CN112354558A

CN112354558A - PDINH @ TiO2Photocatalyst and preparation method and application thereof

Info

Publication number: CN112354558A
Application number: CN202011139497.7A
Authority: CN
Inventors: 许琦; 徐晨晨; 张奇
Original assignee: Yancheng Institute of Technology
Current assignee: Yancheng Institute of Technology
Priority date: 2020-10-22
Filing date: 2020-10-22
Publication date: 2021-02-12

Abstract

The invention discloses PDINH @ TiO₂The photocatalyst is a core-shell flaky nano material and comprises PDInH and TiO in a mass ratio of 1: 0.25-2₂Wherein PDInH is the carrier, TiO₂Is a nano-load. The preparation method comprises the steps of firstly, preparing TiO₂Dispersing in concentrated sulfuric acid and stirring to obtain a mixed solution; then PDInH is added into the mixed solution for ultrasonic treatment, and then distilled water is slowly added into the solution, and temperature control and stirring are carried out; finally, the PDINH @ TiO is obtained by centrifugation, washing and drying₂A photocatalyst. The preparation method is simple and feasible, and the organic-inorganic composite PDInH @ TiO with the nano flaky structure₂The photocatalyst has remarkable photocatalytic kinetic characteristics.

Description

PDINH @ TiO2Photocatalyst and preparation method and application thereof

Technical Field

The invention belongs to the technical field of chemical catalysis, and particularly relates to PDInH @ TiO₂A photocatalyst and a preparation method and application thereof.

Background

Phenol (C)₆H₅OH) has wide application, and can be used for producing certain resins, preservatives, bactericides and medicaments. These organisms reduce the penetration of light into the aquatic ecosystem, thereby affecting the aquatic organismsThe problem of pollution of phenol and its derivatives in the environment is gradually revealed, and these organic compounds are not naturally degraded in the ecological environment and have persistence, causing harm to human health, so that the solution of the problem is urgent. The concentration of organic pollutants in natural environment is low, the traditional technical means is difficult to achieve a good degradation effect, but photocatalysis is a simple and feasible technology, and the organic pollutants can be degraded into small molecules with low toxicity and can also be completely degraded into carbon dioxide and water.

The photocatalytic reaction, a superior redox process, is due to the semiconductor absorbing energy above its band gap to generate electrons and holes that are excited by a light source and then react with surrounding electron acceptors and donors. Photocatalytic reactions are of global interest due to their unique characteristics and offer new opportunities for organic pollutant treatment. Solar energy is considered a "green" renewable energy source, and it can be utilized by photocatalytic technology to convert solar energy into chemical energy. Therefore, sunlight can be used as the most suitable energy source for activating the photocatalyst. Therefore, the preparation of the novel semiconductor composite catalyst is of great importance for improving the utilization rate of sunlight.

In the last decade, research on organic-inorganic composite photocatalysts has been gradually developed and matured, and such catalysts can combine the advantages of organic and inorganic components through a certain technology, thereby improving the performance of the catalysts in degrading target pollutants. Compared with common organic materials such as polyethylene, polypyrrole, epoxy resin and the like, the n-type organic semiconductor perylene-3, 4,9, 10-tetracarboxylic acid diimide (PDInH) has unique optical and electrical properties. The Chunzhu professor takes PDInH small molecules as building units, self-assembles PDInH supermolecules (H-PDInH) through covalent bonding, and has a special band-shaped electronic structure containing a valence band and a conduction band, so that the photocatalysis performance of the H-PDInH supermolecules is more advantageous than that of organic small molecules. However, the PDInH supermolecule has good dispersibility in water, and is difficult to centrifugally separate in the phenol degradation process, so that the detection result of degradation is influenced to a certain extent. And due to insufficient light absorption, rapid recombination of light-induced carriers andlow electronic conductivity, etc., and the practical application thereof in wastewater purification still has a need for intensive research. TiO 2₂The composite catalyst has excellent light stability and high mechanical stability, is rich in resources, low in price, easy to synthesize and non-toxic, and is a preferred inorganic component for preparing the composite catalyst. However, due to TiO₂The forbidden band width of the photocatalyst can not well inhibit the rapid recombination of photo-generated electrons and holes, and the photocatalytic performance of the photocatalyst is greatly reduced. And TiO 2₂PDInH and PDInH @ TiO₂The research of the catalyst for photodegradation of organic pollutants is rarely reported.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides PDInH @ TiO₂Photocatalyst and preparation method and application thereof, the method is simple and easy to implement, and organic-inorganic composite PDINH @ TiO of flaky nano structure₂The photocatalyst has remarkable photocatalytic kinetic characteristics.

