In-situ photo-thermal mid-infrared transient absorption spectrum isotope switching dynamic system

Abstract

The invention relates to an in-situ photo-thermal intermediate infrared transient absorption spectrum isotope switching dynamic system, and belongs to the field of gas-solid phase photo-thermal reaction devices. The device comprises a reaction tank, a switching valve, a mass spectrometer and a spectrograph. The reaction tank is internally provided with a reaction cavity for reacting reaction gas and isotope gas with a catalyst sample, and is provided with a gas inlet and a gas outlet which are communicated with the reaction cavity; the switching valve is provided with an outlet communicated with the gas inlet, a first inlet for reaction gas to enter the switching valve and a second inlet for isotope gas to enter the switching valve; and the mass spectrometer is communicated with the gas outlet of the reaction tank and is used for acquiring kinetic information of reaction gas and product distribution and analyzing isotope products. Meanwhile, the reaction tank can be used for collecting intermediate infrared transient absorption spectrum data, the structure of the reaction tank can meet the requirements of spectrograph light path testing, and the excited state charge dynamics and energy transfer process of the material under the ultrafast scale (femtosecond to microsecond) can be monitored in real time.

Description

Technical Field

[0001] The present invention belongs to the field of solid-phase photothermal reaction devices, and particularly relates to an in-situ photothermal mid-infrared transient absorption spectroscopy isotope-switching kinetic system. Background Art

[0002] Photothermal catalysis technology drives catalytic reactions by combining optical and thermal effects. Compared with traditional thermal catalysis, it can drive reactions under relatively mild conditions, showing great potential. Although certain progress has been made in photothermal catalysis, there are still many challenges in improving conversion efficiency and deeply studying catalytic mechanisms. Energy conversion in photothermal catalysis involves multiple time scales, including processes from femtoseconds to microseconds and milliseconds, covering energy transfer, charge generation, transport, recombination, and molecular structure changes. Controlling the lifetime of photo-generated charge carriers is crucial for enhancing photothermal catalysis efficiency. Time-resolved transient mid-infrared spectroscopy technology can provide charge recombination kinetic information on an ultrafast time scale and directly study the basic photophysical and photochemical processes of photothermal catalysis. In addition, the reactants in photothermal heterogeneous catalytic reactions need to go through one or more surface intermediate species to form products. Understanding the reaction paths of these intermediate species is of great guiding significance for catalyst design. However, most of the existing technologies are non-in-situ tests, without fully considering the external thermal field and truly reflecting the influence of the atmosphere on gas-solid reactions, resulting in unclear research on catalytic reaction mechanisms and the dynamic evolution law of catalytic materials. Summary of the Invention

[0003] In view of the above problems, the embodiments of the present application provide an in-situ photothermal mid-infrared transient absorption spectroscopy isotope-switching kinetic system, which can perform in-situ tests on photothermal catalytic reactions to improve the accuracy of information.

[0004] The embodiments of the present application provide an in-situ photothermal mid-infrared transient absorption spectroscopy isotope-switching kinetic system, including a reaction cell, a switching valve, a mass spectrometer, and a spectrometer. The reaction cell has a reaction chamber for reaction gases and isotope gases to react with a catalyst sample, and has an inlet and an outlet communicating with the reaction chamber; the switching valve has an outlet communicating with the inlet, a first inlet for allowing the reaction gas to enter the switching valve, and a second inlet for allowing the isotope gas to enter the switching valve. The switching valve is used to switch between a first state and a second state. In the first state, the outlet is communicated with the first inlet, and in the second state, the outlet is communicated with the second inlet; the mass spectrometer is communicated with the outlet to obtain information on the distribution of reaction gases and products and isotope product analysis; the spectrometer is used to collect mid-infrared transient absorption spectra of the catalytic reaction process in the reaction cell.

