CN109305665B

CN109305665B - Heteroatom-containing nano carbon material, preparation method and application thereof, and hydrocarbon oxidative dehydrogenation reaction method

Info

Publication number: CN109305665B
Application number: CN201710630736.0A
Authority: CN
Inventors: 谢婧新; 荣峻峰; 李嘉权; 于鹏; 林伟国; 史春风; 宗明生
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2017-07-28
Filing date: 2017-07-28
Publication date: 2020-08-18
Anticipated expiration: 2037-07-28
Also published as: CN109305665A

Abstract

The invention discloses a heteroatom-containing nano carbon material, a preparation method and application thereof, and a hydrocarbon oxidative dehydrogenation reaction method, wherein the heteroatom-containing nano carbon material contains oxygen, hydrogen, phosphorus and carbon, and the concentration of peroxy groups in the heteroatom-containing nano carbon material is 0.1 × 10^‑6mol/g to 3 × 10^‑6mol/g. The nano carbon material containing the heteroatom shows good catalytic activity in the oxidative dehydrogenation reaction of hydrocarbon substances, can obtain good balance between the conversion rate of raw materials and the selectivity of products, and effectively improves the utilization rate of the raw materials and the yield of the products. The heteroatom-containing nano carbon material still keeps the good characteristics of the nano carbon material and has good stability. The preparation method of the nano material containing the heteroatom can stably prepare the nano materialThe content and the existing form of the heteroatom in the nano carbon material are regulated and controlled, and the influence on the structure of the nano carbon material is small.

Description

Heteroatom-containing nano carbon material, preparation method and application thereof, and hydrocarbon oxidative dehydrogenation reaction method

Technical Field

The invention relates to a heteroatom-containing nano carbon material, a preparation method and application thereof, and also relates to a hydrocarbon oxidative dehydrogenation reaction method.

Background

Carbon materials exist in various morphological structures including carbon nanotubes, graphite, graphene, nanodiamonds, activated carbon, onion carbon, and the like. Compared with the traditional metal oxide catalyst, the carbon material has the advantages of environmental friendliness, reproducibility, low energy consumption and the like, and has good heat-conducting property, so that the carbon material is high in energy utilization rate, and is beneficial to reducing the reaction temperature and improving the product selectivity. Various types of carbon materials have been reported for catalytic reactions such as alkane activation and oxidative dehydrogenation, for example, in the sixty-seven decades of the last century, and researchers have found that coke is capable of catalyzing alkane oxidative dehydrogenation (Journal of Catalysis, 31:444-449, 1973).

With the intensive research on nanocarbon materials, researchers began to use Carbon nanotubes for the oxidative dehydrogenation of ethylbenzene (Carbon,42: 2807-. Research shows that the catalytic activity of a pure nano carbon material is not high, but due to the strong controllability of the surface structure, surface modification can be carried out artificially, such as doping oxygen and other heteroatom functional groups, so as to regulate the electron density distribution and acid-base property of the surface of the nano carbon material and improve the catalytic activity of the nano carbon material (Catalysis Today, 102:248-253, 2005).

The oxidative dehydrogenation of low-carbon paraffin to prepare olefin is one of industrially important reactions, and the oxidative dehydrogenation is an exothermic process and can be realized at a lower operation temperature, so that the method has the advantages of low energy consumption, high energy conversion efficiency and the like compared with the direct dehydrogenation. The low-carbon chain olefin of the oxidative dehydrogenation product is a raw material of various chemical products. Butadiene, for example, is a major raw material for producing synthetic rubbers and resins. At present, catalysts used in the reaction of oxidative dehydrogenation of butane to produce butene and butadiene mainly include conventional noble metal (platinum, palladium, etc.) and transition metal oxide (vanadium oxide, etc.) catalysts and novel carbon material catalysts. The traditional metal catalyst is easy to generate carbon deposit in the reaction process, so that the catalyst is poisoned and inactivated. Although emerging nanocarbon materials exhibit better catalytic activity and stability, further improvements in catalyst activity are desired.

Disclosure of Invention

The invention aims to overcome the technical problem that the catalytic activity of the existing nano carbon material is still not high enough when the existing nano carbon material is used as a catalyst for hydrocarbon oxidative dehydrogenation reaction, and provides a heteroatom-containing nano carbon material which can not only obtain higher catalytic stability but also obviously improve the catalytic activity when used as a catalyst for hydrocarbon oxidative dehydrogenation reaction.

According to a first aspect of the present invention, there is provided a heteroatom-containing nanocarbon material containing an oxygen element, a phosphorus element, a hydrogen element and a carbon element, wherein the content of the oxygen element is 3 to 9% by weight, the content of the phosphorus element is 0.1 to 4% by weight, the content of the hydrogen element is 0.1 to 3% by weight and the content of the carbon element is 3 to 3% by weight, in terms of the elements, based on the total amount of the heteroatom-containing nanocarbon materialThe content is 84-96.8 wt%, and the concentration of peroxy group in the nano carbon material containing hetero atom is 0.1 × 10^-6mol/g to 3 × 10^-6mol/g。

According to a second aspect of the present invention, there is provided a method for preparing a heteroatom-containing nanocarbon material, the method comprising:

step A1, contacting the raw material nano carbon material with at least one oxidant to obtain an oxidized nano carbon material;

step B1, under the condition of reduction reaction, the nano carbon material after oxidation treatment is contacted with at least one reducing agent to obtain the nano carbon material after reduction treatment;

step C1, contacting the nano carbon material after reduction treatment with at least one phosphorus source;

the raw material nano carbon material contains oxygen element, hydrogen element and carbon element, wherein the content of the oxygen element is 0.1-1 wt%, the content of the hydrogen element is 0.1-1 wt%, and the content of the carbon element is 99-99.8 wt% calculated by the element based on the total amount of the raw material nano carbon material,

in the raw material nano carbon material, the concentration of peroxy groups is less than 0.1 × 10^-6mol/g, the concentration of peroxy groups in the prepared nano carbon material containing hetero atoms is 0.1 × 10^-6mol/g to 3 × 10^-6mol/g。

According to a third aspect of the present invention, there is provided a heteroatom-containing nanocarbon material produced by the method according to the second aspect of the present invention.

According to a fourth aspect of the present invention there is provided the use of a heteroatom-containing nanocarbon material according to the first aspect of the invention or according to the third aspect of the invention as a catalyst for the oxidative dehydrogenation of a hydrocarbon.

According to a fifth aspect of the present invention there is provided a process for the oxidative dehydrogenation of a hydrocarbon, the process comprising contacting the hydrocarbon under hydrocarbon oxidative dehydrogenation reaction conditions with a heteroatom-containing nanocarbon material according to the first aspect of the invention or according to the third aspect of the invention.

The nano carbon material containing the heteroatom shows good catalytic activity in the oxidative dehydrogenation reaction of hydrocarbon substances, can obtain good balance between the conversion rate of raw materials and the selectivity of products, and effectively improves the utilization rate of the raw materials and the yield of the products. Meanwhile, the heteroatom-containing nano carbon material still maintains the good characteristics of the nano carbon material, such as better stability.

The preparation method of the heteroatom-containing nano material can stably regulate and control the content and existing form of the heteroatom in the nano carbon material, and has small influence on the structure of the nano carbon material.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention.

FIG. 1 is an X-ray photoelectron spectroscopy (XPS) spectrum and a peak of oxygen (O1s) in the nanocarbon material containing hetero atoms prepared in example 1, in which the vertical axis represents the intensity of a signal and the horizontal axis represents binding energy (eV).

FIG. 2 is an XPS spectrum and a peak of oxygen (O1s) in the heteroatom-containing nanocarbon material prepared in comparative example 2, in which the vertical axis represents the intensity of a signal and the horizontal axis represents the binding energy (eV).

FIG. 3 is an XPS spectrum and a peak of oxygen (O1s) in the heteroatom-containing nanocarbon material prepared in comparative example 5, in which the vertical axis represents the intensity of a signal and the horizontal axis represents the binding energy (eV).

Detailed Description

The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

In the invention, the nano carbon material refers to a carbon material with at least one dimension of a disperse phase dimension less than 100 nm.

According to a first aspect of the present invention, there is provided a heteroatom-containing nanocarbon material containing an oxygen element, a phosphorus element, a hydrogen element and a carbon element.

The content of the oxygen element in the heteroatom-containing nanocarbon material according to the present invention is 3 to 9% by weight, preferably 3.5 to 8.5% by weight, in terms of element, based on the total amount of the heteroatom-containing nanocarbon material; the content of the phosphorus element is 0.1-4 wt%, preferably 0.2-3.5 wt%; the content of the hydrogen element is 0.1 to 3 wt%, preferably 0.2 to 2 wt%; the content of the carbon element is 84 to 96.8 weight percent, and preferably 86 to 96.1 weight percent. From the viewpoint of further improving the product selectivity (particularly, olefin selectivity) when the heteroatom-containing nanocarbon material is used as a catalyst for oxidative dehydrogenation of hydrocarbons, the content of the oxygen element is more preferably 4 to 8.5% by weight, the content of the phosphorus element is more preferably 0.3 to 3% by weight, the content of the hydrogen element is more preferably 0.5 to 1.5% by weight, and the content of the carbon element is more preferably 87 to 95.2% by weight, in terms of the element, based on the total amount of the heteroatom-containing nanocarbon material.

In the invention, the content of each element in the heteroatom-containing nano-carbon material and the raw material nano-carbon material is measured by an element analysis method. In the invention, the elemental analysis is carried out on an element analyzer of Elementar Micro Cube, and the specific operation method and conditions are as follows: weighing 1-2mg of a sample in a tin cup, placing the sample into an automatic sample feeding disc, feeding the sample into a combustion tube through a ball valve for combustion, wherein the combustion temperature is 1000 ℃ (atmosphere interference during sample feeding is removed, helium is adopted for blowing), carbon dioxide and water formed by combustion are separated through three desorption columns, and a Thermal Conductivity Detector (TCD) is used for detecting in sequence. The oxygen element is analyzed by converting oxygen in a sample into CO under the action of a carbon catalyst by utilizing pyrolysis, and then detecting the CO by adopting TCD.

According to the heteroatom-containing nanocarbon material of the present invention, the concentration of peroxy groups in the heteroatom-containing nanocarbon material is 0.1 × 10^-6mol/g to 3 × 10^-6When the content of the peroxy group is within the above range, the heteroatom-containing nanocarbon material shows higher catalytic activity when used as a catalyst for oxidative dehydrogenation of hydrocarbon substances. Further improving the catalysis of the finally prepared nano carbon material containing the heteroatom when used as a catalyst for the oxidative dehydrogenation of hydrocarbon substancesFrom the viewpoint of activation activity, the concentration of peroxy groups in the heteroatom-containing nanocarbon material is preferably 0.2 × 10^-6mol/g to 2.8 × 10^-6mol/g, more preferably 0.3 × 10^-6mol/g to 2.5 × 10^-6mol/g。

In the present invention, the peroxy group means O₂ ^2-The group, the concentration of which is determined by iodometry, is carried out according to the titration method disclosed in F.P.Greenspan, D.G.Mackellar (Analytical Chemistry 1948,20,1061-1063), and is determined as follows: 0.3g of a nanocarbon material as a sample to be measured was added to a sample prepared by dissolving 10mL of KI aqueous solution (100g/L) and 5mLH₂SO₄Aqueous solution (0.1mol/L), 30mL deionized water, and 3 drops (NH)₄)₆Mo₇O₂₄Performing ultrasonic treatment (ultrasonic frequency is 45kHz) for 30min at 25 ℃ in a dark place in a mixed solution consisting of aqueous solution (30g/L) to perform a reaction shown in a reaction formula (1); the reaction mixture was filtered and washed 5 times with deionized water, and all filtrates were collected and washed with Na₂S₂O₃The aqueous solution (0.002mol/L) was titrated to carry out the reaction represented by the reaction formula (2). Determining the concentration of peroxy groups of the nanocarbon material according to the titration result by using formula (3).