The invention is realized by the following technical scheme:

PDINH @ TiO₂The photocatalyst is a core-shell flaky nano material and comprises PDINH and TiO in a mass ratio of 1: 0.25-2₂Wherein PDInH is the carrier, TiO₂Is a nano-load.

PDINH @ TiO₂The preparation method of the photocatalyst comprises the following steps:

step 1) dispersing 0.075-0.6 g of titanium dioxide powder in 10mL of concentrated sulfuric acid, and magnetically stirring for 12 hours at room temperature to obtain a mixed solution;

step 2) adding 0.3g of 3,4,9, 10-perylene tetracarboxylic diimide into the mixed solution prepared in the step 1), performing ultrasonic treatment for 10min, slowly adding 100mL of distilled water into the solution, controlling the temperature and stirring for 2-10 h; finally, centrifuging, washing and drying at 60 ℃ for 12h to obtain powder, namely the PDINH @ TiO₂A photocatalyst.

Preferably, the average particle size of the titanium dioxide powder is 5-10 nm, anatase type, hydrophilic oleophilic type; the purities of the concentrated sulfuric acid and the 3,4,9, 10-perylene tetracarboxylic diimide are analytically pure.

Preferably, the temperature controlled in the step 2) is 0-60 ℃.

Preferably, the speed of centrifugation in step 2) is 10000 rpm/min.

Preferably, the washing in step 2) is 3 times of washing with absolute ethyl alcohol and distilled water alternately.

PDINH @ TiO₂The application of the photocatalyst in simulating the degradation of phenol by sunlight.

Preferably, the method comprises the following steps: the light source adopts 100W simulated sunlight and is 15cm away from the upper part of the reaction system; then the PDINH @ TiO₂The photocatalyst is dispersed in an aqueous phenol solution.

The invention has the following beneficial effects:

the invention takes PDINH as a carrier to self-assemble nano anatase TiO₂Synthesized has enhanced PDINH @ TiO₂Photoactive organic-inorganic nanosheets photocatalysts. In-situ self-assembly PDINH @ TiO₂PDInH and TiO in nano photocatalyst₂The intermolecular CO … H hydrogen bond can effectively realize chronic electron delocalization, thereby accelerating the migration and separation of photo-generated charges and leading the photo-generated charges to have remarkable photocatalytic kinetic properties. Experiments show that PDINH @ TiO₂The nano composite material has PDInH and TiO at the loading temperature of 20 ℃ and the loading time of 6h₂The degradation speed of phenol (6ppm) is the fastest under the condition that the mass ratio of (A) to (B) is 1:1. Composite photocatalyst PDInH @ TiO₂The concentration is 20mg/100mL, the concentration of the phenol aqueous solution is 6ppm, and the phenol degradation rate reaches 93% at room temperature.

Drawings

FIG. 1 is a graph showing PDInH @ TiO prepared in examples 1-4(0 ℃, 20 ℃, 40 ℃, 60 ℃)₂A performance curve for catalytic degradation of 6ppm phenol under 100W simulated sunlight;

FIG. 2 is a performance curve of self-degradation of 6ppm phenol solution under 300W simulated sunlight;

FIG. 3 shows commercially available PDInH and TiO₂And PDInH @ TiO prepared in example 2₂Degradation performance curve of 6ppm phenol solution;

FIG. 4 is a commercial TiO₂(a) TEM images of H-PDInH (b) and PDInH (c);

FIG. 5 is a graph showing PDInH @ TiO prepared in examples 1-4(0 ℃, 20 ℃, 40 ℃, 60 ℃)₂TEM images of (a): (a) is 0 ℃; (b) is 20 ℃; (c) is 40 ℃; (d) is 60 ℃;

