阅读说明：本技术 石墨烯负载化过渡金属化合物及其制备方法和在催化氧化燃油脱硫中的应用 (Graphene-loaded transition metal compound, preparation method thereof and application thereof in catalytic oxidation fuel oil desulfurization ) 是由 王蕊欣 刘叶峰 左鹏 焦娇 吕迎 周喜阳 焦纬洲 于 2021-07-12 设计创作，主要内容包括：本发明属非均相催化剂制备技术领域,针对现有催化剂存在的催化活性低、对燃油中较大浓度含硫化合物去除率较低、去除时间久、完全脱除较为困难、稳定性不高、重复利用性差等缺点,提供石墨烯负载化过渡金属化合物及其制备方法和在催化氧化燃油脱硫中的应用。以氧化石墨烯为载体、多金属氧酸盐为钨源、含N聚合物为碳源和氮源,通过静电结合法制得氧化石墨烯负载多金属氧酸盐前驱体,高温热解制备石墨烯负载化过渡金属碳化物、钨掺杂的氮化钨或金属钨非均相催化剂；所得的催化剂化学稳定性好、价格低廉、环境友好、催化性能高。将其用于燃油催化氧化脱硫中,完全脱硫且脱硫速度加快,提高稳定性,重复利用性高,对燃油脱硫以及环境保护有重要意义。(The invention belongs to the technical field of heterogeneous catalyst preparation, and provides a graphene-loaded transition metal compound, a preparation method thereof and application thereof in catalytic oxidation fuel oil desulfurization, aiming at the defects of low catalytic activity, low removal rate of sulfur-containing compounds with larger concentration in fuel oil, long removal time, difficult complete removal, low stability, poor reusability and the like of the existing catalyst. Preparing a graphene oxide loaded polyoxometallate precursor by using graphene oxide as a carrier, polyoxometallate as a tungsten source and a N-containing polymer as a carbon source and a nitrogen source through an electrostatic combination method, and preparing a graphene loaded transition metal carbide, tungsten-doped tungsten nitride or a metal tungsten heterogeneous catalyst through high-temperature pyrolysis; the obtained catalyst has good chemical stability, low price, environmental protection and high catalytic performance. The catalyst is used for catalytic oxidation desulfurization of fuel oil, has complete desulfurization, high desulfurization speed, high stability and high reusability, and has important significance for fuel oil desulfurization and environmental protection.)

1. The graphene-supported transition metal compound is characterized in that: preparing a graphene oxide loaded polyoxometallate precursor by using graphene oxide as a carrier, polyoxometallate as a tungsten source and a N-containing polymer as a carbon source and a nitrogen source through an electrostatic combination method, and then preparing a graphene loaded transition metal carbide, tungsten-doped tungsten nitride or a metal tungsten heterogeneous catalyst through high-temperature pyrolysis;

the transition metal carbide is W₂C or Mo₂C; the tungsten-doped tungsten nitride is W-W₂N；

The graphene-supported transition metal carbide heterogeneous catalyst is prepared from the following components in parts by weight: loading Keggin type polyoxometallate on polymer modified graphene oxide by adopting an electrostatic combination method, and then carrying out high-temperature pyrolysis to obtain the polymer modified graphene oxide;

wherein: the Keggin type polyoxometallate is phosphotungstic acid H₃PW₁₂O₄₀·xH₂O is PW₁₂Or phosphomolybdic acid H₃PMo₁₂O₄₀·xH₂O is PMo₁₂；

The polymer modified graphene oxide is any one of polyethyleneimine modified graphene oxide PEI/GO, dopamine modified graphene oxide PDA/GO, chitosan modified graphene oxide CS/GO, polypyrrole modified graphene oxide PPy/GO and polyaniline modified graphene oxide PANI/GO;

the tungsten nitride or metal tungsten doped with the graphene-loaded tungsten is as follows: loading Keggin type or Dawson type polyoxometallate on polymer modified graphene oxide by adopting an electrostatic combination method, and then carrying out high-temperature pyrolysis to obtain the graphene oxide;

wherein: the Keggin type polyoxometallate is silicotungstic acid H₄SiW₁₂O₄₀·xH₂O is SiW₁₂The Dawson type phosphotungstate is K₆[α-P₂W₁₈O₆₂]·14H₂O is P₂W₁₈Or K₁₀[α-P₂W₁₇O₆₁] ·20H₂O is P₂W₁₇；

The polymer modified graphene oxide is any one of PEI/GO, PDA/GO, CS/GO, PPy/GO or PANI/GO.

2. A method for producing the graphene-supported transition metal compound according to claim 1, characterized in that: the method comprises the following specific steps:

(1) adding 0.05-0.3 g of polymer modified graphene oxide into 10-60 mL of water, and carrying out acidification treatment to obtain solution A;

(2) dissolving 0.2-0.6 g of polyoxometallate in 10-20 mL of deionized water, and carrying out acidification treatment to obtain solution B;

(3) slowly dripping the solution B into the solution A, adjusting the pH value of the solution to 4-5, reacting at normal temperature for 10-12 hours, centrifuging at 25 ℃ and 4000rpm for 10-15 minutes to obtain a solid product, washing with deionized water, and carrying out vacuum freeze drying at-55 ℃ for 48 hours to obtain polymer modified graphene oxide supported polyoxometallate;

(4) and (3) placing 0.1-0.4g of the prepared polymer modified graphene oxide supported polyoxometallate in a porcelain boat, heating to 800-1000 ℃ at the speed of 5 ℃/min in a nitrogen atmosphere, and preserving heat for 2h to obtain the graphene supported transition metal carbide, tungsten-doped tungsten nitride and metal tungsten heterogeneous catalyst.

3. The method for producing a graphene-supported transition metal compound according to claim 2, characterized in that: the acidification treatment comprises the following steps: the pH value of the solution is adjusted to 4-5 by using 4 mol/L hydrochloric acid solution.

