Measurement system and detection method for peak oxidation temperature and weight of trace carbon nanomaterial

Abstract

The invention relates to the field of trace nano material property measurement and chemical analysis, in particular to a system and a method for measuring peak oxidation temperature and weight of a trace carbon nano material. The measuring system is composed of a catalytic reactor, a micro-flow online mass spectrometer and the like, and the detection method is used for analyzing the peak oxidation temperature and weight of a gas product by measuring the gas product generated by the reaction of the carbon nanomaterial and oxygen. The method comprises the following steps: putting a certain amount of carbon nanomaterial into a catalytic reactor, heating or preserving heat in an oxygen-containing atmosphere, transmitting a gaseous reaction product through a micro-flow gas pipeline, carrying out online detection by using a micro-flow online mass spectrometer, and analyzing the carbon dioxide concentration in the gaseous reaction product by analyzing the temperature corresponding to the maximum value of the carbon dioxide concentration and the accumulated value of the mole number of the carbon dioxide. And accurate measurement and analysis of the peak oxidation temperature and weight of the nano material are realized. According to the invention, the peak oxidation temperature of the carbon nanomaterial within the weight range of 10 micrograms to 10 milligrams can be measured, and the weight of the carbon nanomaterial can be evaluated.

Description

Technical Field

[0001] The invention relates to the field of trace nano material property measurement and chemical analysis, and in particular to a measurement system and detection method for peak oxidation temperature and weight of trace carbon nano material, which is suitable for measuring trace carbon nano material samples in different forms. Background Art

[0002] Carbon nanomaterials have attracted wide attention due to their unique one-dimensional hollow structure and excellent electrical, mechanical and thermal properties. There are many methods for preparing carbon nanomaterials, including arc method, laser ablation method, chemical vapor deposition method and floating catalyst chemical vapor deposition method. Different preparation methods and different parameter selections in the preparation process will lead to differences in the crystallinity of the obtained carbon nanomaterials, and the performance of carbon nanomaterials is often affected by their crystallinity. The crystallinity of carbon nanomaterials is determined by the sp 2 、sp 3 The ratio of hybridized carbon atoms is determined by sp 2 The higher the proportion of hybridized carbon atoms, the higher the crystallinity, and in practical applications, it also exhibits higher electrical and thermal conductivity. Since the reaction activities of carbon atoms in these two different hybridization modes are different, they exhibit different reaction temperatures. Therefore, the quality of the crystallinity of carbon nanomaterials can be evaluated by comparing the peak oxidation temperature when the oxidation rate is the highest during the temperature-raising oxidation process. At the same time, for the fields of carbon nanomaterial electronic devices, conductive fillers, etc., their usage is often at the microgram to milligram level, and the amount used greatly affects their final performance. Therefore, accurate analysis of the sample quantity and crystallinity of carbon nanomaterials is the basis for their widespread application.

[0003] Peak oxidation temperature refers to the temperature corresponding to the maximum oxidation reaction rate of the material. It is also called "oxidation temperature" in some standard documents (Standard 1: GB / T 29189-2012), which is different from the generalized oxidation temperature that also includes the initial oxidation temperature. Generally, the higher the crystallinity of the carbon material, the higher its thermal stability, that is, the higher the peak oxidation temperature. The peak oxidation temperature of carbon nanomaterials is generally characterized by thermogravimetric analysis. This method uses an analytical balance to weigh the weight change of carbon nanomaterials during the oxidation process in real time, and then determines its peak oxidation temperature; at the same time, the weight of carbon nanomaterials is generally weighed by an analytical balance. The thermogravimetric characterization method has certain requirements for the sample weight, usually requiring the sample weight to be above the milligram level (Document 1: Chen J, Fan X, et al. Bioresource Technology. 2015, 192, 592-602). However, due to the limitation of the minimum reading capacity of the analytical balance, it is difficult to characterize the peak oxidation temperature and weight of some trace carbon nanomaterial samples (weight below the milligram level, such as carbon nanotube transparent conductive films, few-layer graphene films, etc.) using thermogravimetric methods.

