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Preparation method of a defect-enhanced tungsten-doped carbon nitride photocatalyst

A carbon nitride light and tungsten doping technology, applied in the field of photocatalytic materials, can solve the problems of limiting the performance of photocatalytic water splitting for hydrogen production, low utilization rate, inability to effectively separate, etc., and achieve good photocatalytic water splitting to produce hydrogen. performance effect

Active Publication Date: 2022-04-19
BEIJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Graphite phase carbon nitride material is an organic semiconductor with stable physical and chemical properties, a band gap of 2.7eV, and the ability to absorb visible light not exceeding 460nm. It is an ideal photocatalytic material, but there are some problems that need to be improved. Further improve its photocatalytic performance, for example, it can only absorb a small part of visible light, the light energy used in photocatalysis is less, and the utilization rate is low; photogenerated carriers are easy to recombine, and after photoexcited electrons and holes are separated, they cannot Effective separation, it is easy to recombine here, and cannot migrate to the surface of the catalyst to participate in the photocatalytic reaction; the specific surface area is low, and the specific surface area of ​​pure carbon nitride is only 10m 2 g, the available surface catalytic active sites are few, which greatly limits the rate of photocatalytic reactions
Heteroatom doping is an effective way to improve the light absorption of carbon nitride. By introducing a doping energy level into the energy level of carbon nitride, the forbidden band width is reduced, thereby improving light absorption, but the doped product still has a low specific surface area. Disadvantages, which limit the performance of photocatalytic water splitting and hydrogen production

Method used

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  • Preparation method of a defect-enhanced tungsten-doped carbon nitride photocatalyst
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  • Preparation method of a defect-enhanced tungsten-doped carbon nitride photocatalyst

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Effect test

Embodiment 1

[0022] Take 5.4g of melamine and 0.5% doping amount of ammonium metatungstate and place it in a rotary evaporator, put in a magnet, and add 200mL of water. Stir for 30min. Then take out the magnet, install it on a rotary evaporation drying device, use circulating cooling to lower the temperature, and vacuum dry to remove deionized water. Put the dried mixture in a crucible, wrap the crucible tightly with aluminum foil, place it in a muffle furnace and calcinate at 550°C in an air atmosphere, with a heating rate of 5°C / min, keep it warm for 4 hours and then cool it naturally. The obtained powder is tungsten Doped carbon nitride material. Then put it in the tube furnace, check the airtightness of the tube furnace, feed hydrogen, and control the flow rate to 50mL / min. Calcined at 450°C in a hydrogen atmosphere with a heating rate of 5°C / min, held for 1h, and then cooled naturally to obtain a defect-enhanced tungsten-doped carbon nitride photocatalyst.

Embodiment 2

[0024] Take 5.4g of melamine and 0.5% doping amount of ammonium metatungstate and place it in a rotary evaporator, put in a magnet, and add 200mL of water. Stir for 30min. Then take out the magnet, install it on a rotary evaporation drying device, use circulating cooling to lower the temperature, and vacuum dry to remove deionized water. Put the dried mixture in a crucible, wrap the crucible tightly with aluminum foil, place it in a muffle furnace and calcinate at 550°C in an air atmosphere, with a heating rate of 5°C / min, keep it warm for 4 hours and then cool it naturally. The obtained powder is tungsten Doped carbon nitride material. Then put it in a tube furnace, check the airtightness of the tube furnace, feed argon, and control the flow rate to 30mL / min. Calcined at 500°C in a hydrogen atmosphere with a heating rate of 5°C / min, held for 2h, and then cooled naturally to obtain a defect-enhanced tungsten-doped carbon nitride photocatalyst.

Embodiment 3

[0026] Take 5.4g of melamine and 0.5% doping amount of ammonium metatungstate and place it in a rotary evaporator, put in a magnet, and add 200mL of water. Stir for 30min. Then take out the magnet, install it on a rotary evaporation drying device, use circulating cooling to lower the temperature, and vacuum dry to remove deionized water. Put the dried mixture in a crucible, wrap the crucible tightly with aluminum foil, place it in a muffle furnace and calcinate at 550°C in an air atmosphere, with a heating rate of 5°C / min, keep it warm for 4 hours and then cool it naturally. The obtained powder is tungsten Doped carbon nitride material, named WCN. It was then placed in a crucible, calcined at 520°C in a hydrogen atmosphere, with a heating rate of 5°C / min, kept for 3h, and then naturally cooled to obtain a defect-enhanced tungsten-doped carbon nitride photocatalyst WCNH.

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Abstract

The invention discloses a method for preparing a defect-enhanced tungsten-doped carbon nitride photocatalyst, which belongs to the technical field of photocatalytic materials. The method comprises the following steps: mixing melamine and ammonium metatungstate in liquid phase, rotary evaporating and drying to remove deionized water; calcining the dried product in a muffle furnace, and naturally cooling to room temperature to obtain a tungsten-doped carbon nitride material; The obtained product is calcined at 520° C. for 30-90 min under hydrogen gas, more defects are introduced into the tungsten-doped carbon nitride photocatalyst, and a defect-enhanced tungsten-doped carbon nitride photocatalyst is obtained. A defect-enhanced tungsten-doped carbon nitride photocatalyst provided by the invention has good photocatalytic hydrogen production from water; the defect-enhanced carbon nitride prepared by the method of the invention has high carrier separation efficiency, which is beneficial to The photocatalytic activity is improved.

Description

technical field [0001] The invention relates to a preparation method of a defect-enhanced tungsten-doped carbon nitride photocatalyst, which belongs to the technical field of photocatalytic materials. Background technique [0002] Graphite phase carbon nitride material is an organic semiconductor with stable physical and chemical properties, a band gap of 2.7eV, and the ability to absorb visible light not exceeding 460nm. It is an ideal photocatalytic material, but there are some problems that need to be improved. Further improve its photocatalytic performance, for example, it can only absorb a small part of visible light, the light energy used in photocatalysis is less, and the utilization rate is low; photogenerated carriers are easy to recombine, and after photoexcited electrons and holes are separated, they cannot Effective separation, it is easy to recombine here, and cannot migrate to the surface of the catalyst to participate in the photocatalytic reaction; the specif...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J27/24C01B3/04
CPCY02E60/36
Inventor 王金淑胡鹏车海冰李晓静郑广伟王学凯
Owner BEIJING UNIV OF TECH
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