Precious metal loaded carbon-based catalytic material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of catalyst material preparation, and particularly relates to a noble metal-loaded carbon-based catalytic material as well as a preparation method and application thereof. According to the method, a micro-droplet gas-liquid interface synthesis technology is adopted, a precursor aqueous solution containing precious metal salt is atomized to form micro-droplets, spontaneous reduction occurs at a gas-liquid interface, and controllable preparation of precious metal nanoparticles is achieved; then, spraying the noble metal nanoparticles to the surface of a carbon-based carrier in a high-speed and directional manner by utilizing an electrode channel formed under the action of a gas-liquid interface electric field; in the spraying process, illumination treatment further regulates and controls the electron state on the surfaces of the nano-particles and the combination mechanism between the nano-particles and the carrier, the dispersity and stability of the nano-particles are enhanced, and the precious metal-loaded carbon-based catalytic material is prepared. According to the method, the utilization rate of precious metal can be remarkably increased, the agglomeration phenomenon is avoided, and the prepared catalyst shows excellent catalytic activity and stability in the catalytic degradation reaction of organic pollutants and has wide application prospects.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of catalyst material preparation, and particularly relates to a noble metal supported carbon-based catalyst material and a preparation method and application thereof. BACKGROUND

[0002] Common noble metal catalysts include Au, Ag, Pd, Pt, etc. In a supported noble metal catalyst, the presence of a carrier can make the noble metal nanoparticles have better dispersibility and a more suitable particle size, and exhibit higher catalytic performance in a catalytic reaction. The particle size of the noble metal nanoparticles has a greater influence on the catalytic performance thereof, and the size of the noble metal nanoparticles can generally be controlled by changing the type and concentration of a metal precursor and changing the properties of the carrier.

[0003] The noble metal supported carbon-based catalyst (such as Pt / AC, Pd / AC, Au / AC, etc.) is widely used in many key fields such as energy conversion, environmental protection and chemical synthesis due to its excellent catalytic activity. The core of its performance is to fix the expensive and scarce noble metal in the form of nanoparticles on the surface of the carbon carrier in a highly dispersed manner to achieve the maximum atomic utilization and the highest catalytic efficiency.

[0004] At present, the mainstream method for preparing such catalysts is a wet chemical process, mainly including impregnation, deposition-precipitation, colloid method and ion exchange method. In recent years, some physical methods such as magnetron sputtering have also been tried for preparing supported catalysts. However, the above methods have the problems of complex synthesis, long time consumption, high energy consumption and poor metal particle dispersibility. SUMMARY

[0005] Therefore, the purpose of the present application is to provide a noble metal supported carbon-based catalyst material and a preparation method and application thereof. The noble metal supported carbon-based catalyst material prepared by the present application has the characteristics of small and uniform noble metal nanoparticle size, extremely high dispersibility and strong bonding force with the carbon-based carrier, significantly improves the utilization rate of the noble metal and the stability of the catalyst material, and improves the catalytic efficiency.

[0006] In order to achieve the above purpose, the present application provides the following technical solutions: The present application provides a preparation method of a noble metal supported carbon-based catalyst material, comprising the following steps: In a first carrier gas, a precursor aqueous solution containing a noble metal salt is dispersed into microdroplets by atomization, and the microdroplets undergo a reduction reaction under the action of a gas-liquid interface electric field to obtain a gas aerosol containing noble metal nanoparticles; Under the action of the pressure of the first carrier gas and the gas-liquid interface electric field, the gas aerosol containing noble metal nanoparticles is fused with a carbon-based carrier carried by a second carrier gas, in-situ light treatment is performed, and a noble metal supported carbon-based catalyst material is obtained.

[0007] Preferably, the noble metal in the noble metal salt is Au, Ag, Pd or Pt.

[0008] Preferably, the particle size of the microdroplets is 100-500 nm.

[0009] Preferably, the carbon-based carrier is porous activated carbon.

[0010] Preferably, the light used for the in-situ light treatment is sunlight; the intensity of the light used for the in-situ light treatment is 800-1000 W / m 2 .

[0011] Preferably, the length of the light irradiation area in the in-situ light treatment is 20-50 cm.