[0004] In order to overcome the above limitations, it is necessary to develop methods with higher measurement accuracy. Mass spectrometer is a common means of detecting gas components, which can generally be used for qualitative and high-precision quantitative analysis of gas components. The types of gas molecules in the detected gas can be obtained by mass spectrometer. In the mass spectrometry analysis of gas, different types of gas molecules have different charge-to-mass ratios, so different peaks are formed in the mass spectrum image. By calibrating the relationship between the intensity values ​​of different peaks and the gas concentration with standard gases of known concentration, it is expected to realize the analysis of the concentrations of different components in the gas through mass spectrometry data. Summary of the invention

[0005] The purpose of the present invention is to provide a measurement system and detection method for the peak oxidation temperature and weight of trace carbon nanomaterials. By measuring the change of gas products over time during the oxidation reaction of carbon nanomaterials, the peak oxidation temperature and weight of trace carbon nanomaterial samples can be measured, thereby solving the problem that the weight and peak oxidation temperature of trace carbon nanomaterial samples are difficult to quantitatively analyze.

[0006] The technical solution of the present invention is:

[0007] A measurement system for peak oxidation temperature and weight of trace carbon nanomaterials, characterized in that the measurement system consists of a catalytic reactor and a micro-flow online mass spectrometer. The catalytic reactor is used as a carbon nanomaterial oxidation reaction device, and includes a stainless steel insulation layer, a heating resistor, an asbestos carrier, a hollow crucible and a heating controller. The hollow crucible is arranged in an inner cavity of a sealed shell formed by the stainless steel insulation layer. The hollow crucible is divided into an upper cavity and a lower cavity by the asbestos carrier. A carbon nanomaterial sample is arranged on the asbestos carrier. An air inlet and an air outlet are respectively arranged at the bottom of the inner cavity of the stainless steel insulation layer. The air inlet is communicated with the upper cavity of the hollow crucible, and one end of the air outlet is connected to the lower cavity of the hollow crucible. The lower cavity of the hollow crucible is connected, and the other end of the gas outlet is connected to the micro-flow online mass spectrometer through a gas pipeline. A heating resistor is arranged on the inner wall of the stainless steel insulation layer, and the heating resistor is connected to the heating controller. The carrier gas and the reaction gas flow in from the gas inlet, are preheated to the real-time temperature of the heating controller after passing through the heating resistor, and pass through the carbon nanomaterial sample and the asbestos carrier from the top of the upper cavity of the hollow crucible. The reaction gas product flows out from the gas outlet together with the carrier gas, and the reaction gas product enters the micro-flow online mass spectrometer with the carrier gas to realize the measurement of the reaction gas product composition. Finally, a curve graph of the change of carbon dioxide concentration with temperature is output through a connected computer.

[0008] A method for detecting the peak oxidation temperature and weight of trace carbon nanomaterials comprises placing the carbon nanomaterials in a catalytic reactor and introducing an oxidizing gas, using a heating controller program setting in the catalytic reactor to heat or keep the carbon nanomaterials in the catalytic reactor under an oxygen-containing atmosphere; the gaseous reaction products are transmitted via a micro-flow gas pipeline, and the concentration of carbon dioxide generated by the reaction is detected in real time by a micro-flow online mass spectrometer; by analyzing the temperature corresponding to the highest value of the carbon dioxide concentration in the gaseous reaction products and the cumulative value of the molar number of carbon dioxide, the peak oxidation temperature of carbon nanomaterials in the order of 10 micrograms to 10 milligrams and the weight of trace carbon nanomaterial samples can be measured.

[0009] In the method for detecting the peak oxidation temperature and weight of trace carbon nanomaterials, the catalytic reactor is connected to the micro-flow online mass spectrometer through a gas pipeline, and the gas flow rate is controlled by a flow meter.

[0010] The method for detecting the peak oxidation temperature and weight of trace carbon nanomaterials, wherein the carbon nanomaterials are carbon nanotubes, graphene, C 60 , diamond or graphite samples are placed in a catalytic reactor, and the sample form is powder, aerogel, film or block.