O₂ ^2-+2KI+2H₂SO₄→O^2-+2KHSO₄+I₂+H₂O (1)

I₂+Na₂S₂O₃→2NaI+Na₂S₄O₆(2)

In the formula (3), c is the content of peroxy groups, mol/g;

v is Na consumed by titration₂S₂O₃Volume of aqueous solution, mL;

and m is the mass, g, of the nanocarbon material serving as a sample to be detected.

The heteroatom-containing nanocarbon material according to the present invention has an X-ray photoelectron spectrum pattern of an X-rayThe total amount of surface elements of the heteroatom-containing nano carbon material determined by line photoelectron spectroscopy is used as a reference

The content of oxygen element determined by the peak of the group is 0.1 to 3 mol%, preferably 0.3 to 2.8 mol%, more preferably 0.4 to 2.7 mol%, and further preferably 0.5 to 2.5 mol%. From the viewpoint of further improving the product selectivity (particularly olefin selectivity) when the heteroatom-containing nanocarbon material is used as a catalyst for oxidative dehydrogenation of hydrocarbons, the method is based on

The content of oxygen element determined by the peak of the radical is more preferably 0.85 to 2 mol%.

According to the heteroatom-containing nanocarbon material of the present invention, in the X-ray photoelectron spectroscopy spectrum of the heteroatom-containing nanocarbon material, the content of oxygen element determined from the peak corresponding to the C-O group and the content of oxygen element determined from the peak corresponding to the C-O group

The molar ratio of the oxygen content determined by the peaks of the radicals is greater than 1, preferably between 2 and 10: 1, more preferably 2 to 8: 1, more preferably 2.1 to 6: 1. from the viewpoint of further improving the product selectivity (particularly olefin selectivity) when the heteroatom-containing nanocarbon material is used as a catalyst for oxidative dehydrogenation of hydrocarbons, the content of oxygen element determined from the peak corresponding to the C-O group and the content of oxygen element determined from the peak corresponding to the C-O group

The molar ratio of the content of oxygen element determined by the peak of the group is 2.5-5.8: 1.

the heteroatom-containing nanocarbon material according to the invention has an X-ray photoelectron spectrum corresponding to that of the heteroatom-containing nanocarbon material

The content of oxygen determined by the peak of the radical corresponds to

The molar ratio of the content of oxygen element determined by the peak of the group is 0.1-1: 1, preferably 0.1 to 0.8: 1, more preferably 0.15 to 0.7: 1. from the viewpoint of further improving the product selectivity (particularly olefin selectivity) when the heteroatom-containing nanocarbon material is used as a catalyst for oxidative dehydrogenation of hydrocarbons, the method is based on

The content of oxygen determined by the peak of the radical corresponds to

The molar ratio of the content of oxygen element determined by the spectrum peak of the radical is 0.2-0.65: 1.

according to the heteroatom-containing nanocarbon material of the invention, it is also possible for a certain amount of adsorbed water to be present. In the X-ray photoelectron spectroscopy of the heteroatom-containing nanocarbon material, the content of oxygen element determined from the peak corresponding to the adsorbed water is 5 mol% or less, preferably 0.1 to 1 mol%, based on the total amount of surface elements of the heteroatom-containing nanocarbon material determined by X-ray photoelectron spectroscopy.

In the invention, the content of oxygen elements on the surface of the nano carbon material and the content of each oxygen species are measured by adopting an X-ray photoelectron spectroscopy, and the specific method comprises the following steps:

(1) performing X-ray photoelectron spectroscopy analysis on the nano carbon material to obtain an X-ray photoelectron spectroscopy spectrum, and taking the ratio of the peak area of the 1s spectral peak of one element to the sum of the peak areas of the 1s spectral peaks of the elements as the molar content of the element, wherein the molar content of the oxygen element is recorded as X_O；

(2) The peak of O1s spectrum (generally appearing in the range of 531-535 eV) in the X-ray photoelectron spectrum is marked as A_O) Performing peak separation, respectively corresponding to

The peak of the radical (generally at 532.In the range of 3. + -. 0.2 eV), the peak corresponding to the C-O group (generally in the range of 533.7. + -. 0.2 eV), the peak corresponding to the C-O group

The peak of the radical (generally in the range 531.1 + -0.2 eV), and possibly the peak corresponding to the adsorbed water (generally in the range 535.5 + -0.2 eV), will correspond to

The peak area of the peak of the radical is recorded as A_COOThe peak area corresponding to the peak of the C-O group was taken as A_C-OWill correspond to

The peak area of the peak of the radical is recorded as A_C＝OThe peak area corresponding to the peak of the adsorbed water was designated as A_{Adsorbed water}；

(3) The following formula is adopted to calculate the equation

Molar content X of oxygen determined by the peaks of the radicals_COO：

The molar content X of the oxygen element determined from the peak of the spectrum corresponding to the adsorbed water was calculated by the following formula_{Adsorbed water}：

(4) A is to be_C-O/A_COOThe content of oxygen element determined as a peak corresponding to the C-O group and the content of oxygen element determined as a peak corresponding to the C-O group

The molar ratio of the content of the oxygen element determined by the peak of the group;

(5) a is to be_C＝O/A_COOAs corresponding to

The content of oxygen determined by the peak of the radical corresponds to

The peak of the radical spectrum determines the molar ratio of the content of the oxygen element.

The heteroatom-containing nanocarbon material according to the present invention may exist in various forms, and specifically, may be, but not limited to, one or a combination of two or more of a heteroatom-containing carbon nanotube, a heteroatom-containing graphene, a heteroatom-containing thin-layer graphite, a heteroatom-containing nanocarbon particle, a heteroatom-containing nanocarbon fiber, a heteroatom-containing nanodiamond, and a heteroatom-containing fullerene. The carbon nano-tube containing the heteroatom can be one or the combination of more than two of single-walled carbon nano-tube containing the heteroatom, double-walled carbon nano-tube containing the heteroatom and multi-walled carbon nano-tube containing the heteroatom. The heteroatom-containing nanocarbon material according to the invention is preferably a heteroatom-containing multiwall carbon nanotube.

According to the heteroatom-containing nano carbon material, the specific surface area of the heteroatom-containing multi-wall carbon nano tube is preferably 50-500m²The catalyst performance of the nanometer carbon material containing hetero atom, especially the catalyst for hydrocarbon material oxidative dehydrogenation, can be further improved. The specific surface area of the multi-walled carbon nanotube containing the heteroatom is more preferably 70 to 300m²(ii)/g, more preferably 120-²(ii) in terms of/g. In the present invention, the specific surface area is measured by the nitrogen adsorption BET method.

According to the heteroatom-containing nano carbon material, the weight loss rate of the heteroatom-containing multi-walled carbon nano tube in the temperature range of 400-800 ℃ is w₈₀₀The weight loss rate in the temperature range of 400-500 ℃ is w₅₀₀，w₅₀₀/w₈₀₀Preferably in the range of 0.01 to 0.3, which enables better catalytic performance, particularly when used as a catalyst for the oxidative dehydrogenation of hydrocarbons. w is a₅₀₀/w₈₀₀More preferably in the range of 0.02 to 0.2, still more preferably in the range of 0.1 to 0.15. In the present invention, w₈₀₀＝W₈₀₀－W₄₀₀，w₅₀₀＝W₅₀₀－W₄₀₀，W₄₀₀The mass loss rate, W, measured at a temperature of 400 deg.C₈₀₀The mass loss rate, W, measured at a temperature of 800 deg.C₅₀₀Is the mass loss rate determined at a temperature of 500 ℃; the weight loss rate is measured in an air atmosphere by adopting a thermogravimetric analyzer, the test starting temperature is 25 ℃, and the heating rate is 10 ℃/min; the samples were dried at a temperature of 150 ℃ and 1 atm under a helium atmosphere for 3 hours before testing.

The content of other non-metallic hetero atoms such as sulfur atom and nitrogen atom in the nano carbon material containing hetero atoms according to the present invention may be a conventional content. Generally, in the heteroatom-containing nanocarbon material according to the present invention, the total amount of non-metallic heteroatoms (such as sulfur atoms and nitrogen atoms) other than oxygen atoms and nitrogen atoms may be 1% by weight or less, preferably 0.5% by weight or less. The heteroatom-containing nanocarbon material according to the present invention may further contain a small amount of metal atoms remaining in the nanocarbon material production process, which are generally derived from a catalyst used in the production of the nanocarbon material, and the content of these remaining metal atoms is generally 1% by weight or less, preferably 0.5% by weight or less.

step C1, contacting the reduced nanocarbon material with at least one phosphorus source.

According to the method of the present invention, the raw material nanocarbon material contains an oxygen element, a hydrogen element and a carbon element, and the content of the oxygen element is 0.1 to 1% by weight, preferably 0.5 to 0.9% by weight, in terms of element, based on the total amount of the raw material nanocarbon material; the content of the hydrogen element is 0.1 to 1 wt%, preferably 0.3 to 0.6 wt%; the content of the carbon element is 98 to 99.8 wt%, preferably 98.5 to 99.2 wt%. The raw nanocarbon material generally does not contain phosphorus element.

The total amount of surface elements of the raw nanocarbon material determined by X-ray photoelectron spectroscopy is determined by the X-ray photoelectron spectroscopy

The content of oxygen element determined by the peak of the radical is 0.1 to 1 mol%, preferably 0.2 to 0.8 mol%, more preferably 0.3 to 0.5 mol%.

The raw material nano carbon material has X-ray photoelectron spectrum with oxygen content determined by the peak corresponding to C-O group and the peak corresponding to C-O group

The molar ratio of the content of oxygen elements determined by the peaks of the radicals is not more than 1, preferably from 0.1 to 1: 1, more preferably 0.2 to 0.95: 1, more preferably 0.5 to 0.9: 1.

the raw material nano carbon material has X-ray photoelectron spectrum corresponding to that of

The content of oxygen determined by the peak of the radical corresponds to

The molar ratio of the content of oxygen element determined by the peak of the group is 0.1-1: 1, preferably 0.1 to 0.8: 1, more preferably 0.2 to 0.5: 1.

the raw nanocarbon material generally does not contain adsorbed water.

The concentration of peroxy groups in the raw material nano carbon material is extremely low, even no, generally less than 0.1 × 10^- ⁶mol/g。

According to the method of the present invention, the raw material nanocarbon material may be a nanocarbon material in various existing forms. Specifically, the raw material nanocarbon material may be, but is not limited to, one or a combination of two or more of carbon nanotubes, graphene, nanodiamonds, thin-layer graphites, nanocarbon particles, nanocarbon fibers, and fullerenes. The carbon nanotube can be one or the combination of more than two of a single-walled carbon nanotube, a double-walled carbon nanotube and a multi-walled carbon nanotube. Preferably, the raw material nanocarbon material is a carbon nanotube, more preferably a multiwall carbon nanotube.

In a preferred embodiment, the raw material nanocarbon material is a multi-walled carbon nanotube, and the specific surface area of the multi-walled carbon nanotube may be 50 to 500m²(ii) in terms of/g. Preferably, the specific surface area of the multi-walled carbon nanotube is 70-300m²When the specific surface area of the multi-wall carbon nano tube is within the range, the finally obtained heteroatom-containing nano carbon material has better catalytic activity, and particularly can obtain better catalytic effect when being used as a catalyst for the oxidative dehydrogenation reaction of hydrocarbon substances. More preferably, the specific surface area of the multi-walled carbon nanotube is 130-290m²/g。

When the raw material nano carbon material is the multi-walled carbon nanotube, the weight loss rate of the multi-walled carbon nanotube in the temperature range of 400-800 ℃ is w₈₀₀The weight loss rate in the temperature range of 400-500 ℃ is w₅₀₀，w₅₀₀/w₈₀₀Preferably in the range of 0.01-0.3. More preferably, w₅₀₀/w₈₀₀In the range of 0.02 to 0.2, the thus-prepared heteroatom-containing nanocarbon material shows a better catalytic effect, particularly when used as a catalyst for oxidative dehydrogenation of hydrocarbon substances. Further preferably, w₅₀₀/w₈₀₀In the range of 0.05-0.15.