[0012] Preferably, the first carrier gas and the second carrier gas are independently N2 and / or inert gas, and the flow rate is independently 0.12-0.48 m / s.

[0013] The application also provides a noble metal-loaded carbon-based catalytic material prepared by the preparation method described in the above technical solution, which comprises a carbon-based carrier and noble metal nanoparticles loaded on the surface and pores of the carbon-based carrier; the particle size of the noble metal nanoparticles is 1-3 nm.

[0014] The application also provides an application of the noble metal-loaded carbon-based catalytic material described in the above technical solution in the removal of perfluoro and polyfluoro alkyl substances.

[0015] The application also provides an application of the noble metal-loaded carbon-based catalytic material described in the above technical solution in the removal of perfluoro and polyfluoro alkyl substances.

[0016] The application provides a preparation method of a noble metal-loaded carbon-based catalytic material, which comprises the following steps: dispersing a precursor aqueous solution containing a noble metal salt into microdroplets by atomization in a first carrier gas; the microdroplets undergo a reduction reaction under the action of a gas-liquid interface electric field to obtain an aerosol containing noble metal nanoparticles; under the action of the pressure of the first carrier gas and the gas-liquid interface electric field, the aerosol containing noble metal nanoparticles is fused with a carbon-based carrier carried by a second carrier gas to perform in-situ light treatment to obtain a noble metal-loaded carbon-based catalytic material.

[0017] The preparation method of the noble metal-loaded carbon-based catalytic material provided by the application has the following beneficial effects: (1) The gas-liquid interface synthesis of noble metal nanoparticles: a precursor aqueous solution containing noble metal salt is dispersed into micron-sized microdroplets by atomization, and the microdroplets are introduced into a reaction chamber to generate noble metal nanoparticles under the action of a gas-liquid interface electric field. The interface reaction greatly limits the growth space of the nanoparticles, so that the size of the noble metal nanoparticles can be uniformly and controllably synthesized without adding any stabilizer; (2) Directional injection loading of noble metal nanoparticles: noble metal nanoparticle-containing aerosol is driven by a carrier gas and a gas-liquid interface electric field to be injected and deposited on a carbon-based carrier at a high speed and in a directional manner. This method gives the nanoparticles a very high kinetic energy, enabling them to effectively penetrate and enter the mesopores and even macropores of activated carbon, achieving three-dimensional uniform loading from the outer surface to the inner surface, and greatly improving the pore utilization rate and loading uniformity of the carrier.

[0018] (3) Light treatment to strengthen interface bonding: a light device is arranged on the transmission channel of the noble metal nanoparticles to perform in-situ light treatment on the nanoparticles in flight. This treatment process can clean and activate the surface of the nanoparticles, possibly adjust the surface electronic structure of the nanoparticles through a light excitation effect, and at the same time, enhance the chemical interaction force between the nanoparticles and the carbon-based carrier when they come into contact, forming a stronger bond, thereby fundamentally improving the utilization rate of noble metals, the mechanical stability, catalytic performance and sintering resistance of the catalytic material.

[0019] (4) The synthesis method of the noble metal-loaded carbon-based catalytic material provided by the present application has the advantages of simple process, short time consumption, mild conditions, controllable cost and easy scaling. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The synthesis route of the noble metal-loaded carbon-based catalytic material in the present application; Figure 2 The morphology diagram of the Pd / AC nano-catalytic material prepared in Example 3; Figure 3 The distribution diagram of Pd on AC in the Pd / AC nano-catalytic material prepared in Example 3; Figure 4 The COD removal efficiency of the Pd / AC nano-catalytic material prepared in Comparative Example 1 and Examples 1-4; Figure 5 The COD removal rate of the Pd / AC nano-catalytic material in Examples 4-7 at 160-220 DEG C; Figure 6 The COD removal rate of the Pd / AC nano-catalytic material in Examples 8-11 at 0.5-2 MPa; Figure 7The Pd / AC nanocatalytic material removal rate of PFAS (PFOA or PFOS) in Examples 12-19 and Comparative Examples 2-3 is plotted, wherein Examples 12-15 and Comparative Example 2 are PFOA, and Examples 16-19 and Comparative Example 3 are PFOS. DETAILED DESCRIPTION