[0005] Specifically, a transparent sample tablet pressed from a catalyst sample is placed in the reaction chamber. The switching valve is placed in the first state so that the outlet communicates with the first inlet. Then, the reaction gas is continuously introduced into the reaction chamber so that the reaction gas reacts with the catalyst sample. After the reaction is stable, the spectrometer collects the mid-infrared transient absorption spectrum of the catalytic material, and at the same time, the product is discharged from the gas outlet to facilitate the mass spectrometer to obtain information on the reaction gas and product distribution. Subsequently, the switching valve is switched to the second state so that the outlet communicates with the second inlet, and then the isotope gas enters the reaction chamber. The reaction is carried out under the same conditions, and the reaction product enters the mass spectrometer from the gas outlet for isotope product analysis to obtain relevant kinetic information for the study of the photothermal catalytic reaction mechanism. Thus, the photothermal catalytic reaction can be in-situ tested to improve the information accuracy.

[0006] In some embodiments, the spectrometer includes a titanium sapphire laser generator, a femtosecond optical parametric amplifier, and a mercury cadmium telluride detector. The titanium sapphire laser generator is used to generate a first laser pulse and a second laser pulse. The first laser pulse is used as the pump light; the femtosecond optical parametric amplifier is used to receive the second laser pulse to provide a mid-infrared pulse to the reaction chamber; the mercury cadmium telluride detector is used to collect the mid-infrared spectrum of the reaction gas in the reaction cell.

[0007] Specifically, the laser pulse generated by the titanium sapphire laser generator is divided into a first laser pulse and a second laser pulse for ultraviolet-visible pump / infrared probe spectroscopy research. Among them, the first laser pulse is used as the pump light, and the second laser pulse generates a mid-infrared pulse through a femtosecond optical parametric amplifier. By measuring the absorption of the sample by the pump light pulse irradiation and the non-irradiated detection pulse respectively, the differential optical absorption spectrum of the sample is obtained. The mid-infrared pulse is used as the detection beam and collected by the mercury cadmium telluride detector. In-situ ultrafast infrared spectroscopy collection is carried out under the conditions of heating and introducing the reaction atmosphere to extend the detection range of the transient absorption spectrum to the mid-infrared band.

[0008] In some embodiments, the reaction cell includes a housing and a window. The reaction chamber is provided in the housing, and an observation port communicating with the reaction chamber is provided on the housing. The spectrometer collects the mid-infrared spectrum of the reaction gas during the reaction through the observation port; the window is arranged on the housing and used to cover the observation port.

[0009] In the above technical solution, by providing the window, it is convenient to directly observe the state of the sample during the test, and the pump light and the mid-infrared pulse can also be observed through the window, thus facilitating the adjustment of the optical path.

[0010] In some embodiments, the window is detachably installed on the housing.

[0011] In the above technical solution, after each experiment, components such as the window pane and the sealing gasket that are in close contact with the reaction gas can be disassembled and cleaned separately to ensure the long-term detection effect of the reaction cell.

[0012] In some embodiments, the window pane is made of one of calcium fluoride, quartz, sapphire, and potassium bromide.

[0013] In the above technical solution, using the above materials can make the window pane have good mid-infrared penetrability, facilitating the progress of the experiment.

[0014] In some embodiments, the reaction cell further includes a heating device and a thermocouple. The housing of the heating device is placed on the heating device, and the heating device is used to provide heat to the reaction chamber; the thermocouple is disposed in the reaction chamber to detect the temperature of the reaction sample.

[0015] In the above technical solution, by providing a heating device to heat the reaction chamber, it is convenient for the spectrometer to collect the mid-infrared transient absorption spectra of the materials during the reaction at different temperatures. The thermocouple facilitates the operator to understand the temperature of the reaction sample.

[0016] In some embodiments, the reaction cell further includes a support column. The heating device is adjustably disposed on the support column along the axis of the support column, and the heating device moves along the axis of the support column so that the spectrometer is aligned with the observation port.