When the raw material nanocarbon material is a multiwall carbon nanotube, the tube diameter (outer diameter) of the multiwall carbon nanotube is not particularly limited and may be selected conventionally. Generally, the diameter of the tubes of the multi-walled carbon nanotubes may be in the range of 1-100nm, preferably in the range of 1-50 nm. From the viewpoint of further improving the product selectivity of the finally prepared heteroatom-containing nanocarbon material as a catalyst for oxidative dehydrogenation of hydrocarbon substances, the diameter of the multi-walled carbon nanotube is preferably in the range of 5 to 50nm, more preferably in the range of 8 to 30 nm. The pipe diameter is measured by a transmission electron microscope method.

According to the method of the present invention, the total amount (in terms of elements) of the non-metallic hetero atoms (such as nitrogen atoms and sulfur atoms) other than oxygen atoms and hydrogen atoms in the raw material nanocarbon material may be a conventional amount. Generally, the total amount of the remaining non-metallic hetero atoms other than oxygen atoms and hydrogen atoms in the raw material nanocarbon material is not more than 1% by weight, preferably not more than 0.5% by weight. According to the method of the present invention, the raw material nanocarbon material may further contain some metal elements, depending on the source, which are generally derived from the catalyst used in the preparation of the raw material nanocarbon material, in an amount of generally 1% by weight or less, preferably 0.5% by weight or less.

According to the method of the present invention, the raw nanocarbon material may be pretreated (e.g., washed) before use by a method commonly used in the art to remove some impurities from the surface of the raw nanocarbon material; the raw material nano carbon material can also be directly used without pretreatment, and in the embodiment disclosed by the invention, the raw material nano carbon material is not pretreated before being used.

In step a1, the oxidizing agent is preferably one or more of an oxidizing acid, hydrogen peroxide, and an organic peroxide. In a preferred embodiment of the present invention, the oxidizing agent is selected from HNO₃、H₂SO₄One or more than two of hydrogen peroxide and organic peroxide shown in formula I,

in the formula I, R₁And R₂Each is selected from H, C₄-C₁₂Straight or branched alkyl of (2), C₆-C₁₂Aryl of (C)₇-C₁₂Aralkyl and

and R is₁And R₂Not simultaneously being H or R₃Is C₄-C₁₂Straight or branched alkyl or C₆-C₁₂Aryl group of (1).

In the present invention, C₄-C₁₂Specific examples of the alkyl group of (a) may include, but are not limited to, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, isopentyl, tert-pentyl, hexyl (including various isomers of hexyl), cyclohexyl, octyl (including various isomers of octyl), nonyl (including various isomers of nonyl), decyl (including various isomers of decyl), undecyl (including various isomers of undecyl), and dodecyl (including various isomers of dodecyl).

In the present invention, C₆-C₁₂Specific examples of the aryl group of (a) may include, but are not limited to, phenyl, naphthyl, methylphenyl and ethylphenyl.

In the present invention, C₇-C₁₂Specific examples of the aralkyl group of (a) may include, but are not limited to, a phenylmethyl group, a phenylethyl group, a phenyl-n-propyl group, a phenyl-n-butyl group, a phenyl-tert-butyl group, a phenyl-isopropyl group, a phenyl-n-pentyl group and a phenyl-n-butyl group.

Specific examples of the oxidizing agent may include, but are not limited to: HNO₃、H₂SO₄Hydrogen peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, ethylbenzene hydroperoxide, cyclohexyl hydroperoxide, dicumyl peroxide, dibenzoyl peroxide, di-tert-butyl peroxide and lauroyl peroxide.

Preferably, the oxidizing agent is an acid having oxidizing properties. More preferably, the oxidizing agent is HNO₃And/or H₂SO₄. From the viewpoint of further improving the conversion rate of the raw material and the selectivity of the product, the oxidizing agent is more preferably HNO₃And H₂SO₄. Even more preferably, the oxidizing agent is HNO₃And H₂SO₄And HNO₃And H₂SO₄The molar ratio is 1: 3-10, preferably 1: 3-8, more preferably 1: 3.5-7.5.

In step a1, the oxidizing agent may be provided in pure form or may be provided in the form of a solution (preferably an aqueous solution). Where the oxidant is provided in the form of a solution, the concentration of the solution may be conventionally selected.

In the step A1, the amount of the oxidant may be 500-50000 parts by weight, preferably 1000-15000 parts by weight, more preferably 1500-10000 parts by weight, relative to 100 parts by weight of the raw material nanocarbon material.

In step a1, the raw nanocarbon material and the oxidizing agent may be contacted in a liquid dispersion medium. The liquid dispersion medium may be selected according to the amount of the raw nanocarbon material used. Preferably, the liquid dispersion medium is water. The amount of the liquid dispersion medium may be selected depending on the amounts of the raw nanocarbon material and the oxidizing agent. Generally, the amount of the liquid dispersion medium may be 500-. The oxidant contains HNO₃When used, the liquid dispersion medium is preferably used in such an amount that HNO is present₃The concentration in the liquid phase is 1 to 15mol/L, more preferably such that HNO is present₃The concentration in the liquid phase is 1 to 8mol/L, and it is further preferable that HNO is made to be present₃The concentration in the liquid phase is 1-4 mol/L. In the presence of H in the oxidizing agent₂SO₄When used, the liquid dispersion medium is preferably used in such an amount that H₂SO₄The concentration in the liquid phase is from 5 to 20mol/L, more preferably such that H₂SO₄The concentration in the liquid phase is 7-15 mol/L.

In step A1, the raw nanocarbon material is contacted with the oxidizing agent at a temperature of 10-50 ℃, e.g., at a temperature of 10 ℃, 11 ℃, 12 ℃, 13 ℃, 14 ℃, 15 ℃, 16 ℃, 17 ℃, 18 ℃,19 ℃,20 ℃, 21 ℃, 22 ℃, 23 ℃, 24 ℃, 25 ℃, 26 ℃, 27 ℃, 28 ℃, 29 ℃, 30 ℃, 31 ℃, 32 ℃, 33 ℃, 34 ℃, 35 ℃, 36 ℃, 37 ℃, 38 ℃, 39 ℃, 40 ℃, 41 ℃,42 ℃, 43 ℃, 44 ℃, 45 ℃, 46 ℃, 47 ℃, 48 ℃, 49 ℃ or 50 ℃. From the viewpoint of further improving the catalytic activity of the finally prepared heteroatom-containing nanocarbon material in the oxidative dehydrogenation of hydrocarbon substances, the raw nanocarbon material is contacted with the oxidant at a temperature of 20 to 50 ℃.

In step a1, the raw material nanocarbon material and the oxidizing agent are preferably contacted in the presence of ultrasonic waves, from the viewpoint of further improving the catalytic activity of the finally prepared heteroatom-containing nanocarbon material in the oxidative dehydrogenation reaction of hydrocarbon substances. The contacting in the presence of ultrasonic waves may be achieved by placing the raw nanocarbon material and the oxidizing agent in an ultrasonic cleaner. The frequency of the ultrasonic wave can be 25-100kHz, and is preferably 40-60 kHz.

In step a1, the time for which the raw nanocarbon material is contacted with the oxidizing agent may be selected according to the temperature at which the contact is performed. In general, the duration of the contact may be from 0.5 to 10 hours, preferably from 1 to 6 hours.

According to the method of the present invention, when the raw nanocarbon material is contacted with the oxidizing agent in the liquid dispersion medium, after the contact is completed, the method of the present invention further comprises a step a2 of separating a solid substance from the mixture obtained by the contact in the step a1 in a step a2, and drying the solid substance, thereby obtaining the oxidation-treated nanocarbon material.

In step A2, solid materials can be separated from the mixture obtained by the contacting by a conventional solid-liquid separation method, such as one or a combination of two or more of centrifugation, filtration and decantation. The separated solid material is preferably dried after washing with water (e.g. deionized water) to neutrality (typically to a pH of 6-7 for the wash water). In step A2, the drying conditions are such that the liquid dispersion medium contained in the separated solid matter can be removed. In general, the drying may be carried out at a temperature of from 80 to 180 ℃ and preferably at a temperature of from 100 ℃ to 140 ℃. The duration of the drying may be selected according to the temperature at which the drying is carried out. In general, the duration of the drying may be from 0.5 to 24 hours, preferably from 1 to 20 hours, more preferably from 8 to 16 hours. The drying may be performed in an oxygen-containing atmosphere or in an oxygen-free atmosphere. Such as an air atmosphere, and a non-oxygen-containing atmosphere such as a nitrogen atmosphere, a group zero gas atmosphere (e.g., an argon atmosphere).

According to the method of the present invention, the conditions of step a1 and optionally step a2 are preferably such that the resulting oxidation-treated nanocarbon material has a concentration of peroxy groups of 4 × 10^-6mol/g to 20 × 10^-6From the viewpoint of further improving the catalytic activity of the finally prepared heteroatom-containing nanocarbon material in the oxidative dehydrogenation of hydrocarbons, the conditions of step a1 and optionally step a2 are more preferably such that the concentration of peroxy groups in the resulting oxidation-treated nanocarbon material is 5 × 10^-6mol/g to 10 × 10^- ⁶mol/g。

In step B1, the reducing agent may be a common reducing substance. Specifically, the reducing agent may be one or more of hydrogen, carbon monoxide, hydrogen sulfide, methane, lithium aluminum hydride, sodium borohydride, triethylaluminum, sodium hydride, sodium formate, and ethylene glycol.

Preferably, the reducing agent is one or more than two of lithium aluminum hydride, sodium borohydride, triethylaluminum, sodium hydride and sodium formate. More preferably, the reducing agent is lithium aluminum hydride and/or sodium formate.

The amount of the reducing agent may be selected according to the concentration of peroxy groups in the oxidized nanocarbon material. Generally, the molar ratio of the amount of the reducing agent to the oxygen content in the oxidation-treated nanocarbon material is 0.1 to 10: 1, the heteroatom-containing nano carbon material prepared by the method shows higher catalytic activity in the oxidative dehydrogenation reaction of hydrocarbon substances. From the viewpoint of further improving the catalytic activity of the produced heteroatom-containing nanocarbon material in the oxidative dehydrogenation of hydrocarbon substances, the molar ratio of the amount of the reducing agent to the oxygen content in the oxidation-treated nanocarbon material is 0.1 to 4: 1. more preferably, the molar ratio of the amount of the reducing agent to the oxygen content in the oxidation-treated nanocarbon material is 1 to 3: 1.

in step B1, the oxidation-treated nanocarbon material and the reducing agent may be contacted at ambient temperature or at a temperature higher than ambient temperature. Generally, the oxidation-treated nanocarbon material and the reducing agent may be carried out at a temperature of 10 to 100 ℃. From the viewpoint of further improving the catalytic activity of the finally produced heteroatom-containing nanocarbon material in the oxidative dehydrogenation of hydrocarbon substances, the oxidation-treated nanocarbon material and the reducing agent are preferably carried out at a temperature of 40 to 80 ℃, for example, at a temperature of 50 to 70 ℃.

In step B1, the time for contacting the oxidation-treated nanocarbon material with the reducing agent can be selected according to the contact temperature, and generally, the duration of the contact can be 2 to 24 hours, preferably 8 to 16 hours, such as 5 to 12 hours.