[0021] The application provides a preparation method of a noble metal loaded carbon-based catalytic material, comprising the following steps: In a first carrier gas, a precursor aqueous solution containing a noble metal salt is dispersed into microdroplets by atomization, and the microdroplets are subjected to a reduction reaction under the action of a gas-liquid interface electric field to obtain a gas aerosol containing noble metal nanoparticles; Under the action of the pressure of the first carrier gas and the gas-liquid interface electric field, the gas aerosol containing noble metal nanoparticles is fused with a carbon-based carrier carried by a second carrier gas, and in-situ light treatment is performed to obtain a noble metal loaded carbon-based catalytic material.

[0022] Unless otherwise specified, the application does not have special requirements for the source of the raw materials used, and commercially available goods known to those skilled in the art can be used.

[0023] In the application, a precursor aqueous solution containing a noble metal salt is dispersed into microdroplets by atomization in a first carrier gas, and the microdroplets are subjected to a reduction reaction under the action of a gas-liquid interface electric field to obtain a gas aerosol containing noble metal nanoparticles.

[0024] As an embodiment, the noble metal in the noble metal salt is Au, Ag, Pd or Pt, and in a specific embodiment, it is Pd; the concentration of the noble metal salt in the precursor aqueous solution of the noble metal salt is 0.5-5 mg / mL, and in a specific embodiment, it is 0.5-2 mg / mL; the noble metal salt is a chloride salt, and in a specific embodiment, it is PdCl2.

[0025] As an embodiment, the first carrier gas comprises nitrogen (N2) and / or an inert gas, and in a specific embodiment, it is nitrogen; the inert gas is helium; the pressure of the first carrier gas is 50-120 psi, and in a specific embodiment, it is 80-100 psi; the flow rate is 0.12-0.48 m / s, and in a specific embodiment, it is 0.20-0.40 m / s.

[0026] As an embodiment, the parameters of the atomization include: the liquid feeding rate is 0.12-0.48 m / s, and in particular embodiments, 0.20-0.40 m / s; the inner diameter of the atomizing head is 1-10 mm, and in particular embodiments, 3-6 mm; the atomizing head-liquid surface distance is 200-2000 mm, and in particular embodiments, 800-1600 mm; the ambient temperature is 26-42℃, and in particular embodiments, 30-40℃; and the ambient relative humidity is 40-100%, and in particular embodiments, 50-80%.

[0027] As an embodiment, the particle size of the microdroplets is 100-500 nm, and in particular embodiments, 120-300 nm; the interface electric field of the gas-liquid interface electric field is 10 9 V / m. The present application uses the gas-liquid interface electric field as a reducing agent to reduce the noble metal ions into noble metal nanoparticles.

[0028] In the present application, the first carrier gas drives the precursor aqueous solution containing noble metal salt to generate microdroplets through atomization, the interface formed by the microdroplets and air is a gas-liquid interface, the interface has an interface electric field, and the interface electric field generated by the gas-liquid interface is as high as 10 9 V / m, which provides a high reduction field, such as electrons, which can reduce the noble metal salt into metal particles.

[0029] After obtaining the gas aerosol containing noble metal nanoparticles, the present application fuses the gas aerosol containing noble metal nanoparticles with the carbon-based carrier carried by the second carrier gas under the pressure of the first carrier gas and the action of the gas-liquid interface electric field, and performs in-situ light irradiation treatment to obtain a noble metal-loaded carbon-based catalytic material.

[0030] As an embodiment, the carbon-based carrier is porous activated carbon; the carbon-based carrier is a carbon-based carrier pretreated with an acid solution; the acid solution includes a nitric acid solution; the concentration of the nitric acid solution is 1-20 μmol / L, and in particular embodiments, 8-15 μmol / L; the step of pretreatment with the acid solution is: after the carbon-based carrier is immersed in the acid solution, drying; the temperature of the immersion is 20-40℃, and in particular embodiments, 30-40℃, and the time is 5-30 min, and in particular embodiments, 10-20 min; the temperature of the drying is 40-100℃, and in particular embodiments, 60-80℃, and the time is 10-60 min, and in particular embodiments, 15-25 min.