4. The method for producing a graphene-supported transition metal compound according to claim 2, characterized in that: the mixing ratio range of the solution A and the solution B in the step (3) is V_{Solution A}：V_{Liquid B}=1-3:1。

5. The method for producing a graphene-supported transition metal compound according to claim 2, characterized in that: the polymer-modified graphene oxide carrier is any one of PEI/GO, PDA/GO, CS/GO, PPy/GO or PANI/GO;

the graphene-supported transition metal compound is a graphene-supported transition metal carbide heterogeneous catalyst, and the polyoxometallate is Keggin type polyoxometallate PW₁₂Or PMo₁₂；

The graphene-supported transition metal compound is a tungsten-doped tungsten nitride heterogeneous catalyst or a metal tungsten heterogeneous catalyst, and the polyoxometallate is Keggin type or Dawson type polyoxometallate SiW₁₂、P₂W₁₈Or P₂W₁₇；

The transition metal carbide is molybdenum carbide Mo₂C or ditungsten carbide W₂C; the tungsten doped tungsten nitride is W-W₂N。

6. The method for producing a graphene-supported transition metal compound according to claim 2, characterized in that: the polymer modified graphene oxide supported polyoxometallate is as follows: PW (pseudo wire)₁₂-PEI/GO、PMo₁₂-PEI/GO、SiW₁₂-PEI/GO、P₂W₁₈-PEI/GO、P₂W₁₇- PEI/GO、PW₁₂-PDA/GO、PMo₁₂-PDA/GO、SiW₁₂-PDA/GO、P₂W₁₈-PDA/GO、P₂W₁₇- PDA/GO、PW₁₂-CS/GO、PMo₁₂-CS/GO、SiW₁₂-CS/GO、P₂W₁₈-CS/GO、P₂W₁₇- CS/GO、PW₁₂-PPy/GO、PMo₁₂- PPy /GO、SiW₁₂- PPy /GO、P₂W₁₈- PPy /GO、P₂W₁₇- PPy /GO、PW₁₂- PANI /GO、PMo₁₂- PANI /GO、SiW₁₂- PANI /GO、P₂W₁₈- PANI /GO、P₂W₁₇-any of PANI/GO.

7. The application of the graphene-supported transition metal compound in catalytic oxidation fuel oil desulfurization, which is characterized in that: the graphene-loaded transition metal compound is applied to catalyzing hydrogen peroxide to oxidize fuel oil for desulfurization, hydrogen peroxide is used as an oxidant at normal pressure, graphene-loaded transition metal carbide, tungsten-doped tungsten nitride or metal tungsten are used as heterogeneous catalysts to catalyze dibenzothiophene for oxidative desulfurization, and an oxidation product is dibenzothiophene sulfone.

8. Use according to claim 7, characterized in that: the specific method comprises the following steps: 0.005-0.1g of catalyst was added to 20mL of catalytic oxidation simulating oil containing 4000ppm, followed by 20mL of acetonitrile extractant and 128-510. mu.L of 30% H₂O₂Heating the water solution and the system to 30-70 ℃, and reacting for 2-40 min at 500 rpm; taking 100 mu L of solution from the upper layer of n-octane phase at an interval of 2-5 min in the reaction process, and diluting with 4 mL of n-octane for HPLC test;

the chromatographic conditions for the HPLC tests were as follows: c18 reverse phase chromatography column, inner diameter: 200mm multiplied by 4.6mm multiplied by 5 mu m, catalytic oxidation simulation oil, and gradient leaching to 100% methanol by 10 min with 90% methanol and 10% deionized water as initial mobile phases, wherein the column temperature is 25 ℃; detection wavelength: 254 nm, flow rate 1.0 mL/min^-1；

Wherein the catalytic oxidation simulation oil is an n-octane solution of dibenzothiophene DBT, benzothiophene BT, 4, 6-dimethyldibenzothiophene 4,6-DMDBT and/or thiophene Th; wherein the catalysts are respectively Mo₂C-N/P-rGO、W₂C-N/P-rGO、W-W₂N- N/P-rGO、W- N/P-rGO。

Technical Field

The invention belongs to the technical field of heterogeneous catalyst preparation, and particularly relates to a graphene-loaded transition metal compound, a preparation method thereof and application thereof in catalytic oxidation fuel oil desulfurization. The method specifically relates to preparation of a graphene-loaded transition metal carbide, tungsten-doped tungsten nitride or metal tungsten heterogeneous catalyst and application of the catalyst in fuel oil oxidation desulfurization.

Background

The global economy is developed without fossil fuel, and liquid fuels (gasoline, diesel, etc.) play a great role from power generation to transportation, but contain a large amount of sulfur-containing compounds (such as mercaptans, sulfides, disulfides, thiophenes and derivatives thereof). The combustion of sulfur-containing compounds causes a series of environmental problems such as smoke, acid rain, building corrosion, land eutrophication and the like, and the emerging fog and haze pose serious threats to human health. The pollution source in fuel oil is mainly sulfur pollution, and more scientific researchers are focusing on the removal of sulfur-containing oil products in order to reduce the emission of sulfur dioxide. In view of the harm caused by the combustion of sulfur-containing compounds in fuel oil, the standards of various countries in the world for the sulfur content in the fuel oil are more rigorous, and the countries have a law to require petrochemical enterprises to produce low-sulfur even sulfur-free fuel, and the six standards of the latest countries require that the sulfur content is not more than 10 ppm.

At present, the traditional industrial desulfurization method is hydrodesulfurization, although the method has mature technology, the one-time investment is large, the operation cost is high, a large amount of hydrogen is consumed, the oil product cost is directly and greatly increased, and the method only has obvious effect on removing sulfides such as mercaptan, thioether and the like in the oil product, and is difficult to remove aromatic sulfides. Therefore, researchers develop many non-hydrodesulfurization methods to replace the traditional hydrodesulfurization methods, such as Oxidation Desulfurization (ODS), extraction desulfurization, adsorption desulfurization, biological desulfurization, and photocatalytic desulfurization, wherein Oxidation Desulfurization (ODS) is one of the research hotspots for fuel desulfurization due to the advantages of mild reaction conditions (normal temperature and pressure), no need of hydrogen source, simple process flow, high desulfurization rate (thiophene and its derivatives which are difficult to remove can be removed by oxidation), low equipment investment, low operation cost, no secondary pollution, and the like. In order to improve the effect of catalytic oxidation desulfurization, the selection of the catalyst is crucial, and the currently commonly used catalysts mainly comprise polyoxometallate catalysts, ionic liquid catalysts, transition metal oxide catalysts, inorganic nonmetal catalysts, MOF catalysts, phthalocyanine catalysts and the like, but the catalysts still have the problems of low catalytic activity, low removal rate, long removal time, difficult complete removal, low stability, difficult reutilization and the like for sulfur-containing compounds with larger concentration in fuel oil.

