Rod-like carbon nitride catalyst for photocatalytic preparation of vinyl chloride as well as preparation method and application of rod-like carbon nitride catalyst

Abstract

The invention discloses a rod-like carbon nitride catalyst for photocatalytic preparation of vinyl chloride as well as a preparation method and application thereof, and particularly relates to the field of catalysts. Comprising the following steps: dissolving melamine and trithiocyanuric acid in a solvent, and carrying out hydrothermal reaction to obtain self-assembled precursor powder; calcining the self-assembled precursor powder to obtain a rod-like carbon nitride catalyst; placing the rod-like carbon nitride catalyst in a reactor, and adding a chlorine source and a hydrogen source; and introducing acetylene and oxygen into the reactor, and carrying out photocatalytic reaction to obtain vinyl chloride. The rod-like carbon nitride catalyst is used as a catalyst, and the rod-like carbon nitride catalyst has a large specific area and a wide light absorption range, so that high-conversion-rate and high-selectivity vinyl chloride synthesis can be realized.

Description

Technical Field

[0001] The present application relates to the field of catalysts, and in particular to a rod-shaped carbon nitride catalyst for photocatalytic preparation of vinyl chloride, and a preparation method and application thereof. Background Art

[0002] Graphitic Carbon Nitride (g-C3N4) is a new type of non-metallic two-dimensional nanomaterial with a layered structure similar to graphite, composed of carbon (C) and nitrogen (N) atoms connected by covalent bonds. g-C3N4 has gradually become a widely-regarded photocatalyst due to its excellent visible light catalytic activity and fast separation rate of photogenerated carriers. However, the blocky g-C3N4 obtained by the traditional method of direct calcination of melamine has a small specific surface area, a high recombination rate of photogenerated carriers, and fewer active sites exposed on the catalyst surface, resulting in poor photocatalytic activity, which limits its practical application. Summary of the invention

[0003] The main purpose of the present application is to provide a rod-shaped carbon nitride catalyst for photocatalytic preparation of vinyl chloride and its preparation method and application, aiming to solve the problem of poor catalytic activity of catalysts existing in the prior art.

[0004] To achieve the above-mentioned purpose, the present application provides a method for preparing a rod-shaped carbon nitride catalyst for photocatalytic preparation of vinyl chloride, comprising: dissolving melamine and thiocyanate in a solvent, and conducting a hydrothermal reaction to obtain a self-assembled precursor powder; calcining the self-assembled precursor powder to obtain a rod-shaped carbon nitride catalyst; wherein the calcination temperature is 300~600℃, and the calcination time is 0.5~10h.

[0005] Optionally, the molar ratio of melamine to thiocyanuric acid is 0.1-10:1.

[0006] Optionally, the temperature of the hydrothermal reaction is 80-220° C., and the time is 2-100 h.

[0007] Optionally, the solvent includes deionized water, methanol, ethanol or acetone.

[0008] Optionally, during the calcination process, the heating rate is 0.1-10°C / min.

[0009] To achieve the above objectives, the present application also provides a rod-shaped carbon nitride catalyst for photocatalytic preparation of vinyl chloride, which is obtained by the above preparation method.

[0010] To achieve the above objectives, the present application also provides an application of the above-mentioned rod-shaped carbon nitride catalyst for photocatalytic preparation of vinyl chloride, wherein the rod-shaped carbon nitride catalyst is used as a photocatalyst to prepare vinyl chloride using acetylene.

[0011] Optionally, the method for preparing vinyl chloride using acetylene includes: placing a rod-shaped carbon nitride catalyst in a reactor, and adding a chlorine source and a hydrogen source to obtain a reaction substrate; introducing acetylene and oxygen into the reaction substrate to perform a photocatalytic reaction to obtain vinyl chloride.

[0012] Optionally, the concentration of the rod-shaped carbon nitride catalyst in the reaction substrate is 0.5-10 mg / ml.

