Supramolecular polymerized carbon nitride photocatalyst and preparation method and application thereof

A supramolecular and catalyst technology, applied in the field of photocatalysis, can solve the problems of affecting the morphology and photocatalytic performance of carbon nitride, unfavorable large-scale mass production, high raw material cost, etc., and achieve superior photocatalytic degradation performance and good separation effect of photogenerated charges , the effect of high photogenerated charge separation efficiency

Active Publication Date: 2019-11-19

HUNAN UNIV

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Problems solved by technology

However, in the existing supramolecular polymerization methods, hydrogen bonds are usually used as covalent bonds to carry out superpolymerization to prepare carbon nitride precursors with supramolecular structures. This supramolecular polymerization method using a single hydrogen bond as a covalent bond The prepared carbon nitride still has problems such as small specific surface area, poor separation efficiency of photogenerated charges, and low photocatalytic activity.

In addition, in the process of preparing carbon nitride precursors by supramolecular polymerization, the preparation of carbon nitride precursors is easily affected by factors ...

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Abstract

The invention discloses a supramolecular polymerized carbon nitride photocatalyst and a preparation method and an application thereof. The supramolecular polymerized carbon nitride photocatalyst is prepared from melamine, cyanuric acid, urea and dimethyl sulfoxide through a molecular polymerization reaction and calcination. The supramolecular polymerized carbon nitride photocatalyst has the advantages of high specific surface area, high photocatalytic activity and the like, can efficiently degrade organic wastewater and is a novel visible light catalyst. The preparation method has the advantages of simple synthetic method, low raw material cost, less energy consumption, short time consumption, easy control of conditions and the like, is suitable for continuous large-scale batch productionand facilitates the industrial use. the supramolecular polymerized carbon nitride photocatalyst of the invention can be used for degrading the organic wastewater, has the advantages of good degradation effect and good stability, and has good practical application prospects.

Application Domain

Physical/chemical process catalystsWater/sewage treatment by irradiation +1

Technology Topic

UreaChemistry +9

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Examples

Experimental program(8)

Example Embodiment

[0031] Example 1:

[0032] A preparation method of supramolecular polymerized carbon nitride photocatalyst includes the following steps:

[0033] (1) According to the ratio of the amount of melamine, cyanuric acid and urea to 4:4:1, weigh melamine, cyanuric acid and urea (the total mass of the three is 8g); Melamine, cyanuric acid and urea were added to dimethyl sulfoxide (the total volume of dimethyl sulfoxide used is 160 mL), and ultrasonic treatment was used to completely dissolve melamine, cyanuric acid and urea into dimethyl sulfoxide. , Get melamine solution, cyanuric acid solution and urea solution.

[0034] (2) In a constant temperature water bath, heat the melamine solution, cyanuric acid solution and urea solution obtained in step (1) to 30°C and keep it at a constant temperature, and then mix these three solutions with each other at a speed of 250r The molecular polymerization reaction was carried out for 30 minutes under electric stirring conditions of 1/min. After the reaction was completed, the obtained reaction product was filtered, and the filtered white precipitate was washed several times with ethanol and dried in an oven at 50° C. to obtain a white carbon nitride precursor.

[0035] (3) Grind the carbon nitride precursor obtained in step (2), transfer it to a ceramic crucible, and then place it in a muffle furnace at a heating rate of 2.3°C/min to 550°C for 4h, and naturally cool to room temperature. Grind to obtain supramolecular polymerized carbon nitride photocatalyst, numbered A1.

[0036] In Example 1 of the present invention, under the same conditions, when the ratio of the amounts of melamine, cyanuric acid and urea is 2:2:1, 1:1:1, 1:1:1, 1:1 : At 4 o'clock, the prepared supramolecular polymerized carbon nitride photocatalyst is numbered A2, A3, A4, A5 respectively.

Example Embodiment

[0037] Example 2:

[0038] A preparation method of supramolecular polymerized carbon nitride photocatalyst includes the following steps:

[0039] (1) According to the mass ratio of melamine, cyanuric acid and urea of 1:1:1, weigh melamine, cyanuric acid and urea (the total mass of the three is 8g); the weighed melamine, cyanuric acid and urea Polycyanic acid and urea were added to dimethyl sulfoxide (the total volume of dimethyl sulfoxide used was 160 mL), and ultrasonic treatment was used to completely dissolve melamine, cyanuric acid and urea in dimethyl sulfoxide to obtain melamine Solution, cyanuric acid solution and urea solution.

[0040] (2) In a constant temperature water bath, heat the melamine solution, cyanuric acid solution, and urea solution obtained in step (1) to 60°C and maintain a constant temperature, and then mix these three solutions with each other at a speed of 250r The molecular polymerization reaction was carried out for 30 minutes under electric stirring conditions of 1/min. After the reaction was completed, the obtained reaction product was filtered, and the filtered white precipitate was washed several times with ethanol and dried in an oven at 50° C. to obtain a white carbon nitride precursor.

[0041] (3) Grind the carbon nitride precursor obtained in step (2), transfer it to a ceramic crucible, and then place it in a muffle furnace at a heating rate of 2.3°C/min to 550°C for 4h, and naturally cool to room temperature. Grinding to obtain a supramolecular polymerized carbon nitride photocatalyst, numbered B1.

