Synthesis method of a solar full-spectrum photothermal adsorption catalyst

Abstract

The present invention discloses a synthesis method of a solar full-spectrum photo-thermal adsorption catalyst, comprising the steps of: (1) preparing a metal-titanium peroxide composite precursor, (2) Fenton thermal decomposition, and (3) photoreducing the metal. Compared with traditional structure catalysts, the mesoporous encapsulated catalyst in the synthesis method according to the present invention can confine the active components in a closed space, preventing the high-temperature coalescence and poisoning inactivation of the active components. The present invention synthesizes a metal-TiO2 full-spectrum adsorption catalyst at low temperature by introducing in-situ coupling reaction between a thermal Fenton reaction and photoreduction in activated carbon mesopores, without high-temperature calcination, thus avoiding the blockage of pores caused by crystal growth at high temperature. Compared with the preparation methods reported in the literature, the synthesis method of the present invention has a simple process, strong operability, relatively low cost, is suitable for batch preparation, has the possibility of industrial production, and has broad application prospects.

Description

Technical Field

[0001] The present invention belongs to the field of inorganic catalysts, and particularly relates to a synthesis method of an adsorption-driven photothermal synergistic catalytic material with full-spectrum solar absorption and a catalyst prepared by this method. Background Art

[0002] In 2020, the annual sewage discharge in China was approximately 60 billion m 3 . The average power consumption for urban sewage treatment was 0.292 KWh / m 3 , and the daily power consumption was 48.39 million KWh. The carbon emissions accounted for 1%-2% of the total emissions. Therefore, using solar energy as a clean and sustainable energy source to purify sewage using solar energy has multiple significances such as reducing treatment costs, alleviating energy pressure, and reducing carbon emissions. Among them, the solar advanced oxidation technology can use renewable solar energy to generate hydroxyl radicals to completely oxidize macromolecular and difficult-to-degrade organic substances into small-molecule substances, which has received extensive attention. However, limited by sunlight intensity, spectrum, and energy conversion efficiency, direct solar photocatalysis is only limited to rainwater disinfection. To break through the limitation of the solar energy density, Cao Hongbin et al. reported (Acc. Chem. Res. 2020, 53, 5) that based on CPC solar light collection catalysis to replace the artificial ultraviolet light source to drive the ozone advanced oxidation process, by coupling solar photocatalysis and ozone advanced oxidation, it is possible to reduce both equipment costs and operating costs, providing a new technical approach for the application of solar photocatalysis. However, its technology is only limited to using the ultraviolet-visible part of solar energy, and at the same time, there is a lack of solutions for the non-continuity defects of solar energy. Therefore, the solar advanced oxidation technology with high solar energy utilization efficiency and efficient mass transfer process of ·OH has received extensive attention.

[0003] Sunlight can be divided into three bands: ultraviolet, visible, and infrared according to the spectrum. A technical solution that realizes the hierarchical conversion of the grades of each band according to the energy "grade" of the three bands can achieve the full-spectrum utilization of solar energy. For example, TiO 2 has excellent photocatalytic performance in the ultraviolet region; due to the surface plasmon resonance (SPR) generated by the collective oscillation interaction of free electrons and photons in nanometal (such as Au, Ag, Cu), it can efficiently utilize visible light to generate hot electrons for catalytic chemical reactions; carbon materials can efficiently convert the energy of the near-infrared part of solar energy into heat energy due to the close energy levels of loosely bound π electrons, and are widely used as solar infrared photothermal conversion materials. At the same time, due to the short lifetime and limited diffusion distance of ·OH in the advanced oxidation process, and the developed internal pore structure, large specific surface area, and strong adsorption capacity of activated carbon, it can efficiently enrich organic pollutants and can efficiently utilize the ·OH generated in the advanced oxidation process to produce an adsorption-driven synergistic effect. Therefore, the development of noble metal-TiO supported on activated carbon 2Composite materials have important practical application values for the advanced solar oxidation process. The traditional method for preparing activated carbon / titanium dioxide composite materials uses organic titanium as the titanium source, hydrolyzes it through the hydrothermal method, and finally obtains graphene-titanium dioxide composite materials after high-temperature sintering. The high-temperature process easily causes agglomeration of titanium dioxide nanoparticles. At the same time, in order to protect carbon from being decomposed at high temperatures, an inert gas protection is also required, resulting in a complex process and high costs. When using TiO 2 nanopowder as the titanium source and then compounding it with activated carbon, not only is it difficult to control the uniformity of the components, but it is also difficult to form an effective synergistic effect between titanium oxide and activated carbon. Therefore, it is of great value to develop a preparation method for activated carbon-TiO 2 -metal composite materials with a simple process and low-temperature synthesis suitable for batch preparation. Summary of the Invention

