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CN-122006774-A - Poly (heptazinimide) photocatalytic material, preparation method thereof and photocatalytic preparation H2O2Is a method of (2)

CN122006774ACN 122006774 ACN122006774 ACN 122006774ACN-122006774-A

Abstract

The invention belongs to the technical field of photocatalysis, and in particular relates to a poly (heptazinimide) photocatalysis material, a preparation method thereof and a method for preparing H 2 O 2 by photocatalysis, which comprises the following steps of preparing a mixture by taking dicyandiamide and triaminopyrimidine as raw materials; and mixing the precursor powder with LiCl/KCl molten salt, and calcining again in the protective gas atmosphere to prepare the poly (heptazinimide) photocatalytic material. The invention prepares the high crystallinity poly (heptazinimide) nanorod cluster by taking dicyandiamide and triaminopyrimidine as raw materials, and the addition of the triaminopyrimidine improves the crystallinity of the poly (heptazinimide), improves the efficiency of preparing hydrogen peroxide by photocatalysis of the poly (heptazinimide), and is beneficial to the industrialized application of preparing hydrogen peroxide by photocatalysis.

Inventors

  • CHENG CHENG
  • HE QIAN
  • Luo Wenze
  • CHEN YU
  • SHI JINWEN
  • LIU MAOCHANG
  • JING DENGWEI

Assignees

  • 西安交通大学
  • 陕西燃气集团富平能源科技有限公司

Dates

Publication Date
20260512
Application Date
20260203

Claims (9)

  1. 1. The preparation method of the poly (heptazinimide) photocatalytic material is characterized by comprising the following steps of: preparing a mixture by taking dicyandiamide and triaminopyrimidine as raw materials, wherein the molar ratio of the dicyandiamide to the triaminopyrimidine is 10-30:0.1-3.0; Under the atmosphere of protective gas, the mixture is subjected to a first-step calcination treatment and polymerized to form melem containing pyrimidine rings, cooled to room temperature, and then subjected to a second-step calcination treatment to polymerize the melem to form melon-type carbon nitride, so as to obtain precursor powder; mixing the precursor powder with LiCl/KCl molten salt, and performing a third-step calcination treatment in a protective gas atmosphere to enable the melon-type carbon nitride to be orderly polymerized into a crystalline structure, thereby obtaining the poly (heptazinimide) photocatalytic material.
  2. 2. The preparation method of the poly (heptazinimide) photocatalytic material according to claim 1, wherein the molar ratio of dicyandiamide to triaminopyrimidine is 20:0.25-2.
  3. 3. The method for preparing the poly (heptazinimide) photocatalytic material according to claim 1, wherein the first step of calcination treatment is to heat up the mixture to 450 ℃ and keep the temperature for 2-4 hours, and the second step of calcination treatment is to heat up to 500 ℃ and keep the temperature for 2-4 hours.
  4. 4. The method for preparing the poly (heptazinimide) photocatalytic material according to claim 1, wherein the mass ratio of precursor powder to LiCl/KCl molten salt is 1:1-10, the LiCl/KCl molten salt is a mixed salt of LiCl and KCl, and the molar ratio of LiCl to KCl is 59:41.
  5. 5. The method for preparing a poly (heptazinimide) photocatalytic material according to claim 1, wherein the third calcination treatment is to heat up to 500-600 ℃ and calcine for 2-4 hours.
  6. 6. The method for preparing the poly (heptazinimide) photocatalytic material according to claim 1, wherein the preparation method of the mixture comprises the steps of dissolving dicyandiamide and triaminopyrimidine in water, and then obtaining the mixture through freeze drying.
  7. 7. A poly (heptazinimide) photocatalytic material, characterized in that it is prepared by the preparation method according to any one of claims 1-6.
  8. 8. The poly (heptazinimide) photocatalytic material of claim 7, wherein the poly (heptazinimide) photocatalytic material is in the form of nanorod clusters.
  9. 9. A method for preparing H 2 O 2 by photocatalysis is characterized by comprising the following steps of taking water and oxygen as raw materials, carrying out illumination under the photocatalysis of the poly (heptazinimide) photocatalysis material according to claim 7, and catalyzing the reaction of the water and the oxygen to generate H 2 O 2 .