FIG. 6 is PDInH @ TiO prepared in example 1-2(0 ℃, 20 ℃ C.)₂SEM photograph of (a): (e) is 0 ℃; (f) is 20 ℃;

FIG. 7 shows PDInH @ TiO prepared in example 2(4h), examples 5-8(2h, 6h, 8h, 10h)₂A performance curve for catalytic degradation of 6ppm phenol under 100W simulated sunlight;

FIG. 8 shows a commercially available TiO compound₂H-PDINH and PDINH @ TiO prepared in example 8₂XRD pattern of photocatalytic material;

FIG. 9 shows PDInH @ TiO prepared in example 6(1:1), examples 9-12(1:0.25, 1:0.5, 1:1.5, 1:2)₂A performance curve for catalytic degradation of 6ppm phenol under 100W simulated sunlight;

FIG. 10 is PDINH @ TiO prepared in example 6₂An absorbance-reaction time standard curve for catalytic degradation of 6ppm phenol under 100W simulated sunlight, wherein the curves in the graph are 0h, 1h, 2h, 3h, 4h, 5h and 6h from top to bottom.

Detailed Description

For a better understanding of the present invention, the following further illustrates the contents of the invention with reference to the accompanying drawings and examples, but the contents are not limited to the following examples.

The raw materials used in the following examples: titanium dioxide (TiO)₂) The average particle size of the powder is 5-10 nm, anatase type and hydrophilic oleophilic type; concentrated sulfuric acid (H)₂SO₄) And 3,4,9, 10-perylene tetracarboxylic diimide (pdimh) were all analytically pure.

Examples 1 to 4 are PDInH @ TiO₂Photocatalyst TiO₂Examples of the experimental examples were examined for the loading temperature when PDInH was loaded, wherein example 1 was 0 ℃, example 2 was 20 ℃, and example 3 was 40 DEG CExample 4 was 60 ℃.

Example 1

PDINH @ TiO₂The preparation method of the photocatalyst comprises the following specific steps:

(1) 0.3g of TiO was weighed₂Measuring 10mL of H₂SO₄The mixture was placed in a 250mL beaker and magnetically stirred for 12h to obtain a mixed solution.

(2) After 0.3g of PDInH was added to the mixed solution of (1) and subjected to ultrasonic treatment for 10min, 100mL of distilled water was slowly added to the solution, and then a 250mL beaker containing the solution was placed in a 2000mL beaker, ice water was added thereto to carry out ice-water cooling, and the temperature was maintained at 0 ℃ and stirred for 4 h. Finally, centrifuging at 10000rpm/min, alternately washing with absolute ethyl alcohol and distilled water for 3 times respectively, and drying at 60 ℃ for 12h to obtain PDInH @ TiO₂And (3) powder.

The performance of the catalyst is evaluated, and a light source (PLS-SXE 300+/UV xenon lamp constant current power supply, manufactured by Beijing Pophyillay company) irradiates a phenol water solution through a simulated sunlight filter with the diameter of D63 multiplied by 4mm to perform a photocatalytic degradation experiment. For each experiment, prepare 250mL beaker PDInH @ TiO prepared₂The photocatalyst (20mg) was dispersed in an aqueous phenol solution (6ppm, 100mL) with ultrasound for 2 min. Then, the suspension was stirred in the dark for 30min to ensure adsorption-desorption equilibrium between the photocatalyst and the phenol solution. Subsequently, the solution was illuminated using 100W sunlight as a light source, and samples were collected at fixed time intervals of 1h to determine the phenol concentration by UV-vis spectroscopy.

As shown in FIG. 1, the catalyst of this example had a loading temperature of 0 ℃ to obtain PDInH @ TiO₂The removal rate of phenol degraded by the catalyst was 76.88%.

Example 2

(2) Adding 0.3g PDInH into the mixed solution of (1) for ultrasonic treatment for 10min, slowly adding 100mL distilled water into the solution, and dissolvingThe solution was stirred at 20 ℃ for 4 h. Finally, centrifuging at 10000rpm/min, alternately washing with absolute ethyl alcohol and distilled water for 3 times respectively, and drying at 60 ℃ for 12h to obtain PDInH @ TiO₂And (3) powder.