[0004] In order to overcome the problems existing in the prior art, the key to the synthesis method of the present invention lies in developing an in-situ synthesis of metal-titanium oxide catalyst in the mesopores of activated carbon by coupling Fenton thermal decomposition and low-temperature photodeposition processes, synthesizing an adsorption catalyst with efficient solar ultraviolet-visible-infrared light full-spectrum driving, which is expected to be widely used in the field of gas-solid phase organic pollutant degradation.

[0005] In order to achieve the above object of the present invention, according to one aspect of the present invention, an object of the present invention is to provide a synthesis method of a solar full-spectrum photothermal adsorption catalyst, and the method includes the following steps:

[0006] (1) Preparation of metal-titanium peroxide composite precursor

[0007] Dissolve the freshly prepared titanium hydroxide suspension precursor with an aqueous hydrogen peroxide solution to obtain an aqueous titanium peroxide solution, wherein the molar ratio of hydrogen peroxide to titanium ions in the aqueous metal peroxide solution is 1:1 to 10:1; preferably, the mass percentage concentration of the aqueous hydrogen peroxide solution is 10-50%; then add an aqueous metal nitrate solution to the solution, and control the molar ratio of metal ions to Ti to be 0.1:1 to 1:1 to obtain a metal-titanium peroxide composite precursor solution.

[0008] (2) Fenton thermal decomposition

[0009] Under the condition of an ice-water bath, add activated carbon powder to the metal-titanium peroxide composite precursor solution obtained in step 1), control the volume ratio of the precursor solution to the weight of the activated carbon to be 100 ml:5 g to 100 ml:50 g, stir and adsorb for 10 min to 90 min, then filter the adsorbed solution to obtain carbon powder, and react at 120 °C to 180 °C in an oven for 1 to 6 h to thermally decompose titanium peroxide based on the Fenton principle by metal ions, and in-situ generate nano-titanium oxide and metal oxide in the mesopores of activated carbon.

[0010] (3) Photo-reduction of metal

[0011] React the mesoporous carbon-supported composite oxide obtained in step (2) under the irradiation of a 365 nm mercury lamp for 30 - 120 min, where the intensity of the 365 nm ultraviolet light is 0.1 mW / cm 2 ~500 mW / cm 2 to obtain an activated carbon-supported metal-TiO catalyst powder.

[0012] Preferably, the metal nitrate in step (1) is selected from copper nitrate, silver nitrate, etc.

[0013] Preferably, in step (1), the concentration of Ti ions in the obtained metal-titanium peroxide composite precursor solution is controlled to be 0.01 to 0.3 mol / L, more preferably 0.05 to 0.2 mol / L, and even more preferably 0.1 mol / L.

[0014] Preferably, in step (2), the volume ratio of the precursor solution to the weight of the activated carbon is controlled to be 100 ml:10 g to 100 ml:40 g, more preferably 100 ml:15 g to 100 ml:30 g, and even more preferably 100 ml:20 g.

[0015] Preferably, in step (2), the stirring and adsorption is carried out for 20 min to 60 min, more preferably 30 min to 40 min.

[0016] Preferably, in step (2), the light intensity is 0.5 to 100 mW / cm 2 , more preferably 0.5 mW / cm 2 to 10 mW / cm 2 , most preferably 1 mW / cm 2 .

[0017] Preferably, the synthesis method according to the present invention is carried out as follows:

[0018] 11.6 g of titanium hydroxide precipitate with a solid content of 10% is added to 10 g of a 30 wt% hydrogen peroxide solution, and the volume is fixed to 100 mL to obtain a titanium peroxide solution. Under an ice-water bath condition, 10 mL of 0.1 mol / L AgNO 3 solution is added, and then 20 g of activated carbon is added and stirred for 30 min. The powder obtained after filtering the precipitate is reacted in an oven at 150 °C for 3 h, and then reacted under 365 nm ultraviolet light with an intensity of 1 mW / cm 2 for 30 min to obtain a catalyst product.

[0019] According to another aspect of the present invention, another object of the present invention is to provide a solar full-spectrum photothermal adsorption catalyst, which is prepared by the synthesis method according to the present invention.