Disclosure of Invention

The invention provides a graphene-loaded transition metal compound, a preparation method thereof and application thereof in catalytic oxidation fuel oil desulfurization, aiming at the problems of low catalytic activity, low removal rate of sulfur-containing compounds with larger concentration in fuel oil, long removal time, difficult complete removal, low stability and poor reusability of the existing catalyst.

The invention is realized by adopting the following technical scheme: preparing a graphene oxide-loaded polyoxometallate precursor by using graphene oxide as a carrier, polyoxometallate as a tungsten source and a N-containing polymer as a carbon source and a nitrogen source through an electrostatic combination method, and then preparing a graphene-loaded transition metal carbide, tungsten-doped tungsten nitride or a metal tungsten heterogeneous catalyst through high-temperature pyrolysis;

the transition metal carbide is W₂C or Mo₂C; the tungsten-doped tungsten nitride is W-W₂N；

The graphene-supported transition metal carbide heterogeneous catalyst is prepared from the following components in parts by weight: by electrostatic bondingThe method comprises the steps of loading Keggin type polyoxometallate on polymer-modified graphene oxide, and then carrying out high-temperature pyrolysis to obtain the polymer-modified graphene oxide; wherein: the Keggin type polyoxometallate is phosphotungstic acid H₃PW₁₂O₄₀·xH₂O is PW₁₂Or phosphomolybdic acid H₃PMo₁₂O₄₀·xH₂O is PMo₁₂；

The polymer modified graphene oxide is any one of polyethyleneimine modified graphene oxide PEI/GO, dopamine modified graphene oxide PDA/GO, chitosan modified graphene oxide CS/GO, polypyrrole modified graphene oxide PPy/GO and polyaniline modified graphene oxide PANI/GO;

the graphene-supported tungsten-doped tungsten nitride or metal tungsten is prepared by loading Keggin type or Dawson type polyoxometallate on polymer-modified graphene oxide by adopting an electrostatic combination method and then pyrolyzing at high temperature;

wherein: the Keggin type polyoxometallate is silicotungstic acid H₄SiW₁₂O₄₀·xH₂O is SiW₁₂The Dawson type phosphotungstate is K₆[α-P₂W₁₈O₆₂]·14H₂O is P₂W₁₈Or K₁₀[α-P₂W₁₇O₆₁] ·20H₂O is P₂W₁₇；

The polymer modified graphene oxide is any one of PEI/GO, PDA/GO, CS/GO, PPy/GO or PANI/GO.

The method for preparing the graphene-supported transition metal compound comprises the following specific steps:

(1) adding 0.05-0.3 g of polymer modified graphene oxide into 10-60 mL of water, and carrying out acidification treatment to obtain solution A;

(2) dissolving 0.2-0.6 g of polyoxometallate in 10-20 mL of deionized water, and carrying out acidification treatment to obtain solution B;

(3) slowly dripping the solution B into the solution A, adjusting the pH value of the solution to 4-5, reacting at normal temperature for 10-12 hours, centrifuging at 25 ℃ and 4000rpm for 10-15 minutes to obtain a solid product, washing with deionized water, and carrying out vacuum freeze drying at-55 ℃ for 48 hours to obtain polymer modified graphene oxide supported polyoxometallate;

(4) and (3) placing 0.1-0.4g of the prepared polymer modified graphene oxide supported polyoxometallate in a porcelain boat, heating to 800-1000 ℃ at the speed of 5 ℃/min in a nitrogen atmosphere, and preserving heat for 2h to obtain the graphene supported transition metal carbide, tungsten-doped tungsten nitride and metal tungsten heterogeneous catalyst.

The polymer-modified graphene oxide carrier is any one of PEI/GO, PDA/GO, CS/GO, PPy/GO or PANI/GO;

the acidification treatment method is to use 4 mol/L hydrochloric acid solution to adjust the pH value of the solution to 4-5;

the liquid B is slowly dripped into the liquid A, wherein the mixing ratio range of the liquid A and the liquid B is V_{Solution A}：V_{Liquid B}=1-3:1；

The graphene-supported transition metal compound is a graphene-supported transition metal carbide, and the polyoxometallate is Keggin type polyoxometallate PW₁₂Or PMo₁₂；

The graphene-supported transition metal compound is tungsten-doped tungsten nitride or a tungsten metal heterogeneous catalyst, and the polyoxometallate is Keggin type or Dawson type polyoxometallate SiW₁₂、P₂W₁₈Or P₂W₁₇；

The transition metal carbide is molybdenum carbide Mo₂C or ditungsten carbide W₂C; the tungsten doped tungsten nitride is W-W₂N。

The polymer modified graphene oxide supported polyoxometallate is as follows: PW (pseudo wire)₁₂-PEI/GO、PMo₁₂-PEI/GO、SiW₁₂-PEI/GO、P₂W₁₈-PEI/GO、P₂W₁₇- PEI/GO、PW₁₂-PDA/GO、PMo₁₂-PDA/GO、SiW₁₂-PDA/GO、P₂W₁₈-PDA/GO、P₂W₁₇- PDA/GO、PW₁₂-CS/GO、PMo₁₂-CS/GO、SiW₁₂-CS/GO、P₂W₁₈-CS/GO、P₂W₁₇- CS/GO、PW₁₂-PPy/GO、PMo₁₂- PPy /GO、SiW₁₂- PPy /GO、P₂W₁₈- PPy /GO、P₂W₁₇- PPy /GO、PW₁₂- PANI /GO、PMo₁₂- PANI /GO、SiW₁₂- PANI /GO、P₂W₁₈- PANI /GO、P₂W₁₇-any of PANI/GO.