[0011] The method for detecting the peak oxidation temperature and weight of trace carbon nanomaterials is that a micro-flow online mass spectrometer uses a mixed gas containing carbon dioxide, oxygen, and argon components with known concentrations of various components; after calibration according to the calibration function of the micro-flow online mass spectrometer, the accurate value of the carbon dioxide concentration in the measured gas is calculated.

[0012] In the method for detecting the peak oxidation temperature and weight of trace carbon nanomaterials, after the oxidizing gas reacts with the carbon nanomaterial, the generated gas product flows out of the catalytic reactor and enters the micro-flow online mass spectrometer through the gas pipeline, and the gas product does not chemically react with the pipeline.

[0013] In the method for detecting the peak oxidation temperature and weight of trace carbon nanomaterials, the oxidizing gas is high-purity oxygen or a mixed gas containing oxidizing gas, and the gas flow rate is 10-250sccm.

[0014] The method for detecting the peak oxidation temperature and weight of trace carbon nanomaterials is as follows: the catalytic reactor is set with a heating controller to set a heating program, the heating process adopts any constant heating rate within the range of 0.1 to 100°C / min, and the heating range is within 25 to 1200°C.

[0015] The method for detecting the peak oxidation temperature and weight of trace carbon nanomaterials and calculating the weight of carbon nanomaterials are based on the ideal gas state equation PV=nRT to obtain the molar number n, wherein: P represents the gas pressure, V represents the gas volume, n represents the molar number of carbon dioxide gas, R represents the gas constant, and T represents the gas temperature; the gas pressure, gas flow rate, and gas temperature in the catalytic reactor are known, and the molar number of carbon dioxide produced during the reaction is estimated based on the formula and the real-time carbon dioxide concentration measured by mass spectrometry.

[0016] The peak oxidation temperature and weight detection method of trace carbon nanomaterials, the peak oxidation temperature of the carbon nanomaterials is the temperature corresponding to the peak value in the graph of carbon dioxide variation with temperature obtained by measurement.

[0017] The design concept of the present invention is:

[0018] During the heating process of the carbon nanomaterial sample, the carbon nanomaterial reacts with oxygen to generate gaseous products, and the reaction equation is as follows:

[0019] nC+nO2→nCO2

[0020] As the temperature rises, the oxidation rate of carbon nanomaterials gradually increases. At the same time, as the carbon nanomaterials continue to oxidize, their weight decreases, so the oxidation rate increases to a certain extent and then begins to decrease; and the temperature corresponding to the peak value of the oxidation rate reflects the degree of its crystallinity. The mass spectrometer can be used to measure the carbon dioxide concentration in the reaction product in real time. By measuring the temperature corresponding to the peak value of the carbon dioxide concentration, the temperature corresponding to the peak value of the oxidation reaction rate of the carbon nanomaterial sample, that is, the peak oxidation temperature, can be determined. This method is used to measure the peak oxidation temperature of different trace carbon nanomaterial samples, and by comparing the peak oxidation temperature, the crystallinity of different trace carbon nanomaterial samples can be analyzed.

[0021] At the same time, since the carbon dioxide in the reaction product comes entirely from the carbon nanomaterial, the weight of the carbon nanomaterial sample can be obtained by simply calculating the molar number of carbon dioxide. According to the ideal state gas equation:

[0022] PV=nRT

[0023] Among them, P represents gas pressure, V represents gas volume, n represents the number of moles of carbon dioxide gas, R represents gas constant, and T represents gas temperature. Since the gas pressure, gas flow rate, and gas temperature in the reactor are known, the number of moles of carbon dioxide produced during the reaction can be calculated based on this formula and the real-time carbon dioxide concentration measured by mass spectrometry to obtain the weight of the carbon nanomaterial reactant. Relying on the high sensitivity of mass spectrometry, this method is better than analytical balance in measuring the weight of trace carbon nanomaterials.