[0013] Optionally, the chlorine source includes one or a mixture of sodium chloride, potassium chloride, magnesium chloride, calcium chloride, hydrogen chloride, and ammonium chloride; the hydrogen source includes one or a mixture of deionized water, methanol, ethanol, and triethanolamine.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The preparation method of the rod-shaped carbon nitride catalyst for photocatalytic preparation of vinyl chloride of the present invention can increase the specific surface area of ​​the traditional carbon nitride catalyst and enhance the light absorption capacity of the catalyst by introducing thiocyanuric acid to obtain the rod-shaped carbon nitride catalyst.

[0015] The application of the rod-shaped carbon nitride catalyst for photocatalytic preparation of vinyl chloride of the present invention utilizes a photocatalytic method to prepare vinyl chloride from acetylene. Compared with a method for preparing vinyl chloride by addition of coal-based acetylene and hydrogen chloride under the action of mercuric chloride, no mercury needs to be introduced, no pollution will be caused, and photocatalysis is carried out at room temperature without high temperature, thereby reducing energy consumption and cost. The rod-shaped carbon nitride catalyst is used as a catalyst. The rod-shaped carbon nitride catalyst has a large comparative area and a wide light absorption range, and can achieve high conversion rate and high selectivity synthesis of vinyl chloride. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Electron microscope images of the rod-shaped carbon nitride catalyst obtained in Example 1 of the method for preparing a rod-shaped carbon nitride catalyst for photocatalytic preparation of vinyl chloride in the present application and the carbon nitride catalyst obtained by the traditional method; Figure 2 A comparison chart of the catalytic effects of a rod-shaped carbon nitride catalyst for photocatalytic preparation of vinyl chloride in this application; Figure 3 This is a comparison chart of the specific surface areas of three carbon nitride catalysts; Figure 4 This is a graph showing the UV-visible spectroscopic test results of a rod-shaped carbon nitride catalyst used for photocatalytic preparation of vinyl chloride in the present application.

[0017] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions in this application will be clearly and completely described below in conjunction with the drawings in this application. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0019] The first embodiment of the present invention provides a method for preparing a rod-shaped carbon nitride catalyst for photocatalytic preparation of vinyl chloride, which specifically comprises the following steps: Step S1, dissolving melamine and thiocyanate in a solvent, and performing a hydrothermal reaction, wherein the temperature of the hydrothermal reaction is 80-220° C., and the time is 2-100 hours, to obtain a self-assembly precursor powder; The molar ratio of melamine to thiocyanuric acid is 0.1-10:1, and the solvent includes deionized water, methanol, ethanol or acetone.

[0020] Step S2, calcining the self-assembled precursor powder to obtain a rod-shaped carbon nitride catalyst; wherein the calcination temperature is 300-600° C., the calcination time is 0.5-10 h, and the heating rate is 0.1-10° C. / min.

[0021] In this embodiment, thiocyanuric acid can form a coordination with melamine to obtain rod-shaped carbon nitride with uniform size and high specific surface area, which can generate a supramolecular intermediate with a long molecular chain through self-assembly. The rod-shaped carbon nitride catalyst obtained after heat treatment has a large comparative area and a wide light absorption range, and can achieve high conversion rate and high selectivity of vinyl chloride synthesis.

[0022] The second embodiment of the present invention provides a rod-shaped carbon nitride catalyst for photocatalytic preparation of vinyl chloride, which is obtained by the above-mentioned preparation method.

[0023] The third embodiment of the present invention provides an application of the above-mentioned rod-shaped carbon nitride catalyst for photocatalytic preparation of vinyl chloride, wherein the rod-shaped carbon nitride catalyst is used as a photocatalyst to prepare vinyl chloride using acetylene.

[0024] Specifically, the method for preparing vinyl chloride using acetylene includes: A rod-shaped carbon nitride catalyst is placed in a reactor, and a chlorine source and a hydrogen source are added to obtain a reaction substrate; acetylene and oxygen are introduced into the reaction substrate, the reactor is sealed, and a light source is turned on to irradiate the reactor, and a photocatalytic reaction is carried out at room temperature. After irradiation for 0.1 to 20 hours, vinyl chloride is obtained.

[0025] The concentration of the rod-shaped carbon nitride catalyst in the reaction substrate is 0.5-10 mg / ml, the chlorine source includes one or a mixture of sodium chloride, potassium chloride, magnesium chloride, calcium chloride, hydrogen chloride, and ammonium chloride; the hydrogen source includes one or a mixture of deionized water, methanol, ethanol, and triethanolamine. The light source includes a xenon lamp, a mercury lamp, a 365nm LED lamp, a 405nm LED lamp, a 420nm LED lamp, or a 450nm LED lamp, and the light power is 0.01-20W.

