A ruthenium phosphide supported spherical carbon nitride photocatalyst, a preparation method and application thereof

Abstract

The application discloses a kind of phosphorus ruthenium supported globular carbon nitride photocatalyst and its preparation method and application.A kind of phosphorus ruthenium supported globular carbon nitride photocatalyst preparation method, comprising the following steps: melamine solution, cyanuric acid solution is mixed and stirred, to obtain globular precursor;Globular precursor is calcined to obtain globular carbon nitride;Globular carbon nitride is dispersed in solvent, add ruthenium trichloride hydrate, stir, add sodium borohydride reduction, to obtain ruthenium supported globular carbon nitride;Ruthenium supported globular carbon nitride is placed with hypophosphite under protective atmosphere calcination to obtain the phosphorus ruthenium supported globular carbon nitride.The phosphorus ruthenium supported globular carbon nitride photocatalytic material prepared by morphology control and catalyst support in the application has a large specific surface area, effectively inhibits the recombination of photo-generated electron-hole, improves the visible light response performance and photocatalytic activity of the material, and has good photocatalytic degradation of new pollutants and hydrogen production performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photocatalytic water treatment, in particular to a ruthenium phosphide loaded spherical carbon nitride photocatalyst and a preparation method and application thereof. BACKGROUND

[0002] Pharmaceuticals and personal care products (PPCPs) exist widely in environmental waters due to their structural stability, bioaccumulation, trace, and difficult biodegradation. The traditional water treatment process has poor treatment effect, so as a new pollutant, it has attracted widespread attention. Most PPCPs are highly polar and difficult to volatilize. When they are discharged into the water environment, their own characteristics hinder the escape of such substances, thereby causing the water environment to become a "repository" of PPCPs. The necessity of reducing the ecological risk of PPCPs in the environment and solving the pollution problem has become increasingly prominent. Among them, non-steroidal drugs (taking naproxen as an example) as an important member of PPCPs have also received a lot of attention and have been frequently detected in groundwater and sewage. At present, the treatment methods for such substances in wastewater mainly include physical treatment, chemical treatment and biological treatment. Although they have certain removal effect, the above-mentioned methods all have certain disadvantages, and different degrees of carbon emissions are caused in the treatment process, which limits the application to a certain extent.

[0003] Among many technologies, photocatalytic technology relying on green and clean solar energy as the driving force of the reaction has been widely studied. Among them, non-metal-based photocatalyst carbon nitride is widely used in photocatalysis due to its good light response, stability, suitable valence band position, simple preparation and other characteristics. However, the traditional phase carbon nitride has small specific surface area, few active sites, and low visible light utilization efficiency, which leads to low photocatalytic activity and limits its degradation of non-steroidal drugs (taking naproxen as an example) and other new pollutants in water and clean energy production. Therefore, it is necessary to modify carbon nitride to improve the photocatalytic performance of the material. SUMMARY

[0004] In order to overcome the shortcomings of the prior art, the present application provides a ruthenium phosphide loaded spherical carbon nitride photocatalyst and a preparation method and application thereof. The prepared ruthenium phosphide loaded spherical carbon nitride photocatalyst has a large specific surface area, more active sites and stronger photocatalytic activity, and can be effectively applied to photocatalytic degradation of wastewater containing naproxen and a synchronous hydrogen production system.

[0005] In order to achieve the above purpose, the technical scheme adopted by the present application is:

[0006] The first aspect of the present application provides a preparation method of a ruthenium phosphide loaded spherical carbon nitride photocatalyst, comprising the following steps:

[0007] (1) mixing and stirring a melamine solution and a cyanuric acid solution to obtain a spherical precursor through supramolecular self-assembly;

[0008] (2) obtaining spherical carbon nitride by placing the spherical precursor in a muffle furnace and heating and calcining;

[0009] (3) obtaining ruthenium-loaded spherical carbon nitride by dispersing the spherical carbon nitride in a solvent, adding ruthenium trichloride hydrate, stirring, and adding sodium borohydride for reduction;

[0010] (4) obtaining the phosphorized ruthenium-loaded spherical carbon nitride by placing the ruthenium-loaded spherical carbon nitride and hypophosphite in a protective atmosphere and performing low-temperature phosphorization calcination.

