention

[0006] In order to solve the above problems, the present invention provides a pump-probe TAP instrument, which can realize continuous pulse or intermittent pulse or pump-probe pulse experiments of one or two gas molecules, thereby obtaining surface chemical and microscopic dynamics information related to the elementary steps.

[0007] The first aspect of the present invention provides a pump-detection TAP instrument, comprising a sampling pulse system, a microreactor, a liquid nitrogen cooling system, a mass spectrometer system and a vacuum system; the vacuum system comprises a first vacuum chamber, a second vacuum chamber and a vacuum pump group connected in sequence; a vacuum gauge with a working end extending into the inner cavity of the first vacuum chamber is provided on the side wall of the first vacuum chamber; the liquid nitrogen cooling system comprises an annular liquid nitrogen chamber arranged in the first vacuum chamber; the sampling pulse system comprises a pulse flange arranged at the top of the first vacuum chamber, a first pulse valve and a second pulse valve are provided in the pulse flange, and the first pulse valve and the second pulse valve are connected to each other. An angle α is formed between the pulse valves; the pulse flange is also provided with a condensate pipeline channel for loading the condensate pipeline; the microreactor is arranged 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, and the mass spectrometer is arranged on the side wall of the first vacuum cavity, and the mass spectrometer filament of the mass spectrometer extends to the center of the first vacuum cavity; the bottom of the microreactor is also provided with an extension tube extending toward the mass spectrometer filament and located above the mass spectrometer filament.

[0008] In a feasible embodiment, the microreactor includes an insulation layer and a reactor body arranged inside the insulation layer, the reactor body is provided with a reaction channel running through from top to bottom, and the reaction channel is suitable for loading samples; the first pulse valve and the second pulse valve are connected to the air inlet of the reaction channel through the pulse channel, and the air outlet of the reaction channel is connected to the extension tube; a spiral groove is provided on the outer wall of the reactor body, and a heating coil is provided in the spiral groove.

[0009] In a feasible embodiment, the pulse channel includes a first bifurcated channel, a second bifurcated channel and a converging channel; the air inlet of the first bifurcated channel is connected to the first pulse valve, and the air inlet of the second bifurcated channel is connected to the second pulse valve; the air outlet of the first bifurcated channel and the air outlet of the second bifurcated 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 bifurcated channel and the second bifurcated channel.

[0010] In a feasible implementation manner, the angle α is 30-150°; and / or the angle β is 30-150°; and / or the angle α and the angle β are the same.

[0011] In a feasible embodiment, the liquid nitrogen cooling system further includes an upper liquid level temperature sensor disposed on the upper portion of the outer wall of the annular liquid nitrogen cavity and a lower liquid level temperature sensor disposed on the lower portion of the outer wall of the annular liquid nitrogen cavity, and 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 a feasible implementation manner, it further includes a control module, which is connected to the injection pulse system, the microreactor, the liquid nitrogen cooling system, the mass spectrometry system and the vacuum system through a circuit.

[0013] In some feasible embodiments, an electromagnetic signal shielding net is provided on the top of the annular liquid nitrogen chamber; and / or the vacuum pump group 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 a working end extending into its inner cavity is also provided on the side wall of the second vacuum chamber.

[0014] In one feasible implementation, the inner diameter of the first vacuum cavity 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 cavity 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 cavity 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 degree of the first vacuum cavity and the second vacuum cavity 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 bifurcated channel and the second bifurcated channel are both 2 to 20 mm, and the inner diameter is both 0.05 to 2 mm.

[0015] In one feasible embodiment, the material of the reactor body is 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, and the thickness of the quartz coating 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 is 25 to 1000° C.; and / or the length of the extension tube is 5 to 200 mm, and the inner diameter is 2 to 100 mm.