[0031] As an embodiment, the second carrier gas is nitrogen (N2) and / or an inert gas, and in particular embodiments, nitrogen; the inert gas is helium; the pressure of the second carrier gas is 50-120 psi, and in particular embodiments, 80-100 psi, and the flow rate is 0.12-0.48 m / s, and in particular embodiments, 0.2-0.4 m / s.

[0032] As an implementation form, the light used in the in-situ light treatment is sunlight; the intensity of the light used in the in-situ light treatment is 800-1000 W / m 2 , and in a specific embodiment, 850-950 W / m 2 ; the length of the light irradiation area in the in-situ light treatment is 20-50 cm, and in a specific embodiment, 30 cm; after the in-situ light treatment, cooling is further included; the cooling is natural cooling.

[0033] As an implementation form, the spray microdroplet synthesis method of the noble metal loaded carbon-based catalytic material is carried out at normal temperature and pressure, and the used equipment includes a carrier gas device, an atomizer, a “Y” type reactor and a cooling system.

[0034] Figure 1 It is a synthesis route of the noble metal loaded carbon-based catalytic material in the application. As shown in the figure, Figure 1 the noble metal salt solution atomized into microdroplets carried by the inert gas with pressure and the activated carbon carried by the inert gas are respectively introduced into the two ends of the bifurcated “Y” type reactor, the noble metal salt in the microdroplets is spontaneously reduced to noble metal nanoparticles under the action of the gas-liquid interface electric field, after the fusion of the two gas streams, the noble metal nanoparticles are sprayed and deposited on the activated carbon in a high-speed and directional manner under the action of the inert gas pressure and the gas-liquid interface electric field, and through light treatment, the surface electronic state of the nanoparticles and the binding mechanism between the nanoparticles and the activated carbon are further regulated to enhance the dispersity and stability of the nanoparticles, and the noble metal loaded carbon-based catalytic material is prepared. The application utilizes the characteristics of the low free energy barrier of the microdroplet interface and the strong electric field of the interface, so that the metal nanoparticles spontaneously and rapidly form the noble metal loaded carbon-based catalytic material in a directional manner under the characteristics of the microdroplet gas-liquid interface, thereby realizing the in-situ synthesis and growth on the microsecond scale.

[0035] The application further provides the noble metal loaded carbon-based catalytic material prepared by the preparation method, which includes a carbon-based carrier and noble metal nanoparticles loaded on the surface of the carbon-based carrier; the particle size of the noble metal nanoparticles is 1-3 nm.

[0036] As an implementation form, the mass fraction of the noble metal nanoparticles in the noble metal loaded carbon-based catalytic material is 1-10%, and in a specific embodiment, 3-5%.

[0037] The application further provides the application of the noble metal loaded carbon-based catalytic material in the wet catalytic oxidation degradation of the COD of the hydrothermal carbonization liquid.

[0038] As an implementation form, the COD in the hydrothermal carbonization liquid is 10000-60000 mg / L, and in a specific embodiment, 60000 mg / L; the pressure of the wet catalytic oxidation degradation is 0.5-2 MPa, and in a specific embodiment, 0.5 MPa, 1 MPa, 1.5 MPa or 2 MPa, the temperature is 160-220 ℃, and in a specific embodiment, 160 ℃, 180 ℃, 200 ℃ or 220 ℃, the time is 0.5-2 h, and in a specific embodiment, 1-1.5 h; the mass of the noble metal loaded carbon-based catalytic material is 0.5-2% of the mass of the hydrothermal carbonization liquid, and in a specific embodiment, 1%.

[0039] The application also provides an application of the noble metal loaded carbon-based catalytic material in the removal of perfluoro and polyfluoroalkyl substances (PFAS).