[0042] In Example 2 of the present invention, under the same conditions, when the molecular polymerization reaction temperature in step (2) is 90°C and 120°C, the prepared supramolecular polymerized carbon nitride photocatalyst is numbered B2 and B3 respectively. .

Example Embodiment

[0043] Example 3:

[0044] A preparation method of supramolecular polymerized carbon nitride photocatalyst includes the following steps:

[0045] (1) According to the mass ratio of melamine, cyanuric acid and urea of 1:1:1, weigh melamine, cyanuric acid and urea (the total mass of the three is 8g); the weighed melamine, cyanuric acid and urea Polycyanic acid and urea were added to dimethyl sulfoxide (the total volume of dimethyl sulfoxide used was 160 mL), and ultrasonic treatment was used to completely dissolve melamine, cyanuric acid and urea in dimethyl sulfoxide to obtain melamine Solution, cyanuric acid solution and urea solution.

[0046] (2) In a constant temperature water bath, heat the melamine solution, cyanuric acid solution and urea solution obtained in step (1) to 30°C and keep it at a constant temperature, and then mix these three solutions with each other at a speed of 250r The molecular polymerization reaction was carried out for 30 minutes under electric stirring conditions of 1/min. After the reaction was completed, the obtained reaction product was filtered, and the filtered white precipitate was washed several times with ethanol and dried in an oven at 50° C. to obtain a white carbon nitride precursor.

[0047] (3) Grind the carbon nitride precursor obtained in step (2), transfer it to a ceramic crucible, and then place it in a muffle furnace at a heating rate of 2.3°C/min to 550°C for 2h, and naturally cool to room temperature. Grinding to obtain supramolecular polymerized carbon nitride photocatalyst, numbered C1.

[0048] In Example 3 of the present invention, under the same conditions, when the calcination time in step (3) is 8 hours, the prepared supramolecular polymeric carbon nitride photocatalyst is numbered C2.

[0049] figure 1 This is the XRD pattern of the supramolecular polymerized carbon nitride photocatalyst (A1, A2, A3, A4, A5) prepared in Example 1 of the present invention. by figure 1 It can be seen that all the supramolecular polymeric carbon nitride photocatalysts (A1, A2, A3, A4, A5) prepared in Example 1 of the present invention have two characteristic diffraction peaks, which are due to the typical graphite-like phase layered structure Formed, the characteristic peak at 27.4° corresponds to gC 3 N 4 的(002) crystal plane. The characteristic peak at 13.1° 2θ corresponds to g-C 3 N 4 的(100) crystal plane. At the same time, by figure 1 It can be seen that the characteristic peaks of the supramolecular polymerized carbon nitride photocatalyst (A1, A2, A3, A4, A5) prepared by the present invention are small and broad, indicating that the supramolecular polymerized carbon nitride photocatalyst of the present invention has low crystallinity.

[0050] figure 2 This is the TEM image of the supramolecular polymerized carbon nitride photocatalyst (A3) prepared in Example 1 of the present invention. figure 2 Among them, (a) and (b) are TEM images at different magnifications. by figure 2 It can be seen that the supramolecular polymerized carbon nitride photocatalyst prepared by the present invention exhibits a layered porous morphology.

[0051] image 3 This is the photocurrent density diagram of the supramolecular polymerized carbon nitride photocatalyst (A3) prepared in Example 1 of the present invention. by image 3 It can be seen that the supramolecular polymerized carbon nitride photocatalyst (A3) has a high photocurrent response, indicating that the photo-generated charges generated by it are effectively separated during the photocatalytic degradation process, which is beneficial to the improvement of its photocatalytic degradation performance.

[0052] Table 1 is the data of specific surface area, pore volume and average pore diameter of the supramolecular polymeric carbon nitride photocatalyst (A3) prepared in Example 1 of the present invention.

[0053] Table 1 The specific surface area, pore volume and average pore diameter of the supramolecular polymeric carbon nitride photocatalyst (A3) prepared in Example 1 of the present invention

[0054] The data

[0055] sample Specific surface area (m 2 g -1 )

[0056] It can be seen from Table 1 that the supramolecular polymerized carbon nitride photocatalyst (A3) has a larger specific surface area of 122.53m 2 /g, the pore volume is 0.20cm 3 /g, the average pore size is 6.48nm. Since photocatalytic degradation of pollutants is an interface reaction, a large specific surface area will provide more reactive sites, promote the adsorption of more pollutants and the progress of photocatalytic degradation of pollutants, so the supramolecular polymerization and nitridation prepared by the present invention The carbon photocatalyst will have excellent photocatalytic degradation performance.

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PUM

Property	Measurement	Unit
Specific surface area	122.53	m²/g
Pore volume	0.2	cm³/g
Average pore size	6.48	nm
tensile		MPa
Particle size		Pa
strength	10

Description & Claims & Application Information

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Classification and recommendation of technical efficacy words

Improve photocatalytic activity
High specific surface area

Supramolecular polymerized carbon nitride photocatalyst and preparation method and application thereof

AI-Extracted Technical Summary

Problems solved by technology

Abstract

Image

Examples

Example Embodiment

Example Embodiment

Example Embodiment

PUM

Description & Claims & Application Information

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