[0016] The second aspect of the present invention provides a method for using the pump-probe TAP instrument provided in the first aspect of the present invention, characterized in that it comprises at least the following steps:

[0017] S1): evacuating the first vacuum cavity and the second vacuum cavity by using a vacuum pump group, and detecting the vacuum degree of the first vacuum cavity 51 by using a vacuum gauge 54;

[0018] S2): heating the temperature of 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 to react with the sample;

[0020] S4): The gas after reacting with the sample enters into the first vacuum chamber surrounded by the annular liquid nitrogen chamber through the extension tube, and is ionized by the mass spectrometer filament, and finally detected by the mass spectrometer.

[0021] The present invention provides a pump-probe TAP instrument, which has the following beneficial effects:

[0022] 1) The present invention realizes the experiment of continuous pulse or intermittent pulse or pump-probe pulse of one or two gas molecules by setting up a sampling pulse system, a microreactor, a liquid nitrogen cooling system, a mass spectrometer system and a vacuum system, thereby obtaining surface chemical and microscopic dynamic information related to the elementary steps.

[0023] 2) The present invention realizes the separate control of two gas pulses 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, while being able to shorten the gas passing volume, reduce the dead volume of the gas path and ensure stable connection.

[0024] 3) The microreactor of the present invention can achieve a temperature rise from room temperature to 1000°C, and by setting a spiral groove and a heating coil on the outer wall of the reactor, the heating coil can fit more closely with the reactor when heated and expanded, which can improve the heat utilization efficiency, reduce power output, and enhance the thermal stability of the reactor. This solves the problem that the distance between the heating wire and the reactor gradually increases during heating in the current commercial TAP instrument, resulting in low heat utilization under high temperature conditions.

[0025] 4) The liquid nitrogen cooling system of the present invention can cool down the area surrounded by the annular liquid nitrogen cavity in the first vacuum cavity. By arranging an upper liquid level temperature sensor and a lower liquid level temperature sensor on the annular liquid nitrogen cavity, the temperature in the inner cavity of the annular liquid nitrogen cavity can be detected in real time, and the liquid level of the above-mentioned area can be indirectly detected, and then the temperature of the above-mentioned area can be cooled down by controlling the pump body to pump in liquid nitrogen.

[0026] 5) The reactor of the present invention is made of stainless steel, and a quartz coating is plated on the inner wall of the reactor, which solves the problem of the stainless steel reactor being inert at high temperatures.

[0027] 6) The present invention arranges an electromagnetic signal shielding net on the top of the annular liquid nitrogen chamber, which can isolate the influence of the electromagnetic signal generated during heating on the mass spectrometry data acquisition and reduce the background noise, thereby achieving a clear mass spectrometry response signal at the minimum current amplification factor.

[0028] 7) The vacuum pump group of the present invention adopts three pumps in series, which can increase the compression rate of small molecule gases while ensuring the 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 the use of diffusion pumps, which affects the life of the mass spectrometer. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the overall structure of the present invention and a partially enlarged cross-sectional diagram thereof.

[0030] Figure 2 It is a cross-sectional view of the microreactor and injection pulse system of the present invention.

[0031] Figure 3 It is a cross-sectional view of the first vacuum chamber, microreactor and injection pulse system of the present invention.

[0032] Figure 4 It is a schematic diagram of the structure of the annular liquid nitrogen chamber of the present invention.

[0033] Figure 5 It is a cross-sectional schematic diagram of the annular liquid nitrogen chamber of the present invention.

[0034] Figure 6 It is a schematic diagram of the pulse flange and condensate water pipeline channel of the present invention.

[0035] Figure 7 It is a top view of the pulse flange and condensate water pipeline channel of the present invention.