As shown in FIG. 1, the catalyst of this example had a loading temperature of 20 ℃ to obtain PDInH @ TiO₂The removal rate of phenol degraded by the catalyst was 91.29%.

FIG. 2 is a performance curve of the self-degradation of the 6ppm phenol solution under 300W simulated sunlight, and it can be seen from FIG. 2 that the 6ppm phenol solution is not substantially self-degraded under natural light.

FIG. 3 shows commercially available PDInH and TiO₂And PDInH @ TiO prepared in example 2₂Performance curves for the degradation of 6ppm phenol solution, as can be seen in FIG. 3, PDInH @ TiO₂The degradation capability of the polymer is obviously better than that of PDInH and TiO₂。

Example 3

(2) After 0.3g of PDInH was added to the mixture of (1) and sonicated for 10min, 100mL of distilled water was slowly added to the above solution, and the solution was stirred at 40 ℃ for 4 h. Finally, centrifuging at 10000rpm/min, alternately washing with absolute ethyl alcohol and distilled water for 3 times respectively, and drying at 60 ℃ for 12h to obtain PDInH @ TiO₂And (3) powder.

As shown in FIG. 1, the catalyst of this example had a loading temperature of 40 ℃ to obtain PDInH @ TiO₂The removal rate of phenol degraded by the catalyst was 80.33%.

Example 4

(2) Adding 0.3g PDInH into the mixed solution of (1) for ultrasonic treatment for 10min, and slowly adding 100mL distilled waterInto the above solution, and then the solution was heated to 60 ℃ and stirred for 4 h. Finally, centrifuging at 10000rpm/min, alternately washing with absolute ethyl alcohol and distilled water for 3 times respectively, and drying at 60 ℃ for 12h to obtain PDInH @ TiO₂And (3) powder.

As shown in FIG. 1, the catalyst of this example had a loading temperature of 60 ℃ to obtain PDInH @ TiO₂The removal rate of phenol degraded by the catalyst was 78.87%.

FIG. 4 is a commercial TiO₂(a) TEM images of PDInH (b), and H-PDInH (c). As can be seen from FIG. 4, commercially available TiO₂PDInH is nano-particles, PDInH single molecules are treated by concentrated sulfuric acid to generate pi-pi accumulation and hydrogen bonding among molecules, and the nano-particles are stacked into nano-sheets with the size of about 200 nm.

FIG. 5 is a graph of in situ self-assembled PDInH @ TiO prepared in examples 1-4₂TEM images of the series of products. PDInH @ TiO can be seen in FIG. 5₂Comprising nanoscale particles, which can be regarded as PDInH, on the surface of which TiO has been successfully supported₂. As can be seen from FIG. 5, the composite photocatalyst PDInH @ TiO has an increasing temperature change₂Presents a particular morphological evolution: the thick and long rod-shaped lamellar structure is changed into a thinner irregular lamellar structure. These morphological changes also account for the nanoscale PDInH @ TiO₂In contrast to TiO₂And has more excellent shape adjustability and configuration flexibility. As shown in FIG. 5(b), the chip structure has a width of about 200-250 nm and a length of about 200nm, relative to PDINH @ TiO in a rod-like structure₂Synthetic lamellar PDInH @ TiO₂Exhibit a nanoscale structure that reduces the transfer of photogenerated carriers to TiO₂The path of the particle surface can also provide more surface active sites and high specific surface area.

FIG. 6 is PDInH @ TiO prepared in example 1-2₂SEM image of (d). As is evident from FIG. 6, the former (e) is a catalyst with a rod-shaped structure at low temperature and is formed by stacking rectangular nano-sheets with different sizes, and then loading TiO₂(ii) a The latter (f) is TiO loaded on a carrier formed by stacking sheet-shaped nano sheets₂And (3) granules.

From examples 1 to 4, it is understood that the efficiency of phenol degradation is the best when the catalyst supporting temperature is 20 ℃.

The catalyst synthesis temperatures in examples 5-8 were all 20 ℃ and the catalyst loading times were investigated, with example 5 being 2h, example 6 being 6h, example 7 being 8h, and example 8 being 10 h.