[0017] In the above technical solution, the heating device is adjustably disposed on the support column along the axis of the support column, so that it is convenient to adjust the position of the housing by adjusting the position of the heating device relative to the support column, and further convenient to adjust the optical paths of the pump light and the mid-infrared pulse through the observation port.

[0018] In some embodiments, the in-situ photothermal mid-infrared transient absorption spectroscopy isotope switching kinetic system further includes a first gas path and a second gas path. The first gas path is used to connect the reaction gas source and the first inlet, and is also used to connect the first inert gas source and the first inlet; the second gas path is used to connect the isotope gas source and the second inlet, and is also used to connect the second inert gas source and the first inlet.

[0019] In some embodiments, the first gas path includes a first branch pipe, a second branch pipe, a first flow meter, and a second flow meter. The first branch pipe is used to connect the reaction gas source and the first inlet; the second branch pipe is used to connect the first inert gas source and the first inlet; the first flow meter is disposed in the first branch pipe and is used to detect the gas flow rate in the first branch pipe; the second flow meter is disposed in the second branch pipe and is used to detect the gas flow rate in the second branch pipe.

[0020] In some embodiments, the second gas path includes a third branch pipe, a fourth branch pipe, a third flowmeter, and a fourth flowmeter. The third branch pipe is used to connect the isotope gas source and the second inlet; the fourth branch pipe is used to connect the second inert gas source and the second inlet; the third flowmeter is disposed on the third branch pipe and is used to detect the gas flow rate in the third branch pipe; the fourth flowmeter is disposed on the fourth branch pipe and is used to detect the gas flow rate in the fourth branch pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 FIG. is a schematic structural diagram of an in-situ photothermal mid-infrared transient absorption spectroscopy isotope switching kinetic system provided by an embodiment of the present invention;

[0023] Figure 2 FIG. is a schematic structural diagram of a reaction cell provided by an embodiment of the present invention;

[0024] Figure 3 FIG. is a schematic structural diagram of the reaction cell in another direction provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The following will describe the embodiments of the present application in detail with reference to the drawings.

[0026] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application 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 should not be construed as a limitation to the present application.

[0027] The terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, unless otherwise specified, the meaning of "plurality" is two or more.

[0028] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be a direct connection or an indirect connection through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0029] Photothermal catalytic technology drives catalytic reactions by combining optical and thermal effects. Compared with traditional thermal catalysis, it can drive reactions under milder conditions and shows great potential. Although certain progress has been made in photothermal catalysis, there are still many challenges in improving conversion efficiency and deeply studying catalytic mechanisms. Energy conversion in photothermal catalysis involves multiple time scales, including processes from femtoseconds to microseconds and milliseconds, covering energy transfer, charge generation, transport, recombination, and molecular structure changes. Controlling the lifetime of photo-generated charge carriers is crucial for enhancing photothermal catalytic efficiency. Time-resolved transient mid-infrared spectroscopy can provide charge recombination kinetic information on an ultrafast time scale and directly study the basic photophysical and photochemical processes of photothermal catalysis. In addition, the reactants in photothermal heterogeneous catalytic reactions need to go through one or more surface intermediate species to form products. Understanding the reaction paths of these intermediate species is of great guiding significance for catalyst design. However, most of the existing technologies are non-in-situ tests, which do not fully consider the external thermal field and truly reflect the influence of the atmosphere on gas-solid reactions, resulting in unclear catalytic reaction mechanisms and the dynamic evolution laws of catalytic materials.