[0011] The phosphorized ruthenium-loaded spherical carbon nitride photocatalytic material prepared by morphology regulation and catalyst loading has a large specific surface area, effectively inhibits the recombination of photo-generated electrons and holes, improves the visible light response performance and photocatalytic activity of the material, effectively adjusts the imbalance of the oxidation-reduction reaction rate at both ends in the photocatalytic reaction process of the carbon nitride-based photocatalytic material, has good performance of photocatalytic degradation of new pollutants and simultaneous hydrogen production, and has good application prospects in new pollutant wastewater treatment and energy recovery.

[0012] Preferably, in step (1), the mass ratio of melamine in the melamine solution to cyanuric acid in the cyanuric acid solution is (0.9-1.1):1; further preferably, in step (1), the mass ratio of melamine in the melamine solution to cyanuric acid in the cyanuric acid solution is 1.02:1.

[0013] Preferably, the solvent of the melamine solution is dimethyl sulfoxide; and the solvent of the cyanuric acid solution is dimethyl sulfoxide.

[0014] Preferably, in step (1), the concentration of the melamine solution is 0.045-0.055 g / mL; further preferably, the concentration of the melamine solution is 0.048-0.053 g / mL.

[0015] Preferably, in step (1), the concentration of the cyanuric acid solution is 0.08-0.12 g / mL; further preferably, the concentration of the cyanuric acid solution is 0.09-0.11 g / mL.

[0016] Preferably, in step (1), the mixing and stirring time is 10-20 min.

[0017] Preferably, in step (2), the heating rate is 1.8-2.8℃ / min; the calcination temperature is 500-600℃; and the calcination time is 3-5h; further preferably, in step (2), the heating rate is 2.0-2.5℃ / min; the calcination temperature is 540-560℃; and the calcination time is 3.5-4.5h.

[0018] Preferably, in step (3), the mass ratio of the ruthenium element in the ruthenium trichloride hydrate to the spherical carbon nitride is 1:(90-110); further preferably, in step (3), the mass ratio of the ruthenium element in the ruthenium trichloride hydrate to the spherical carbon nitride is 1:(95-105).

[0019] Preferably, in step (3), the solvent is an alcohol solution; further preferably, in step (3), the solvent is ethylene glycol.

[0020] Preferably, in step (3), the mass-volume ratio of the spherical carbon nitride to the solvent is 1mg:(0.8-1.2)mL.

[0021] Preferably, in step (4), the mass ratio of the ruthenium-loaded spherical carbon nitride to the hypophosphite is 1:(4-6); further preferably, in step (4), the mass ratio of the ruthenium-loaded spherical carbon nitride to the hypophosphite is 1:5.

[0022] Preferably, in step (4), the hypophosphite is selected from at least one of sodium hypophosphite and a hydrate thereof.

[0023] Preferably, in step (4), the heating rate of the low-temperature phosphorization calcination is 4-6℃ / min, the temperature of the low-temperature phosphorization calcination is 250-350℃, and the maintenance time is 1.5-2.5h; further preferably, in step (4), the heating rate of the low-temperature phosphorization calcination is 4.5-5.5℃ / min, the temperature of the low-temperature phosphorization calcination is 280-320℃, and the maintenance time is 1.8-2.2h.

[0024] The second aspect of the present application provides a phosphorized ruthenium-loaded spherical carbon nitride photocatalyst prepared by the preparation method of the phosphorized ruthenium-loaded spherical carbon nitride photocatalyst.