[0036] Reference numerals

[0037] Injection pulse system 1

[0038] Pulse flange 11

[0039] Pulse channel 12

[0040] First bifurcation channel 12.1

[0041] Second bifurcation channel 12.2

[0042] Aggregate channel 12.3

[0043] First pulse valve 13

[0044] Second pulse valve 14

[0045] Condensate pipe channel 15

[0046] Microreactor 2

[0047] Insulation layer 21

[0048] Reactor body 22

[0049] Reaction channel 22.1

[0050] Spiral groove 22.2

[0051] Heating coil 22.3

[0052] Extension tube 24

[0053] Liquid nitrogen cooling system 3

[0054] Annular liquid nitrogen chamber 31

[0055] Upper liquid level temperature sensor 32

[0056] Lower liquid level temperature sensor 33

[0057] Liquid nitrogen pipeline 34

[0058] Mass spectrometer quadrupole through hole 35

[0059] Mass Spectrometry System 4

[0060] Mass Spectrum 41

[0061] Mass spectrometer filament 42

[0062] Electromagnetic signal shielding net 43

[0063] Vacuum system 5

[0064] The first vacuum chamber 51

[0065] The second vacuum chamber 52

[0066] Vacuum pump set 53

[0067] The first molecular pump 53.1

[0068] The second molecular pump 53.2

[0069] Mechanical pump 53.3

[0070] Vacuum gauge 54 DETAILED DESCRIPTION

[0071] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without creative work belong to the scope of protection of the present invention. In the description of the present invention, it should be noted that the orientation or position relationship indicated by the terms "left side", "right side", "upper side", "lower side", "above", "below" and the like is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0072] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0073] Furthermore, in the description of the present invention, unless otherwise specified, “plurality” means two or more.

[0074] The present invention provides a pump-probe TAP instrument, referring to Figure 1, including a sampling pulse system 1, a microreactor 2, a liquid nitrogen cooling system 3, a mass spectrometer system 4 and a vacuum system 5. The vacuum system 5 includes a first vacuum cavity 51, a second vacuum cavity 52 and a vacuum pump group 53 connected in sequence. A vacuum gauge 54 with a working end extending into its inner cavity is provided on the side wall of the first vacuum cavity 51. The side wall of the second vacuum cavity 52 can be provided with a vacuum gauge 54 according to actual conditions. The so-called working end of the vacuum gauge 54 is the vacuum detection probe of the vacuum gauge 54. The vacuum gauge 54 body is provided on the side wall of the first vacuum cavity 51, and the vacuum detection probe passes through the side wall of the first vacuum cavity 51 and enters the inner cavity of the first vacuum cavity 51. Therefore, the vacuum gauge 54 can detect the vacuum degree of the first vacuum cavity 51. The second vacuum cavity 52 and the first vacuum cavity 51 can be obtained in the same way. The liquid nitrogen cooling system 3 includes an annular liquid nitrogen cavity 31 provided in the first vacuum cavity 51. The injection pulse system 1 includes a pulse flange 11 disposed at the top of the first vacuum chamber 51, wherein the pulse flange 11 is provided with a first pulse valve 13 and a second pulse valve 14, wherein the first pulse valve 13 and the second pulse valve 14 form an angle α, and wherein the pulse flange 11 is also provided with a condensate pipeline channel 15 for loading the condensate pipeline. During the use of the first pulse valve 13 and the second pulse valve 14, the temperature of the pulse flange 11 will rise sharply, and the condensate pipeline plays a role in cooling the pulse flange 11. The microreactor 2 is disposed at the bottom of the pulse flange 11, wherein the pulse flange 11 is also provided with a pulse channel 12, wherein 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, and the microreactor 2 is suitable for loading samples. The mass spectrometer system 4 includes a mass spectrometer 41, wherein the mass spectrometer 41 is disposed on the side wall of the first vacuum chamber 51, and wherein 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 toward the mass spectrometer filament 42 and located above the mass spectrometer filament. Generally speaking, the extension tube 24 is located a few millimeters vertically above the mass spectrometer filament. As an illustration, the first vacuum chamber 51 and the second vacuum chamber 52 can usually be connected by a flange, and a vacuum valve is also provided between the first vacuum chamber 51 and the second vacuum chamber 52. In the process of taking out the sample after completing a test, the first vacuum chamber 51 and the second vacuum chamber 52 will inevitably be broken, resulting in the need to re-evacuate the next experiment. The vacuum valve can be closed after completing a test, isolating the first vacuum chamber 51 and the second vacuum chamber 52, thereby preventing the second vacuum chamber 52 from being broken, which can effectively reduce the vacuum time of the next test and improve the efficiency of the device when continuously testing samples. Through the above-mentioned arrangement, the present invention realizes the experiment of continuous pulse or intermittent pulse or pump-probe pulse of one or two gas molecules, thereby obtaining surface chemical and microscopic dynamic information related to the elementary steps.As a supplementary explanation, the side walls of the first vacuum cavity 51 and the second vacuum cavity 52 are both provided with a vacuum gauge 54 with a working end extending into the inner cavity, and the vacuum gauge 54 can detect whether the vacuum degree in the first vacuum cavity 51 and the second vacuum cavity 52 meets the standard.