[0024] The advantages and beneficial effects of the present invention are:

[0025] 1. The present invention constructs a measurement system consisting of a catalytic reactor and a micro-flow online mass spectrometer, adopts the high-precision measurement principle of the mass spectrometer on the reaction tail gas, and realizes the measurement of the peak oxidation temperature and weight of the carbon nanomaterial by connecting the catalytic reactor and the micro-flow online mass spectrometer.

[0026] 2. The present invention provides a method for detecting the peak oxidation temperature of trace carbon nanomaterial samples. The weight of the carbon nanomaterial sample required to measure the peak oxidation temperature can be in the range of 10 μg to 10 mg, and the minimum sample weight required is one percent of the sample weight required by thermogravimetric analysis. This solves the problem of difficulty in analyzing the peak oxidation temperature of trace carbon nanomaterial samples, such as carbon nanomaterial transparent conductive films, carbon nanomaterial fibers, carbon nanomaterial-based transistors, etc.

[0027] 3. The present invention provides a method for measuring the weight of trace carbon nanomaterial samples, which can measure the weight of carbon nanomaterials in the range of 10 μg to 10 mg, thus overcoming the problem that analytical balances cannot weigh extremely small amounts of carbon nanomaterials. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The schematic diagram of the catalytic reactor (carbon nanomaterial oxidation reaction chamber) device and the measurement system of the micro-flow online mass spectrometer data output used in the present invention. In the figure, 1 is a stainless steel insulation layer, 2 is a heating resistor, 3 is an asbestos carrier, 4 is a hollow crucible, 5 is an air inlet, 6 is an air outlet, and 7 is a carbon nanomaterial sample.

[0029] Figure 2 The present invention is a flow chart of the process for measuring the peak oxidation temperature and weight of trace carbon nanomaterials.

[0030] Figure 3 The graphs of (a) carbon dioxide concentration in the reaction product and (b) the change of carbon dioxide mole number in the reaction product during the measurement of milligram-level carbon nanomaterials (carbon nanotube macroscopic bodies) in Example 1 are shown in Figure 1. The graph (a) can reflect the oxidation rate of the carbon nanomaterial, with the horizontal axis T being the temperature (°C) and the vertical axis CO2 being the carbon dioxide gas concentration (%); the graph (b) has the horizontal axis T being the temperature (°C) and the vertical axis being the change of CO2 mole number (mol%).

[0031] Figure 4 The graphs of (a) carbon dioxide concentration in the reaction product and (b) the change of carbon dioxide mole number in the reaction product during the measurement of microgram-level carbon nanomaterial (carbon nanotube film) in Example 2 are shown in Figure (a). The graph can reflect the oxidation rate of the carbon nanomaterial, with the horizontal axis T being the temperature (°C) and the vertical axis CO2 being the carbon dioxide gas concentration (%); in the graph (b), the horizontal axis T is the temperature (°C) and the vertical axis is the change of CO2 mole number (mol%). DETAILED DESCRIPTION

[0032] In the specific implementation process, the present invention uses a measurement system composed of a catalytic reactor and a micro-flow online mass spectrometer, and a detection method for analyzing the peak oxidation temperature (temperature corresponding to the maximum value of the oxidation reaction rate) and weight of carbon nanomaterials by measuring the gas products generated by the reaction of carbon nanomaterials with oxygen. A certain amount of carbon nanomaterials is placed in a catalytic reactor and an oxidizing gas is introduced; the heating controller program in the catalytic reactor is used to heat or keep the carbon nanomaterials in the catalytic reactor under an oxygen-containing atmosphere; the gaseous reaction products are transmitted through a micro-flow gas pipeline, and then the percentage of carbon dioxide concentration generated by the reaction is detected in real time by an online mass spectrometer; finally, by analyzing the temperature corresponding to the highest value of the carbon dioxide concentration in the gaseous reaction products and the cumulative value of the number of carbon dioxide moles, the peak oxidation temperature and weight of the nanomaterials are accurately measured and analyzed. The system and method of the present invention can achieve the measurement of the peak oxidation temperature of carbon nanomaterials in the weight range of 10 micrograms to 10 milligrams and their weight evaluation.