In step B1, the contacting of the oxidation-treated nanocarbon material with the reducing agent may be performed in the presence of at least one liquid dispersion medium, in which case, the oxidation-treated nanocarbon material may be dispersed in the liquid dispersion medium, the reducing agent supplied in the form of gas may be introduced into the liquid dispersion medium, or the oxidation-treated nanocarbon material and the reducing agent may be dispersed in the liquid dispersion medium, thereby contacting the oxidation-treated nanocarbon material with the reducing agent. The liquid dispersion medium may be a liquid dispersion medium capable of dissolving or dispersing the reducing agent, and in general, the liquid dispersion medium may be water and/or an ether-type organic solvent, and specific examples of the liquid dispersion medium may include, but are not limited to, one or more of water, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, ethylene glycol dipropyl ether, ethylene glycol dibutyl ether, propylene glycol dimethyl ether, and propylene glycol diethyl ether. Preferably, in step B1, the liquid dispersion medium is water and/or an oxetane type organic solvent, such as water and/or tetrahydrofuran. In step B1, the amount of the liquid dispersion medium may be selected according to the amount of the reducing agent and the oxidized nanocarbon material, and generally, the amount of the liquid dispersion medium may be 10000 parts by weight, preferably 3000 parts by weight, more preferably 2500 parts by weight, per 100 parts by weight of the oxidized nanocarbon material.

In the step B1, when the oxidation-treated nanocarbon material is contacted with the reducing agent in the presence of at least one dispersion medium, the method according to the present invention may further include a step B2 of subjecting the contacted mixture to solid-liquid separation in a step B2, and drying the solid matter obtained by the solid-liquid separation, thereby obtaining a reduction-treated nanocarbon material. In step B2, a solid material can be separated from the mixture obtained by the contacting by a common solid-liquid separation method, such as one or a combination of two or more of centrifugation, filtration and decantation. The separated solid material is preferably dried after washing with water (e.g. deionized water) to neutrality (typically to a pH of 6-7 for the wash water). In step B2, the drying conditions are such that the liquid dispersion medium contained in the separated solid matter is removed. In general, the drying may be carried out at a temperature of from 80 to 180 ℃ and preferably at a temperature of from 100 ℃ to 140 ℃. The duration of the drying may be selected according to the temperature at which the drying is carried out. In general, the duration of the drying may be from 0.5 to 24 hours, preferably from 1 to 20 hours, more preferably from 6 to 16 hours. The drying may be performed in an oxygen-containing atmosphere or in an oxygen-free atmosphere. Such as an air atmosphere, and a non-oxygen-containing atmosphere such as a nitrogen atmosphere, a group zero gas atmosphere (e.g., an argon atmosphere).

According to the method of the present invention, the conditions of step B1 and optionally step B2 are preferably such that the concentration of peroxy groups in the finally prepared heteroatom-containing nanocarbon material is 0.1 × 10^-6mol/g to 3 × 10^-6mol/g, more preferably, the concentration of peroxy groups in the finally prepared heteroatom-containing nano carbon material is 0.2 × 10^-6mol/g to 2.8 × 10^-6molFrom the viewpoint of further improving the catalytic activity of the finally prepared heteroatom-containing nanocarbon material in oxidative dehydrogenation of hydrocarbon materials, the conditions of step B1 and optionally step B2 are further preferably such that the concentration of peroxy groups in the finally prepared heteroatom-containing nanocarbon material is 0.3 × 10^-6mol/g to 2.5 × 10^-6mol/g。

In step C1, the reduced nanocarbon material is contacted with at least one phosphorus source according to the method of the invention. The phosphorus source may be an acid containing a phosphorus element and/or a salt containing a phosphorus element. Specific examples of the phosphorus source may include, but are not limited to, one or more of diammonium hydrogen phosphate, ammonium dihydrogen phosphate, ammonium phosphate, phosphoric acid, pyrophosphoric acid, and metaphosphoric acid. From the viewpoint of further improving the catalytic performance of the finally prepared nano carbon material containing the heteroatom, particularly the catalytic performance of the catalyst used for the dehydrogenation and oxidation reaction of the hydrocarbon, the phosphorus source is one or more than two of ammonium dihydrogen phosphate, diammonium hydrogen phosphate and ammonium phosphate.

According to the method of the present invention, in step C1, the reduced nanocarbon material: the weight ratio of the phosphorus source can be 1: in the range of 0.001 to 5, preferably in the range of 1: in the range of 0.004 to 2, more preferably in the range of 1: in the range of 0.006 to 1, further preferably in the range of 1: in the range of 0.005 to 0.5, more preferably in the range of 1: in the range of 0.005-0.2, the phosphorus source is calculated as a phosphorus-containing compound.

According to the method of the invention, in step C1, the reduced nanocarbon material is contacted with a source of phosphorus in at least one liquid dispersion medium. The oxidation-treated nanocarbon material and the phosphorus source may be dispersed in the liquid dispersion medium, thereby contacting the reduction-treated nanocarbon material with the phosphorus source. The amount of the liquid dispersion medium may be selected depending on the amount of the nanocarbon material subjected to the reduction treatment. Generally, the reduced nanocarbon material: the weight ratio of the liquid dispersion medium may be in the range of 1: 2-100, preferably in the range of 1: 3 to 80, more preferably in the range of 1: in the range of 5 to 60, further preferably in the range of 1: 7 to 30, particularly preferably in the range of 1: in the range of 8-20. The liquid adsorption amount of the reduced nanocarbon material is a saturated adsorption amount of water measured under a condition of a temperature of 25 ℃ and a pressure of 1 standard atmosphere.

According to the method of the present invention, in step C1, the reduced nanocarbon material and the phosphorus source may be contacted with or without heating. Generally, the reduced nanocarbon material and the phosphorus source may be contacted at a temperature of 10 to 250 ℃. From the viewpoint of further improving the catalytic performance of the finally produced heteroatom-containing nanocarbon material, the reduction-treated nanocarbon material is contacted with the phosphorus source preferably at a temperature of 15 to 100 ℃, more preferably at a temperature of 20 to 50 ℃. The contact time of the reduced nanocarbon material with the phosphorus source may be selected depending on the temperature at which the contact is performed. Generally, the contact time of the reduced nanocarbon material with the phosphorus source may be 6 to 72 hours, preferably 8 to 48 hours, more preferably 12 to 36 hours.

According to the method, the mixture obtained by contacting the reduced nano carbon material with a phosphorus source can be directly dried without solid-liquid separation, so that the heteroatom-containing nano carbon material is obtained; solid-liquid separation may also be carried out, and the solid matter obtained by the separation is dried, thereby obtaining the heteroatom-containing nanocarbon material according to the present invention. From the viewpoint of further improving the catalytic performance of the finally produced heteroatom-containing nanocarbon material, the mixture obtained by contacting the nanocarbon material subjected to reduction treatment with a phosphorus source is preferably dried directly without solid-liquid separation. The drying may be carried out without heating or with heating. Specifically, the drying may be carried out at a temperature of from ambient temperature (generally not lower than 10 ℃) to 200 ℃, preferably at a temperature of from ambient temperature to 140 ℃. From the viewpoint of further improving the catalytic performance of the finally produced heteroatom-containing nanocarbon material, the drying includes a first drying and a second drying which are sequentially performed, the first drying being performed at a temperature of ambient temperature (generally not lower than 10 ℃) to 40 ℃, and the second drying being performed at a temperature of 80 ℃ to 140 ℃. The duration of the first drying may be 6 to 72 hours, preferably 12 to 60 hours, more preferably 24 to 36 hours. The duration of the second drying may be 0.5 to 8 hours, preferably 2 to 6 hours.

According to the method of the present invention, the content of phosphorus in the obtained heteroatom-containing nanocarbon material is preferably 0.1 to 4 wt%, more preferably 0.2 to 3.5 wt%, and still more preferably 0.3 to 3 wt%; the content of the oxygen element is preferably 3 to 9% by weight, more preferably 3.5 to 8.5% by weight, and still more preferably 4 to 8.5% by weight. The content of the hydrogen element in the obtained heteroatom-containing nanocarbon material is usually 0.1 to 3% by weight, preferably 0.2 to 2% by weight, and more preferably 0.5 to 1.5% by weight.

The heteroatom-containing nano carbon material or the heteroatom-containing nano carbon material prepared by the method has good catalytic performance, particularly shows higher catalytic activity in the oxidative dehydrogenation reaction of hydrocarbon substances, and can obviously improve the selectivity of olefin under the condition of obtaining higher raw material conversion rate, thereby effectively improving the raw material utilization rate and the product yield.

The heteroatom-containing nanocarbon material according to the invention or the heteroatom-containing nanocarbon material prepared by the process of the invention can be used as such as a catalyst or can be used in the form of a shaped catalyst. The shaped catalyst may contain a heteroatom-containing nanocarbon material according to the invention or a heteroatom-containing nanocarbon material prepared by the method of the invention and a binder. The binder may be selected according to the specific application of the formed catalyst, and may be, for example, an organic binder and/or an inorganic binder, so as to meet the application requirements.

According to a fourth aspect of the present invention there is provided the use of a heteroatom-containing nanocarbon material according to the first aspect of the invention or a heteroatom-containing nanocarbon material according to the third aspect of the invention as a catalyst for the oxidative dehydrogenation of hydrocarbons.

According to the application of the invention, the heteroatom-containing nano carbon material can be directly used for hydrocarbon oxidative dehydrogenation reaction, and can also be used for hydrocarbon oxidative dehydrogenation reaction after being formed.

According to a fifth aspect of the present invention there is provided a process for the oxidative dehydrogenation of a hydrocarbon, the process comprising contacting the hydrocarbon with a heteroatom-containing nanocarbon material according to the first aspect of the invention or a heteroatom-containing nanocarbon material according to the third aspect of the invention under hydrocarbon oxidative dehydrogenation reaction conditions.

According to the hydrocarbon oxidative dehydrogenation reaction method, the heteroatom-containing nano carbon material can be directly used for contacting with hydrocarbon, or the heteroatom-containing nano carbon material can be formed and then used for contacting with hydrocarbon.

The hydrocarbon oxidative dehydrogenation reaction process according to the present invention can dehydrogenate various types of hydrocarbons to obtain unsaturated hydrocarbons such as olefins. The process according to the invention is particularly suitable for dehydrogenating alkanes, thereby obtaining alkenes.

In the present invention, the hydrocarbon is preferably an alkane, such as C₂-C₁₂Of (a) an alkane. Specifically, the hydrocarbon may be, but is not limited to, ethane, propane, n-butane, isobutane, n-pentane, isopentane, neopentane, cyclopentane, n-hexane, 2-methylpentane, 3-methylpentane, 2, 3-dimethylbutane, cyclohexane, methylcyclopentane, n-heptane, 2-methylhexane, 3-methylhexane, 2-ethylpentane, 3-ethylpentane, 2, 3-dimethylpentane, 2, 4-dimethylpentane, n-octane, 2-methylheptane, 3-methylheptane, 4-methylheptane, 2, 3-dimethylhexane, 2, 4-dimethylhexane, 2, 5-dimethylhexane, 3-ethylhexane, 2, 3-trimethylpentane, 2,3, 3-trimethylpentane, isobutane, n-pentane, isopentane, neopentane, cyclopentane, n-hexane, 2,2,4, 4-trimethylpentane, 2-methyl-3-ethylpentane, n-nonane, 2-methyloctane, 3-methyloctane, 4-methyloctane, 2, 3-dimethylheptane, 2, 4-dimethylheptane, 3-ethylheptane, 4-ethylheptane, 2,3, 4-trimethylhexane, 2,3, 5-trimethylhexane, 2,4, 5-trimethylhexane, 2, 3-trimethylhexane, 2, 4-trimethylhexane, 2, 5-trimethylhexane, 2,3, 3-trimethylhexane, 2,4, 4-trimethylhexane, 2-methyl-3-ethylhexaneAlkanes, 2-methyl-4-ethylhexane, 3-methyl-3-ethylhexane, 3-methyl-4-ethylhexane, 3-diethylpentane, 1-methyl-2-ethylcyclohexane, 1-methyl-3-ethylcyclohexane, 1-methyl-4-ethylcyclohexane, n-propylcyclohexane, isopropylcyclohexane, trimethylcyclohexane (including various isomers of trimethylcyclohexane, such as 1,2, 3-trimethylcyclohexane, 1,2, 4-trimethylcyclohexane, 1,2, 5-trimethylcyclohexane, 1,3, 5-trimethylcyclohexane), n-decane, 2-methylnonane, 3-methylnonane, 4-methylnonane, 5-methylnonane, 3-methylnonane, 4-ethylnonane, 3-methylnonane, 3-ethylhexanes, 3-methyl, 2, 3-dimethyloctane, 2, 4-dimethyloctane, 3-ethyloctane, 4-ethyloctane, 2,3, 4-trimethylheptane, 2,3, 5-trimethylheptane, 2,3, 6-trimethylheptane, 2,4, 5-trimethylheptane, 2,4, 6-trimethylheptane, 2, 3-trimethylheptane, 2, 4-trimethylheptane, 2, 5-trimethylheptane, 2, 6-trimethylheptane, 2,3, 3-trimethylheptane, 2,4, 4-trimethylheptane, 2-methyl-3-ethylheptane, 2-methyl-4-ethylheptane, 2-methyl-5-ethylheptane, 3-methyl-3-ethylheptane, 3-ethyl-3-ethylheptane, 4-methyl-3-ethylheptane, 5-methyl-3-ethylheptane, 4-methyl-4-ethylheptane, 4-propylheptane, 3-diethylhexane, 3, 4-diethylhexane, 2-methyl-3, 3-diethylpentane, phenylethane, 1-phenylpropane, 2-phenylpropane, 1-phenylbutane, 2-phenylbutane, 1-phenylpentane, 2-phenylpentane and 3-phenylpentane. More preferably, the hydrocarbon is one or two or more of propane, n-butane, isobutane and phenylethane. Further preferably, the hydrocarbon is n-butane.