[0026] Example 1 Preparation of catalyst: a certain amount of melamine was dispersed in 60 ml of deionized water, and after being evenly dispersed, it was transferred to the inner lining of a 100 ml reactor, and a hydrothermal reaction was carried out at 180°C for 12 hours. The product was centrifuged to obtain melamine powder; the melamine powder was dried, fully ground and placed in a quartz boat, and calcined in a tubular furnace, and the temperature was raised to 550°C at a rate of 5°C / min, and the temperature was maintained for 3 hours. After natural cooling, it was ground evenly to obtain a blocky carbon nitride catalyst material, and its SEM photo is shown as follows Figure 1 As shown in a.

[0027] Photocatalytic acetylene production of vinyl chloride: Place 1 mg of blocky carbon nitride catalyst in a 10 ml quartz tube, and add 3 mL of 0.6 M sodium chloride aqueous solution; pass sufficient acetylene and 2 ml of oxygen into the quartz tube, seal the reactor, move the reaction tube to the light source equipment, apply continuous stirring at 1000 r / min, turn on the 420 nm LED light source, and irradiate for 8 h to obtain a vinyl chloride sample.

[0028] The generation rate of vinyl chloride was 300 μmol·g -1 ·h -1 , the selectivity is 85%, and the by-products are carbon monoxide and carbon dioxide.

[0029] Example 2 Preparation of catalyst: Melamine and thiocyanate were dispersed in 60 ml of deionized water at a mass molar ratio of 1:1, and then transferred to the inner lining of a 100 ml reactor after being evenly dispersed. A hydrothermal reaction was carried out at 180°C for 12 hours, and the product was centrifuged to obtain a yellow self-assembled precursor powder. The self-assembled precursor powder was dried, fully ground and placed in a quartz boat, and calcined in a tubular furnace. The temperature was raised to 550°C at a rate of 5°C / min, and the temperature was maintained for 3 hours. After natural cooling, the powder was evenly ground to obtain a rod-shaped carbon nitride catalyst material, and its morphology is as follows: Figure 1 As shown in b.

[0030] Photocatalytic acetylene production of vinyl chloride: Place 1 mg of rod-shaped carbon nitride catalyst in a 10 ml quartz tube, and add 3 mL of 0.6 M sodium chloride aqueous solution; pass sufficient acetylene and 2 ml of oxygen into the quartz tube, seal the reactor, move the reaction tube to the light source equipment, apply continuous stirring at 1000 r / min, turn on the 420 nm LED light source, and irradiate for 8 h to obtain a vinyl chloride sample.

[0031] The vinyl chloride sample obtained in this example was passed into a gas chromatograph for qualitative and quantitative analysis. The results are as follows: Figure 2 As shown in the figure, a new peak corresponding to vinyl chloride appears at 5.9 minutes, successfully proving the generation of vinyl chloride. The generation rate of vinyl chloride was measured to be 550 μmol·g -1 ·h -1 , the selectivity is 93%, and the by-products are carbon monoxide and carbon dioxide.

[0032] Example 3 Preparation of catalyst: a certain mass of thiocyanuric acid was dispersed in 60 ml of deionized water, and after being evenly dispersed, it was transferred to the inner lining of a 100 ml reactor, and a hydrothermal reaction was carried out at 180°C for 12 hours. The product was centrifuged to obtain thiocyanuric acid powder; the thiocyanuric acid powder was dried, fully ground and placed in a quartz boat, and calcined in a tubular furnace, and the temperature was raised to 550°C at a rate of 5°C / min, and the temperature was maintained for 3 hours. After natural cooling, the material was ground evenly to obtain a nitrogen-doped carbon catalyst material, and its SEM image is shown as follows: Figure 1 As shown in c.

[0033] The specific surface areas of the three catalysts obtained in Examples 1-3 are as follows Figure 3 As shown, compared with the conventional carbon nitride (Examples 1 and 3), the specific surface area of ​​the rod-shaped carbon nitride catalyst material (Example 2) is increased by 75%.