[0075] In the pump-probe TAP instrument provided by the present invention, refer to Figure 2 , the 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 symmetrically arranged in a V shape as a whole, and the first pulse valve 13, the second pulse valve 14 and the pulse channel 12 are Y-shaped as a whole. Through the above arrangement, the present invention realizes the separate control of the two-way gas pulse, and can shorten the gas passing volume, reduce the dead volume of the gas path and ensure stable connection.

[0076] In the pump-probe TAP instrument provided by the present invention, a sealing member is provided between the pulse flange 11 and the microreactor 2, and the sealing member may be an O-ring.

[0077] The pump-probe TAP instrument provided by the present invention further comprises a control module, which is connected to the injection pulse system 1, the microreactor 2, the liquid nitrogen cooling system 3, the mass spectrometry system 4 and the vacuum system 5 through a circuit.

[0078] In the pump-probe TAP instrument provided by the present invention, refer to Figure 1 , Figure 4 and Figure 5 , the inner cavity of the annular liquid nitrogen cavity 31 is loaded with liquid nitrogen for condensing water molecules entering the first vacuum cavity 51; the liquid nitrogen cooling system 3 also includes an upper liquid level temperature sensor 32 arranged at the upper part of the outer wall of the annular liquid nitrogen cavity 31 and a lower liquid level temperature sensor 33 arranged at the lower part of the outer wall of the annular liquid nitrogen cavity 31, and 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. As an illustration, the upper liquid level temperature sensor 32 is used to detect the temperature of the upper part of the inner cavity of the annular liquid nitrogen cavity 31, and the lower liquid level temperature sensor 33 is used to detect the temperature of the lower part of the inner cavity of the annular liquid nitrogen cavity 31. Generally speaking, the upper liquid level temperature sensor 32, the lower liquid level temperature sensor 33 and the pump body are all connected to the control module or the host computer through a circuit. When in use, the host computer or control module can obtain 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 upper 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 cavity 31 through the liquid nitrogen pipeline 34, so that the temperature in the annular liquid nitrogen cavity 31 decreases; until the temperature difference ΔT is lower than the temperature threshold T θ When the upper computer or control module sends a stop signal to the pump body, the pump body stops pumping liquid nitrogen.

[0079] In the pump-probe TAP instrument provided by the present invention, continue to refer to Figure 3 , an electromagnetic signal shielding net 43 is provided on the top of the annular liquid nitrogen cavity 31, and the electromagnetic signal shielding net 43 can isolate the background noise influence of the electromagnetic signal generated during heating on the data acquisition of the mass spectrum 41, and can achieve a clear mass spectrum 41 response signal at the minimum current amplification factor. As an illustration, the mass spectrometry system 4 also includes a mass spectrometry data acquisition system that can receive and process the data collected by the mass spectrometry 41, and the mass spectrometry 41 is preferably a quadrupole mass spectrometer. Furthermore, a mass spectrometry quadrupole through hole 35 is also provided on the annular liquid nitrogen cavity 31, so that the mass spectrometry quadrupole of the mass spectrometry 4 can pass through the mass spectrometry quadrupole through hole 35 to enter the first vacuum cavity 51 and the mass spectrometry filament 42 located at the front end of the mass spectrometry quadrupole can be in the center of the first vacuum cavity 51 and surrounded by the annular liquid nitrogen cavity 31.