The amount of oxygen used in the process for the oxidative dehydrogenation of hydrocarbons according to the present invention may be conventionally selected. Generally, the molar ratio of hydrocarbon to oxygen may be from 0.2 to 3: 1, preferably 0.5 to 2.5: 1, more preferably 1-2: 1.

according to the hydrocarbon oxidative dehydrogenation reaction method, the hydrocarbon and optional oxygen can be fed into the reactor through the carrier gas to contact and react with the heteroatom-containing nano carbon material. The carrier gas may be a commonly used gas that does not chemically interact with the reactants and the reaction product under the reaction conditions and does not undergo decomposition, such as one or a combination of two or more of nitrogen, carbon dioxide, a noble gas, and water vapor. The amount of carrier gas may be conventionally selected. Generally, the content of the carrier gas may be 30 to 99.5% by volume, preferably 50 to 99% by volume, more preferably 70 to 98% by volume.

In the process for the oxidative dehydrogenation of hydrocarbons according to the present invention, the temperature of the contacting may be conventionally selected to be sufficient to effect dehydrogenation of the hydrocarbon. Generally, the contacting may be performed at a temperature of 200-650 ℃, preferably at a temperature of 300-600 ℃, more preferably at a temperature of 350-550 ℃, and even more preferably at a temperature of 400-450 ℃.

According to the process for the oxidative dehydrogenation of hydrocarbons of the present invention, the contact may be carried out in a fixed bed reactor or a fluidized bed reactor, and is not particularly limited. Preferably, the contacting is carried out in a fixed bed reactor.

According to the hydrocarbon oxidative dehydrogenation reaction process of the present invention, the duration of the contacting can be selected according to the contacting temperature, for example, when the contacting is carried out in a fixed bed reactor, the duration of the contacting can be expressed in terms of the gas hourly volume space velocity of the feed. Generally, the gas hourly space velocity of the feed can be 500-2000h^-1Preferably 800-^-1。

The present invention will be described in detail with reference to examples, but the scope of the present invention is not limited thereto.

In the following examples and comparative examples, X-ray photoelectron spectroscopy was carried out on an ESCALB 250 type X-ray photoelectron spectrometer equipped with Thermo Avantage V5.926 software, manufactured by Thermo Scientific, with an excitation source of monochromated Al K α X rays, an energy of 1486.6eV, a power of 150W, a transmission energy for narrow scanning of 30eV, and a base vacuum of 6.5 × 10 for analytical tests^-10mbar, electron binding energy was corrected for the C1s peak (284.6eV) of elemental carbon, data processed on ThermoAvantage software, and quantified in the analytical module using the sensitivity factor method. The samples were dried at a temperature of 150 ℃ and 1 atm under a helium atmosphere for 3 hours before testing.

In the following examples and comparative examples, thermogravimetric analysis was performed on a TA5000 thermal analyzer under air atmosphere at a temperature rise rate of 10 ℃/min and in the temperature range of room temperature (25 ℃) to 1000 ℃. The samples were dried at a temperature of 150 ℃ and 1 atm under a helium atmosphere for 3 hours before testing.

In the following examples and comparative examples, the ASAP2000 type N from micrometrics, USA, was used₂The physical adsorption apparatus measures the specific surface area.

In the following examples and comparative examples, the peroxy group is O₂ ^2-The group, the concentration of which is determined iodometric method, is carried out according to the titration method disclosed in F.P. Greenspan, D.G. Mackellar (Analytical Chemistry 1948,20,1061-1063), and is determined as follows: 0.3g of a nanocarbon material as a sample to be measured was added to a sample prepared from 10mL of KI aqueous solution (100g/L) and 5mL of H₂SO₄Aqueous solution (0.1mol/L), 30mL deionized water, and 3 drops (NH)₄)₆Mo₇O₂₄Performing ultrasonic treatment (ultrasonic frequency is 45kHz) for 30min at 25 ℃ in a dark place in a mixed solution consisting of aqueous solution (30g/L) to perform a reaction shown in a reaction formula (1); the reaction mixture was filtered and washed 5 times with deionized water, and all filtrates were collected and washed with Na₂S₂O₃The aqueous solution (0.002mol/L) was titrated to carry out the reaction represented by the reaction formula (2). Determining the concentration of peroxy groups of the nanocarbon material according to the titration result by using formula (3).

O₂ ^2-+2KI+2H₂SO₄→O^2-+2KHSO₄+I₂+H₂O (1)

I₂+Na₂S₂O₃→2NaI+Na₂S₄O₆(2)

In the formula (3), c is the content of peroxy groups, mol/g;

v is Na consumed by titration₂S₂O₃Volume of aqueous solution, mL;

In the following examples and comparative examples, elemental analysis was performed on an Elementar Micro Cube elemental analyzer, and the specific operating methods and conditions were as follows: the sample is weighed in a tin cup to be about 1-2mg, placed in an automatic sample feeding disc, enters a combustion tube through a ball valve for combustion, the combustion temperature is 1000 ℃ (atmospheric interference is removed during sample feeding, helium is adopted for blowing), carbon dioxide and water formed by combustion are separated through three desorption columns, and a TCD detector is sequentially used for detection. The oxygen element is analyzed by converting oxygen in a sample into CO under the action of a carbon catalyst by utilizing pyrolysis, and then detecting the CO by adopting TCD.

In the following examples and comparative examples, the tube diameter of the multi-walled carbon nanotube was measured by a transmission electron microscopy method, and the specific test method was: at 10⁶Under the magnification of (2), the tube diameters (which are the outer diameters) of all the carbon nanotubes appearing in the eyepiece are measured, 10 groups of samples are taken for testing, the range formed by the maximum value and the minimum value of all the measured tube diameter values is taken, and the range is taken as the tube diameter range of the carbon nanotubes.

Examples 1 to 13 are for illustrating the heteroatom-containing nanocarbon material of the present invention and the method for preparing the same.

Example 1

(1) 5g of multi-walled carbon nanotubes (diameter of 1-8nm, specific surface area 273 m) as a raw material nanocarbon material²The weight loss rate of the material in the temperature range of 400-800 ℃ is w₈₀₀The weight loss rate in the temperature range of 400-500 ℃ is w₅₀₀，w₅₀₀/w₈₀₀0.13, a peroxy group content of 0mol/g, from Gentle organic chemistry, Inc., of China academy of sciences) and 250mL of an acid solution (H)₂SO₄Is 1380g/L, HNO₃227.5g/L, and the solvent of the acid solution is water), and the obtained dispersion is put into an ultrasonic cleaner for ultrasonic treatment, wherein the temperature of the dispersion in the ultrasonic cleaner is controlled at 50 ℃, the duration of the ultrasonic treatment is 6 hours, and the frequency of the ultrasonic wave is 45 kHz. After the ultrasonic treatment is completed, the dispersion is filtered, and the collected solid matter is washed with deionized water until the pH of the washing solution is at6-7, drying the washed solid matter in an air atmosphere at a temperature of 120 ℃ for 12 hours to obtain an oxidation-treated nanocarbon material in which the content of peroxy groups is 7.2 × 10^-6mol/g。

(2) 2g of the oxidized nanocarbon material was refluxed at 70 ℃ for 12 hours in 40mL of a tetrahydrofuran solution of lithium aluminum hydride (concentration of lithium aluminum hydride was 0.65mol/L, molar ratio of lithium aluminum hydride to oxygen content in the oxidized nanocarbon material was 1.3: 1). And carrying out solid-liquid separation on the obtained reaction liquid, and washing the separated solid substances by using hydrochloric acid (the concentration of HCl is 35 weight percent) and deionized water sequentially until the pH value of washing water is in the range of 6-7. The washed solid matter was dried at 120 ℃ for 12 hours in an air atmosphere, thereby obtaining a reduction-treated nanocarbon material.

(3) 1g of the reduced nanocarbon material was impregnated with 8mL of an aqueous solution containing 0.0081g of ammonium dihydrogen phosphate at room temperature (25 ℃ C., the same applies hereinafter) for 24 hours, and then the impregnated mixture was directly dried at room temperature for 24 hours, followed by drying at 120 ℃ for 6 hours, to thereby obtain a heteroatom-containing nanocarbon material according to the present invention, the composition and property parameters of which are shown in Table 1, and the X-ray photoelectron spectroscopy (XPS) spectrum and the peak separation of oxygen (O1s) in the heteroatom-containing nanocarbon material are shown in FIG. 1.

Example 2

A heteroatom-containing nanocarbon material was prepared in the same manner as in example 1, except that, in the step (2), 2g of the oxidized nanocarbon material was refluxed at 70 ℃ for 12 hours in 40mL of a tetrahydrofuran solution of lithium aluminum hydride (the concentration of lithium aluminum hydride was 0.05mol/L, and the molar ratio of lithium aluminum hydride to the oxygen content in the oxidized nanocarbon material was 0.1: 1). The composition and property parameters of the prepared heteroatom-containing nanocarbon material are listed in table 1.

Example 3

A nanocarbon material containing hetero atoms was produced in the same manner as in example 1, except that, in the step (3), diammonium phosphate was used in an amount of 0.081 g. The composition and property parameters of the prepared heteroatom-containing nanocarbon material are listed in table 1.

Comparative example 1

A heteroatom-containing nanocarbon material was prepared in the same manner as in example 1, except that, in the step (2), 2g of the oxidized nanocarbon material was refluxed at 70 ℃ for 12 hours in 40mL of tetrahydrofuran. The composition and property parameters of the prepared heteroatom-containing nanocarbon material are listed in table 1.

Comparative example 2

A heteroatom-containing nanocarbon material was prepared in the same manner as in example 1, except that step (2) was not performed (i.e., the oxidation-treated nanocarbon material was directly subjected to step (3) — the composition and property parameters of the prepared heteroatom-containing nanocarbon material are listed in table 1, and an X-ray photoelectron spectroscopy (XPS) spectrum and a peak separation of oxygen (O1s) in the heteroatom-containing nanocarbon material are shown in fig. 2.

Comparative example 3

A heteroatom-containing nanocarbon material was produced in the same manner as in example 1, except that the step (1) was not performed, but instead, multiwall carbon nanotubes as the raw nanocarbon material were directly fed into the step (2), and the reflux reaction was performed in the same manner as in example 1. The compositions of the prepared heteroatom-containing nanocarbon materials and their property parameters are listed in table 1.