[0034] Photocatalytic acetylene preparation of vinyl chloride: Place 1 mg of nitrogen-doped carbon catalyst in a 10 ml quartz tube and add 3 mL of 0.6 M sodium chloride aqueous solution; pass sufficient acetylene and 2 ml of oxygen into the quartz tube, seal the reactor, move the reaction tube to the light source equipment, apply continuous stirring at 1000 r / min, turn on the 420 nm LED light source, and irradiate for 8 h to obtain a vinyl chloride sample.

[0035] The vinyl chloride sample obtained in this example was passed into a gas chromatograph for qualitative and quantitative analysis, and the generation rate of vinyl chloride was measured to be 450 μmol·g -1 ·h -1 , the selectivity is 89%, and the by-products are carbon monoxide and carbon dioxide.

[0036] Example 4 Preparation of catalyst: Melamine and thiocyanuric acid were dispersed in 60 ml of deionized water at a mass molar ratio of 3:1, and after uniform dispersion, they were transferred to the lining of a 100 ml reactor, and hydrothermal reaction was carried out at 180°C for 12 hours. The product was centrifuged to obtain a yellow self-assembled precursor powder; the self-assembled precursor powder was dried, fully ground and placed in a quartz boat, and calcined in a tubular furnace, heated to 550°C at a rate of 5°C / min, maintained at a constant temperature for 3 hours, and ground evenly after natural cooling to obtain a rod-shaped carbon nitride catalyst material.

[0037] Photocatalytic acetylene production of vinyl chloride: Place 1 mg of rod-shaped carbon nitride catalyst in a 10 ml quartz tube, and add 3 mL of 0.6 M sodium chloride aqueous solution; pass sufficient acetylene and 2 ml of oxygen into the quartz tube, seal the reactor, move the reaction tube to the light source equipment, apply continuous stirring at 1000 r / min, turn on the 420 nm LED light source, and irradiate for 8 h to obtain a vinyl chloride sample.

[0038] The vinyl chloride sample obtained in this example was passed into a gas chromatograph for qualitative and quantitative analysis, and the generation rate of vinyl chloride was measured to be 420 μmol·g -1 ·h -1 , the selectivity is 91%, and the by-products are carbon monoxide and carbon dioxide.

[0039] Example 5 Preparation of catalyst: Melamine and thiocyanuric acid were dispersed in 60 ml of deionized water at a mass molar ratio of 1:3, and after uniform dispersion, they were transferred to the lining of a 100 ml reactor, and hydrothermal reaction was carried out at 180°C for 12 hours. The product was centrifuged to obtain a yellow self-assembled precursor powder; the self-assembled precursor powder was dried, fully ground and placed in a quartz boat, and calcined in a tubular furnace, heated to 550°C at a rate of 5°C / min, maintained at a constant temperature for 3 hours, and ground evenly after natural cooling to obtain a rod-shaped carbon nitride catalyst material.

[0040] Photocatalytic acetylene production of vinyl chloride: Place 1 mg of rod-shaped carbon nitride catalyst in a 10 ml quartz tube, and add 3 mL of 0.6 M sodium chloride aqueous solution; pass sufficient acetylene and 2 ml of oxygen into the quartz tube, seal the reactor, move the reaction tube to the light source equipment, apply continuous stirring at 1000 r / min, turn on the 420 nm LED light source, and irradiate for 8 h to obtain a vinyl chloride sample.

[0041] The vinyl chloride sample obtained in this example was passed into a gas chromatograph for qualitative and quantitative analysis, and the generation rate of vinyl chloride was measured to be 490 μmol·g -1 ·h -1 , the selectivity is 93%, and the by-products are carbon monoxide and carbon dioxide.

[0042] Example 6 Preparation of catalyst: Melamine and thiocyanuric acid were dispersed in 60 ml of deionized water at a mass molar ratio of 1:1, and after uniform dispersion, they were transferred to the lining of a 100 ml reactor, and hydrothermal reaction was carried out at 180°C for 12 hours. The product was centrifuged to obtain a yellow self-assembled precursor powder; the self-assembled precursor powder was dried, fully ground and placed in a quartz boat, and calcined in a tubular furnace, heated to 550°C at a rate of 5°C / min, maintained at a constant temperature for 3 hours, and ground evenly after natural cooling to obtain a rod-shaped carbon nitride catalyst material.