[0030] To solve the above technical problems, referring to Figures 1-3 , an in-situ photothermal mid-infrared transient absorption spectroscopy isotope switching kinetic system 100 is provided in an embodiment of the present application, including a reaction cell 10, a switching valve 20, a mass spectrometer 30, and a spectrometer 40. The reaction cell 10 has a reaction chamber for reaction gases and isotope gases to react with a catalyst sample, and has an inlet 111 and an outlet 112 communicating with the reaction chamber; the switching valve 20 has an outlet communicating with the inlet 111, a first inlet for supplying reaction gases into the switching valve 20, and a second inlet for supplying isotope gases into the switching valve 20. The switching valve 20 is used to switch between a first state and a second state. In the first state, the outlet communicates with the first inlet, and in the second state, the outlet communicates with the second inlet; the mass spectrometer 30 is connected to the outlet 112 to obtain information on reaction gas and product distribution and isotope product analysis; the spectrometer 40 is used to collect mid-infrared transient absorption spectroscopy data of the catalytic material in the reaction cell 10.

[0031] In some embodiments, the switching valve 20 can be a four-way switching valve 20 or a six-way switching valve 20. There can be two first inlets, and the two first inlets are respectively for a reaction gas and an inert gas (such as argon) to enter the switching valve 20. There can be two second inlets, and the two second inlets are respectively for an isotope gas and an inert gas (such as argon) to enter the switching valve 20. Exemplarily, the reaction chamber can be continuously purged with an inert gas for 30 minutes to 1 hour before the experiment to reduce the influence of air on the experimental data.

[0032] It can be understood that the isotope gas refers to a gas composed of isotopes of a certain element in the reaction gas. Switching is used to quickly switch between the first state and the second state to switch the reaction gas to another gas labeled with an isotope. When switching, the flow rate and pressure of the reactants need to remain unchanged, and the stable state of the reaction will not be affected when the isotope effect can be ignored. At the same time, transient mid-infrared spectral information is collected under the same temperature and atmosphere conditions.

[0033] The mass spectrometer 30 is an on-line quadrupole mass spectrometer 30 which is equipped with a fast-response inlet capillary / leak valve and a data acquisition system, and the gas response signal obtained by mass spectrometry can be calibrated with a standard gas mixture.

[0034] In some embodiments, the reaction cell 10 also has a vacuum port 113 for connecting the evacuation device to the reaction chamber. Through the above-mentioned vacuum port 113, it is convenient to reduce the air in the reaction chamber before the experiment and thus reduce the influence of air on the experimental data.

[0035] Specifically, a transparent sample tablet pressed from a catalyst sample is placed in the reaction chamber. It can be understood that there is a certain degree of scattering in the powder catalyst itself, and there are certain difficulties in collecting signals. Therefore, when pressing the tablet, it should be ensured to be as uniform as possible and have good light transmittance to ensure that the detection light can pass through the catalyst and reach the detector. Subsequently, the switching valve 20 is placed in the first state so that the outlet is connected to the first inlet, and then the reaction gas is continuously introduced into the reaction chamber so that the reaction gas reacts with the catalyst sample. After the reaction is stable, the spectrometer 40 collects the mid-infrared transient absorption spectrum of the real-time reaction of the material, and at the same time the product is discharged from the gas outlet 112, so that the mass spectrometer 30 obtains information on the reaction gas and product distribution. Subsequently, by switching the switching valve 20 to the second state so that the outlet is connected to the second inlet, the isotope gas is then introduced into the reaction chamber, and the reaction is carried out under the same conditions, and the reaction product enters the mass spectrometer 30 from the gas outlet 112 for isotope product analysis, so as to obtain relevant kinetic information for the study of the photothermal catalytic reaction mechanism. Thus, the photothermal catalytic reaction can be in-situ tested to improve the accuracy of the information.

[0036] According to some embodiments of the present application, the spectrometer 40 includes a titanium sapphire laser generator, a femtosecond optical parametric amplifier, and a mercury cadmium telluride detector. The titanium sapphire laser generator is used to generate a first laser pulse and a second laser pulse, and the first laser pulse is used as pump light; the femtosecond optical parametric amplifier is used to receive the second laser pulse to provide a mid-infrared pulse to the reaction chamber; the mercury cadmium telluride detector is used to collect the mid-infrared spectrum of the reaction gas in the reaction cell 10.