The graphene-loaded transition metal compound is applied to catalyzing hydrogen peroxide to oxidize fuel oil for desulfurization, hydrogen peroxide is used as an oxidant at normal pressure, graphene-loaded transition metal carbide, tungsten-doped tungsten nitride or metal tungsten are used as heterogeneous catalysts to catalyze dibenzothiophene for oxidative desulfurization, and an oxidation product is dibenzothiophene sulfone.

The specific method comprises the following steps: 0.005-0.1g of catalyst was added to 20mL of catalytic oxidation simulating oil containing 4000ppm, followed by 20mL of acetonitrile extractant and 128-510. mu.L of 30% H₂O₂Heating the water solution and the system to 30-70 ℃, and reacting for 2-40 min at 500 rpm. Taking 100 mu L of solution from the upper layer of n-octane phase at an interval of 2-5 min in the reaction process, and diluting with 4 mL of n-octane for HPLC test;

the chromatographic conditions for the HPLC tests were as follows: c18 reverse phase chromatography column, inner diameter: 200mm multiplied by 4.6mm multiplied by 5 mu m, catalytic oxidation simulation oil, and gradient leaching to 100% methanol by 10 min with 90% methanol and 10% deionized water as initial mobile phases, wherein the column temperature is 25 ℃; detection wavelength: 254 nm, flow rate 1.0 mL/min^-1；

Wherein the catalytic oxidation simulation oil is an n-octane solution of dibenzothiophene DBT, benzothiophene BT, 4, 6-dimethyldibenzothiophene 4,6-DMDBT and/or thiophene Th; wherein the catalysts are respectively Mo₂C-N/P-rGO、W₂C-N/P-rGO、W-W₂N- N/P-rGO、W- N/P-rGO。

Polymer (PEI, PDA, CS, PPy or PANI) modified graphene oxide for use in The present invention is based on The reference [ Xiaoing Cai, Mining Lin, Shaozao Tan, et al, The use of polyethylene-modified reduced graphene oxide as a substrate for silver nanoparticles to product a material with low cellulose activity and long-term antibody activity [ J ] N]. Carbon, 2012, 50:3407-3415.]Preparing; p used₂W₁₇According to the literature [ cyanine ] withPreparation and photoelectric property research of covalent bond combined polyacid/naphthalene and porphyrin hybrid material [ D]University of north Hu, 2014.]Preparing; p used₂W₁₈According to The literature [ Graham C R, Finke R G, The classic Wells-Dawson polyoxometalate, K₆[α-P₂W₁₈O₆₂]·14H₂O. Answering an 88 year-old question: what is its preferred, optimum synthesis[J]. Inorganic Chemistry, 2008, 47(9): 3679-3686.]And (4) preparation.

Compared with the prior art, the invention has the following remarkable advantages: (1) transition metal carbide (Mo)₂C or W₂C) Is developed for the first time to be used as a fuel oil oxidation desulfurization catalyst; (2) the prepared graphene-loaded transition metal carbide, tungsten-doped tungsten nitride or metal tungsten heterogeneous catalyst contains Mo₂C、W₂C、W₂N and W can be well dispersed on the ultrathin graphene sheet, the dispersibility of the N and W in acetonitrile is good, the N and W are convenient to contact with a substrate better, the mass transfer and diffusion processes of the substrate can be favorably carried out smoothly, and the catalytic oxidation activity of the N and W can be favorably improved; (3) in the oxidation process of the dibenzothiophene catalyzed and oxidized by the prepared graphene-loaded transition metal carbide, tungsten-doped tungsten nitride or metal tungsten heterogeneous catalyst, the reaction condition is mild, the oxidation product is single (only dibenzothiophene sulfone), and the rapid (10 min) complete removal of dibenzothiophene with larger concentration (4000 ppm) can be realized under the condition of less catalyst dosage (0.03 g), so that the desulfurization efficiency is greatly improved; (4) the prepared graphene-loaded transition metal carbide, tungsten-doped tungsten nitride or metal tungsten heterogeneous catalyst is convenient to separate and recover and good in reusability.

In order to illustrate the structure of the graphene-supported transition metal carbide, tungsten-doped tungsten nitride or metal tungsten heterogeneous catalyst prepared by the invention, the structure is further illustrated with reference to the attached drawings.

Drawings

FIG. 1 shows W obtained in example 2₂XRD spectrum of C-N/P-rGO;

FIG. 2 shows W obtained in example 2₂EDS spectra of C-N/P-rGO;

FIG. 3 shows Mo obtained in example 4₂XRD spectrum of C-N/P-rGO;

FIG. 4 shows Mo obtained in example 4₂EDS spectra of C-N/P-rGO;

FIG. 5 shows W-W obtained in example 1₂XRD spectrum of N-N/P-rGO;

FIG. 6 is the XRD spectrum of W-N/P-rGO obtained in example 5.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments; all other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The preparation of graphene-supported transition metal carbides, tungsten-doped tungsten nitride or metallic tungsten heterogeneous catalysts by high temperature pyrolysis is illustrated below by way of example.

Example 1: polyethyleneimine modified graphene oxide loaded P₂W₁₈Composite catalyst P₂W₁₈Preparation of PEI/GO: the method comprises the following steps: 0.05 g of polyethyleneimine modified graphene oxide is added into 10mL of water, the pH value of the solution is adjusted to be 4 by 4 mol/L hydrochloric acid solution to obtain solution A, and 0.2 g P₂W₁₈Dissolving in 11 mL of deionized water, and adjusting the pH value of the solution to 4.7 by using a 4 mol/L hydrochloric acid solution to obtain a solution B; slowly dripping the solution B into the solution A, adjusting the pH value of the solution to 4.5 by using a 4 mol/L hydrochloric acid solution, reacting for 10 hours at normal temperature, centrifugally separating at 4000rpm (25 ℃) for about 10 minutes to obtain a solid product, washing with deionized water for multiple times, and carrying out vacuum freeze drying for 48 hours at-55 ℃ to obtain the polyethyleneimine modified graphene oxide loaded P₂W₁₈Composite catalyst (P)₂W₁₈-PEI/GO）。