[0043] Photocatalytic acetylene production of vinyl chloride: Place 1 mg of rod-shaped carbon nitride catalyst in a 10 ml quartz tube, and add 3 mL of 0.6 M sodium chloride aqueous solution; pass sufficient acetylene and 1 ml of oxygen into the quartz tube, seal the reactor, move the reaction tube to the light source equipment, apply continuous stirring at 1000 r / min, turn on the 420 nm LED light source, and irradiate for 8 h to obtain a vinyl chloride sample.

[0044] The vinyl chloride sample obtained in this example was passed into a gas chromatograph for qualitative and quantitative analysis, and the generation rate of vinyl chloride was measured to be 270 μmol·g -1 ·h -1 , the selectivity is 95%, and the by-products are carbon monoxide and carbon dioxide.

[0045] Example 7 Preparation of catalyst: Melamine and thiocyanuric acid were dispersed in 60 ml of deionized water at a mass molar ratio of 1:1, and after uniform dispersion, they were transferred to the lining of a 100 ml reactor, and hydrothermal reaction was carried out at 180°C for 12 hours. The product was centrifuged to obtain a yellow self-assembled precursor powder; the self-assembled precursor powder was dried, fully ground and placed in a quartz boat, and calcined in a tubular furnace, heated to 550°C at a rate of 5°C / min, maintained at a constant temperature for 3 hours, and ground evenly after natural cooling to obtain a rod-shaped carbon nitride catalyst material.

[0046] Photocatalytic acetylene preparation of vinyl chloride: Place 1 mg of rod-shaped carbon nitride catalyst in a 10 ml quartz tube, and add 3 mL of 0.6 M sodium chloride aqueous solution; pass sufficient acetylene and 3 ml of oxygen into the quartz tube, seal the reactor, move the reaction tube to the light source equipment, apply continuous stirring at 1000 r / min, turn on the 420 nm LED light source, and irradiate for 8 h to obtain a vinyl chloride sample.

[0047] The vinyl chloride sample obtained in this example was passed into a gas chromatograph for qualitative and quantitative analysis, and the generation rate of vinyl chloride was measured to be 700 μmol·g -1 ·h -1, the selectivity is 88%, and the by-products are carbon monoxide and carbon dioxide.

[0048] Example 8 Preparation of catalyst: Melamine and thiocyanuric acid were dispersed in 60 ml of deionized water at a mass molar ratio of 1:1, and after uniform dispersion, they were transferred to the lining of a 100 ml reactor, and a hydrothermal reaction was carried out at 160°C for 12 hours. The product was centrifuged to obtain a yellow self-assembled precursor powder; the self-assembled precursor powder was dried, fully ground and placed in a quartz boat, and calcined in a tubular furnace, heated to 550°C at a rate of 10°C / min, maintained at a constant temperature for 3 hours, and ground evenly after natural cooling to obtain a rod-shaped carbon nitride catalyst material.

[0049] Photocatalytic acetylene production of vinyl chloride: Place 1 mg of rod-shaped carbon nitride catalyst in a 10 ml quartz tube, and add 3 mL of 0.6 M sodium chloride aqueous solution; pass sufficient acetylene and 2 ml of oxygen into the quartz tube, seal the reactor, move the reaction tube to the light source equipment, apply continuous stirring at 1000 r / min, turn on the 420 nm LED light source, and irradiate for 8 h to obtain a vinyl chloride sample.

[0050] The vinyl chloride sample obtained in this example was passed into a gas chromatograph for qualitative and quantitative analysis, and the generation rate of vinyl chloride was measured to be 540 μmol·g -1 ·h -1 , the selectivity is 90%, and the by-products are carbon monoxide and carbon dioxide.