Comparative example 4

A heteroatom-containing nanocarbon material was prepared in the same manner as in example 1, except that no oxidizing agent was used in the step (1), i.e., H was not contained in water₂SO₄And HNO₃. The prepared heteroatom-containing nanocarbon materials and their property parameters are listed in table 1.

Comparative example 5

A heteroatom-containing nanocarbon material was prepared in the same manner as in example 1, except that the step (3) was not performed (i.e., the reduced nanocarbon material was directly used as a heteroatom-containing nanocarbon material). The composition and property parameters of the prepared heteroatom-containing nanocarbon material are shown in Table 1, and the X-ray photoelectron spectroscopy (XPS) spectrum and the peak separation of oxygen (O1s) in the heteroatom-containing nanocarbon material are shown in FIG. 3.

Comparative example 6

A heteroatom-containing nanocarbon material was produced in the same manner as in example 1, except that the steps (1) and (2) were not performed, but the raw nanocarbon material was directly fed into the step (3), thereby obtaining a heteroatom-containing nanocarbon material. The composition and property parameters of the prepared heteroatom-containing nanocarbon material are listed in table 1.

Example 4

A heteroatom-containing nanocarbon material was prepared in the same manner as in example 1, except that, in the step (3), 1g of the reduced nanocarbon material was impregnated with 35mL of an aqueous solution containing 0.0081g of ammonium dihydrogen phosphate at room temperature for 24 hours, and then the impregnated mixture was directly air-dried at room temperature for 24 hours, followed by drying at 120 ℃ for 6 hours, to thereby obtain a heteroatom-containing nanocarbon material according to the present invention, the composition and property parameters of which are shown in Table 1.

Example 5

A heteroatom-containing nanocarbon material was prepared in the same manner as in example 4, except that, in the step (3), after completion of impregnation, the impregnated mixture was filtered, and the collected solid matter was air-dried at room temperature for 24 hours, followed by drying at 120 ℃ for 6 hours, to thereby obtain a heteroatom-containing nanocarbon material according to the present invention, the composition and property parameters of which are listed in table 1.

Example 6

A heteroatom-containing nanocarbon material was prepared in the same manner as in example 1, except that, in the step (3), the impregnated mixture was dried directly at 120 ℃ for 6 hours, thereby obtaining a heteroatom-containing nanocarbon material according to the present invention, the composition and property parameters of which are listed in table 1.

Example 7

A heteroatom-containing nanocarbon material was prepared in the same manner as in example 1, except that in the step (1), H was added to the acid solution₂SO₄Is 1380g/L, HNO₃The concentration of (2) was 0g/L, and the content of peroxy groups in the obtained oxidized nanocarbon material was 6.3 × 10^-6mol/g. Prepared nano carbon material containing hetero atom and its property parameterThe numbers are listed in table 1.

Example 8

A heteroatom-containing nanocarbon material was prepared in the same manner as in example 1, except that in the step (1), the acid solution was replaced with hydrogen peroxide of the same volume (330 g/L in hydrogen peroxide), and the obtained oxidized nanocarbon material had a peroxy group content of 9.7 × 10^-6mol/g. The prepared heteroatom-containing nanocarbon materials and their property parameters are listed in table 1.

Example 9

A heteroatom-containing nanocarbon material was prepared in the same manner as in example 1, except that, in the step (1), the multi-walled carbon nanotubes used as the raw nanocarbon material had a diameter of from 8 to 15nm and a specific surface area of 131m²The weight loss rate of the material in the temperature range of 400-800 ℃ is w₈₀₀The weight loss rate in the temperature range of 400-500 ℃ is w₅₀₀，w₅₀₀/w₈₀₀0.15, and a peroxy group content of 0mol/g, obtained from Chengdu organic chemistry, Inc., of Chinese academy of sciences, to obtain an oxidized nanocarbon material having a peroxy group content of 6.1 × 10^-6mol/g, to obtain the heteroatom containing nanocarbon material according to the invention, the composition and the property parameters of which are listed in table 1.

Example 10

A heteroatom-containing nanocarbon material was prepared in the same manner as in example 1, except that, in the step (3), 1g of the reduced nanocarbon material was impregnated with 15mL of an aqueous solution containing 0.0207g of phosphoric acid at room temperature for 24 hours, and then the impregnated mixture was directly air-dried at room temperature for 24 hours, followed by drying at 120 ℃ for 6 hours, to thereby obtain a heteroatom-containing nanocarbon material according to the present invention, the composition and property parameters of which are listed in Table 1.

Example 11

A heteroatom-containing nanocarbon material was prepared in the same manner as in example 1, except that, in the step (3), 1g of the reduced nanocarbon material was impregnated with 8mL of an aqueous solution containing 0.05g of ammonium phosphate at room temperature for 24 hours, and then the impregnated mixture was directly air-dried at room temperature for 24 hours, followed by drying at 120 ℃ for 6 hours, to thereby obtain a heteroatom-containing nanocarbon material according to the present invention, the composition and property parameters of which are shown in Table 1.

Example 12

(1) 5g of multiwall carbon nanotube (diameter of 12-15nm, specific surface area of 152 m) as raw material nanocarbon material²The weight loss rate of the material in the temperature range of 400-800 ℃ is w₈₀₀The weight loss rate in the temperature range of 400-500 ℃ is w₅₀₀，w₅₀₀/w₈₀₀0.11, a peroxy group content of 0mol/g, from Shandong Dazhan nanometer materials Co., Ltd.) and 250mL of an acid solution (H)₂SO₄Is 1380g/L, HNO₃126g/L, the solvent of the acid solution is water), the obtained dispersion is placed in an ultrasonic cleaner for ultrasonic treatment, wherein the temperature of the dispersion in the ultrasonic cleaner is controlled to be 40 ℃, the duration time of the ultrasonic treatment is 2 hours, the frequency of the ultrasonic wave is 40khz, after the ultrasonic treatment is finished, the dispersion is filtered, the collected solid matter is washed by deionized water until the pH of the washing liquid is in the range of 6-7, the washed solid matter is dried for 16 hours at the temperature of 100 ℃ in the air atmosphere, and the nano carbon material after the oxidation treatment is obtained, wherein the content of peroxy groups in the nano carbon material after the oxidation treatment is 7.8 × 10^-6mol/g。

(2) 2g of the oxidized nanocarbon material was reacted in 40mL of a tetrahydrofuran solution of lithium aluminum hydride (concentration of lithium aluminum hydride was 1mol/L, molar ratio of lithium aluminum hydride to oxygen content in the oxidized nanocarbon material was 2.7: 1) at a temperature of 50 ℃ for 5 hours. And (3) carrying out solid-liquid separation on the obtained reaction liquid, and washing the separated solid substances by using hydrochloric acid (the concentration is 35 weight percent) and deionized water sequentially until the pH value of the washing water is in the range of 6-7. The washed solid matter was dried at 120 ℃ for 12 hours in an air atmosphere, thereby obtaining a reduction-treated nanocarbon material.

(3) 1g of the reduced nanocarbon material was impregnated with 20mL of an aqueous solution containing 0.1g of ammonium phosphate at 30 ℃ for 24h, and the impregnated mixture was then dried directly at 35 ℃ for 32h and subsequently dried at 120 ℃ for 2h, to give a heteroatom-containing nanocarbon material according to the invention, the composition and property parameters of which are listed in Table 1.

Comparative example 7

A heteroatom-containing nanocarbon material was prepared in the same manner as in example 12, except that the step (3) was not performed, and the composition and property parameters of the prepared heteroatom-containing nanocarbon material were as listed in Table 1.

Comparative example 8

A heteroatom-containing nanocarbon material was produced in the same manner as in example 12, except that the steps (1) and (2) were not performed, and the raw nanocarbon material was directly fed into the step (3), and the composition and property parameters of the produced heteroatom-containing nanocarbon material were as listed in Table 1.

Example 13

(1) 5g of multi-wall carbon nano-tube (the tube diameter is 10-20nm, the specific surface area is 191 m) used as the raw material nano-carbon material²The weight loss rate of the material in the temperature range of 400-800 ℃ is w₈₀₀The weight loss rate in the temperature range of 400-500 ℃ is w₅₀₀，w₅₀₀/w₈₀₀0.09, a peroxy group content of 0mol/g, from Gentle organic chemistry, Inc., of China academy of sciences) and 250mL of an acid solution (H)₂SO₄Has a concentration of 690g/L, HNO₃114g/L, the solvent of the acid solution is water), the obtained dispersion is placed in an ultrasonic cleaner for ultrasonic treatment, wherein the temperature of the dispersion in the ultrasonic cleaner is controlled to be 25 ℃, the duration of the ultrasonic treatment is 1 hour, the frequency of ultrasonic waves is 60khz, after the ultrasonic treatment is finished, the dispersion is filtered, the collected solid matter is washed by deionized water until the pH of the washing liquid is in the range of 6-7, the washed solid matter is dried for 8 hours at the temperature of 140 ℃ in the air atmosphere, and the nano carbon material after the oxidation treatment is obtained, wherein the content of peroxy groups in the nano carbon material after the oxidation treatment is 5.5 × 10^-6mol/g。

(2) 2g of the oxidized nanocarbon material was reacted in 40mL of an aqueous solution of sodium formate (the concentration of sodium formate was 1mol/L, and the molar ratio of sodium formate to the oxygen content in the oxidized nanocarbon material was 2.6: 1) at 70 ℃ for 12 hours. And carrying out solid-liquid separation on the obtained reaction liquid, and washing the separated solid matters for multiple times by using deionized water. The washed solid matter was dried at 120 ℃ for 12 hours in an air atmosphere, thereby obtaining a reduction-treated nanocarbon material.

(3) 1g of the reduced nanocarbon material was impregnated with 10mL of an aqueous solution containing 0.2g of diammonium phosphate at 40 ℃ for 12 hours, and then the impregnated mixture was dried at 35 ℃ for 32 hours and then at 80 ℃ for 6 hours, to obtain a heteroatom-containing nanocarbon material according to the present invention, the composition and property parameters of which are listed in Table 1.

Comparative example 9

A heteroatom-containing nanocarbon material was prepared in the same manner as in example 13, except that the step (3) was not performed, and the composition and property parameters of the prepared heteroatom-containing nanocarbon material were as listed in Table 1.

Comparative example 10

A heteroatom-containing nanocarbon material was produced in the same manner as in example 13, except that the steps (1) and (2) were not carried out, and the raw nanocarbon material was directly fed into the step (3), and the composition and property parameters of the produced heteroatom-containing nanocarbon material were as listed in Table 1.

Experimental examples 1-13 are provided to illustrate the use of the heteroatom-containing nanocarbon material of the present invention and the oxidative dehydrogenation reaction method of hydrocarbons.

Experimental examples 1 to 13

The heteroatom-containing nanocarbon materials prepared in examples 1 to 13 were used as a catalyst for oxidative dehydrogenation of n-butane, as follows.

0.2g (packing volume of 0.5mL) of the heteroatom-containing nanocarbon material prepared in examples 1 to 13 as a catalyst was packed in a universal fixed bed miniature quartz tube reactor each having quartz sand sealed at both ends, and a gas containing n-butane and oxygen (concentration of n-butane of 0.7 vol%, molar ratio of n-butane to oxygen of 1: 2, and balance of nitrogen as a carrier gas) was evacuated in total volume under normal pressure (i.e., 1 atm) and at 450 deg.CThe speed is 1000h^-1The reaction was conducted by passing it into the reactor, and the composition of the reaction mixture discharged from the reactor was continuously monitored, and the n-butane conversion, the total olefin selectivity, the n-butene selectivity, and the butadiene selectivity were calculated, and the results of the reaction for 5 hours are shown in Table 2.