Preparing a graphene-loaded tungsten-doped tungsten nitride heterogeneous catalyst: the method for preparing the graphene-loaded tungsten-doped tungsten nitride heterogeneous catalyst by a high-temperature pyrolysis method comprises the specific steps ofThe method comprises the following steps: loading P on the polyethyleneimine modified graphene oxide in the step₂W₁₈Composite catalyst P₂W₁₈Weighing 0.1 of PEI/GO in a porcelain boat under a protective atmosphere of nitrogen (N)₂) Heating to 800 ℃ at the speed of 5 ℃/min in the atmosphere, and preserving the heat for 2h to obtain the graphene-loaded tungsten-doped tungsten nitride heterogeneous catalyst (W-W)₂N- N/P-rGO）。

The XRD spectrum of the obtained material is shown in FIG. 5. From FIG. 5, W-W can be seen₂The XRD spectrogram of the N-N/P-rGO is basically consistent with that of standard cards (PDF # 04-0806) and (PDF # 25-1257), diffraction peaks of 2 theta at 40.26 degrees, 58.27 degrees, 73.18 degrees and 87.02 degrees respectively correspond to 110, 200, 211 and 220 crystal faces in the W crystal of the elemental metal, and diffraction peaks of 2 theta at 37.73 degrees, 43.85 degrees, 63.37 degrees and 76.52 degrees respectively correspond to that of the W crystal of the standard cards₂The crystal planes of 111, 200, 220 and 311 in the N crystal prove that the W-W is successfully synthesized₂N-N/P-rGO。

Example 2: polyethyleneimine-modified graphene oxide-loaded PW₁₂Composite catalyst PW₁₂Preparation of PEI/GO: the method comprises the following steps: adding 0.1g of polyethyleneimine modified graphene oxide into 20mL of water, adjusting the pH value of the solution to be 4.1 by using 4 mol/L hydrochloric acid solution to obtain solution A, and 0.6g of PW₁₂Dissolving in 10mL of deionized water to obtain solution B; slowly dripping the solution B into the solution A, adjusting the pH value of the solution to 4.8 by using 4 mol/L hydrochloric acid solution, reacting for 10 hours at normal temperature, centrifugally separating at 4000rpm (25 ℃) for about 15 minutes to obtain a solid product, washing with deionized water for multiple times, and carrying out vacuum freeze drying for 48 hours at-55 ℃ to obtain the polyethyleneimine modified graphene oxide loaded PW₁₂Composite catalyst (PW)₁₂-PEI/GO）。

Preparing a graphene-supported tungsten carbide heterogeneous catalyst: the method comprises the following steps: loading the polyethyleneimine modified graphene oxide into PW in the steps₁₂Composite catalyst PW₁₂Weighing 0.4 of PEI/GO in a porcelain boat under a protective atmosphere of nitrogen (N)₂) Heating to 1000 ℃ at the speed of 5 ℃/min under the atmosphere, and preserving heat for 2h to obtain the graphene-loaded tungsten carbide heterogeneous catalyst (W)₂C- N/P-rGO）。

Obtained byXRD and EDS detection are carried out on the material, and the spectrum is shown in figure 1 and figure 2; from the figure, W can be seen₂The XRD pattern of C-N/P-rGO is substantially identical to that of standard card (PDF # 35-0776), and the diffraction peaks at 34.46 DEG, 38 DEG, 39.99 DEG, 52.2 DEG, 61.8 DEG, 69.8 DEG and 74.9 DEG of 2 theta correspond to W respectively₂The crystal planes of 100, 002, 101, 102, 110, 103 and 112 in the C crystal are successfully synthesized into W₂C. From the EDS spectrum of FIG. 2, the presence of C, N, O, P, W element is clearly seen, indicating W₂C was successfully loaded on N, P doped graphene (W)₂C-N/P-rGO）。

Example 3: polyethyleneimine modified graphene oxide loaded SiW₁₂Composite catalyst SiW₁₂Preparation of PEI/GO: the method comprises the following steps: 0.15g of polyethyleneimine modified graphene oxide is added into 30mL of water, the pH value of the solution is adjusted to be 4.3 by 4 mol/L hydrochloric acid solution to obtain solution A, and 0.6g of SiW₁₂Dissolving in 15mL of deionized water to obtain solution B; slowly dripping the solution B into the solution A, adjusting the pH value of the solution to 5 by using 4 mol/L hydrochloric acid solution, reacting for 12 hours at normal temperature, centrifugally separating at 4000rpm (25 ℃) for about 12 minutes to obtain a solid product, washing with deionized water for multiple times, and carrying out vacuum freeze drying for 48 hours at-55 ℃ to obtain the polyethyleneimine modified graphene oxide loaded SiW₁₂Composite catalyst (SiW)₁₂-PEI/GO）。

Preparing a graphene-loaded tungsten-doped tungsten nitride heterogeneous catalyst: the method comprises the following steps: loading SiW on polyethyleneimine modified graphene oxide in the step₁₂Composite catalyst SiW₁₂Weighing 0.35 of PEI/GO in a porcelain boat under a protective atmosphere of nitrogen (N)₂) Heating to 900 ℃ at the speed of 5 ℃/min in the atmosphere, and preserving the heat for 2h to obtain the graphene-loaded tungsten-doped tungsten nitride heterogeneous catalyst (W-W)₂N- N/P-rGO）。

Example 4: polyethyleneimine modified graphene oxide loaded PMo₁₂Composite catalyst PMo₁₂Preparation of PEI/GO: the method comprises the following steps: 0.3 g of polyethyleneimine modified graphene oxide is added into 60 mL of water, the pH value of the solution is adjusted to be 4.5 by 4 mol/L hydrochloric acid solution to be solution A, and 0.6g of PMo₁₂Dissolving in 15mL of deionized water to obtain solution B; slowly adding liquid BSlowly dripping the solution into the solution A, adjusting the pH value of the solution to be 4.5, reacting for 11 hours at normal temperature, centrifugally separating at 4000rpm (25 ℃) for about 14 minutes to obtain a solid product, washing with deionized water for multiple times, and carrying out vacuum freeze drying at-55 ℃ for 48 hours to obtain the polyethyleneimine modified graphene oxide loaded PMo₁₂Composite catalyst (PMo)₁₂-PEI/GO）。