[0051] Example 9 Preparation of catalyst: Melamine and thiocyanate were dispersed in 60 ml of deionized water at a mass molar ratio of 1:1, and after uniform dispersion, they were transferred to the lining of a 100 ml reactor, and hydrothermal reaction was carried out at 200°C for 12 hours. The product was centrifuged to obtain a yellow self-assembled precursor powder; the self-assembled precursor powder was dried, fully ground and placed in a quartz boat, calcined in a tubular furnace, heated to 550°C at a rate of 10°C / min, maintained at a constant temperature for 3 hours, and ground evenly after natural cooling to obtain a rod-shaped carbon nitride catalyst material.

[0052] Photocatalytic acetylene production of vinyl chloride: Place 1 mg of rod-shaped carbon nitride catalyst in a 10 ml quartz tube, and add 3 mL of 0.6 M sodium chloride aqueous solution; pass sufficient acetylene and 2 ml of oxygen into the quartz tube, seal the reactor, move the reaction tube to the light source equipment, apply continuous stirring at 1000 r / min, turn on the 420 nm LED light source, and irradiate for 8 h to obtain a vinyl chloride sample.

[0053] The vinyl chloride sample obtained in this example was passed into a gas chromatograph for qualitative and quantitative analysis, and the generation rate of vinyl chloride was measured to be 500 μmol·g -1 ·h -1 , the selectivity is 92%, and the by-products are carbon monoxide and carbon dioxide.

[0054] Example 10 Preparation of catalyst: Melamine and thiocyanuric acid were dispersed in 60 ml of deionized water at a mass molar ratio of 1:1, and after uniform dispersion, they were transferred to the lining of a 100 ml reactor, and hydrothermal reaction was carried out at 180°C for 12 hours. The product was centrifuged to obtain a yellow self-assembled precursor powder; the self-assembled precursor powder was dried, fully ground and placed in a quartz boat, calcined in a tubular furnace, heated to 550°C at a rate of 10°C / min, maintained at a constant temperature for 3 hours, and ground evenly after natural cooling to obtain a rod-shaped carbon nitride catalyst material.

[0055] Photocatalytic acetylene preparation of vinyl chloride: Place 1 mg of rod-shaped carbon nitride catalyst in a 10 ml quartz tube, and add 3 mL of 0.6 M sodium chloride aqueous solution; pass sufficient acetylene and 2 ml of oxygen into the quartz tube, seal the reactor, move the reaction tube to the light source equipment, apply continuous stirring at 1000 r / min, turn on the 450 nm LED light source, and irradiate for 8 h to obtain a vinyl chloride sample.

[0056] The vinyl chloride sample obtained in this example was passed into a gas chromatograph for qualitative and quantitative analysis, and the generation rate of vinyl chloride was measured to be 150 μmol·g -1 ·h -1 , the selectivity is 91%, and the by-products are carbon monoxide and carbon dioxide.

[0057] Embodiment 11 Preparation of catalyst: Melamine and thiocyanuric acid were dispersed in 60 ml of deionized water at a mass molar ratio of 1:1, and after uniform dispersion, they were transferred to the lining of a 100 ml reactor, and hydrothermal reaction was carried out at 180°C for 12 hours. The product was centrifuged to obtain a yellow self-assembled precursor powder; the self-assembled precursor powder was dried, fully ground and placed in a quartz boat, calcined in a tubular furnace, heated to 550°C at a rate of 10°C / min, maintained at a constant temperature for 3 hours, and ground evenly after natural cooling to obtain a rod-shaped carbon nitride catalyst material.

[0058] Photocatalytic acetylene preparation of vinyl chloride: Place 1 mg of rod-shaped carbon nitride catalyst in a 10 ml quartz tube, and add 3 mL of 0.6 M sodium chloride aqueous solution; pass sufficient acetylene and 2 ml of oxygen into the quartz tube, seal the reactor, move the reaction tube to the light source equipment, apply continuous stirring at 1000 r / min, turn on the 365 nm LED light source, and irradiate for 8 h to obtain a vinyl chloride sample.

[0059] The vinyl chloride sample obtained in this example was passed into a gas chromatograph for qualitative and quantitative analysis, and the generation rate of vinyl chloride was measured to be 700 μmol·g -1 ·h -1 , the selectivity is 90%, and the by-products are carbon monoxide and carbon dioxide.