[0025] Preferably, the specific surface area of the phosphorized ruthenium-loaded spherical carbon nitride photocatalyst is 50-65m 2 / g.

[0026] The third aspect of the present application provides the application of the phosphorized ruthenium-loaded spherical carbon nitride photocatalyst in organic pollutant wastewater photocatalytic degradation, photocatalytic hydrogen production, and simultaneous hydrogen production in organic pollutant wastewater photocatalytic degradation.

[0027] Preferably, the organic contaminant comprises naproxen.

[0028] The present application has the following advantages compared with the prior art:

[0029] The application provides a preparation method of a phosphorus-ruthenium-loaded spherical carbon nitride photocatalyst. The method comprises the following steps: preparing a layered and stacked spherical carbon nitride material by means of a supermolecular self-assembly assisted calcination method, and then preparing the phosphorus-ruthenium-loaded spherical carbon nitride photocatalyst by means of a sodium borohydride chemical reduction and low-temperature phosphorization method. The method has the advantages of simple process, good repeatability and large-scale production. The 3D spherical morphology of the material has a large specific surface area, increases the reflection and absorption of light, provides more reaction sites for the loading of a cocatalyst and subsequent photocatalytic reactions, the introduction of the phosphorus-ruthenium cocatalyst effectively controls the separation and migration of photogenerated carriers and the reaction energy barrier of the redox end in the photocatalytic reaction, effectively improves the photocatalytic performance of the carbon nitride material, and the carbon nitride material can be applied to the photocatalytic treatment and synchronous hydrogen production of wastewater containing new pollutants such as naproxen, has high application prospect and use value, and the like. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is a transmission electron microscope (TEM) image of the phosphorus-ruthenium-loaded spherical carbon nitride (RuP-CNS);

[0031] Figure 2 It is an N2 adsorption-desorption curve of different carbon nitride materials;

[0032] Figure 3 It is a performance graph of the photocatalytic degradation of naproxen and synchronous hydrogen production of different carbon nitride materials;

[0033] Figure 4 It is a performance graph of the photocatalytic degradation of naproxen and synchronous hydrogen production of RuP-CNS;

[0034] Figure 5 It is a cycle performance graph of the photocatalytic degradation of naproxen and synchronous hydrogen production of RuP-CNS;

[0035] Figure 6 It is a performance graph of the photocatalytic degradation of naproxen and synchronous hydrogen production of RuP-CNS under different light conditions. DETAILED DESCRIPTION

[0036] The specific embodiments of the application are described below. It should be noted that the description of the embodiments is used to help understand the application, but does not constitute a limitation on the application. In addition, the technical features involved in the various embodiments of the application described below can be combined with each other as long as they do not conflict with each other.

[0037] The experimental methods in the following examples are all conventional methods unless otherwise specified. The experimental materials used in the following examples are all commercially available unless otherwise specified.

[0038] Example 1

[0039] The present example provides a preparation method of a phosphorus-ruthenium-loaded spherical carbon nitride (RuP-CNS) photocatalyst, comprising the following steps:

[0040] (1) Dissolve 1.02 g of melamine in 20 mL of dimethyl sulfoxide solvent under ultrasonic to prepare A liquid, dissolve 1 g of cyanuric acid in 10 mL of dimethyl sulfoxide solvent under ultrasonic to prepare B liquid, then mix A liquid and B liquid and stir for 15 min, under the action of specific and directional hydrogen bonds and other non-covalent bonds, the supramolecular self-assembles to form a 3D nanoscale morphology of flaky stacked, which is a supramolecular spherical precursor (CM);

[0041] (2) Place the supramolecular spherical precursor (CM) in an alumina crucible and then transfer it to a muffle furnace, heat to 550℃ at a heating rate of 2.3℃ / min under air atmosphere and keep for 4 h, and then obtain a yellow solid after calcination, which is spherical carbon nitride (CNS);