Experimental comparative examples 1 to 10

Hydrocarbon oxidative dehydrogenation reactions were carried out in the same manner as in experimental examples 1 to 10, except that the heteroatom-containing nanocarbon materials prepared in comparative examples 1 to 10 were packed in a universal type fixed bed microtquartz tube reactor as catalysts, respectively. The results of the reaction for 5 hours are shown in Table 2.

Comparative Experimental examples 1 to 4

Hydrocarbon oxidative dehydrogenation reactions were carried out in the same manner as in experimental examples 1 to 13, except that the raw material nanocarbon materials in step (1) of examples 1, 9, 12 and 13 were packed as catalysts in a universal fixed bed microtube reactor, respectively. The results of the reaction for 5 hours are shown in Table 2.

The results in table 2 demonstrate that the nanocarbon materials containing heteroatoms according to the present invention show good catalytic performance in oxidative dehydrogenation of hydrocarbons, and significantly improved product selectivity can be obtained.

Comparing example 1 with comparative example 6, example 12 with comparative example 8, and example 13 with comparative example 10, it can be seen that the heteroatom-containing nanocarbon material according to the present invention can achieve a better balance between product selectivity and raw material conversion rate, and not only can achieve higher product selectivity, but also can maintain the raw material conversion rate at a higher level.

Comparing example 1 with comparative example 5, example 12 with comparative example 7, and example 13 with comparative example 9, it can be seen that, with the heteroatom-containing nanocarbon material according to the present invention as a catalyst, although the conversion of the raw material is reduced, the product selectivity is significantly improved, and since the unconverted raw material can be recovered and reused, higher raw material utilization and product yield can be obtained overall with the heteroatom-containing nanocarbon material according to the present invention as a catalyst.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

TABLE 2

¹: the raw material nanocarbon material in example 1

²: the raw material nanocarbon material in example 9

³: the raw material nanocarbon material in example 12

⁴: the raw material nanocarbon material in example 13.

Claims

1. A heteroatom-containing nanocarbon material contains an oxygen element, a phosphorus element, a hydrogen element and a carbon element, wherein the content of the oxygen element is 3-9 wt%, the content of the phosphorus element is 0.1-4 wt%, the content of the hydrogen element is 0.1-3 wt%, the content of the carbon element is 84-96.8 wt%, and the concentration of peroxy groups in the heteroatom-containing nanocarbon material is 0.1 × 10^-6mol/g to 3 × 10^- ⁶mol/g。

2. The heteroatom-containing nanocarbon material of claim 1, wherein the concentration of peroxy groups in the heteroatom-containing nanocarbon materialDegree of 0.2 × 10^-6mol/g to 2.8 × 10^-6mol/g。

3. The heteroatom-containing nanocarbon material as claimed in claim 2, wherein the concentration of peroxy groups in the heteroatom-containing nanocarbon material is 0.3 × 10^-6mol/g to 2.5 × 10^-6mol/g。

4. The heteroatom-containing nanocarbon material as claimed in any one of claims 1 to 3, wherein the heteroatom-containing nanocarbon material has an X-ray photoelectron spectrum pattern corresponding to the total amount of surface elements of the heteroatom-containing nanocarbon material determined by X-ray photoelectron spectrum

The content of oxygen element determined by the peak of the radical is 0.1-3 mol%.

5. The heteroatom-containing nanocarbon material as claimed in claim 4, wherein the total amount of surface elements of the heteroatom-containing nanocarbon material determined by X-ray photoelectron spectroscopy is determined by X-ray photoelectron spectroscopy

The content of oxygen element determined by the peak of the radical is 0.3-2.8 mol%.

6. The heteroatom-containing nanocarbon material as claimed in claim 5, wherein the total amount of surface elements of the heteroatom-containing nanocarbon material determined by X-ray photoelectron spectroscopy is determined by X-ray photoelectron spectroscopy

The content of oxygen element determined by the peak of the radical is 0.4-2.7 mol%.

7. The heteroatom-containing nanocarbon material as claimed in claim 6, wherein the total amount of surface elements of the heteroatom-containing nanocarbon material determined by X-ray photoelectron spectroscopy is determined by X-ray photoelectron spectroscopy

The content of oxygen element determined by the peak of the radical is 0.5-2.5 mol%.

8. The heteroatom-containing nanocarbon material as claimed in any one of claims 1 to 3, wherein the content of oxygen element determined from a peak corresponding to a C-O group and the content of oxygen element determined from a peak corresponding to a C-O group in an X-ray photoelectron spectrum of the heteroatom-containing nanocarbon material

The molar ratio of the content of oxygen element determined by the peak of the radical is more than 1.

9. The heteroatom-containing nanocarbon material as claimed in claim 8, wherein the content of oxygen element determined from a peak corresponding to a C-O group and the content of oxygen element determined from a peak corresponding to a C-O group in an X-ray photoelectron spectroscopy spectrum of the heteroatom-containing nanocarbon material

The molar ratio of the content of oxygen element determined by the peak of the group is 2-10: 1.

10. the heteroatom-containing nanocarbon material as claimed in claim 9, wherein the content of oxygen element determined from a peak corresponding to a C-O group and the content of oxygen element determined from a peak corresponding to a C-O group in an X-ray photoelectron spectroscopy spectrum of the heteroatom-containing nanocarbon material

The molar ratio of the content of oxygen element determined by the peak of the group is 2-8: 1.

11. the heteroatom-containing nanocarbon material as claimed in claim 10, wherein the content of oxygen element determined from a peak corresponding to a C-O group and the content of oxygen element determined from a peak corresponding to a C-O group in an X-ray photoelectron spectroscopy spectrum of the heteroatom-containing nanocarbon material

The molar ratio of the content of oxygen element determined by the peak of the group is 2.1-6: 1.

12. the heteroatom-containing nanocarbon material as claimed in any one of claims 1 to 3, wherein the X-ray photoelectron spectrum of the heteroatom-containing nanocarbon material corresponds to

The content of oxygen determined by the peak of the radical corresponds to

The molar ratio of the content of oxygen element determined by the peak of the group is 0.1-1: 1.

13. the heteroatom-containing nanocarbon material of claim 12, wherein the X-ray photoelectron spectrum of the heteroatom-containing nanocarbon material corresponds to

The content of oxygen determined by the peak of the radical corresponds to

The molar ratio of the content of oxygen element determined by the peak of the group is 0.1-0.8: 1.

14. the heteroatom-containing nanocarbon material of claim 13, wherein the X-ray photoelectron spectrum of the heteroatom-containing nanocarbon material corresponds to

The content of oxygen determined by the peak of the radical corresponds to

The molar ratio of the content of oxygen element determined by the peak of the group is 0.15-0.7: 1.

15. the heteroatom-containing nanocarbon material as claimed in any one of claims 1 to 3, wherein in an X-ray photoelectron spectrum of the heteroatom-containing nanocarbon material, the content of oxygen element determined from a peak corresponding to adsorbed water is 5 mol% or less based on the total amount of surface elements of the heteroatom-containing nanocarbon material determined by X-ray photoelectron spectrum.

16. The heteroatom-containing nanocarbon material as claimed in claim 15, wherein the content of oxygen element determined from a peak corresponding to adsorbed water in an X-ray photoelectron spectroscopy spectrum of the heteroatom-containing nanocarbon material is 0.1 to 1 mol% based on the total amount of surface elements of the heteroatom-containing nanocarbon material determined from X-ray photoelectron spectroscopy.

17. The heteroatom-containing nanocarbon material as claimed in any one of claims 1 to 3, wherein the content of oxygen element is 3.5 to 8.5 wt%, the content of phosphorus element is 0.2 to 3.5 wt%, the content of hydrogen element is 0.2 to 2 wt%, and the content of carbon element is 86 to 96.1 wt%, in terms of element, based on the total amount of the heteroatom-containing nanocarbon material.

18. The heteroatom-containing nanocarbon material of claim 17, wherein the content of oxygen element is 4 to 8.5 wt%, the content of phosphorus element is 0.3 to 3 wt%, the content of hydrogen element is 0.5 to 1.5 wt%, and the content of carbon element is 87 to 95.2 wt% in terms of element based on the total amount of the heteroatom-containing nanocarbon material.

19. The heteroatom-containing nanocarbon material according to any one of claims 1 to 3, wherein the heteroatom-containing nanocarbon material is a heteroatom-containing carbon nanotube.

20. The heteroatom-containing nanocarbon material of claim 19, wherein the heteroatom-containing nanocarbon material is a heteroatom-containing multi-walled carbon nanotube.

21. The heteroatom-containing nanocarbon material of claim 20, wherein the heteroatom-containing multiwall carbon nanotube has a specific surface area of 50 to 500m²/g。

22. The heteroatom-containing nanocarbon material of claim 21, wherein the heteroatom-containing multiwall carbon nanotube has a specific surface area of 70-300m²/g。

23. The heteroatom-containing nanocarbon material of claim 22, wherein the heteroatom-containing multiwall carbon nanotube has a specific surface area of 120-285m²/g。

24. The heteroatom-containing nanocarbon material of claim 20, wherein the heteroatom-containing multi-walled carbon nanotube has a weight loss ratio w within a temperature range of 400-800 ℃₈₀₀The weight loss rate in the temperature range of 400-500 ℃ is w₅₀₀，w₅₀₀/w₈₀₀In the range of 0.01-0.3.

25. The heteroatom-containing nanocarbon material of claim 24, wherein w₅₀₀/w₈₀₀In the range of 0.02-0.2.

26. The heteroatom-containing nanocarbon material of claim 25, wherein w₅₀₀/w₈₀₀In the range of 0.1-0.15.

27. A method for preparing a heteroatom-containing nanocarbon material, the method comprising:

the raw material nano carbon material contains oxygen element, hydrogen element and carbon element, wherein the content of the oxygen element is 0.1-1 wt%, the content of the hydrogen element is 0.1-1 wt%, and the content of the carbon element is 98-99.8 wt% calculated by the element based on the total amount of the raw material nano carbon material,

28. The method according to claim 27, wherein the content of the oxygen element is 0.5 to 0.9% by weight, the content of the hydrogen element is 0.3 to 0.6% by weight, and the content of the carbon element is 98.5 to 99.2% by weight, in terms of element, based on the total amount of the raw nanocarbon material.

29. The method according to claim 27, wherein the concentration of peroxy groups in the prepared heteroatom-containing nanocarbon material is 0.2 × 10^-6mol/g to 2.8 × 10^-6mol/g。

30. The method according to claim 29, wherein the concentration of peroxy groups in the prepared heteroatom-containing nanocarbon material is 0.3 × 10^-6mol/g to 2.5 × 10^-6mol/g。

31. According to claim27 wherein in step a1 the oxidizing agent is selected from HNO₃、H₂SO₄One or more than two of hydrogen peroxide and peroxide shown in formula I,

32. The method of claim 31, wherein the oxidizing agent is HNO₃And/or H₂SO₄。

33. The method of claim 32, wherein the oxidizing agent is HNO₃And H₂SO₄。

34. The method of claim 33, wherein the oxidizing agent is HNO₃And H₂SO₄And HNO₃And H₂SO₄The molar ratio is 1: 3-10.

35. The method of claim 34, wherein HNO₃And H₂SO₄The molar ratio is 1: 3.5-7.5.

36. The method as claimed in any one of claims 27 to 35, wherein the oxidizing agent is used in an amount of 500-50000 parts by weight per 100 parts by weight of the raw nanocarbon material in step a 1.

37. The method as claimed in claim 36, wherein the oxidant is used in an amount of 1000-15000 parts by weight per 100 parts by weight of the raw nanocarbon material in step a 1.

38. The method as claimed in claim 37, wherein in the step a1, the oxidizing agent is used in an amount of 1500-10000 parts by weight per 100 parts by weight of the raw nanocarbon material.

39. The method of claim 27, wherein in step a1, the raw nanocarbon material is contacted with the oxidizing agent in the presence of ultrasound.

