Nitrogen vacancy and hydroxyl synergistically modified graphite-phase carbon nitride photocatalyst as well as preparation and application thereof in photocatalytic hydrogen production

Abstract

The invention discloses a nitrogen vacancy and hydroxyl synergistically modified graphite phase carbon nitride photocatalyst as well as preparation and application thereof in photocatalytic hydrogen production. The preparation method comprises the following steps: mixing melamine and oxalyl dihydrazine, and calcining to obtain nitrogen vacancy modified g-C3N4; carrying out ultrasonic mixing on thenitrogen vacancy modified g-C3N4 and ammonia water, and then carrying out hydrothermal reaction to obtain the nitrogen vacancy and hydroxyl synergistically modified g-C3N4 photocatalyst. According tothe catalyst, the hydrogen production rate of the g-C3N4 photocatalyst is increased through the synergistic effect of nitrogen vacancy and hydroxyl on photo-induced electron holes, wherein the maximum H2 yield can reach 107.4 micromoles / g*h. The preparation method of the catalyst is simple, low in cost and beneficial to large-scale production.

Description

technical field [0001] The invention relates to a photocatalyst, in particular to a nitrogen vacancy and hydroxyl synergistic modification of g-C 3 N 4 Photocatalyst and its preparation method, and nitrogen vacancy and hydroxyl synergistic modification of g-C 3 N 4 The application of photocatalyst in photocatalytic water splitting to produce hydrogen belongs to the technical field of photocatalytic hydrogen production. Background technique [0002] With the development of industrialization of human society, the excessive consumption of traditional energy sources, the energy crisis has gradually become the biggest problem facing mankind in the 21st century. The reserves of fossil energy in the earth's crust are limited and non-renewable, and CO will be generated during use 2 、CH 4 Greenhouse gases that harm the atmosphere. Therefore, people try to find green energy to replace fossil fuels, and renewable energy such as wind energy, water energy, and solar energy are ther...

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Problems solved by technology

[0004] Aiming at the deficiencies of the prior art, the first object of the present invention is to provide a nitrogen vacancy and hydroxyl synergistically modified g-C 3 N 4 Photocatalyst, which synergistically modifies g-C via nitrogen vacancies and hydroxyl groups 3 N 4 Excellent photocatalytic hydrogen production performance has been obtained, nitrogen vacancies can change the electronic structure, reduce the band gap value, increase the light absorption ability, and can also be used as electron or hole traps, while the hydroxyl group has good hydrophilicity and hole capture ability , after the nitrogen atom connected to the two-coordinated carbon atom is lost to form a nitrogen vacancy, the attraction of the lone pair of electrons exposed on the carbon atom to the hydroxyl group further increases, so more hydroxyl groups are loaded on the g-C 3 N 4 On the surface, not only the hydrophilicity of the material is further improved, but also the two cooperate to capture electrons and holes, so that the recombination of photogenerated carriers is suppressed to a greater extent, thus achieving high-efficiency photocatalytic hydrogen production. performance, solved the basic g-C 3 N 4 The material has disadvantages such as high carrier recombination efficiency, poor hydrophilicity and wide band gap

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