[0080] In the pump-probe TAP instrument provided by the present invention, the extension tube 24 as a pipeline for the outflow of the reaction gas usually needs to have a suitable length and inner diameter. The length of the extension tube 24 is 10 to 200 mm, preferably 10 to 100 mm, and the inner diameter is 2 to 100 mm, preferably 5 to 20 mm. The first pulse valve 13 and the second pulse valve 14 usually need to have a suitable pulse width and pulse frequency when providing a gas pulse signal. The pulse width of the first pulse valve 13 and the second pulse valve 14 are both 5 to 500 μs, preferably 10 to 150 μs, and the pulse frequency is 1 to 50 times / s. The first vacuum chamber 51, the second vacuum chamber 52 and the annular liquid nitrogen chamber 31 are usually required to have appropriate heights, inner diameters and wall thicknesses. The inner diameter of the first vacuum chamber 51 is 200-1000 mm, preferably 100-500 mm, the height is 50-1500 mm, preferably 200-1000 mm, and the 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 outer and inner ring wall thicknesses are both 1-100mm, preferably 5-50mm.

[0081] In the pump-probe TAP instrument provided by the present invention, refer to Figure 2The microreactor 2 body includes a heat preservation layer 21 and a reactor body 22 disposed inside the heat preservation layer 21. The heat preservation layer 21 can prevent a large amount of temperature loss during the reaction process, and the reactor body 22 serves as a reaction site for the gas. A reaction channel 22.1 is provided in the reactor body 22, which is connected from top to bottom. The reaction channel 22.1 is suitable for loading samples. 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, and an extension pipe 24 is provided at the air outlet of the reaction channel 22.1. A plurality of spiral grooves 22.2 are provided on the outer wall of the reactor body 22, and a heating coil 22.3 is provided in the spiral groove 22.2. The heating coil 22.3 can heat the reactor body 22. At present, when the commercial TAP instrument body 22 is heated, the distance between the heating wire and the reactor body 22 will gradually increase, resulting in low heat utilization under high temperature conditions. Then, through the above-mentioned setting, the heating coil 22.3 can be more closely attached to the reactor body 22 when heated and expanded, which can improve the utilization efficiency of heat, reduce power output, and enhance the thermal stability of the reactor body 22. As an illustration, the microreactor 2 is usually provided with a heating program, which can heat the temperature of the microreactor to 1000°C through the heating coil 22.3, and the heating rate and heating mode can be determined by the operator according to actual conditions. As an illustration, the inner diameter of the reactor body 22 is 2 to 50 mm, preferably 2 to 10 mm, the outer diameter is 20 to 500 mm, preferably 20 to 100 mm, and the height is 20 to 500 mm, preferably 50 to 100 mm.

[0082] Furthermore, a catalyst is also provided in the reaction channel 22.1, and the catalyst loading range is: 5 to 500 mg. The reactor can be made of stainless steel material, and the inner wall of the reactor is plated with a quartz coating. The stainless steel material can increase the stability of the reactor, and the quartz coating can solve the problem of the stainless steel reactor being inert at high temperatures. The thickness of the quartz coating is 10 to 500 nm. The insulating layer 21 can be a hollow cylinder made of stainless steel. Generally speaking, the spiral groove 22.2 needs to have a sufficient depth to place the heating coil 22.3, and the depth of the spiral groove 22.2 is 0.1 to 5 mm. The heating coil 22.3 usually requires 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 to 1000 ° C.