[0060] Example 12 Preparation of catalyst: Melamine and thiocyanuric acid were dispersed in 60 ml of deionized water at a mass molar ratio of 1:1, and after uniform dispersion, they were transferred to the lining of a 100 ml reactor, and hydrothermal reaction was carried out at 180°C for 12 hours. The product was centrifuged to obtain a yellow self-assembled precursor powder; the self-assembled precursor powder was dried, fully ground and placed in a quartz boat, calcined in a tubular furnace, heated to 550°C at a rate of 10°C / min, maintained at a constant temperature for 3 hours, and ground evenly after natural cooling to obtain a rod-shaped carbon nitride catalyst material.

[0061] Photocatalytic production of vinyl chloride from acetylene: Place 1 mg of rod-shaped carbon nitride catalyst in a 10 ml quartz tube, and add 3 mL of 0.2 M sodium chloride aqueous solution; pass sufficient acetylene and 2 ml of oxygen into the quartz tube, seal the reactor, move the reaction tube to the light source equipment, apply continuous stirring at 1000 r / min, turn on the 420 nm LED light source, and irradiate for 8 h to obtain a vinyl chloride sample.

[0062] The vinyl chloride sample obtained in this example was passed into a gas chromatograph for qualitative and quantitative analysis, and the generation rate of vinyl chloride was measured to be 330 μmol·g -1 ·h -1 , the selectivity is 88%, and the by-products are carbon monoxide and carbon dioxide.

[0063] Example 13 Preparation of catalyst: Melamine and thiocyanuric acid were dispersed in 60 ml of deionized water at a mass molar ratio of 1:1, and after uniform dispersion, they were transferred to the lining of a 100 ml reactor, and hydrothermal reaction was carried out at 180°C for 12 hours. The product was centrifuged to obtain a yellow self-assembled precursor powder; the self-assembled precursor powder was dried, fully ground and placed in a quartz boat, calcined in a tubular furnace, heated to 550°C at a rate of 10°C / min, maintained at a constant temperature for 3 hours, and ground evenly after natural cooling to obtain a rod-shaped carbon nitride catalyst material.

[0064] Photocatalytic acetylene preparation of vinyl chloride: Place 1 mg of rod-shaped carbon nitride catalyst in a 10 ml quartz tube, and add 3 mL of 0.4 M sodium chloride aqueous solution; pass sufficient acetylene and 2 ml of oxygen into the quartz tube, seal the reactor, move the reaction tube to the light source equipment, apply continuous stirring at 1000 r / min, turn on the 420 nm LED light source, and irradiate for 8 h to obtain a vinyl chloride sample.

[0065] The vinyl chloride sample obtained in this example was passed into a gas chromatograph for qualitative and quantitative analysis, and the generation rate of vinyl chloride was measured to be 460 μmol·g -1 ·h -1 , the selectivity is 90%, and the by-products are carbon monoxide and carbon dioxide.

[0066] Embodiment 14 Preparation of catalyst: Melamine and thiocyanuric acid were dispersed in 60 ml of deionized water at a mass molar ratio of 1:1, and after uniform dispersion, they were transferred to the lining of a 100 ml reactor, and hydrothermal reaction was carried out at 180°C for 12 hours. The product was centrifuged to obtain a yellow self-assembled precursor powder; the self-assembled precursor powder was dried, fully ground and placed in a quartz boat, calcined in a tubular furnace, heated to 550°C at a rate of 10°C / min, maintained at a constant temperature for 3 hours, and ground evenly after natural cooling to obtain a rod-shaped carbon nitride catalyst material.

[0067] Photocatalytic production of vinyl chloride from acetylene: Place 1 mg of rod-shaped carbon nitride catalyst in a 10 ml quartz tube, and add 3 mL of 1 M sodium chloride aqueous solution; pass sufficient acetylene and 2 ml of oxygen into the quartz tube, seal the reactor, move the reaction tube to the light source equipment, apply continuous stirring at 1000 r / min, turn on the 420 nm LED light source, and irradiate for 8 h to obtain a vinyl chloride sample.

[0068] The vinyl chloride sample obtained in this example was passed into a gas chromatograph for qualitative and quantitative analysis, and the generation rate of vinyl chloride was measured to be 690 μmol·g -1 ·h -1 , the selectivity is 95%, and the by-products are carbon monoxide and carbon dioxide.