[0020] According to another aspect of the present invention, yet another object of the present invention is to provide the use of the solar full-spectrum photothermal adsorption catalyst in the catalytic degradation of organic pollutants.

[0021] Preferably, the organic pollutants include, but are not limited to, volatile halogenated hydrocarbons, volatile organic compounds, aromatic organic compounds, and more preferably methylene blue, methyl blue, rhodamine, benzene, toluene, phenol.

[0022] Beneficial effects

[0023] Compared with traditional structure catalysts, mesoporous encapsulated catalysts can confine active components in a closed space, preventing high-temperature coalescence and poisoning inactivation of active components. The crystallization process of metal oxide catalytic materials generally requires high-temperature sintering, and the high-temperature process usually leads to structural collapse and solid-phase reactions that damage the catalyst activity. In the present invention, by introducing the thermal Fenton reaction and in-situ coupling reaction of photoreduced activated carbon in mesopores, metal-TiO 2 adsorption full-spectrum catalyst is synthesized at low temperature without high-temperature calcination, which can avoid crystal growth and pore blockage at high temperature. Compared with the preparation methods reported in the literature, the synthesis method of the present invention has a simple process, strong operability, relatively low cost, is suitable for batch preparation, has the possibility of industrial production, and has broad application prospects. Description of the drawings

[0024] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0025] Figure 1 TEM results of the sample obtained in Example 1;

[0026] Figure 2 XRD results of the sample obtained in Example 1. Specific embodiments

[0027] The present invention will be described in detail below. Before the description, it should be understood that the terms used in this specification and the appended claims should not be construed as limited to the general meaning and dictionary meaning, but should be interpreted according to the meanings and concepts corresponding to the technical aspects of the present invention on the basis of the principle that allows the inventor to appropriately define the terms for the best interpretation. Therefore, the description presented here is only a preferred example for illustrative purposes and is not intended to limit the scope of the present invention. Thus, it should be understood that other equivalent ways or improved ways can be obtained without departing from the spirit and scope of the present invention.

[0028] As used herein, the terms "comprising", "including", "having", "containing" or any other similar terms are all open-ended transitional phrases, which are intended to cover non-exclusive inclusions. For example, a composition or article containing plural elements is not limited only to the elements listed herein, but may also include other elements that are not explicitly listed but are normally inherent in the composition or article. In addition, unless there is a clear contrary indication, the term "or" means an inclusive "or", rather than an exclusive "or". For example, any of the following situations satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), A and B are both true (or exist). Further, as used herein, the interpretations of the terms "comprising", "including", "having", "containing" should be regarded as having specifically disclosed and simultaneously covered closed or semi-closed transitional phrases such as "consisting of" and "substantially consisting of".

[0029] As used herein, all features or conditions defined in the form of numerical ranges or percentage ranges are only for the sake of brevity and convenience. Accordingly, the description of a numerical range or percentage range should be regarded as having covered and specifically disclosed all possible sub-ranges and individual values within the range, especially integer values. For example, the description of the range "1 to 8" should be regarded as having specifically disclosed all sub-ranges such as 1 to 7, 2 to 8, 2 to 6, 3 to 6, 4 to 8, 3 to 8, etc., especially the sub-ranges defined by all integer values, and should be regarded as having specifically disclosed the individual values such as 1, 2, 3, 4, 5, 6, 7, 8 within the range. Unless otherwise specified, the foregoing interpretation method applies to all contents of the present invention, regardless of the breadth of the range.

[0030] If a quantity or other numerical value or parameter is expressed as a range, a preferred range, or a series of upper and lower limits, it should be understood that all ranges formed by any pair of the upper limit or preferred value of the range and the lower limit or preferred value of the range have been specifically disclosed herein, whether or not these ranges are separately disclosed. In addition, when a range of numerical values is mentioned herein, unless otherwise specified, the range should include its endpoints and all integers and fractions within the range.

[0031] In this article, on the premise that the purpose of the invention can be achieved, a numerical value should be understood to have the precision of the significant digits of that numerical value. For example, the number 40.0 should be understood to cover the range from 39.50 to 40.49.

[0032] The following examples are merely listed as examples of the implementation schemes of the present invention and do not constitute any limitation to the present invention. Those skilled in the art can understand that modifications within the scope not deviating from the essence and concept of the present invention fall within the protection scope of the present invention. Unless otherwise specified, the reagents and solvents disclosed below are purchased from Beijing Innochem (innochem). The spectrophotometer is Shimadzu Uv 2600, and the VOC concentration is measured by a Shenguoan PID sensor.