[0083] In the pump-probe TAP instrument provided by the present invention, refer to Figure 2The pulse channel 12 includes a first bifurcated channel 12.1, a second bifurcated channel 12.2 and a collection channel 12.3. The air inlet of the first bifurcated channel 12.1 is connected to the first pulse valve 13, and the air inlet of the second bifurcated channel 12.2 is connected to the second pulse valve 14. Further, the air outlet of the first bifurcated channel 12.1 and the air outlet of the second bifurcated channel 12.2 are both connected to the air inlet of the collection channel 12.3, and the air outlet of the collection channel 12.3 is connected to the air inlet of the reaction channel 22.1. An angle β is formed between the first bifurcated channel 12.1 and the second bifurcated channel 12.2. The angle β is 30 to 150°, preferably 60 to 120°. Generally speaking, the angle α is consistent with the angle β. The overall shape of the pulse channel 12 is Y-shaped.

[0084] Furthermore, the first bifurcated channel 12.1, the second bifurcated channel 12.2 and the converging channel 12.3 usually need to have sufficient length. The length of the first bifurcated channel 12.1 and the second bifurcated channel 12.2 can be: 2 to 20 mm, preferably 5 to 10 mm; the inner diameter of the first bifurcated channel 12.1 and the second bifurcated channel 12.2 can be: 0.05 to 2 mm, preferably 0.1 to 1 mm; the length of the converging channel 12.3 can be: 0.1 to 10 mm, preferably 0.5 to 3 mm; the inner diameter of the converging channel 12.3 can be: 0.05 to 5 mm, preferably 0.1 to 3 mm.

[0085] In the pump-probe TAP instrument provided by the present invention, refer to Figure 1 , the vacuum pump group 53 includes a first molecular pump 53.1, a second molecular pump 53.2 and a mechanical pump 53.3 which are connected in sequence. The first molecular pump 53.1, the second molecular pump 53.2 and the mechanical pump 53.3 are connected by vacuum flanges and vacuum bellows. Generally speaking, the first molecular pump 53.1 has a higher pumping speed than the second molecular pump 53.2, the second molecular pump 53.2 has a lower pumping speed but a faster rotation speed than the first molecular pump 53.1, and the mechanical pump 53.3 uses a dry pump. The vacuum pump group 53 can increase the compression rate of small molecule gas while ensuring the pumping speed and vacuum degree, and can avoid the risk of vacuum silicone oil contamination caused by the use of a diffusion pump, which affects the life of the mass spectrometer 41. Further, the model of the first molecular pump 53.1 can be: Pufa 2300, Pufa 700 or Pufa 300, etc., and the model of the second molecular pump 53.2 can be: Pufa 30 or Pufa 80, etc. When the vacuum pump group 53 is working, the vacuum degree of the first vacuum chamber 51 and the second vacuum chamber 52 can be maintained at 10 -7 ~10 -10 mbar.

[0086] The present invention also provides a method for using a pump-probe TAP instrument, which is specifically described as follows:

[0087] S1): The first vacuum chamber 51 and the second vacuum chamber 52 are evacuated by the vacuum pump group 53, and the vacuum degree in the first vacuum chamber 51 is detected by the vacuum gauge 54. If the second vacuum chamber 52 is also provided with a vacuum gauge 54, the vacuum degree in the second vacuum chamber 52 is detected at the same time. Further, the first vacuum chamber 51 and / or the second vacuum chamber 52 are evacuated by the first molecular pump 53.1, the second molecular pump 53.2 and the mechanical pump 53.3 in series, and the vacuum degree is maintained at 10 -7 ~10 -10 mbar.

[0088] 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 by the heating coil 22.3. Generally speaking, the heating program is responsible for controlling the heating rate and heating mode of the reactor body 22. When the heating coil 22.3 heats the reactor body 22, the temperature of the sample in the reaction channel 22.1 also rises. The temperature of the reactor body 22 can be detected by burying a thermocouple in the side wall of the reactor body 22 and obtaining the temperature of the sample in the reaction channel 22.1, so as to ensure that the sample is heated to the reaction temperature.