[0040] As an implementation form, the perfluoro and polyfluoroalkyl substances (PFAS) include perfluorooctanoic acid (PFOA) and / or perfluorooctylsulfonic acid (PFOS); the application is to add the noble metal loaded carbon-based catalytic material into a solution containing the perfluoro and polyfluoroalkyl substances (PFAS) to perform a degradation reaction; the concentration of the perfluoro and polyfluoroalkyl substances in the solution containing the perfluoro and polyfluoroalkyl substances is 2-50 ppm, and in a specific embodiment, 10 ppm; the degradation reaction is performed at normal temperature and pressure; the time of the degradation reaction is 0.5-2 h, and in a specific embodiment, 30 min; the mass ratio of the noble metal loaded carbon-based catalytic material to the solution containing the perfluoro and polyfluoroalkyl substances is 1-5:1000, and in a specific embodiment, 1:1000.

[0041] The technical solutions in the application will be described clearly and completely below in combination with the embodiments in the application, but they should not be understood as limitations on the protection scope of the application.

[0042] Example 1 A PdCl2 aqueous solution with a concentration of 0.5 mg / mL is prepared, N2 with a pressure of 100 psi and a flow rate of 0.3 m / s is used as the first carrier gas, and the solution is dispersed into microdroplets with a particle size of about 100-500 nm by using an atomizer, the atomization parameters include: a liquid feeding rate of 0.3 m / s, an inner diameter of the atomizer head of 8 mm, an atomizer head-liquid surface distance of 1000 mm, an ambient temperature of 32 ℃, and an ambient relative humidity of 53%, and the microdroplets are introduced into a reaction chamber through the first carrier gas, so that the microdroplets are subjected to a gas-liquid interface electric field (10 9Under the influence of V / m, a reduction reaction occurs, generating an aerosol containing palladium nanoparticles. Under the pressure of the first carrier gas and the electric field at the gas-liquid interface, the palladium nanoparticle-containing aerosol fuses with a carbon-based support (porous activated carbon) pretreated with dilute nitric acid carried by the second carrier gas (N2, pressure 90 psi, flow rate 0.25 m / s). The palladium nanoparticles are rapidly ejected and deposited on the surface and pores of the carbon-based support under the interfacial electric field and carrier gas pressure. During transport, the nanoparticles undergo a 30 cm long process with an intensity of 900 W / m. 2 The area exposed to sunlight was subjected to in-situ light treatment and naturally cooled to finally obtain a noble metal-supported carbon-based catalyst material, denoted as 0.5Pd / AC; The dilute nitric acid pretreatment involved immersing the carbon-based support in a 10 μmol / L dilute nitric acid solution, followed by drying. The immersion temperature was 30°C for 10 min, and the drying temperature was 80°C for 20 min.

[0043] Two g of Pd / AC nanocatalyst material was added to 200 mL of hydrothermal carbonization liquid containing 60,000 mg / L COD for wet catalytic oxidation degradation experiment. The reaction pressure was 1.5 MPa, the reaction temperature was 160 °C, and the reaction time was 60 min. In this example, the COD removal efficiency was 68.5%.

[0044] Example 2 The same steps as in Example 1 were followed, except that the concentration of the PdCl2 aqueous solution was changed to 1 mg / mL to obtain Pd metal particle-supported AC nanocatalytic material, denoted as 1Pd / AC.

[0045] Similar to the COD removal steps in Example 1, the COD removal efficiency in this example is 76.5%.

[0046] Example 3 The same steps as in Example 1 were followed, except that the concentration of the PdCl2 aqueous solution was changed to 1.5 mg / mL to obtain Pd metal particle-supported AC nanocatalytic material, denoted as 1.5Pd / AC.

[0047] Similar to the COD removal steps in Example 1, the COD removal efficiency in this example is 80.9%.

[0048] Example 4 The same steps were followed as in Example 1, except that the concentration of the PdCl2 aqueous solution was changed to 2 mg / mL to obtain Pd metal particle-supported AC nanocatalytic material, denoted as 2Pd / AC.

[0049] Similar to the COD removal steps in Example 1, the COD removal efficiency in this example is 84.7%.

[0050] Example 5 The catalytic material in Example 4 was used for COD removal at different temperatures and same pressure: the COD removal step was the same as in Example 1, only the reaction temperature was changed to 180°C. The COD removal efficiency in this example was 88.5%.

[0051] Example 6 The catalytic material in Example 4 was used for COD removal at different temperatures and same pressure: the COD removal step was the same as in Example 1, only the reaction temperature was changed to 200°C. The COD removal efficiency in this example was 90.5%.

