阅读说明：本技术 一种二氧化碳辅助制备多孔氮化碳材料的方法及多孔氮化碳材料及其用途 (method for preparing porous carbon nitride material with assistance of carbon dioxide, porous carbon nitride material and application of porous carbon nitride material ) 是由 蔡可迎 周颖梅 王轩 王月鑫 王鹏 徐蕾 于 2019-08-16 设计创作，主要内容包括：一种二氧化碳辅助制备多孔氮化碳材料的方法及多孔氮化碳材料及其用途,采用反应-煅烧两步法,其制备步骤包括：按称取计量的三聚氰胺加入反应釜中,加入计量的去离子水,通入二氧化碳进行反应,反应温度为50～100℃,反应压力为0.01～1.0MPa,反应时间为2～6h；反应结束后自然冷却,抽滤得到中间体；将中间体转移至带盖坩埚中,并一同置于马弗炉中进行煅烧,马弗炉以2～6℃/min的速率升温至炉腔内温度为540～580℃,保温2～5h,冷却到室温后得到多孔氮化碳。本方法原料来源丰富、成本低廉、环境友好、产品收率高、制备工艺简单；制备的多孔氮化碳材料比表面积大,能够有效催化光降解罗丹明B。(A method for preparing a porous carbon nitride material with the assistance of carbon dioxide, the porous carbon nitride material and the application thereof adopt a reaction-calcination two-step method, and the preparation steps comprise: weighing and adding metered melamine into a reaction kettle, adding metered deionized water, and introducing carbon dioxide for reaction, wherein the reaction temperature is 50-100 ℃, the reaction pressure is 0.01-1.0 MPa, and the reaction time is 2-6 h; naturally cooling after the reaction is finished, and performing suction filtration to obtain an intermediate; and transferring the intermediate into a crucible with a cover, putting the crucible and the intermediate into a muffle furnace for calcining, heating the muffle furnace to 540-580 ℃ in a furnace cavity at the speed of 2-6 ℃/min, preserving the temperature for 2-5 h, and cooling to room temperature to obtain the porous carbon nitride. The method has the advantages of rich raw material sources, low cost, environmental friendliness, high product yield and simple preparation process; the prepared porous carbon nitride material has large specific surface area and can effectively catalyze photodegradation of rhodamine B.)

1. A method for preparing a porous carbon nitride material with the assistance of carbon dioxide is characterized by comprising the following steps:

(1) adding the measured melamine into a reaction kettle, adding the measured deionized water, starting magnetic stirring, introducing carbon dioxide into the deionized water for reaction, controlling the reaction temperature to be 50-100 ℃, keeping the pressure in the reaction kettle to be 0.01-0.1 MPa, reacting for 2-6 h, naturally cooling after the reaction is finished, and performing suction filtration to obtain an intermediate; the mass ratio of the melamine to the deionized water is 1: (20-100);

(2) and (2) transferring the intermediate obtained in the step (1) into a crucible with a cover, putting the crucible and the crucible into a muffle furnace for calcining, raising the temperature of the muffle furnace to 540-580 ℃ in a furnace cavity at the speed of 2-6 ℃/min, preserving the temperature for 2-5 h, naturally cooling the temperature in the furnace cavity to room temperature, and taking out the product to obtain the porous carbon nitride.

2. The method for preparing the porous carbon nitride material with the assistance of the carbon dioxide as claimed in claim 1, wherein the mass ratio of the melamine to the deionized water in the step (1) is 1: 50.

3. the method for preparing the porous carbon nitride material by the aid of the carbon dioxide according to claim 1 or 2, wherein the reaction temperature in the step (1) is controlled to be 80 ℃, the pressure in the reaction kettle is controlled to be 0.05MPa, and the reaction is carried out for 4 hours.

4. The method for preparing the porous carbon nitride material by the aid of the carbon dioxide as claimed in claim 1 or 2, wherein in the step (2), the temperature of the muffle furnace is increased to 550 ℃ at a speed of 4 ℃/min, and the temperature is kept for 3 hours.

5. A porous carbon nitride material produced by the production method according to any one of claims 1 to 4.

6. The use of the porous carbon nitride material according to claim 5 in catalyzing photodegradation of rhodamine B.

Technical Field

The invention belongs to the technical field of preparation and application of materials, and particularly relates to a method for preparing a porous carbon nitride material with the aid of carbon dioxide, the porous carbon nitride material and application of the porous carbon nitride material.

background

the carbon nitride is an inorganic metal material, has high stability, acid and alkali resistance and semiconductor property, and has wide application prospect in the fields of heterogeneous catalysis, fuel cells, gas adsorption and storage and the like. The carbon nitride is prepared by thermal polymerization of nitrogen-containing precursors (such as melamine, dicyandiamide, urea, thiourea, cyanuric acid, etc.). However, the specific surface area and pore volume of carbon nitride prepared by the common thermal polymerization method are small, so that the catalytic performance of the carbon nitride is not high. Increasing the specific surface area of carbon nitride is the key to improving its performance. At present, the methods for preparing carbon nitride with high specific surface area mainly comprise: hard template, soft template, and no template methods.