[0037] In some embodiments, the first laser pulse (center wavelength 800 nm) and the second laser pulse (center wavelength 800 nm) generated by the titanium sapphire laser system are used for ultraviolet-visible pump / infrared probe spectroscopy. Among them, the first laser pulse is used as pump light, and the second laser pulse generates a mid-infrared pulse with a bandwidth of about 200 cm -1 through the femtosecond optical parametric amplifier, and the tunable frequency range is 1000 cm -1 to 3500 cm -1 . By separately measuring the absorption of the sample by the pump light pulse irradiation and the non-irradiated probe pulse, the differential optical absorption spectrum of the sample is obtained. The mid-infrared pulse is used as the probe beam and collected by the mercury cadmium telluride detector. In-situ mid-infrared transient absorption spectrum data collection is carried out under the conditions of heating and introducing a reaction atmosphere. This system broadens the application range of mid-infrared transient absorption spectroscopy and provides strong technical support for the study of reaction kinetics mechanisms in complex photothermal fields.

[0038] According to some embodiments of the present application, the reaction cell 10 includes a housing 11 and a window 12. A reaction chamber is provided inside the housing 11, and an observation port communicating with the reaction chamber is provided on the housing 11. The spectrometer 40 collects the mid-infrared spectrum of the reaction gas in the reaction through the observation port; the window 12 is provided on the housing 11 and is used to cover the observation port.

[0039] It can be understood that, for light transmittance, there are two observation ports correspondingly arranged on opposite sides of the housing 11, and there are also two windows 12 corresponding to the observation ports. Preferably, the catalyst sample can be placed in the sample cell between the front and rear windows by means of pressing and sample preparation.

[0040] In this technical solution, by providing the window 12, it is convenient to directly observe the state of the sample during the test, and the pump light and the mid-infrared pulse can also be observed through the window 12, thus facilitating the adjustment of the optical path.

[0041] According to some embodiments of the present application, the window 12 is detachably installed on the housing 11.

[0042] In some embodiments, the window pane 12 and the housing 11 can be connected through the window flange 121. To ensure the sealing performance, high-temperature resistant sealing gaskets are clamped between the housing 11 and the window pane 12, and between the window flange 121 and the window pane 12. The window pane 12 is sealed through the window flange 121, and the window flange 121 squeezes the sealing gasket to achieve the sealing effect.

[0043] In this technical solution, after each experiment, components such as the window pane 12 and the sealing gasket that are in close contact with the reaction gas can be disassembled and cleaned separately to ensure the long-term detection effect of the reaction cell 10.

[0044] According to some embodiments of the present application, the window pane 12 is made of one of calcium fluoride, quartz, sapphire, and potassium bromide.

[0045] In some embodiments, the window pane 12 can be a polished calcium fluoride window pane 12 with a thickness of 2 mm. Understandably, the light transmittance of the window pane 12 should be guaranteed to be greater than 95%.

[0046] In this technical solution, using the above materials can enable the window pane 12 to have good mid-infrared penetrability, so as to meet the optical path requirements of mid-infrared transient absorption spectroscopy testing, and thus realize the mid-infrared transient absorption spectroscopy characterization of gas-solid phase reactions under working conditions, facilitating the collection of experimental data.

[0047] According to some embodiments of the present application, the reaction cell 10 further includes a heating device 13 and a thermocouple. The housing 11 of the heating device 13 is placed on the heating device 13, and the heating device 13 is used to provide heat to the sample in the reaction chamber; the thermocouple is arranged in the reaction chamber to detect the temperature in the reaction chamber.

[0048] Exemplarily, the outer shell of the heating device 13 can be made of 316L stainless steel.

[0049] The heating device 13 is below the housing 11, and the sample and catalyst in the reaction chamber are heated in real time by heating the heating wire 132 in the heating tank. The maximum temperature can reach 500 °C, and the control accuracy is ±1 °C.