[0052] Example 7 The catalytic material in Example 4 was used for COD removal at different temperatures and same pressure: the COD removal step was the same as in Example 1, only the reaction temperature was changed to 220°C. The COD removal efficiency in this example was 92.3%.

[0053] Example 8 The catalytic material in Example 4 was used for COD removal at different pressures and same temperature: 1wt% Pd / AC nanocatalytic material was added to 200 mL of hydrothermal carbonization liquid containing 60000 mg / L to conduct wet catalytic oxidation degradation experiment, wherein the reaction temperature was 220°C and the reaction pressure was 0.5 MPa. The COD removal efficiency in this example was 79.5%.

[0054] Example 9 The catalytic material in Example 4 was used for COD removal at different pressures and same temperature: the COD removal step was the same as in Example 8, only the reaction pressure was changed to 1 MPa. The COD removal efficiency in this example was 87.3%.

[0055] Example 10 The catalytic material in Example 4 was used for COD removal at different pressures and same temperature: the COD removal step was the same as in Example 8, only the reaction pressure was changed to 1.5 MPa. The COD removal efficiency in this example was 91.9%.

[0056] Example 11 The catalytic material in Example 4 was used for COD removal at different pressures and same temperature: the COD removal step was the same as in Example 8, only the reaction pressure was changed to 2 MPa. The COD removal efficiency in this example was 95.3%.

[0057] Example 12 100 mg of Pd / AC nanocatalyst material from Example 1 was used to test the removal of 100 mL of 10 ppm perfluorooctanoic acid (PFOA) aqueous solution. The reaction was carried out at room temperature and pressure for 30 min. The removal efficiency of PFOA in this example was 78.8%.

[0058] Example 13 The nanocatalytic material from Example 2 was used, and the PFOA removal steps were the same as in Example 12. The PFOA removal efficiency in this example was 82.4%.

[0059] Example 14 The nanocatalytic material from Example 3 was used, and the PFOA removal steps were the same as in Example 12. The PFOA removal efficiency in this example was 84.6%.

[0060] Example 15 The nanocatalytic material from Example 4 was used, and the PFOA removal steps were the same as in Example 12. In this example, the PFOA removal efficiency was 90.5%.

[0061] Example 16 100 mg of Pd / AC nanocatalyst material from Example 1 was used to test the removal of 100 mL of 10 ppm perfluorooctyl sulfonic acid (PFOS) aqueous solution. The reaction was carried out at room temperature and pressure for 30 min. The removal efficiency of PFOS in this example was 65.8%.

[0062] Example 17 The nanocatalytic material from Example 2 was used, and the PFOS removal steps were the same as in Example 16. In this example, the PFOS removal efficiency was 70.6%.

[0063] Example 18 The nanocatalytic material from Example 3 was used, and the PFOS removal steps were the same as in Example 16. The PFOS removal efficiency in this example was 79.2%.

[0064] Example 19 The nanocatalytic material from Example 4 was used, and the PFOS removal steps were the same as in Example 16. In this example, the PFOS removal efficiency was 83.5%.

[0065] Comparative Example 1 Take 100 mg of porous activated carbon pretreated with dilute nitric acid, denoted as 0Pd / AC. Following the same COD removal steps as in Example 1, the COD removal efficiency in this example is 55.2%.

[0066] Comparative Example 2 The nanocatalytic material in Comparative Example 1 was used, and the PFOA removal steps were the same as in Example 12. In this example, the PFOA removal efficiency was 60.2%.

[0067] Comparative Example 3 The nanocatalytic material in Comparative Example 1 was used, and the PFOS removal steps were the same as in Example 16. The PFOS removal efficiency in this example was 49.6%.

[0068] Performance testing (1) Figure 2 The image shows the morphology (TEM image) of the Pd / AC nanocatalyst material prepared in Example 3. Figure 3 The distribution of Pd on AC in the Pd / AC nanocatalytic material prepared in Example 3 is shown in the TEM image.