The hard template method is to use the existing solid as a template, introduce liquid organic precursors such as cyanamide, dicyandiamide and urea into the template, fill the liquid organic precursors into the pores or gaps of the hard template, and remove the template by acid or alkali etching after high-temperature roasting to obtain the porous carbon nitride material (Wangyue, Jianright, ShangZhongkun, Shangjie, LiYongxin. Proc. physico-chemistry report, 2016, 32 (8): 1913-1928). However, the hard template method uses a large amount of acid or alkali for removing the template, which is not environmentally friendly. The soft template method is to use surfactant as soft template, self-assemble the precursor and the soft template to form an ordered structure, decompose the soft template to form a pore channel in the high-temperature polymerization stage, and obtain the porous graphite phase carbon nitride (Lirong, Rongrui, Gonghong, Hengheng. novel chemical material, 2017, 45(1): 35-37.). Compared with the hard template method, the soft template method is simple and convenient to prepare and environment-friendly, but the soft template is high in price and not beneficial to large-scale production. The template-free method is to prepare the porous carbon nitride material by using gas released by raw materials in the high-temperature polymerization process as a pore-foaming agent. Urea or thiourea is taken as a raw material and is directly calcined in the air, and a pore structure is formed in a bubbling manner by gas generated in the calcining process, so that a carbon nitride material (Fanqijing, Liujian Jun, in spring, in the first resort, in the left-hand victory, in the chemical engineering progress 2014, 33 (5): 1185-1194) is obtained, but the product yield is only 4-6% generally by adopting the method, and the product yield is lower. Therefore, the development of a high-efficiency preparation method which has the advantages of simple process, low cost and environmental friendliness is of great significance.

Disclosure of Invention

the invention aims to provide a method for preparing a porous carbon nitride material with the assistance of carbon dioxide, the porous carbon nitride material and application thereof, wherein the method can simplify the preparation process, reduce the production cost and the pollution to the environment and improve the product yield; the prepared porous carbon nitride material has large comparative area and can effectively catalyze photodegradation of rhodamine B.

In order to achieve the aim, the method for preparing the porous carbon nitride material by the aid of the carbon dioxide comprises the following steps:

(1) Adding the measured melamine and deionized water into a reaction kettle, starting magnetic stirring, introducing carbon dioxide into the deionized water for reaction, controlling the reaction temperature to be 50-100 ℃, keeping the pressure in the reaction kettle to be 0.01-0.1 MPa, reacting for 2-6 h, naturally cooling after the reaction is finished, and performing suction filtration to obtain an intermediate; the mass ratio of the melamine to the deionized water is 1: (20-100);

(2) And (2) transferring the intermediate obtained in the step (1) into a crucible with a cover, putting the crucible and the crucible into a muffle furnace for calcining, heating the muffle furnace to 540-580 ℃ in a furnace cavity at the speed of 2-6 ℃/min, preserving the temperature for 2-5 h, naturally cooling the temperature in the furnace cavity to room temperature, and taking out the product to obtain the porous carbon nitride.

Preferably, the mass ratio of melamine to deionized water in step (1) is 1: 50.

Preferably, in the step (1), the reaction temperature is controlled to be 80 ℃, the pressure in the reaction kettle is 0.05MPa, and the reaction is carried out for 4 hours.

Preferably, in the step (2), the temperature of the muffle furnace is increased to 550 ℃ at the speed of 4 ℃/min, and the temperature is kept for 3 h.

A porous carbon nitride material is prepared by the preparation method.

The porous carbon nitride material prepared by the preparation method is applied to catalytic photodegradation of rhodamine B.

According to the invention, cheap melamine is used as a raw material, carbon dioxide is used as an auxiliary material, water is used as a medium for the raw material and the carbon dioxide to react in a reaction kettle to generate melamine carbonate, the melamine carbonate is continuously decomposed in the calcining process to release carbon dioxide gas to form a pore channel, and meanwhile, the melamine is continuously polymerized to finally form the porous carbon nitride material.

Compared with the prior art, the invention takes cheap and nontoxic carbon dioxide as an auxiliary material and a pore-forming agent, and can obviously reduce the production cost; the carbon dioxide escaping in the calcining process is easy to treat and has little influence on the environment; porous carbon nitride is directly obtained after calcination without post-treatment, so that the production process is simplified; in addition, the yield of the porous carbon nitride material prepared by the method is up to 48%, and the product yield is improved. The invention does not need to use complex and expensive instruments and equipment, and is easy for industrial production. The porous carbon nitride material prepared by the preparation method has large specific surface area, has higher catalytic activity and better repeatability when being used as a catalyst for photodegradation of rhodamine B, and has potential utilization value in the aspect of sewage treatment.

Drawings

FIG. 1 is an X-ray diffraction pattern of a porous carbon nitride material prepared in accordance with example one of the present invention;

FIG. 2 is a scanning electron microscope image of a porous carbon nitride material prepared according to a first embodiment of the present invention;

FIG. 3 is an infrared spectrum of a porous carbon nitride material prepared according to the first embodiment of the present invention;

FIG. 4 is an isothermal adsorption-desorption curve of the porous carbon nitride material prepared in the first embodiment of the present invention;

FIG. 5 is an activity diagram of the porous carbon nitride material prepared in the first embodiment of the invention catalyzing photodegradation of rhodamine B solution;

FIG. 6 is a repeated diagram of the porous carbon nitride material prepared in the first embodiment of the invention catalyzing photodegradation of rhodamine B solution.

Detailed Description

The present invention will be described in further detail with reference to the following drawings and examples.