[0089] S3): The first pulse valve 13 and the second pulse valve 14 pulse different reaction gases into the microreactor 2 in sequence and react with the sample. Further, the two pulse gases respectively pass through the first bifurcated channel 12.1 and the second bifurcated channel 12.2 into the converging channel 12.3, and then enter the reaction channel 22.1 in the reactor body 22 to react with the sample therein; at the same time, the condensed water pipeline channel cools down the pulse flange 11.

[0090] S4): The gas after reacting with the sample enters the first vacuum chamber 31 surrounded by the annular liquid nitrogen chamber 31 through the extension tube 24 and is detected by the mass spectrometer filament 42. Further, the gas carrying the product molecules after reacting with the sample in step S3) contacts the mass spectrometer filament 42 through the extension tube 24 to obtain the corresponding mass spectrometer 41 signal, and the water molecules that may be contained in the product molecules condense to the inner wall of the annular liquid nitrogen chamber 31, and other gas molecules that have not condensed diffuse into the second vacuum chamber 52 and are pumped out by the vacuum pump group 53.

[0091] Example 1

[0092] Pump-probe experiment

[0093] Before the test: Use the vacuum pump group 53 to pump the vacuum degree of the first vacuum chamber 51 and the second vacuum chamber 52 to 10 -7 ~10-10 mbar, and then the sample is heated to the desired reaction temperature by means of the heating coil 22.3.

[0094] During the test: the first pulse valve 13 pulses a certain amount of gas small molecules (such as H2, CO2, CO, CH4, etc.) (pump molecules) adsorbed on the sample surface, and the peak shape of the outlet pulse is detected by the mass spectrometry system 4. Next, the second pulse valve 14 uses pulse detection molecules (such as low-carbon alkanes, etc.) to detect the influence of chemical changes on the sample surface caused by the pump molecules on the activation and reaction of the detection molecules. The delay of the two pulses can be achieved by adjusting the time difference between the two pulses, so as to study the dynamic change process of the substance on different time scales and obtain information about active sites and elementary reaction kinetics.

[0095] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A pump-probe TAP instrument, characterized in that: It comprises a sample injection pulse system (1), a microreactor (2), a liquid nitrogen cooling system (3), a mass spectrometer system (4) and a vacuum system (5); The vacuum system (5) comprises a first vacuum cavity (51), a second vacuum cavity (52) and a vacuum pump group (53) which are connected in sequence, and a vacuum gauge (54) with a working end extending into the inner cavity of the first vacuum cavity (51) is provided on the side wall of the first vacuum cavity (51); the liquid nitrogen cooling system (3) comprises an annular liquid nitrogen cavity (31) provided in the first vacuum cavity (51); The injection pulse system (1) comprises a pulse flange (11) arranged at the top of a first vacuum chamber (51), wherein a first pulse valve (13) and a second pulse valve (14) are arranged in the pulse flange (11), and an angle α is formed between the first pulse valve (13) and the second pulse valve (14); and a condensate pipeline channel (15) for loading a condensate pipeline is also arranged in the pulse flange (11); The microreactor (2) is arranged at the bottom of the pulse flange (11), and a pulse channel (12) is also arranged in the pulse flange (11). 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), and the microreactor (2) is suitable for loading samples; The mass spectrometer system (4) comprises a mass spectrometer (41), wherein the mass spectrometer (41) is arranged on the side wall of a first vacuum chamber (51), and a mass spectrometer filament (42) of the mass spectrometer (41) extends to the center of the first vacuum chamber (51); and an extension tube (24) extending toward the mass spectrometer filament (42) and located above the mass spectrometer filament (42) is also arranged at the bottom of the microreactor (2).