[0042] (3) Disperse 80 mg of spherical carbon nitride (CNS) in 80 mL of ethylene glycol solvent under ultrasonic, add ruthenium trichloride hydrate to it and stir for 12 h to adsorb, the mass ratio of ruthenium element to spherical carbon nitride is 1:100, then add 25 mg of sodium borohydride for chemical reduction, and finally obtain ruthenium-loaded spherical carbon nitride (Ru-CNS) by suction filtration, washing and drying;

[0043] (4) Place 50 mg of ruthenium-loaded spherical carbon nitride (Ru-CNS) and 250 mg of sodium hypophosphite monohydrate in two porcelain boats respectively and then transfer them to a tube furnace, heat to 300℃ at a heating rate of 5℃ / min under nitrogen atmosphere and keep for 42 h, and then obtain phosphorus-ruthenium-loaded spherical carbon nitride (RuP-CNS) after calcination.

[0044] The TEM observation results of the RuP-CNS photocatalyst are shown in Figure 1 Figure 1 In the figure, a is a TEM image of RuP-CNS at a scale of 0.2 μm, and b is an enlarged image of the lamellar structure at a scale of 50 nm; it can be seen that the photocatalyst has a layered and stacked hollow spherical morphology, and there are phosphorus-ruthenium particles dispersed on the lamellar structure, indicating that the phosphorus-ruthenium is successfully loaded on the surface of the spherical carbon nitride.

[0045] Comparative Example 1

[0046] Preparation of common bulk carbon nitride (BCN) photocatalyst​

[0047] 5 g of melamine was placed in an alumina crucible and then transferred to a muffle furnace, heated to 550°C at a heating rate of 2.3°C / min under air atmosphere and kept for 4 h, and a yellow solid was obtained after calcination, which was ordinary bulk carbon nitride (BCN).

[0048] Comparative Example 2

[0049] Preparation of spherical carbon nitride photocatalyst (CNS)

[0050] (1) 1.02 g of melamine was ultrasonically dissolved in 20 mL of dimethyl sulfoxide solvent to prepare A liquid, 1 g of cyanuric acid was ultrasonically dissolved in 10 mL of dimethyl sulfoxide solvent to prepare B liquid, then A liquid and B liquid were mixed and stirred for 15 min, and the supramolecular spherical precursor (CM) was obtained by filtration, washing and drying.

[0051] (2) The supramolecular spherical precursor (CM) was placed in an alumina crucible and then transferred to a muffle furnace, heated to 550°C at a heating rate of 2.3°C / min under air atmosphere and kept for 4 h, and a yellow solid was obtained after calcination, which was spherical carbon nitride (CNS).

[0052] Comparative Example 3

[0053] Preparation of ruthenium-loaded spherical carbon nitride (Ru-CNS) photocatalyst

[0054] (1) 2 g of melamine was ultrasonically dissolved in 20 mL of dimethyl sulfoxide solvent to prepare A liquid, 1 g of cyanuric acid was ultrasonically dissolved in 10 mL of dimethyl sulfoxide solvent to prepare B liquid, then A liquid and B liquid were mixed and stirred for 15 min, and the supramolecular spherical precursor (CM) was obtained by filtration, washing and drying.

[0055] (2) The supramolecular spherical precursor (CM) was placed in an alumina crucible and then transferred to a muffle furnace, heated to 550°C at a heating rate of 2.3°C / min under air atmosphere and kept for 4 h, and a yellow solid was obtained after calcination, which was spherical carbon nitride (CNS).

[0056] (3) 80 mg of spherical carbon nitride (CNS) was ultrasonically dispersed in 80 mL of ethylene glycol solvent, 25 mg of sodium borohydride was added to the mixture and stirred for 12 h, and the mass ratio of ruthenium element to spherical carbon nitride was 1:100, then the mixture was subjected to chemical reduction, and finally the ruthenium-loaded spherical carbon nitride (Ru-CNS) was obtained by filtration, washing and drying.