Preparing a graphene-loaded molybdenum carbide heterogeneous catalyst: the method comprises the following steps: loading the polyethyleneimine modified graphene oxide (PMo) in the step₁₂Composite catalyst PMo₁₂Weighing 0.3 of PEI/GO in a porcelain boat under a protective atmosphere of nitrogen (N)₂) Heating to 1000 ℃ at the speed of 5 ℃/min under the atmosphere, and preserving heat for 2h to obtain the graphene-loaded tungsten-doped tungsten nitride heterogeneous catalyst (Mo)₂C- N/P-rGO）。

XRD and EDS detection are carried out on the obtained material, and the spectra are shown in figure 3 and figure 4; mo can be seen from the figure₂The XRD pattern of C-N/P-rGO is substantially identical to that of standard card (PDF # 65-8766), with diffraction peaks at 34.53 °, 38 °, 39.69 °, 52.5 °, 61.9 °, 69.8 °, 74.9 ° and 75.9 ° for 2 θ corresponding to Mo₂Mo is successfully synthesized by 100, 002, 101, 102, 110, 103, 112 and 201 crystal faces in the C crystal₂C. From the EDS spectrum of FIG. 4, the existence of C, N, O, P, Mo element is clearly seen, indicating Mo₂C is successfully loaded on N, P doped graphene (Mo)₂C-N/P-rGO）。

Example 5: polyethyleneimine modified graphene oxide loaded SiW₁₂Composite catalyst SiW₁₂Preparation of PEI/GO: the method comprises the following steps: adding 0.2 g of polyethyleneimine modified graphene oxide into 20mL of water, adjusting the pH value of the solution to 5.0 by using 4 mol/L hydrochloric acid solution to obtain solution A, and 0.6g of SiW₁₂Dissolving in 10mL of deionized water to obtain solution B; slowly dripping the solution B into the solution A, adjusting the pH value of the solution to 5 by using 4 mol/L hydrochloric acid solution, reacting for 10 hours at normal temperature, centrifugally separating at 4000rpm (about 25 ℃) for 13 minutes to obtain a solid product, washing with deionized water for multiple times, and carrying out vacuum freeze drying at-55 ℃ for 48 hours to obtain the polyethyleneimine modified graphene oxide loaded SiW₁₂Composite catalyst (SiW)₁₂-PEI/GO）。

Preparing a graphene-loaded metal simple substance tungsten heterogeneous catalyst: the method comprises the following steps: loading SiW on polyethyleneimine modified graphene oxide in the step₁₂Composite catalyst SiW₁₂Weighing 0.25 of PEI/GO in a porcelain boat under a protective atmosphere of nitrogen (N)₂) And (3) heating to 1000 ℃ at the speed of 5 ℃/min under the atmosphere, and preserving the temperature for 2h to obtain the graphene-loaded metal simple substance tungsten heterogeneous catalyst (W-N/P-rGO).

The XRD spectrum of the obtained material is shown in FIG. 6, and the XRD spectrum of the W-N/P-rGO is basically consistent with that of a standard card (PDF # 04-0806) from FIG. 6, which proves that the W-N/P-rGO is successfully synthesized.

Example 6: dopamine modified graphene oxide loaded P₂W₁₇Composite catalyst P₂W₁₇Preparation of PDA/GO: the method comprises the following steps: adding 0.05 g of dopamine modified graphene oxide into 15mL of water, adjusting the pH value of the solution to be 4.8 by using 4 mol/L hydrochloric acid solution to obtain solution A, and adding 0.2 g P₂W₁₇Dissolving in 10mL of deionized water, and adjusting the pH value of the solution to 4.3 by using 4 mol/L hydrochloric acid solution to obtain solution B; slowly dripping the solution B into the solution A, adjusting the pH value of the solution to 4.4 by using 4 mol/L hydrochloric acid solution, reacting for 11 hours at normal temperature, centrifugally separating at 4000rpm (25 ℃) for about 10 minutes to obtain a solid product, washing with deionized water for multiple times, and freeze-drying for 48 hours under vacuum at-55 ℃ to obtain the dopamine-modified graphene oxide-loaded P₂W₁₇Composite catalyst (P)₂W₁₇-PDA/GO）。

Preparing a graphene-loaded tungsten-doped tungsten carbide heterogeneous catalyst: the method comprises the following steps: carrying P on the dopamine modified graphene oxide in the step₂W₁₇Composite catalyst P₂W₁₇PDA/GO weighing 0.2 into a porcelain boat under a protective atmosphere of nitrogen (N)₂) Heating to 800 ℃ at the speed of 5 ℃/min in the atmosphere, and preserving the heat for 2h to obtain the graphene-loaded tungsten-doped tungsten carbide heterogeneous catalyst (W-W)₂N-N/P-rGO）。

Example 7: chitosan modified graphene oxide loaded P₂W₁₈Composite catalyst P₂W₁₈-CS/GPreparation of O: the method comprises the following steps: 0.2 g of chitosan-modified graphene oxide is added into 40 mL of water, the pH value of the solution is adjusted to be 4.6 by 4 mol/L hydrochloric acid solution to be solution A, and 0.5 g P₂W₁₈Dissolving in 14 mL of deionized water, and adjusting the pH value of the solution to 4.0 by using a 4 mol/L hydrochloric acid solution to obtain a solution B; slowly dripping the solution B into the solution A, adjusting the pH value of the solution to 4.1 by using 4 mol/L hydrochloric acid solution, reacting for 12 hours at normal temperature, centrifugally separating at 4000rpm (25 ℃) for about 15 minutes to obtain a solid product, washing with deionized water for multiple times, and carrying out vacuum freeze drying for 48 hours at-55 ℃ to obtain the chitosan modified graphene oxide loaded P₂W₁₈Composite catalyst (P)₂W₁₈-CS/GO）。