[0033] like Figure 1 As shown, a schematic diagram of the measurement system of the catalytic reactor (carbon nanomaterial oxidation reaction chamber) device and the micro-flow online mass spectrometer data output. The measuring system consists of a catalytic reactor and a micro-flow online mass spectrometer. The catalytic reactor is used as a carbon nano material oxidation reaction device. The catalytic reactor is used as a carbon nano material oxidation reaction device. The catalytic reactor includes a stainless steel insulation layer 1, a heating resistor 2, an asbestos carrier 3, a hollow crucible 4, an air inlet 5, and an air outlet 6. The hollow crucible 4 is arranged in the inner cavity of a sealed shell formed by the stainless steel insulation layer 1. The hollow crucible 4 is divided into an upper cavity and a lower cavity by the asbestos carrier 3. A carbon nano material sample 7 is arranged on the asbestos carrier 3. An air inlet 5 and an air outlet 6 are respectively arranged at the bottom of the inner cavity of the stainless steel insulation layer 1. The air inlet 5 is communicated with the upper cavity of the hollow crucible 4. One end of the air outlet 6 is communicated with the lower cavity of the hollow crucible 4. The other end of the air outlet 6 is connected to the micro-flow online mass spectrometer through a gas pipeline. A heating resistor 2 is arranged on the inner side wall of the stainless steel insulation layer 1 to heat the carbon nano material sample 7 on the asbestos carrier 3. The heating resistor 2 is connected to a heating controller. Argon and air flow in from the air inlet 5, are preheated to the real-time temperature of the heating controller after passing through the heating resistor 2, and pass through the carbon nanomaterial sample 7 and the asbestos carrier 3 from the top of the upper cavity of the hollow crucible 4. The reaction gas product flows out from the air outlet 6 together with the carrier gas, and enters the micro-flow online mass spectrometer through the gas pipeline to measure the composition of the reaction gas product. The gas flow rate is controlled by the flow meter, and finally the connected computer outputs the curve of the change of carbon dioxide concentration with temperature. Among them, the air intake flow rate of the micro-flow online mass spectrometer is less than 0.1sccm.

[0034] like Figure 2As shown, the process flow chart of measuring the peak oxidation temperature and weight of trace carbon nanomaterials. The carbon nanomaterial sample is placed in a catalytic reactor, and the heating controller sets the heating program. The heating process adopts 10℃ / min, and the heating range is within 25~1200℃; during the oxidation reaction between the carbon nanomaterial and the oxidizing gas, the mass spectrometer outputs the carbon dioxide concentration value of the gas product in real time, thereby obtaining the curve of the change of carbon dioxide concentration with temperature; then combined with the ideal gas state equation, the integral curve of carbon dioxide moles is obtained; finally, the peak oxidation temperature is obtained according to the temperature corresponding to the peak of the carbon dioxide concentration curve, and the weight of the carbon nanomaterial is obtained according to the integral curve of carbon dioxide moles.

[0035] In order to further understand the content of the present invention, the present invention is described in detail below with reference to the accompanying drawings and examples (taking carbon nanotube materials as an example).

[0036] Example 1

[0037] In this embodiment, the method for measuring the peak oxidation temperature and weight of milligram-level carbon nanomaterials (carbon nanotube macroscopic bodies) is as follows:

[0038] First, an asbestos carrier is placed at the bottom of the upper cavity of the hollow crucible of the reactor, and then 1 mg of carbon nanotube macroscopic sample is placed into the asbestos carrier in the hollow crucible. See the flow chart for details. Figure 2 . 50 sccm of air and 200 sccm of argon were introduced into the reactor at room temperature. After the measurement data output by the mass spectrometer stabilized, the temperature was raised. The stabilization time was about 5 minutes. The time of starting the temperature rise was recorded at the same time. The temperature was raised at a rate of 10°C / min. The temperature was raised from 25°C to 1000°C and then lowered at a rate of 50°C / min. After the temperature dropped to room temperature, the content of various gases in the mass spectrometry data returned to the concentration range before the experiment began.