[0057] Experimental Example 1

[0058] Performance test of photocatalytic degradation of naproxen and simultaneous hydrogen production of carbon nitride photocatalytic material

[0059] (1) Performance test of photocatalytic degradation of naproxen and simultaneous hydrogen production by different carbon nitride photocatalysts

[0060] Five mg of ordinary bulk carbon nitride (BCN), spherical carbon nitride (CNS), ruthenium-supported spherical carbon nitride (Ru-CNS), and ruthenium phosphide-supported spherical carbon nitride (RuP-CNS) were ultrasonically dispersed in 100 mL of naproxen aqueous solution (20 mg / L). Then, the photocatalytic degradation of naproxen and simultaneous hydrogen production were tested under visible light for 2 h. The hydrogen content was detected by gas chromatography every 10 min, and 2 mL of the reaction solution was taken at 0 min and 120 min for naproxen content test by high performance liquid chromatography.

[0061] Depend on Figure 2 It can be seen that the specific surface area of ​​CNS, Ru-CNS, and RuP-CNS prepared by supramolecular self-assembly is significantly improved compared with that of BCN prepared by direct calcination. The specific surface area of ​​RuP-CNS is 3.44 times that of BCN. Figure 3 Figures showing the photocatalytic degradation performance of naproxen and simultaneous hydrogen production using different carbon nitride materials. Figure 3 In Figure a, the curves of BCN and CNS coincide, due to... Figure 3 It can be seen that, for different carbon nitride materials, the photocatalytic degradation performance of naproxenol and simultaneous hydrogen production is RuP-CNS>Ru-CNS>CNS>BCN.

[0062] (2) Performance test of photocatalytic degradation of naproxen at different concentrations by ruthenium phosphide-supported spherical carbon nitride to produce hydrogen simultaneously

[0063] 5 mg of ruthenium phosphide-supported spherical carbon nitride (RuP-CNS) was ultrasonically dispersed in 100 mL of naproxen aqueous solution (5 mg / L, 10 mg / L, 20 mg / L), and then subjected to photocatalytic degradation of naproxen and simultaneous hydrogen production under visible light for 1 h. The hydrogen content was detected by gas chromatography every 10 min, and 2 mL of the reaction solution was taken at 0 min and 60 min for naproxen content detection by high performance liquid chromatography.

[0064] Depend on Figure 4 It can be seen that for naproxen aqueous solutions of different concentrations, the photocatalytic degradation efficiency decreases with increasing concentration, while the photocatalytic hydrogen production increases with increasing concentration.

[0065] (3) Performance test of photocatalytic degradation of naproxen and simultaneous hydrogen production cycle of ruthenium phosphide-supported spherical carbon nitride

[0066] 5mg of the phosphorus ruthenium loaded spherical carbon nitride (RuP-CNS) was ultrasonically dispersed in 100mL of a naproxen aqueous solution (20mg / L), and then the photocatalytic degradation of naproxen and hydrogen production were tested under visible light for 2h for 5 times; the hydrogen content was detected by gas chromatography every 10min, and 2mL of the reaction solution was taken at 0min and 120min for naproxen content detection by high performance liquid chromatography.

[0067] By Figure 5 As can be seen, the phosphorus ruthenium loaded spherical carbon nitride has good stability in the performance of photocatalytic degradation of naproxen and hydrogen production, and maintains good naproxen degradation efficiency and hydrogen production performance after 5 reaction cycles.

[0068] (4) Performance test of the phosphorus ruthenium loaded spherical carbon nitride in photocatalytic degradation of naproxen and hydrogen production under different light conditions

[0069] 5mg of the phosphorus ruthenium loaded spherical carbon nitride (RuP-CNS) was ultrasonically dispersed in 100mL of a naproxen aqueous solution (20mg / L), and then the photocatalytic degradation of naproxen and hydrogen production were tested under visible light and full spectrum light for 2h; the hydrogen content was detected by gas chromatography every 10min, and 2mL of the reaction solution was taken at 0min and 120min for naproxen content detection by high performance liquid chromatography.