[0050] In some embodiments, the heating device 13 can include a heating wire 132 for providing heat to the reaction cell 10 when powered on, and a part of the heating wire 132 is located in the reaction chamber. Specifically, a probe of the thermocouple is arranged in the reaction chamber to detect the temperature of the sample. The probe of the thermocouple is located at the edge of the sample to ensure the accuracy of temperature measurement. A display screen 131 for electrically connecting with the thermocouple is arranged on the heating device 13. The thermocouple is connected to the heating device 13, and the actual temperature is displayed in real time by the display screen 131.

[0051] In this technical solution, a heating device 13 is provided to heat the reaction chamber, so as to facilitate the spectrometer 40 to collect the mid-infrared transient absorption spectra of reaction gases and reaction products at different temperatures. The thermocouple facilitates the operator to understand the temperature inside the reaction chamber.

[0052] According to some embodiments of the present application, the reaction cell 10 further includes a support column 14. The heating device 13 is arranged on the support column 14 in an adjustable manner along the axis of the support column 14, and the heating device 13 moves along the axis of the support column 14 so that the spectrometer 40 is aligned with the observation port.

[0053] In some embodiments, the support column 14 and the heating device 13 are fixed by screws and can be disassembled very conveniently. Specifically, the heating device 13 can slide relative to the support column 14 along the axis of the support column 14 and is fixed relative to the support column 14 by screws. By adjusting the screws, the height between the window pane 12 and the ground can be adjusted to more conveniently adjust the optical path coincidence of the pump light and the probe light of the spectrometer 40.

[0054] In this technical solution, the heating device 13 is arranged on the support column 14 in an adjustable manner along the axis of the support column 14, so as to facilitate adjusting the position of the housing 11 by adjusting the position of the heating device 13 relative to the support column 14, and further facilitate adjusting the optical path of the pump light and the mid-infrared pulse to pass through the observation port.

[0055] According to some embodiments of the present application, the in-situ photothermal mid-infrared transient absorption spectroscopy isotope switching kinetic system 100 further includes a first gas path and a second gas path. The first gas path is used to connect the reaction gas source and the first inlet, and is also used to connect the first inert gas source and the first inlet; the second gas path is used to connect the isotope gas source and the second inlet, and is also used to connect the second inert gas source and the first inlet.

[0056] Exemplarily, the above gas source can be a gas cylinder filled with gas. It can be understood that the first inert gas source and the second inert gas source should provide the same inert gas.

[0057] According to some embodiments of the present application, the first gas path includes a first branch pipe, a second branch pipe, a first flowmeter 51 and a second flowmeter 52. The first branch pipe is used to connect the reaction gas source and the first inlet; the second branch pipe is used to connect the first inert gas source and the first inlet; the first flowmeter 51 is arranged on the first branch pipe and is used to detect the gas flow in the first branch pipe; the second flowmeter 52 is arranged on the second branch pipe and is used to detect the gas flow in the second branch pipe.

[0058] According to some embodiments of the present application, the second gas path includes a third branch pipe, a fourth branch pipe, a third flowmeter 53, and a fourth flowmeter 54. The third branch pipe is used to connect the isotope gas source and the second inlet; the fourth branch pipe is used to connect the second inert gas source and the second inlet; the third flowmeter 53 is disposed in the third branch pipe and is used to detect the gas flow rate in the third branch pipe; the fourth flowmeter 54 is disposed in the fourth branch pipe and is used to detect the gas flow rate in the fourth branch pipe.

[0059] By setting flowmeters to monitor the flow rates of various gases, it is convenient to control the gas flow velocity, thereby reducing the risk of reduced experimental accuracy caused by different gas flow rates.