[0069] from Figure 2 and Figure 3 As can be seen, the present invention can rapidly synthesize carbon-based catalytic materials supported by highly dispersed metal nanoparticles, with the particle size range of the metal nanoparticles being 1~3nm and the metal nanoparticles being relatively uniformly distributed on the carbon-based material, which helps to improve the performance of the subsequent catalytic material.

[0070] (2) Figure 4 The COD removal efficiency of the Pd / AC nanocatalyst materials prepared in Comparative Example 1 and Examples 1-4 is shown.

[0071] from Figure 4 It can be seen that the COD removal efficiency of the catalytic material increases with the increase of precious metal content.

[0072] (3) Figure 5 The COD removal rate of the Pd / AC nanocatalyst materials in Examples 4-7 at 160-220℃ is shown.

[0073] from Figure 5 It can be seen that the COD removal efficiency of Pd / AC nanocatalyst material increases with increasing reaction temperature.

[0074] (4) Figure 6 The COD removal rate of the Pd / AC nanocatalyst materials in Examples 8-11 at 0.5-2 MPa is shown.

[0075] from Figure 6 It can be seen that the COD removal efficiency of Pd / AC nanocatalyst material increases with increasing reaction pressure.

[0076] from Figures 4-6 It can be seen that the removal rate of COD by Pd / AC nanocatalyst materials is 68.5%~95.3%.

[0077] (5) Figure 7 The Pd / AC nanocatalytic material removal rate of PFAS (PFOA or PFOS) in Examples 12-19 and Comparative Examples 2-3 is shown in the figure, wherein Examples 12-15 and Comparative Example 2 are PFOA, and Examples 16-19 and Comparative Example 3 are PFOS.

[0078] From Figure 7 It can be seen that as the noble metal content increases, the removal efficiency of Pd / AC nanocatalytic material for PFOA and PFOS increases. The removal rate of Pd / AC nanocatalytic material for 10 ppm PFOA is 78.8-90.5%; the removal rate for PFOS is 65.9-83.5%.

[0079] Although the above examples make a detailed description of the present application, it is only a part of the embodiments of the present application but not all the embodiments, and other embodiments can be obtained according to the present embodiments without creativity, which all belong to the protection scope of the present application.

Claims

1. A method for preparing a noble metal-supported carbon-based catalytic material, characterized in that, Includes the following steps: In the first carrier gas, an aqueous solution containing a noble metal salt is dispersed into microdroplets by atomization. The microdroplets undergo a reduction reaction under the action of the electric field at the gas-liquid interface to obtain an aerosol containing noble metal nanoparticles. Under the pressure of the first carrier gas and the electric field at the gas-liquid interface, the aerosol containing noble metal nanoparticles is fused with the carbon-based support carried by the second carrier gas and subjected to in-situ photo-irradiation to obtain a noble metal-supported carbon-based catalytic material.

2. The preparation method according to claim 1, characterized in that, The precious metal in the precious metal salt is Au, Ag, Pd or Pt.

3. The preparation method according to claim 1, characterized in that, The microdroplets have a particle size of 100~500nm.

4. The preparation method according to claim 1, characterized in that, The carbon-based support is porous activated carbon.

5. The preparation method according to claim 1, characterized in that, The light used in the in-situ illumination treatment is sunlight; the intensity of the light used in the in-situ illumination treatment is 800~1000W / m. 2 .

6. The preparation method according to claim 1, characterized in that, The length of the light-irradiated area in the in-situ light treatment is 20~50cm.

7. The preparation method according to claim 1, characterized in that, The first carrier gas and the second carrier gas are independently N2 and / or inert gas, and their flow rates are independently 0.12~0.48 m / s.

8. The noble metal-supported carbon-based catalytic material prepared by the preparation method according to any one of claims 1 to 7, characterized in that, It includes a carbon-based support and noble metal nanoparticles loaded on the surface and pores of the carbon-based support; the particle size of the noble metal nanoparticles is 1~3nm.

9. The application of the noble metal-supported carbon-based catalytic material according to claim 8 in the wet catalytic oxidation degradation of COD in hydrothermal carbonization liquid.

10. The application of the noble metal-supported carbon-based catalytic material of claim 8 in the removal of perfluorinated and polyfluoroalkyl substances.

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