Description

Poly (heptazinimide) photocatalytic material, preparation method thereof and method for preparing H 2O2 through photocatalysis Technical Field The invention belongs to the technical field of photocatalysis, and particularly relates to a poly (heptazinimide) photocatalysis material, a preparation method thereof and a method for preparing H 2O2 by photocatalysis. Background With the rapid development of social science and technology, the industrialization process is continuously advanced, the demand of human beings on energy is increasing, the world energy safety and environmental protection problems are increasing, and the development of clean renewable energy technology is urgent. In the technical field, research on efficient and orderly conversion of energy sources and development of green clean energy source technology are focused hot spots. In a plurality of solutions, the photocatalysis technology can directly utilize solar energy to convert the solar energy into chemical energy, and an effective way is provided for realizing sustainable development. Hydrogen peroxide (H 2O2) is a strong oxidant, is widely applied to the fields of medical treatment, chemical industry and the like, is mainly prepared by an anthraquinone method in the industry at present, but has complex reaction process and is accompanied by the generation of a plurality of byproducts. The method for synthesizing hydrogen peroxide by photocatalytic decomposition of water to generate hydrogen peroxide is an emerging green and clean method, and has great application prospect. The principle of preparing hydrogen peroxide by photocatalysis is that under the irradiation of light with certain energy, the semiconductor photocatalyst is excited by light to generate electron and hole pairs, and the electron and hole migrate to the surface of the catalyst to generate oxidation-reduction reaction with the reaction substance. Because the raw materials of the reaction only comprise water and oxygen, and the required energy can be obtained from sunlight, one of the keys for realizing the preparation of hydrogen peroxide by photocatalytic oxygen reduction is to find a visible light photocatalyst which is nontoxic, low in cost, high in efficiency, stable and suitable in energy band. According to the prior researches, among various photocatalytic materials, the crystalline carbon nitride has proper energy band, good physical and chemical stability and unique two-dimensional structural characteristics, wherein one of the crystalline carbon nitrides named as poly (heptazinimide) (PHI) has a special large pi conjugated system, is favorable for the migration of photo-generated electrons and holes, and has good photocatalytic reaction activity. At present, the efficiency of the photocatalytic production of H 2O2 by PHI needs to be further improved. Improving the crystallinity of PHI is considered as an important means for further improving the efficiency of producing H 2O2 by photocatalysis, but the current method is complex and difficult to implement, thus preventing the industrialized application of PHI in preparing hydrogen peroxide by photocatalysis. Disclosure of Invention In order to solve the technical problems, the invention provides a poly (heptazinimide) photocatalysis material, a preparation method thereof and a method for preparing H 2O2 by photocatalysis, the invention prepares high-crystallinity poly (heptazinimide) (PHI) nanorod clusters by taking dicyandiamide and triaminopyrimidine as raw materials, the addition of the triaminopyrimidine improves the crystallinity of the PHI carbon nitride, improves the efficiency of preparing hydrogen peroxide by photocatalysis of PHI, and is beneficial to industrial application of preparing hydrogen peroxide by photocatalysis. The invention is realized by the following technical scheme. The first object of the invention is to provide a preparation method of a poly (heptazinimide) photocatalytic material, which comprises the following steps: preparing a mixture by taking dicyandiamide and triaminopyrimidine as raw materials, wherein the molar ratio of the dicyandiamide to the triaminopyrimidine is 10-30:0.1-3.0; Under the atmosphere of protective gas, the mixture is subjected to a first-step calcination treatment and polymerized to form melem containing pyrimidine rings, cooled to room temperature, and then subjected to a second-step calcination treatment to polymerize the melem to form melon-type carbon nitride, so as to obtain precursor powder; mixing the precursor powder with LiCl/KCl molten salt, and performing a third-step calcination treatment in a protective gas atmosphere to enable the melon-type carbon nitride to be orderly polymerized into a crystalline structure, thereby obtaining the poly (heptazinimide) photocatalytic material. Preferably, the molar ratio of dicyandiamide to triaminopyrimidine is 20:0.25-2. More preferably, the molar ratio of dicyandiamide to triaminopyrimidine is 20:0.75. Prefe