Preparing a graphene-loaded tungsten-doped tungsten nitride heterogeneous catalyst: the method comprises the following steps: loading the chitosan modified graphene oxide with P in the above step₂W₁₈Composite catalyst P₂W₁₈Weighing 0.1 of CS/GO, placing in a porcelain boat, and keeping in a protective gas of nitrogen (N)₂) Heating to 800 ℃ at the speed of 5 ℃/min in the atmosphere, and preserving the heat for 2h to obtain the graphene-loaded tungsten-doped tungsten nitride heterogeneous catalyst (W-W)₂N-N/P-rGO）。

Example 8: polyaniline modified graphene oxide loaded PW₁₂Composite catalyst PW₁₂Preparation of PANI/GO: the method comprises the following steps: adding 0.15g of polyaniline-modified graphene oxide into 30mL of water, adjusting the pH value of the solution to be 5 by using 4 mol/L hydrochloric acid solution to obtain solution A, and 0.4g of PW₁₂Dissolving in 10mL of deionized water to obtain solution B; slowly dripping the solution B into the solution A, adjusting the pH value of the solution to 5 by using 4 mol/L hydrochloric acid solution, reacting at normal temperature for 12 hours, centrifugally separating at 4000rpm (about 25 ℃) for 12 minutes to obtain a solid product, washing with deionized water for multiple times, and carrying out vacuum freeze drying at-55 ℃ for 48 hours to obtain the PW loaded with the polyaniline-modified graphene oxide₁₂Composite catalyst (PW)₁₂- PANI /GO）。

Preparing a graphene-supported tungsten carbide heterogeneous catalyst: the method comprises the following steps: loading the polyaniline modified graphene oxide in the step into PW₁₂Composite catalyst PW₁₂-PANI/GO weighing 0.28 in porcelain boat under protective gas nitrogen (N)₂) Heating to 900 ℃ at the speed of 5 ℃/min in the atmosphere, and preserving the heat for 2h to obtain the graphene-loaded tungsten carbide heterogeneous catalyst (W)₂C - N/P- rGO）。

Example 9: polypyrrole-modified graphene oxide-loaded PMo₁₂Composite catalyst PMo₁₂Preparation of PPy/GO: the method comprises the following steps: 0.35 g of polypyrrole-modified graphene oxide is added into 50 mL of water, the pH value of a solution is adjusted to be 4.8 by 4 mol/L hydrochloric acid solution to obtain solution A, and 0.5 g of PMo₁₂Dissolving in 20mL of deionized water, and carrying out acidification treatment to obtain solution B; slowly dripping the solution B into the solution A, adjusting the pH value of the solution to 4.7 by using 4 mol/L hydrochloric acid solution, reacting for 12 hours at normal temperature, centrifugally separating at 4000rpm (25 ℃) for about 15 minutes to obtain a solid product, washing with deionized water for multiple times, and carrying out vacuum freeze drying for 48 hours at-55 ℃ to obtain the polypyrrole imine modified graphene oxide loaded PMo₁₂Composite catalyst (PMo)₁₂- PPy /GO）。

Preparing a graphene-loaded molybdenum carbide heterogeneous catalyst: the method comprises the following steps: the polypyrrole modified graphene oxide in the step is loaded with PMo₁₂Composite catalyst PMo₁₂Weighing 0.26 of PEI/GO in a porcelain boat under a protective atmosphere of nitrogen (N)₂) Heating to 1000 ℃ at the speed of 5 ℃/min under the atmosphere, and preserving heat for 2h to obtain the graphene-loaded molybdenum carbide heterogeneous catalyst (Mo)₂C - N/P- rGO）。

The use of graphene supported transition metal carbides, tungsten doped tungsten nitride or metallic tungsten heterogeneous catalysts is illustrated by way of example.

Example 10: application of the graphene-loaded tungsten-doped tungsten nitride heterogeneous catalyst: 0.03 g of the catalysts W to W prepared in example 1₂N-N/P-rGO was added to 20mL of an N-octane solution containing 4000ppm dibenzothiophene (mock oil), followed by 20mL of Acetonitrile (ACN) extractant and 510 μ L of 30% H₂O₂Heating the water solution and the system to 70 ℃, starting the reaction at 500 rpm, taking 100 mu L of solution from the upper layer of n-octane phase at intervals of 5min, diluting the solution with 4 mL of n-octane for HPLC test,

the chromatographic conditions for the HPLC tests were as follows: c18 reverse phase chromatography column, inner diameter: 200mm multiplied by 4.6mm multiplied by 5 mu m, catalytic oxidation simulation oil, and gradient leaching to 100% methanol by 10 min with 90% methanol and 10% deionized water as initial mobile phases, wherein the column temperature is 25 ℃; detection wavelength: 254 nm, flow rate 1.0 mL/min^-1；

The removal rate of dibenzothiophene was 85.99% after 40 min. And (3) centrifugally separating the catalyst recovered by the reaction, washing the catalyst with ethanol and acetonitrile for multiple times in sequence, drying the catalyst, and repeatedly recycling the catalyst for five times, wherein the removal rate of dibenzothiophene reaches 84.69%.

Example 11: the application of the graphene-loaded tungsten carbide heterogeneous catalyst comprises the following steps: 0.03 g of catalyst W prepared in example 2₂C-N/P-rGO was added to 20mL of an N-octane solution containing 4000ppm dibenzothiophene (mock oil), followed by 20mL of Acetonitrile (ACN) extractant and 510 μ L of 30% H₂O₂And (3) heating the aqueous solution and the system to 70 ℃, starting the reaction at 500 rpm, taking 100 mu L of solution from the upper layer of n-octane phase at intervals of 5min, diluting the solution with 4 mL of n-octane, and performing HPLC test until the removal rate of dibenzothiophene is 100% after 10 min. And (3) centrifugally separating the catalyst recovered by the reaction, washing the catalyst with ethanol and acetonitrile for multiple times in sequence, drying the catalyst, and repeatedly recycling the catalyst for five times, wherein the removal rate of dibenzothiophene reaches 99.79%.