[0033] Example 1

[0034] 11.6 g of titanium hydroxide precipitate with a solid content of 10% was added with 10 g of hydrogen peroxide solution with a mass percentage concentration of 30 wt%, and the volume was fixed to 100 mL to obtain a titanium peroxide solution. 10 mL of 0.1 mol / L AgNO 3 solution was added under an ice-water bath, and then 20 g of activated carbon was added and stirred for 30 min. The powder obtained after filtering the precipitate was reacted at 150 °C in an oven for 3 h, and then reacted under ultraviolet light of 365 nm with a light intensity of 1 mW / cm 2 for 30 min to obtain a catalyst product.

[0035] 0.1 g of the prepared catalyst product was immersed in 50 ml of methylene blue solution with a concentration of 0.01 mmol / L for 2 h; then, after irradiating with a 300 W xenon lamp light source on the surface of the solution for 2 h, the absorption value of the solution under ultraviolet light at a wavelength of 665 nm (the maximum absorption of methylene blue) was measured, and the degradation rate was 91%.

[0036] Figure 1 This is the TEM result of the sample obtained in this example, confirming that the product is a porous material loaded with nanocrystals; Figure 2 This is the XRD result of the sample obtained in this example, confirming that the nanocrystals are silver-titanium dioxide composites.

[0037] Example 2

[0038] 11.6 g of titanium hydroxide precipitate with a solid content of 10% was added to 10 g of a hydrogen peroxide solution with a mass percentage concentration of 30 wt%, and the volume was fixed to 100 mL to obtain a titanium peroxide solution. 10 mL of 0.1 mol / L Cu(NO 3 ) 2 solution was added under an ice-water bath, and then 20 g of activated carbon was added and stirred for reaction for 30 min. The powder obtained after filtering the precipitate was reacted in an oven at 150 °C for 3 h, and then reacted under 365 nm ultraviolet light with a light intensity of 1 mW / cm 2 for 30 min to obtain a catalyst product.

[0039] 0.1 g of the prepared catalyst product was immersed in 50 mL of a methylene blue solution with a concentration of 0.01 mmol / L for 2 h; then, after irradiating for 2 h with a 300 W xenon lamp light source on the surface of the solution, the absorbance value of the solution under ultraviolet light at a wavelength of 665 nm (the maximum absorption of methylene blue) was measured, and the degradation rate was 86%.

[0040] Comparative Example 1

[0041] 11.6 g of titanium hydroxide precipitate with a solid content of 10% was added to 10 g of a hydrogen peroxide solution with a mass percentage concentration of 30 wt%, and the volume was fixed to 100 mL to obtain a titanium peroxide solution. 10 mL of 0.1 mol / L Cu(NO 3 ) 2 solution was added under an ice-water bath, and then 20 g of activated carbon was added and stirred for reaction for 30 min. The powder obtained after filtering the precipitate was reacted in an oven at 150 °C for 3 h to obtain a catalyst product.

[0042] 0.1 g of the prepared catalyst product was immersed in 50 mL of a methylene blue solution with a concentration of 0.01 mmol / L for 2 h; then, after irradiating for 2 h with a 300 W xenon lamp light source on the surface of the solution, the absorbance value of the solution under ultraviolet light at a wavelength of 665 nm (the maximum absorption of methylene blue) was measured, and the degradation rate was 56%.

[0043] Comparative Example 2

[0044] 11.6 g of titanium hydroxide precipitate with a solid content of 10% was added to 10 g of a hydrogen peroxide solution with a mass percentage concentration of 30 wt%, and the volume was fixed to 100 mL to obtain a titanium peroxide solution. 20 g of activated carbon was added and stirred for reaction for 30 min under an ice-water bath. The powder obtained after filtering the precipitate was reacted in an oven at 150 °C for 3 h, and then reacted under 365 nm ultraviolet light with a light intensity of 1 mW / cm 2 for 30 min to obtain a catalyst product.

[0045] Take 0.1 g of the prepared catalyst product and soak it in 50 ml of methylene blue solution with a concentration of 0.01 mmol / L for 2 h; then measure the absorbance of the solution under ultraviolet light at a wavelength of 665 nm (the maximum absorption of methylene blue) after irradiating it with a 300 W xenon lamp light source on the surface of the solution for 2 h, and the degradation rate is 42%.

