Porous nanosheet-shaped graphite-phase carbon nitride as well as preparation method and application thereof

Abstract

The invention provides a preparation method of porous nano flaky graphite-phase carbon nitride. The preparation method comprises the following steps: S1, calcining melamine to prepare graphite-phase carbon nitride powder; S2, adding the graphite-phase carbon nitride powder prepared in the step S1 into a sodium bicarbonate solution for reaction, centrifuging the reacted solution to obtain a precipitate, and drying the precipitate to obtain an intermediate product; S3, preparing nitric acid, hydrofluoric acid and water into a mixed solution according to a certain proportion, slowly adding the mixed solution into the intermediate product obtained in the step S2, and after ultrasonic treatment and stirring, placing the intermediate product in a high-pressure hydrothermal reaction kettle for areaction; and S4, centrifuging, washing and drying the solution obtained in the step S3. Compared with the prior art, the modified graphite-phase carbon nitride prepared by the invention is ultrathinnanosheet-shaped and has a porous and nitrogen defect structure, photo-induced electrons and holes in the graphite-phase carbon nitride can be effectively separated, the recombination rate of the photo-induced electrons and the holes can be reduced, and the photocatalytic activity and stability can be improved.

Description

technical field [0001] The invention relates to the technical field of photocatalytic materials, in particular to a porous nano-sheet graphitic carbon nitride and its preparation method and application. Background technique [0002] Graphite carbon nitride (g-C 3 N 4 ) is an organic polymer semiconductor, the C and N atoms in its structure are sp 2 Hybridization forms a highly delocalized π-conjugated system; the study found that the graphitic carbon nitride (g-C 3 N 4 ) in the semiconductor band structure, there is an E between the highest occupied orbital (HOMO) and the lowest unoccupied orbital (LUMO) g With a forbidden band width of about 2.7eV, it can absorb blue-violet light with a wavelength less than 475nm in the solar spectrum, and graphite phase carbon nitride (g-C 3 N 4 )'s HOMO and LUMO band edge positions are at +1.6eV and -1.0V (vs) NHE (standard hydrogen electrode), which can decompose water to generate H and O in thermodynamics. Therefore, graphitic ca...

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Problems solved by technology

[0003] However, in the actual application process, it is found that the pure graphitic carbon nitride prepared in the prior art still has many defects, and these defects specifically include: (1) the graphitic carbon nitride can only absorb blue light at 450nm, so the The utilization rate of visible light is low; (2) the photogenerated electrons and holes of graphite phase carbon nitride are easy to recombine, resulting in a relatively small number of effective photogenerated electrons or holes; Dissociation of holes leads to poor cycle stability of graphitic carbon nitride

[0004] Therefore, based on the above defects, the photocatalytic activity and stability of graphitic carbon nitride are low, which cannot meet the application requirements of high efficiency and stability, which limits its wide application in the field of photocatalytic material technology.

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