2. The pump-probe TAP instrument according to claim 1, characterized in that: The microreactor (2) comprises a heat-insulating layer (21) and a reactor body (22) arranged inside the heat-insulating layer (21), wherein a reaction channel (22.1) is arranged in the reactor body (22) and runs through from top to bottom, and 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-probe TAP instrument according to claim 1 or 2, characterized in that: The pulse channel (12) comprises a first bifurcated channel (12.1), a second bifurcated channel (12.2) and a converging channel (12.3); The air inlet of the first bifurcated channel (12.1) is connected to the first pulse valve (13), and the air inlet of the second bifurcated channel (12.2) is connected to the second pulse valve (14); the air outlet of the first bifurcated channel (12.1) and the air outlet of the second bifurcated channel (12.2) are both connected to the air inlet of the aggregation channel (12.3), and the air outlet of the aggregation channel (12.3) is connected to the air inlet of the reaction channel (22.1); an angle β is formed between the first bifurcated channel (12.1) and the second bifurcated channel (12.2).

4. The pump-probe TAP instrument according to claim 3, characterized in that: The angle α is between 30° and 150°; and / or the angle β is between 30° and 150°; and / or the angle α and the angle β are the same.

5. The pump-probe TAP instrument according to claim 1, characterized in that: The liquid nitrogen cooling system (3) further comprises an upper liquid level temperature sensor (32) arranged at the upper part of the outer wall of the annular liquid nitrogen cavity (31) and a lower liquid level temperature sensor (33) arranged at the lower part of the outer wall of the annular liquid nitrogen cavity (31), wherein 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-probe TAP instrument of claim 1, wherein: It also includes a control module, which is connected to the injection pulse system (1), the microreactor (2), the liquid nitrogen cooling system (3), the mass spectrometry system (4) and the vacuum system (5) through a circuit.

7. The pump-probe TAP instrument of claim 1, wherein: An electromagnetic signal shielding net (43) is provided on the top of the annular liquid nitrogen chamber (31); And / or, the vacuum pump group (53) comprises 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 sealing member is provided between the pulse flange (11) and the microreactor (2); And / or, the mass spectrometer (41) is a quadrupole mass spectrometer; And / or, a vacuum gauge (54) with a working end extending into the inner cavity of the second vacuum cavity (52) is also provided on the side wall of the second vacuum cavity (52).

8. The pump-probe TAP instrument of claim 4, wherein: The first vacuum chamber (51) has an inner diameter of 200 to 1000 mm, a height of 50 to 1500 mm, and a wall thickness of 1 to 200 mm; and / or the second vacuum chamber (52) has an inner diameter of 20 to 1000 mm, a height of 50 to 500 mm, and a wall thickness of 1 to 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 the outer ring and the inner ring are both 1-100 mm; And / or, the vacuum degree of the first vacuum chamber (51) and the second vacuum chamber (52) are both 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 lengths of the first bifurcated channel (12.1) and the second bifurcated channel (12.2) are both 2 to 20 mm, and the inner diameters are both 0.05 to 2 mm.

9. The pump-probe TAP instrument of claim 2, wherein: The material of the reactor body (22) is 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 plated with a quartz coating, the thickness of the quartz coating 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 extension tube (24) has a length of 10 to 200 mm and an inner diameter of 2 to 100 mm.

10. A method for using the pump-probe TAP instrument as claimed in claims 1 to 9, characterized in that: At least the following steps are included: S1): using a vacuum pump group (53) to evacuate the first vacuum cavity (51) and the second vacuum cavity (52), and using a vacuum gauge (54) to detect the vacuum degree of the first vacuum cavity (51); S2): heating the temperature of the microreactor (2) to the reaction temperature; S3): the first pulse valve (13) and the second pulse valve (14) pulse different reaction gases into the microreactor (2) in sequence to react with the sample; S4): The gas after reacting with the sample enters into the first vacuum chamber (51) surrounded by the annular liquid nitrogen chamber (31) through the extension tube (24), and is ionized by the mass spectrometer filament (42), and finally detected by the mass spectrometer (41).

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