Example 5

(2) After 0.3g of PDInH was added to the mixed solution of (1) and sonicated for 10min, 100mL of distilled water was slowly added to the above solution, and the solution was stirred at 20 ℃ for 2 h. Finally, centrifuging at 10000rpm/min, alternately washing with absolute ethyl alcohol and distilled water for 3 times respectively, and drying at 60 ℃ for 12h to obtain PDInH @ TiO₂And (3) powder.

As shown in FIG. 7, the catalyst of this example had a loading time of 2h, and produced PDINH @ TiO₂The removal rate of phenol degraded by the catalyst was 83.05%.

Example 6

(2) After 0.3g of PDInH was added to the mixed solution of (1) and sonicated for 10min, 100mL of distilled water was slowly added to the above solution, and the solution was stirred at 20 ℃ for 6 h. Finally, centrifuging at 10000rpm/min, alternately washing with absolute ethyl alcohol and distilled water for 3 times respectively, and drying at 60 ℃ for 12h to obtain PDInH @ TiO₂And (3) powder.

As shown in FIG. 7, the catalyst of this example had a loading time of 6 hours, and produced PDINH @ TiO₂The removal rate of phenol degraded by the catalyst was 93.56%.

Example 7

PDINH @ TiO₂Preparation of the photocatalystThe method comprises the following specific steps:

(2) After 0.3g of PDInH was added to the mixture of (1) and sonicated for 10min, 100mL of distilled water was slowly added to the above solution, and the solution was stirred at 20 ℃ for 8 h. Finally, centrifuging at 10000rpm/min, alternately washing with absolute ethyl alcohol and distilled water for 3 times respectively, and drying at 60 ℃ for 12h to obtain PDInH @ TiO₂And (3) powder.

As shown in FIG. 7, the catalyst of this example had a loading time of 8h, and produced PDINH @ TiO₂The removal rate of the phenol degraded by the catalyst was 77.95%.

Example 8

(2) After 0.3g of PDInH was added to the mixed solution of (1) and sonicated for 10min, 100mL of distilled water was slowly added to the above solution, and the solution was stirred at 20 ℃ for 10 h. Finally, centrifuging at 10000rpm/min, alternately washing with absolute ethyl alcohol and distilled water for 3 times respectively, and drying at 60 ℃ for 12h to obtain PDInH @ TiO₂And (3) powder.

As shown in FIG. 7, the catalyst of this example had a loading time of 10 hours, and produced PDINH @ TiO₂The removal rate of phenol degraded by the catalyst was 85.31%.

FIG. 8 shows commercially available H-PDInH, TiO₂And PDInH @ TiO prepared in example 8₂XRD pattern of photocatalytic material. As can be seen from FIG. 8, the composite photocatalyst PDInH @ TiO₂Almost all diffraction peaks are associated with TiO₂And the diffraction peaks of H-PDInH. As shown in FIG. 8, the characteristic peaks of 2 θ at 25.28 °, 37.80 °, 48.04 °, 55.06 °, 62.68 °, 70.30 ° and 75.02 ° are obvious and correspond to the (101), (004), (200), (211), (204), (220) and (215) crystal planes respectively, and the characteristic peaks and the searched TiO are found₂Anatase ofPhase (ICDD/JCPSD No. 21-1272). Is present in H-PDInH of FIG. 8

The XRD diffraction peak of (A) corresponds to the pi-pi stacking distance between the PDInH perylene core frameworks. In PDINH @ TiO₂Has no change in characteristic diffraction peak position 2 theta of H-PDINH at d 7.45, 3.53, 3.27, 2.95, etc., and has PDINH @ TiO₂Anatase phase TiO on spectrogram₂All diffraction peaks of the basic channel body of (1) are in contact with the unsupported TiO₂Consistent, therefore, corroborating that photocatalysis was successfully synthesized.

From examples 5 to 8, it is clear that the efficiency of phenol degradation is the best when the catalyst loading time is 6 hours.

The catalysts of examples 9-12 were all synthesized at 20 ℃ for 6h of TiO₂The amounts of (A) were investigated, wherein 0.075g was used in example 9, 0.15g in example 10, 0.45g in example 11 and 0.6g in example 12.

Example 9

(1) 0.075g of TiO is weighed₂Measuring 10mL of H₂SO₄The mixture was placed in a 250mL beaker and magnetically stirred for 12h to obtain a mixed solution.