[0070] Figure 6 The performance of the RuP-CNS in photocatalytic degradation of naproxen and hydrogen production under different light conditions is shown in the figure Figure 6 As can be seen, the phosphorus ruthenium loaded spherical carbon nitride has good stability in the performance of photocatalytic degradation of naproxen and hydrogen production under different light conditions.

[0071] As can be seen, the phosphorus ruthenium loaded spherical carbon nitride has good stability in the performance of photocatalytic degradation of naproxen and hydrogen production under different light conditions.

[0072] The embodiments of the present application are described in detail above, but the present application is not limited to the described embodiments. For those skilled in the art, various changes, modifications, replacements and variations of the embodiments can be made without departing from the principles and spirits of the present application, and still fall within the protection scope of the present application.

Claims

1. The application of a ruthenium phosphide-supported spherical carbon nitride photocatalyst in the photocatalytic treatment and simultaneous hydrogen production of naproxen-containing wastewater, characterized in that, The preparation method of the ruthenium phosphide supported spherical carbon nitride photocatalyst includes the following steps: (1) Mix and stir melamine solution and cyanuric acid solution to obtain spherical precursor through supramolecular self-assembly; (2) The spherical precursor is placed in a muffle furnace and heated and calcined to obtain spherical carbon nitride; (3) Disperse the spherical carbon nitride in a solvent, add ruthenium trichloride hydrate, stir, add sodium borohydride to reduce, and obtain ruthenium-supported spherical carbon nitride; (4) The ruthenium-supported spherical carbon nitride and hypophosphite are placed in a protective atmosphere and subjected to low-temperature phosphating calcination to obtain the ruthenium-supported spherical carbon nitride phosphide; In step (3), the mass ratio of ruthenium to spherical carbon nitride in the ruthenium trichloride hydrate is 1:(90-110). In step (3), the solvent is ethylene glycol, and the stirring time is 12 h.

2. The application of the ruthenium phosphide-supported spherical carbon nitride photocatalyst according to claim 1 in the photocatalytic treatment and simultaneous hydrogen production of naproxen-containing wastewater, characterized in that, In step (1), the mass ratio of melamine in the melamine solution to cyanuric acid in the cyanuric acid solution is (0.9-1.1):

1.

3. The application of the ruthenium phosphide-supported spherical carbon nitride photocatalyst according to claim 2 in the photocatalytic treatment and simultaneous hydrogen production of naproxen-containing wastewater, characterized in that, In step (1), the concentration of the melamine solution is 0.045-0.055 g / mL; the concentration of the cyanuric acid solution is 0.08-0.12 g / mL.

4. The application of the ruthenium phosphide-supported spherical carbon nitride photocatalyst according to claim 1 in the photocatalytic treatment and simultaneous hydrogen production of naproxen-containing wastewater, characterized in that, In step (2), the heating rate is 1.8-2.8 ℃ / min; the calcination temperature is 500-600 ℃; and the calcination time is 3-5 h.

5. The application of the ruthenium phosphide-supported spherical carbon nitride photocatalyst according to claim 1 in the photocatalytic treatment and simultaneous hydrogen production of naproxen-containing wastewater, characterized in that, In step (4), the mass ratio of the ruthenium-supported spherical carbon nitride to hypophosphite is 1:(4-6).

6. The application of the ruthenium phosphide-supported spherical carbon nitride photocatalyst according to claim 1 in the photocatalytic treatment and simultaneous hydrogen production of naproxen-containing wastewater, characterized in that, In step (4), the heating rate of the low-temperature phosphating calcination is 4-6 ℃ / min, the temperature of the low-temperature phosphating calcination is 250-350 ℃, and the holding time is 1.5-2.5 h.

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