[0046] As mentioned above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, and all of them should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A method for synthesizing a solar full-spectrum photothermal adsorption catalyst, the method comprises the following steps: (1) Preparation of metal-titanium peroxide composite precursor Dissolve the freshly prepared titanium hydroxide suspension precursor with an aqueous hydrogen peroxide solution to obtain an aqueous titanium peroxide solution, wherein the molar ratio of hydrogen peroxide to titanium ions in the metal peroxide aqueous solution is 1:1 to 10:1; wherein the mass percentage concentration of the aqueous hydrogen peroxide solution is 10-50%; then add an aqueous metal nitrate solution to the solution, and control the molar ratio of metal ions to Ti to be 0.1:1 to 1:1 to obtain a metal-titanium peroxide composite precursor solution, and the metal nitrate is selected from copper nitrate and silver nitrate; (2) Fenton thermal decomposition Under the condition of an ice-water bath, add activated carbon powder to the metal-titanium peroxide composite precursor solution obtained in step 1), and control the volume ratio of the precursor solution to the weight of the activated carbon to be 100 mL:5 g to 100 mL:50 g. After stirring and adsorbing for 10 min to 90 min, filter the adsorbed solution to obtain carbon powder, and react in an oven at 120 °C to 180 °C for 1 to 6 h to thermally decompose titanium peroxide based on the Fenton principle with metal ions, and in-situ generate nano-titanium oxide and metal oxide in the mesopores of the activated carbon; (3) Photoreduction of metal React the mesoporous carbon-supported composite oxide obtained in step 2) under irradiation of a 365 nm mercury lamp for 30 to 120 min, where the 365 nm ultraviolet light intensity is 0.1 mW / cm 2 ~500 mW / cm 2 , to obtain an activated carbon-supported metal-TiO 2 catalyst powder.

2. The synthesis method according to claim 1, characterized in that in step 1), the concentration of Ti ions in the obtained metal-titanium peroxide composite precursor solution is controlled to be 0.01 to 0.3 mol / L.

3. The synthesis method according to claim 2, characterized in that in step 1), the concentration of Ti ions in the obtained metal-titanium peroxide composite precursor solution is controlled to be 0.05 to 0.2 mol / L.

4. The synthesis method according to claim 3, characterized in that in step 1), the concentration of Ti ions in the obtained metal-titanium peroxide composite precursor solution is controlled to be 0.1 mol / L.

5. The synthesis method according to claim 1, characterized in that in step 2), the volume ratio of the precursor solution to the weight of the activated carbon is controlled to be 100 mL:10 g to 100 mL:40 g; in step 2), the stirring and adsorption is carried out for 20 min to 60 min; The light intensity described in step 3) is 0.5 to 100 mW / cm 2 .

6. The synthesis method according to claim 5, characterized in that in step 2), the volume ratio of the precursor solution to the weight of the activated carbon is controlled to be 100 mL:15 g to 100 mL:30 g; in step 2), the stirring and adsorption is carried out for 30 min to 40 min; The light intensity described in step 3) is 0.5 mW / cm 2 to 10 mW / cm 2 .

7. The synthesis method according to claim 6, characterized in that in step 2), the volume ratio of the precursor solution to the weight of the activated carbon is controlled to be 100 mL:20 g; The light intensity described in step 3) is 1 mW / cm 2 .

8. The synthesis method according to claim 1, characterized in that the synthesis method is carried out as follows: 11.6 g of titanium hydroxide precipitate with a solid content of 10% was added to 10 g of hydrogen peroxide solution with a mass percentage concentration of 30 wt%, and the volume was fixed to 100 mL to obtain a titanium peroxide solution. 10 mL of 0.1 mol / L AgNO 3 solution was added, and then 20 g of activated carbon was added and stirred for reaction for 30 min. The powder obtained after filtering the precipitate was reacted in an oven at 150 °C for 3 h, and then reacted under 365 nm ultraviolet light with a light intensity of 1 mW / cm 2 for 30 min to obtain a catalyst product.

9. A solar full-spectrum photothermal adsorption catalyst, which is prepared by the synthesis method according to any one of claims 1 to 8.

10. Use of the solar full-spectrum photothermal adsorption catalyst according to claim 9 in the catalytic degradation of organic pollutants.

11. The use according to claim 10, characterized in that, the organic pollutant is methylene blue, methyl blue, rhodamine, benzene, toluene or phenol.

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