[0039] like Figure 3 As shown in the figure, the change value of carbon dioxide gas concentration over time in the mass spectrometry data is extracted for data processing. According to the recorded heating start time and the heating rate of 10℃ / min, the temperature value corresponding to each time in the mass spectrometry data is calculated, and the carbon dioxide gas concentration value is used as the vertical axis and the temperature value is used as the horizontal axis to draw a curve of the change of carbon dioxide gas concentration over temperature ( Figure 3 a). The concentration of carbon dioxide gas reflects the rate of oxidation reaction. A high concentration of carbon dioxide means a violent oxidation reaction and a high oxidation reaction rate. The peak of carbon dioxide concentration in the curve indicates the maximum oxidation reaction rate, and the corresponding temperature is the peak oxidation temperature of the carbon nanotube macrobody. At the same time, since the gas pressure, gas flow rate and gas temperature in the reactor are known, the molar number of carbon dioxide produced during the reaction can be calculated based on the ideal gas state equation and the real-time carbon dioxide concentration measured by mass spectrometry, thereby obtaining the weight of the reactant carbon nanomaterial ( Figure 3 b) According to calculation, the weight of the reactant carbon nanomaterial in this embodiment is 0.974 mg.

[0040] Example 2

[0041] In this embodiment, the method for measuring the peak oxidation temperature and weight of microgram-level carbon nanomaterials (carbon nanotube films) is basically the same as in Embodiment 1, except that the carbon nanotube film sample used in this embodiment weighs less (1 / 40 of the sample weight used in Embodiment 1).

[0042] First, an asbestos carrier is placed at the bottom of the upper cavity of the hollow crucible of the reactor, and then a small amount of carbon nanotube film sample (the gravimetric analytical balance cannot be weighed) is placed into the asbestos carrier in the hollow crucible. The measurement process is the same as in Example 1. Figure 4 As shown in (a)-(b), the carbon dioxide concentration and molar number during the measurement process are much lower than the measurement process of milligram-level carbon nanomaterial samples, and there is still a clear carbon dioxide concentration peak value used to calculate the peak oxidation temperature of the carbon nanotube film. The weight of the reactant carbon nanomaterial is calculated to be 50 micrograms.

[0043] The results of the embodiments show that the present invention proposes a method for calculating the peak oxidation temperature and reactant weight of carbon nanomaterials based on mass spectrometry analysis, and measures the peak oxidation temperature and weight of carbon nanomaterials by analyzing the oxidation reaction products of carbon nanomaterials through devices such as catalytic reactors, gas pipelines and micro-flow online mass spectrometers. A method for measuring the peak oxidation temperature of trace carbon nanomaterial samples is provided, which solves the problem of difficult analysis of the crystallinity of trace carbon nanomaterials such as carbon nanomaterial transparent conductive films, carbon nanomaterial fibers, and carbon nanomaterial transistors, and provides a method for measuring the weight of trace carbon nanomaterial samples.

Claims

1. A system for measuring peak oxidation temperature and weight of trace carbon nanomaterials, characterized in that: The measurement system consists of a catalytic reactor and a micro-flow online mass spectrometer. The catalytic reactor is used as a carbon nanomaterial oxidation reaction device, including a stainless steel insulation layer, a heating resistor, an asbestos carrier, a hollow crucible and a heating controller. The hollow crucible is arranged in the inner cavity of a sealed shell formed by the stainless steel insulation layer. The hollow crucible is divided into an upper cavity and a lower cavity by the asbestos carrier. A carbon nanomaterial sample is arranged on the asbestos carrier. An air inlet and an air outlet are respectively arranged at the bottom of the inner cavity of the stainless steel insulation layer. The air inlet is communicated with the upper cavity of the hollow crucible, one end of the air outlet is communicated with the lower cavity of the hollow crucible, and the other end of the air outlet is communicated with the lower cavity of the hollow crucible. One end is connected to a micro-flow online mass spectrometer through a gas pipeline, a heating resistor is arranged on the inner wall of the stainless steel insulation layer, and the heating resistor is connected to a heating controller; the carrier gas and the reaction gas flow in from the air inlet, are preheated to the real-time temperature of the heating controller after passing through the heating resistor, and pass through the carbon nanomaterial sample and the asbestos carrier from the top of the upper cavity of the hollow crucible, and the reaction gas product flows out from the air outlet together with the carrier gas, and the reaction gas product enters the micro-flow online mass spectrometer with the carrier gas to measure the composition of the reaction gas product, and finally a curve graph of the change of carbon dioxide concentration with temperature is output through a connected computer.