[0060] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0061] The above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An in-situ photothermal mid-infrared transient absorption spectroscopy isotope switching kinetic system, characterized in that: include: A reaction cell having a reaction chamber for reacting the reaction gas and the isotope gas with the catalyst sample, and having an air inlet and an air outlet communicated with the reaction chamber; a switching valve having an outlet connected to the gas inlet and a first inlet for the reaction gas to enter the switching valve and a second inlet for the isotope gas to enter the switching valve, the switching valve being used to switch between a first state and a second state, in which the outlet is connected to the first inlet in the first state and the outlet is connected to the second inlet in the second state; A mass spectrometer, connected to the gas outlet, for obtaining information on the distribution of reaction gases and products and for isotope product analysis; The mid-infrared transient absorption spectrometer is used to collect the mid-infrared transient absorption spectrum of the catalytic reaction process in the reaction cell.

2. The in-situ photothermal mid-infrared transient absorption spectroscopy isotope switching kinetic system according to claim 1, characterized in that: The spectrometer comprises: A titanium sapphire laser generator, used to generate a first laser pulse and a second laser pulse, wherein the first laser pulse is used as a pump light; a femtosecond optical parametric amplifier, configured to receive the second laser pulse to provide a mid-infrared pulse to the reaction chamber; The mercury cadmium telluride detector is used to collect the mid-infrared spectrum of the catalytic material under the reaction gas in the reaction cell.

3. The in-situ photothermal mid-infrared transient absorption spectroscopy isotope switching kinetic system according to claim 2, characterized in that: The reaction tank comprises: A shell having the reaction chamber therein, the shell being provided with an observation port connected to the reaction chamber, and the spectrometer collecting the mid-infrared transient absorption spectrum of the material in the reaction through the observation port; A window sheet is arranged on the housing and is used to cover the observation port.

4. The in-situ photothermal mid-infrared transient absorption spectroscopy isotope switching kinetic system according to claim 3, characterized in that: The window sheet is detachably mounted on the housing.

5. According to the in-situ photothermal mid-infrared transient absorption spectroscopy isotope switching dynamics system of claim 3, the window is made of one of calcium fluoride, quartz, sapphire and potassium bromide.

6. The in-situ photothermal mid-infrared transient absorption spectroscopy isotope switching kinetic system according to claim 3, characterized in that: The reaction tank also includes: A heating device, the housing is placed on the heating device, and the heating device is used to provide heat to the catalytic material in the reaction chamber; A thermocouple is arranged in the reaction chamber to detect the temperature of the sample in the reaction chamber.

7. The in-situ photothermal mid-infrared transient absorption spectroscopy isotope switching kinetic system according to claim 6, characterized in that: The reaction tank also includes: The support column, the heating device can be adjusted along the axis of the support column on the support column, and the heating device moves along the axis of the support column to align the spectrometer with the observation port.

8. The in-situ photothermal mid-infrared transient absorption spectroscopy isotope switching kinetic system according to claim 1, characterized in that: The in-situ photothermal mid-infrared transient absorption spectroscopy isotope switching kinetic system also includes: a first gas path, used to connect a reaction gas source and the first inlet, and used to connect a first inert gas source and the first inlet; The second gas path is used to connect the isotope gas source and the second inlet, and is used to connect the second inert gas source and the first inlet.

9. The in-situ photothermal mid-infrared transient absorption spectroscopy isotope switching kinetic system according to claim 8, characterized in that: The first gas path comprises: A first branch pipe, used to connect the reaction gas source and the first inlet; a second branch pipe, used to connect the first inert gas source and the first inlet; a first flow meter, disposed on the first branch pipe and used to detect the flow of gas in the first branch pipe; The second flow meter is arranged on the second branch pipe and is used for detecting the flow of the gas in the second branch pipe.

10. The in-situ photothermal mid-infrared transient absorption spectroscopy isotope switching kinetic system according to claim 9, characterized in that: The second gas path comprises: a third branch pipe, used for connecting the isotope gas source and the second inlet; a fourth branch pipe, used to connect the second inert gas source and the second inlet; a third flow meter, disposed in the third branch pipe and used for detecting the flow of gas in the third branch pipe; The fourth flow meter is arranged on the fourth branch pipe and is used for detecting the flow of the gas in the fourth branch pipe.

Images