Example 12: application of the graphene-loaded tungsten-doped tungsten nitride heterogeneous catalyst: 0.03 g of the catalysts W to W prepared in example 3₂N-N/P-rGO was added to 20mL of an N-octane solution containing 4000ppm dibenzothiophene (mock oil), followed by 20mL of Acetonitrile (ACN) extractant and 510 μ L of 30% H₂O₂And (3) heating the aqueous solution and the system to 70 ℃, starting reaction at 500 rpm, taking 100 mu L of solution from the upper layer of n-octane phase at intervals of 5min, diluting the solution with 4 mL of n-octane, and performing HPLC test until the removal rate of dibenzothiophene is 85.8% after 40 min. The catalyst recovered by the reaction is centrifugally separated, washed by ethanol and acetonitrile for multiple times in sequence, dried and recycled for five times, and the removal rate of dibenzothiophene reaches 84.21%.

Example 13: application of the graphene-loaded tungsten-doped tungsten nitride heterogeneous catalyst: 0.03 g of that prepared in example 4Catalyst Mo₂C-N/P-rGO was added to 20mL of an N-octane solution containing 4000ppm dibenzothiophene (mock oil), followed by 20mL of Acetonitrile (ACN) extractant and 510 μ L of 30% H₂O₂And (3) heating the aqueous solution and the system to 70 ℃, starting reaction at 500 rpm, taking 100 mu L of solution from the upper layer of n-octane phase at intervals of 5min, diluting the solution with 4 mL of n-octane, and performing HPLC test until the removal rate of dibenzothiophene is 100% after 10 min. The catalyst recovered by the reaction is centrifugally separated, washed by ethanol and acetonitrile for multiple times in sequence, dried and recycled for five times, and the removal rate of dibenzothiophene reaches 99.83 percent.

Example 14: the application of the graphene-loaded metal simple substance tungsten heterogeneous catalyst comprises the following steps: 0.03 g of the catalyst W-N/P-rGO prepared in example 5 was added to 20mL of an N-octane solution (simulated oil) containing 4000ppm of dibenzothiophene, followed by 20mL of Acetonitrile (ACN) extractant and 510 μ L of 30% H₂O₂And (3) heating the aqueous solution and the system to 70 ℃, starting reaction at 500 rpm, taking 100 mu L of solution from the upper layer of n-octane phase at intervals of 5min, diluting the solution with 4 mL of n-octane, and performing HPLC test until the removal rate of dibenzothiophene is 100% after 20 min. And (3) centrifugally separating the catalyst recovered by the reaction, washing the catalyst with ethanol and acetonitrile for multiple times in sequence, drying the catalyst, and repeatedly recycling the catalyst for five times, wherein the removal rate of dibenzothiophene reaches 98.89%.

Example 15: the graphene-supported tungsten-doped tungsten carbide heterogeneous catalyst has the following characteristics: 0.02 g of the catalyst W-W prepared in example 6₂C-N/P-rGO was added to 20mL of an N-octane solution containing 4000ppm dibenzothiophene (mock oil), followed by 20mL of Acetonitrile (ACN) extractant and 510 μ L of 30% H₂O₂And (3) heating the aqueous solution and the system to 70 ℃, starting reaction at 500 rpm, taking 100 mu L of solution from the upper layer of n-octane phase at intervals of 5min, diluting the solution with 4 mL of n-octane, and performing HPLC test until the removal rate of dibenzothiophene is 99.01% after 30 min. The catalyst recovered by the reaction is centrifugally separated, washed by ethanol and acetonitrile for multiple times in sequence, dried and recycled for five times, and the removal rate of dibenzothiophene reaches 98.86%.

Example 16: grapheneApplication of the supported tungsten-doped tungsten nitride heterogeneous catalyst: 0.005 g of the catalysts W to W prepared in example 7₂N-N/P-rGO was added to 20mL of an N-octane solution containing 4000ppm benzothiophene (mock oil), followed by 20mL of Acetonitrile (ACN) extractant and 128. mu.L of 30% H₂O₂And (3) heating the aqueous solution and the system to 60 ℃, starting reaction at 500 rpm, taking 100 mu L of solution from the upper layer of n-octane phase at intervals of 2min, diluting the solution with 4 mL of n-octane, and performing HPLC test until the removal rate of benzothiophene is 55.21% after 2 min. And (3) centrifugally separating the catalyst recovered by the reaction, washing the catalyst with ethanol and acetonitrile for multiple times in sequence, drying the catalyst, and repeatedly recycling the catalyst for five times, wherein the removal rate of the benzothiophene reaches 54.85%.

Example 17: the application of the graphene-loaded tungsten carbide heterogeneous catalyst comprises the following steps: 0.1g of catalyst W prepared in example 8₂C-N/P-rGO was added to 20mL of an N-octane solution containing 4000ppm thiophene (mock oil), followed by 20mL of Acetonitrile (ACN) extractant and 382. mu.L of 30% H₂O₂And (3) heating the aqueous solution and the system to 30 ℃, starting reaction at 500 rpm, taking 100 mu L of solution from the upper layer of n-octane phase at intervals of 3 min, diluting the solution with 4 mL of n-octane, and performing HPLC test until the removal rate of thiophene is 57.35% after 6 min. The catalyst recovered by the reaction is centrifugally separated, washed by ethanol and acetonitrile for multiple times in sequence, dried and repeatedly recycled for five times, and the removal rate of thiophene reaches 56.23%.

Example 18: the application of the graphene-loaded molybdenum carbide heterogeneous catalyst comprises the following steps: 0.06 g of catalyst Mo prepared in example 9₂C-N/P-rGO was added to 20mL of an N-octane solution containing 4000ppm of 4, 6-dimethyldibenzothiophene (mock oil), followed by 20mL of Acetonitrile (ACN) extractant and 776 μ L of 30% H₂O₂And (3) heating the aqueous solution and the system to 50 ℃, starting reaction at 500 rpm, taking 100 mu L of solution from the upper layer of n-octane phase at intervals of 5min, diluting the solution with 4 mL of n-octane for HPLC test until the removal rate of 4, 6-dimethyldibenzothiophene is 99.45% after 15 min. Centrifugally separating the catalyst recovered from the reaction, washing with ethanol and acetonitrile for multiple times, drying, and repeatedly recycling for five times, namely 4, 6-dimethylThe removal rate of dibenzothiophene reaches 99.31 percent.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.