2. A method for detecting peak oxidation temperature and weight of trace carbon nanomaterials using the measurement system of claim 1, characterized in that: The carbon nanomaterial is placed in a catalytic reactor and an oxidizing gas is introduced. The heating controller program in the catalytic reactor is used to heat or keep the carbon nanomaterial in the catalytic reactor warm in an oxygen-containing atmosphere. The gaseous reaction products are transmitted via a micro-flow gas pipeline, and the concentration of carbon dioxide generated by the reaction is detected in real time by a micro-flow online mass spectrometer. By analyzing the temperature corresponding to the highest carbon dioxide concentration in the gaseous reaction products and the cumulative value of the molar number of carbon dioxide, the peak oxidation temperature of carbon nanomaterials in the range of 10 micrograms to 10 milligrams and the weight of trace carbon nanomaterial samples can be measured.

3. The method for detecting peak oxidation temperature and weight of trace carbon nanomaterials according to claim 2, characterized in that: The catalytic reactor is connected to the micro-flow online mass spectrometer through a gas pipeline, and the gas flow rate is controlled by a flow meter.

4. The method for detecting peak oxidation temperature and weight of trace carbon nanomaterials according to claim 2, characterized in that: Carbon nanomaterials include carbon nanotubes, graphene, 60 , diamond or graphite samples are placed in a catalytic reactor, and the sample form is powder, aerogel, film or block.

5. The method for detecting peak oxidation temperature and weight of trace carbon nanomaterials according to claim 2, characterized in that: The micro-flow online mass spectrometer uses a mixed gas containing carbon dioxide, oxygen, and argon, and the concentrations of each component are known; after calibration according to the calibration function of the micro-flow online mass spectrometer, the accurate value of the carbon dioxide concentration in the measured gas is calculated.

6. The method for detecting peak oxidation temperature and weight of trace carbon nanomaterials according to claim 2, characterized in that: After the oxidizing gas reacts with the carbon nanomaterial, the generated gas product flows out of the catalytic reactor and enters the micro-flow online mass spectrometer through the gas pipeline, and the gas product does not chemically react with the pipeline.

7. The method for detecting peak oxidation temperature and weight of trace carbon nanomaterials according to claim 2, characterized in that: The oxidizing gas is high-purity oxygen or a mixed gas containing an oxidizing gas, and the gas flow rate is 10 to 250 sccm.

8. The method for detecting peak oxidation temperature and weight of trace carbon nanomaterials according to claim 2, characterized in that: The catalytic reactor is set with a heating controller to set a heating program, and the heating process adopts any constant heating rate within the range of 0.1-100°C / min, and the heating range is within 25-1200°C.

9. The method for detecting peak oxidation temperature and weight of trace carbon nanomaterials according to claim 2, characterized in that: The weight of the carbon nanomaterial is calculated based on the ideal gas state equation PV=nRT to obtain the molar number n, where: P represents the gas pressure, V represents the gas volume, n represents the molar number of carbon dioxide gas, R represents the gas constant, and T represents the gas temperature; the gas pressure, gas flow rate, and gas temperature in the catalytic reactor are known, and the molar number of carbon dioxide produced during the reaction is estimated based on this formula and the real-time carbon dioxide concentration measured by the mass spectrometer.

10. The method for detecting peak oxidation temperature and weight of trace carbon nanomaterials according to claim 2, characterized in that: The peak oxidation temperature of carbon nanomaterials is the temperature corresponding to the peak in the graph of carbon dioxide changing with temperature obtained by measurement.

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