As shown in FIG. 9, PDInH and TiO in this example₂The mass ratio of (1: 0.25) to obtain PDINH @ TiO₂The removal rate of phenol degraded by the catalyst was 41.62%.

Example 10

(1) 0.15g of TiO was weighed₂Measuring 10mL of H₂SO₄The mixture was placed in a 250mL beaker and magnetically stirred for 12h to obtain a mixed solution.

As shown in FIG. 9, PDInH and TiO in this example₂The mass ratio of (1: 0.5) to obtain PDINH @ TiO₂The removal rate of phenol degraded by the catalyst was 65.21%.

Example 11

(1) 0.45g of TiO was weighed₂Measuring 10mL of H₂SO₄The mixture was placed in a 250mL beaker and magnetically stirred for 12h to obtain a mixed solution.

As shown in FIG. 9, PDInH and TiO in this example₂The mass ratio of (1: 1.5) to prepare PDINH @ TiO₂The removal rate of the catalyst degraded phenol was 79.43%.

Example 12

(1) 0.6g of TiO was weighed₂Measuring 10mL of H₂SO₄The mixture was placed in a 250mL beaker and magnetically stirred for 12h to obtain a mixed solution.

As shown in FIG. 9, PDInH and TiO in this example₂The mass ratio of (1: 2) to prepare PDINH @ TiO₂The removal rate of phenol degraded by the catalyst was 74.30%.

The removal rate of phenol degraded by the catalysts prepared in examples 9-12 is lower than that of example 6, so that the catalysts have PDInH and TiO₂The mass ratio of (a) to (b) is 1:1, the efficiency of degrading phenol is optimum.

By combining the embodiments 1-12, the technical solution of embodiment 6, i.e., PDInH @ TiO₂The catalyst has the loading temperature of 20 ℃ and the loading time of 6h, PDInH and TiO₂The mass ratio of (A) to (B) is 1:1, the performance of photocatalytic degradation of phenol is optimal. The degradation results under the optimum conditions for the catalyst are shown in fig. 10.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. PDINH @ TiO₂The photocatalyst is characterized in that the photocatalyst is a core-shell flaky nano material and comprises PDInH and TiO in a mass ratio of 1: 0.25-2₂Wherein PDInH is the carrier, TiO₂Is a nano-load.

2. The PDINH @ TiO of claim 1₂The preparation method of the photocatalyst is characterized by comprising the following steps:

step 2) adding 0.3g of 3,4,9, 10-perylene tetracarboxylic diimide into the mixed solution prepared in the step 1), performing ultrasonic treatment for 10min, slowly adding 100mL of distilled water into the solution, controlling the temperature and stirring for 2-10 h; finally, the mixture is centrifuged and washed at 60 DEG CDrying for 12h to obtain powder, namely the PDINH @ TiO₂A photocatalyst.

3. The PDINH @ TiO of claim 2₂The preparation method of the photocatalyst is characterized in that the average particle size of the titanium dioxide powder is 5-10 nm, anatase type and hydrophilic oleophilic type; the purities of the concentrated sulfuric acid and the 3,4,9, 10-perylene tetracarboxylic diimide are analytically pure.

4. The PDINH @ TiO of claim 2₂The preparation method of the photocatalyst is characterized in that the temperature controlled in the step 2) is 0-60 ℃.

5. The PDINH @ TiO of claim 2₂The preparation method of the photocatalyst is characterized in that the centrifugation speed in the step 2) is 10000 rpm/min.

6. The PDINH @ TiO of claim 2₂The preparation method of the photocatalyst is characterized in that the washing in the step 2) is that absolute ethyl alcohol and distilled water are alternately washed for 3 times respectively.

7. The PDInH @ TiO of claim 1₂Photocatalyst or PDINH @ TiO obtainable by the process according to any one of claims 2 to 6₂The application of the photocatalyst in simulating the degradation of phenol by sunlight.

8. Use according to claim 7, characterized in that it comprises the following steps: the light source adopts 100W simulated sunlight and is 15cm away from the upper part of the reaction system; then the PDINH @ TiO₂The photocatalyst is dispersed in an aqueous phenol solution.