40. The method of claim 39, wherein the frequency of the ultrasonic waves is 25-100 kHz.

41. The method of claim 40, wherein the frequency of the ultrasonic waves is 40-60 kHz.

42. The method of any one of claims 27 and 39-41, wherein in step A1, the duration of the contacting is 0.5-10 hours.

43. The method of claim 42, wherein in step A1, the duration of contact is 1-6 hours.

44. The method of any one of claims 27 and 39-41, wherein in step A1, the contacting is performed in water.

45. The method as claimed in claim 44, wherein in the step A1, the amount of water used is 500-10000 parts by weight per 100 parts by weight of the raw nanocarbon material.

46. The method as claimed in claim 45, wherein the amount of water used in step A1 is 1000-8000 parts by weight per 100 parts by weight of the raw nanocarbon material.

47. The method as claimed in claim 46, wherein, in the step A1, the amount of water used is 4000-6000 parts by weight relative to 100 parts by weight of the raw nano-carbon material.

48. The method according to any one of claims 27 to 35 and 39 to 41, further comprising a step A2 of separating solid matter from the contacted mixture of step A1 and drying the solid matter to obtain the oxidation-treated nanocarbon material in a step A2.

49. The method of claim 48, wherein said drying is carried out at a temperature of 80-180 ℃ and the duration of said drying is 0.5-24 hours.

50. The method as claimed in claim 49, wherein the drying is carried out at a temperature of 100-140 ℃ and the duration of the drying is 1-20 hours.

51. The method of claim 50, wherein the duration of drying is 8-16 hours.

52. The method of any one of claims 27-35 and 39-41, wherein the contacting in step A1 is performed at a temperature of 10-50 ℃.

53. The process of claim 52, wherein the contacting in step A1 is carried out at a temperature of 20-50 ℃.

54. The method of any one of claims 27 to 35 and 39 to 41, wherein the concentration of peroxy groups in the oxidatively treated nanocarbon material obtained in step A1 is 4 × 10^-6mol/g to 20 × 10^-6mol/g。

55. The method of claim 54, wherein the concentration of peroxy groups in the oxidized nanocarbon material of step A1 is 5 × 10^-6mol/g to 10 × 10^-6mol/g。

56. The method of claim 27, wherein in step B1, the reducing agent is one or more of hydrogen, carbon monoxide, hydrogen sulfide, methane, lithium aluminum hydride, sodium borohydride, triethylaluminum, sodium hydride, sodium formate, and ethylene glycol.

57. The process of claim 56, wherein in step B1, the reducing agent is lithium aluminum hydride and/or sodium formate.

58. The method according to any one of claims 27, 56 and 57, wherein in step B1, the molar ratio of the amount of reducing agent to oxygen in the oxidatively treated nanocarbon material is in the range of 0.1 to 10: 1.

59. the method according to claim 58, wherein in step B1, the molar ratio of the amount of the reducing agent to the oxygen in the oxidation-treated nanocarbon material is 0.1-4: 1.

60. the method according to claim 59, wherein in step B1, the molar ratio of the amount of the reducing agent to the oxygen in the oxidation-treated nanocarbon material is 1-3: 1.

61. the process of any one of claims 27, 56 and 57, wherein in step B1, the contacting is carried out at a temperature of 10-100 ℃.

62. The process of claim 61, wherein in step B1, the contacting is carried out at a temperature of 40-80 ℃.

63. The method of claim 62, wherein in step B1, the contacting is performed at a temperature of 50-70 ℃.

64. The method of any one of claims 27, 56 and 57, wherein in step B1, the duration of contact is between 2 and 24 hours.

65. The method of claim 64, wherein in step B1, the duration of contact is between 8 and 16 hours.

66. The method of claim 65, wherein in step B1, the duration of said contacting is between 5 and 12 hours.

67. The process of any one of claims 27, 56 and 57, wherein the contacting in step B1 is carried out in the presence of at least one liquid dispersion medium, the process further comprising step B2, in step B2, separating solid matter from the mixture resulting from the contacting in step B1, and drying the separated solid matter.

68. The method according to claim 67, wherein the liquid dispersion medium is water and/or an ether-type organic solvent.

69. The method of claim 68, wherein the liquid dispersion medium is water and/or an oxetane type organic solvent.

70. The method of claim 69, wherein the liquid dispersion medium is water and/or tetrahydrofuran.

71. The process of claim 67, wherein in step B2, the drying is carried out at a temperature of 80-180 ℃ and the duration of the drying is 0.5-24 hours.

72. The method as claimed in claim 71, wherein the drying in step B2 is carried out at a temperature of 100-140 ℃ and the duration of the drying is 1-20 hours.

73. The method of claim 72, wherein in step B2, the duration of drying is 6-16 hours.

74. The method of claim 27, wherein in step C1, the phosphorus source is an acid containing phosphorus element and/or a salt containing phosphorus element.

75. The method of claim 74, wherein in step C1, the source of phosphorus is one or more of diammonium phosphate, ammonium dihydrogen phosphate, ammonium phosphate, phosphoric acid, pyrophosphoric acid, and metaphosphoric acid.

76. The method of claim 75, wherein in step C1, the phosphorus source is one or more of monoammonium phosphate, diammonium phosphate, and ammonium phosphate.

77. The method of any one of claims 27 and 74-76, wherein the reduced nanocarbon material: the weight ratio of the phosphorus source is 1: in the range of 0.001 to 5, based on the phosphorus-containing compound.

78. A process as claimed in claim 77, wherein the reduced nanocarbon material: the weight ratio of the phosphorus source is 1: in the range of 0.004-2, the phosphorus source is based on a phosphorus-containing compound.

79. A process as claimed in claim 78, wherein the reduced nanocarbon material: the weight ratio of the phosphorus source is 1: in the range of 0.006 to 1, the phosphorus source being based on the phosphorus-containing compound.

80. The method of claim 79, wherein the reduced nanocarbon material: the weight ratio of the phosphorus source is 1: in the range of 0.005-0.5, the phosphorus source is calculated as a phosphorus-containing compound.

81. The method of any one of claims 27 and 74-76, wherein in step C1, the contacting is performed in water.

82. The method of claim 81, wherein the reduced nanocarbon material: the weight ratio of water is 1: 2-100.

83. A process as claimed in claim 82, wherein the reduced nanocarbon material: the weight ratio of water is 1: 3-80.

84. The method of claim 83, wherein the reduced nanocarbon material: the weight ratio of water is 1: 5-60.

85. The method of claim 84, wherein the reduced nanocarbon material: the weight ratio of water is 1: 7-30.

86. The method of any one of claims 27 and 74-76, wherein the contacting in step C1 is performed at a temperature of 10-250 ℃.

87. The process of claim 86, wherein in step C1, the contacting is carried out at a temperature of 15-100 ℃.

88. The method of any one of claims 27 and 74-76, wherein in step C1, the duration of the contacting is 6-72 hours.

89. The method of claim 88, wherein in step C1, the duration of the contacting is 8-48 hours.

90. The method of claim 89, wherein in step C1, the duration of said contacting is 12-36 hours.

91. The process of any one of claims 27 and 74 to 76, wherein the process further comprises a step C2, wherein in step C2, the mixture obtained in step C1 is optionally subjected to solid-liquid separation and then dried.

92. The method of claim 91, wherein in step C2, the drying is performed at a temperature of from ambient temperature to 200 ℃.

93. The method of claim 92, wherein in step C2, the drying is performed at a temperature of ambient to 140 ℃.

94. The method of claim 91, wherein the drying in step C2 comprises a first drying and a second drying performed sequentially, the first drying being performed at a temperature of ambient to 40 ℃ and the second drying being performed at a temperature of 80-140 ℃.

95. The method of claim 94, wherein the duration of the first drying is 6-72 hours.

96. The method of claim 95, wherein said first drying is for a duration of 12-60 hours.

97. The method of claim 94, wherein the duration of said second drying is 0.5-8 hours.

98. The method according to claim 27, wherein the raw nanocarbon material has an X-ray photoelectron spectrum corresponding to a total amount of surface elements of the raw nanocarbon material determined by the X-ray photoelectron spectrum

The content of oxygen element determined by the peak of the group is 0.1-1 mol%, and the content of oxygen element determined by the peak corresponding to C-O group

The molar ratio of the content of the oxygen element determined by the spectrum peak of the radical is not more than 1.

99. The method according to claim 98, wherein the raw nanocarbon material has an X-ray photoelectron spectrum corresponding to a total amount of surface elements of the raw nanocarbon material determined by the X-ray photoelectron spectrum

The content of oxygen element determined by the peak of the group is 0.2-0.8 mol%, and the content of oxygen element determined by the peak corresponding to C-O group

100. the method according to claim 99, wherein the raw nanocarbon material has an X-ray photoelectron spectrum corresponding to a total amount of surface elements of the raw nanocarbon material determined by the X-ray photoelectron spectrum

The content of oxygen element determined by the peak of the group is 0.3-0.5 mol%, and the content of oxygen element determined by the peak corresponding to C-O group

The molar ratio of the oxygen content determined by the peak of the radical is 0.2-0.95: 1.

101. the method as claimed in claim 100, wherein the raw nanocarbon material has an X-ray photoelectron spectrum in which the content of oxygen element determined from a peak corresponding to a C — O group and the content of oxygen element determined from a peak corresponding to a C — O group are the same

The molar ratio of the content of oxygen element determined by the peak of the group is 0.5-0.9: 1.

102. the method according to claim 27, wherein the raw nanocarbon material has an X-ray photoelectron spectrum corresponding to that of the sample nanocarbon

The content of oxygen determined by the peak of the radical corresponds to

103. the method of claim 102, wherein the raw nanocarbon material has an X-ray photoelectron spectrum corresponding to that of claim 102

The content of oxygen determined by the peak of the radical corresponds to

104. the method of claim 103, wherein the raw nanocarbon material has an X-ray photoelectron spectrum corresponding to that of claim 103

The content of oxygen determined by the peak of the radical corresponds to

The molar ratio of the content of oxygen element determined by the peak of the group is 0.2-0.5: 1.

105. the method of any one of claims 27-30 and 98-104, wherein the feedstock nanocarbon material is carbon nanotubes.

106. The method of claim 105, wherein the feedstock nanocarbon material is multi-walled carbon nanotubes.

107. The method of claim 106, wherein said multi-walled carbon nanotubes have a specific surface area of 50-500m²/g。

108. The method of claim 107, wherein the multi-walled carbon nanotubes have a specific surface area of 70-300m²/g。

109. The method as claimed in claim 108, wherein the multi-walled carbon nanotube has a specific surface area of 130-290m²/g。

110. The method as claimed in claim 106, wherein the weight loss ratio of the multi-walled carbon nanotube in the temperature range of 400-800 ℃ is w₈₀₀The weight loss rate in the temperature range of 400-500 ℃ is w₅₀₀，w₅₀₀/w₈₀₀In the range of 0.01-0.3.

111. The method of claim 110, wherein w₅₀₀/w₈₀₀In the range of 0.02-0.2.

112. The method of claim 111, wherein w₅₀₀/w₈₀₀In the range of 0.05-0.15, in the above range.

113. A heteroatom-containing nanocarbon material produced by the method of any one of claims 27 to 112.

114. Use of the heteroatom-containing nanocarbon material of any one of claims 1 to 26 and 113 as a catalyst for oxidative dehydrogenation of hydrocarbons.

115. The use of claim 114, wherein the hydrocarbon is an alkane.

116. The use of claim 115, wherein the hydrocarbon is C₂-C₁₂Of (a) an alkane.

117. The use of claim 116, wherein the hydrocarbon is n-butane.

118. A process for the oxidative dehydrogenation of a hydrocarbon, the process comprising contacting the hydrocarbon with the heteroatom-containing nanocarbon material of any one of claims 1-26 and 113 under hydrocarbon oxidative dehydrogenation reaction conditions.

119. The method of claim 118, wherein the hydrocarbon is an alkane.

120. The method of claim 119, wherein the hydrocarbon is C₂-C₁₂Of (a) an alkane.

121. The method of claim 120, wherein the hydrocarbon is n-butane.