[0069] According to Examples 1-3, compared with the block carbon nitride catalyst and the nitrogen-doped carbon catalyst, the rod-shaped carbon nitride catalyst has higher reaction activity and selectivity. Figure 4 According to the results of UV-visible spectrophotometry, rod-shaped carbon nitride has a wide light absorption range and a high light absorption capacity, and therefore has higher photocatalytic performance. According to Examples 2, 4-5, as the proportion of thiocyanate increases, the catalytic performance of the catalyst increases first and then decreases, and a 1:1 ratio of melamine to thiocyanate precursor has a higher catalytic performance. According to Examples 2, 6-7, 2 ml of oxygen is the optimal amount added. When the amount of oxygen decreases, the generation rate decreases. When the amount of oxygen is too high, the generation rate increases but the selectivity decreases, and over-oxidation of acetylene intensifies. According to Examples 2, 8-9, when the synthesis hydrothermal temperature is 180°C, the catalytic performance is better. According to Examples 2, 10-11, the longer the wavelength of the light source, the lower the synthesis rate, which conforms to Figure 4 According to Examples 2, 12-14, the higher the concentration of sodium chloride in the reaction substrate, the higher the generation efficiency and the higher the selectivity, and the concentration of chloride ions affects the catalytic performance.

[0070] The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for preparing a rod-shaped carbon nitride catalyst for photocatalytic preparation of vinyl chloride, characterized in that: include: Dissolving melamine and thiocyanate in a solvent and performing a hydrothermal reaction to obtain a self-assembly precursor powder; calcining the self-assembled precursor powder to obtain a rod-shaped carbon nitride catalyst; Among them, the calcination temperature is 300~600℃, and the calcination time is 0.5~10 h.

2. The method for preparing a rod-shaped carbon nitride catalyst for photocatalytic preparation of vinyl chloride according to claim 1, characterized in that: The molar ratio of melamine to thiocyanuric acid is 0.1-10:

1.

3. The method for preparing a rod-shaped carbon nitride catalyst for photocatalytic preparation of vinyl chloride according to claim 1, characterized in that: The temperature of the hydrothermal reaction is 80-220°C and the time is 2-100 h.

4. The method for preparing a rod-shaped carbon nitride catalyst for photocatalytic preparation of vinyl chloride according to claim 1, characterized in that: The solvent includes deionized water, methanol, ethanol or acetone.

5. The method for preparing a rod-shaped carbon nitride catalyst for photocatalytic preparation of vinyl chloride according to claim 1, characterized in that: During the calcination process, the heating rate is 0.1-10 °C / min.

6. A rod-shaped carbon nitride catalyst for photocatalytic preparation of vinyl chloride, characterized in that: The method is obtained by the preparation method according to any one of claims 1 to 5.

7. A use of a rod-shaped carbon nitride catalyst for photocatalytic preparation of vinyl chloride as claimed in claim 6, characterized in that: The rod-shaped carbon nitride catalyst is used as a photocatalyst to prepare vinyl chloride using acetylene.

8. The use of the rod-shaped carbon nitride catalyst for photocatalytic preparation of vinyl chloride according to claim 7, characterized in that: The method for preparing vinyl chloride using acetylene comprises: The rod-shaped carbon nitride catalyst is placed in a reactor, and a chlorine source and a hydrogen source are added to obtain a reaction substrate; Acetylene and oxygen are introduced into the reaction substrate to carry out a photocatalytic reaction to obtain vinyl chloride.

9. The use of the rod-shaped carbon nitride catalyst for photocatalytic preparation of vinyl chloride according to claim 7, characterized in that: The concentration of the rod-shaped carbon nitride catalyst in the reaction substrate is 0.1-10 mg / ml.

10. The use of the rod-shaped carbon nitride catalyst for photocatalytic preparation of vinyl chloride according to claim 7, characterized in that: The chlorine source includes one or a mixture of sodium chloride, potassium chloride, magnesium chloride, calcium chloride, hydrogen chloride, and ammonium chloride; the hydrogen source includes one or a mixture of deionized water, methanol, ethanol, and triethanolamine.

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