A deep-crosslinked cu nano-alloy coupled PHI photocatalytic material of d orbit and a preparation method and application thereof

Abstract

The application belongs to the technical field of atmospheric environmental pollution treatment, and particularly relates to a D-track deep cross-linked Cu-Au nano-alloy coupled PHI photocatalytic material and a preparation method and application thereof. The novel photocatalytic material provided by the application has good light response and light absorption capacity. The Cu-Au nano-alloy as an external 'electron pump' can efficiently pump out photo-generated charges, thereby promoting the effective separation of photo-generated electron-hole pairs and increasing the utilization rate. Meanwhile, the bimetallic sites of the Cu-Au nano-alloy have strong adsorption and activation capacity for small molecules such as water and oxygen and organic waste gas molecules, can generate a large number of active free radicals, and finally realize efficient removal of organic waste gas, which is helpful to realize air purification. The photocatalytic material has simple preparation process, wide raw material sources, low price, no secondary pollution, and is easy to be industrialized and mass-produced and widely applied to photocatalytic removal of various volatile organic compounds (VOCs).

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of atmospheric environmental pollution control. More specifically, it relates to a D-orbital deep cross-linked Cu-Au nanometer alloy coupled PHI photocatalytic material and its preparation method and application. BACKGROUND

[0002] As a major component of industrial waste gas, organic waste gas has a greater impact on the atmospheric environment and human health. At the same time, it is widely sourced (urban waste management facilities such as sewage treatment plants, garbage transfer stations and garbage landfills, the mining and refining process of petrochemical products in the petrochemical industry, and industrial production activities such as livestock breeding, food processing and rubber products), complex in composition (Cl-VOCs, S-VOCs, NO x , aromatic compounds, olefins, etc.), and the content of organic matter fluctuates greatly, has a foul odor, high biological toxicity and low environmental threshold (0.004-0.02 mg·m -3 ), and long-term exposure to an environment polluted by organic waste gas can easily cause a series of irreversible damage, and in severe cases, it can endanger life. In addition, organic waste gas released into the atmosphere is prone to photochemical reactions with oxygen-containing groups such as hydroxyl radicals (•OH) and primary pollutants such as NO x , etc. in the atmosphere, forming photochemical smog, and thus causing more serious atmospheric environmental pollution problems; at the same time, the chlorides, sulfates and nitrates formed by the oxidation of sulfur-containing, chlorine-containing and nitrogen-containing (Cl-VOCs, S-VOCs, NO x ) organic waste gas will exacerbate the acid deposition phenomenon, causing "acid rain" and endangering agricultural production and outdoor construction. Therefore, exploring effective green environmental protection technology to convert organic waste gas (Cl-VOCs, S-VOCs, NO x , aromatic compounds, olefins) in production and life into non-toxic and harmless substances, and thus achieving air purification, has important social significance.

[0003] The traditional technical methods for treating organic waste gas mainly include physical methods (adsorption method, absorption method, condensation method, membrane separation method), biological methods and chemical methods (electrocatalysis method, combustion method, catalytic combustion method, plasma purification method). However, the above methods have the disadvantages of low removal efficiency, limited material capacity, easy desorption, easy secondary pollution, complex operation conditions, high cost and site requirement, and are difficult to meet the demand between the growing environmental air pollution problem and the development of efficient harmless removal of organic waste gas technology. In recent years, the photocatalytic oxidation (PCO) technology has become a new strategy for eliminating organic waste gas in the atmosphere. The technology mainly uses broad-spectrum sunlight to excite photocatalytic materials to generate electron-hole pairs, promotes their migration to the surface of the catalyst material, and reacts with adsorbed O2, H2O and other active substances to produce a large amount of active oxygen species (•OH, •O2 - , 1 O2), and can be operated on a large scale and continuously under mild and controlled environmental conditions, and can effectively oxidize organic waste gas to non-toxic and harmless small molecular substances ( ). However, in the process of photocatalytic oxidation, how to promote the efficient separation, transfer and utilization of photo-generated carriers, and enhance the effective adsorption and removal of organic waste gas molecules on the surface of the photocatalytic material, is still a bottleneck problem hindering the development of PCO technology. Therefore, providing a new type of photocatalytic material with high efficiency of photo-generated carrier utilization and good affinity for organic waste gas molecules is one of the driving forces for further expanding the development of the field of PCO technology. SUMMARY

[0004] The technical problem to be solved by the present application is to overcome the defects and deficiencies that photo-generated carriers cannot be efficiently separated, transferred and utilized in the existing photocatalytic oxidation technology, and that organic waste gas molecules cannot be effectively adsorbed and removed on the surface of the photocatalytic material, and to provide a photocatalytic material of D-orbital deeply cross-linked Cu-Au nanometer alloy coupled with PHI.

[0005] The purpose of the present application is to provide a preparation method of the photocatalytic material of D-orbital deeply cross-linked Cu-Au nanometer alloy coupled with PHI.

[0006] Another purpose of the present application is to provide an application of the photocatalytic material of D-orbital deeply cross-linked Cu-Au nanometer alloy coupled with PHI.

[0007] Another purpose of the present application is to provide a continuous flow photocatalytic organic waste gas elimination system.

[0008] The above purposes of the present application are achieved by the following technical solutions:

[0009] The application discloses a kind of D orbit deep crosslinking Cu-Au nano alloy coupling PHI photocatalytic material, the photocatalytic material is obtained by coupling PHI by Cu-Au nano alloy (Cu-Au Nano Alloy) with different Cu / Au atomic ratio under hydrothermal condition through forming Cu-N bond;Wherein, the atomic ratio of Cu / Au in the Cu-Au nano alloy is 8~2:8~2;Preferably, Cu / Au atomic ratio is 8:2, 5:5, 2:8 respectively.

[0010] When Cu / Au atomic ratio is 8:2, Cu8Au2 nano alloy is prepared;When Cu / Au atomic ratio is 5:5, Cu5Au5 nano alloy is prepared;When Cu / Au atomic ratio is 2:8, Cu2Au8 nano alloy is prepared.

[0011] More preferably, the photocatalytic material is the material Cu8Au2 / PHI obtained by coupling PHI when Cu / Au atomic ratio of Cu-Au nano alloy is 8:2, which has the most excellent adsorption and activation capacity to O2 and H2O molecules, can significantly accelerate the generation of reactive oxygen species, and significantly improve the removal efficiency of organic waste gas under simulated sunlight irradiation, thereby achieving the purpose of air purification.

[0012] The application also protects the preparation method of the photocatalytic material of the D orbit deep crosslinking Cu-Au nano alloy coupling PHI, specifically comprising the following steps: mixing PHI, Cu-Au nano alloy and reducing agent uniformly in water, hydrothermal reaction at 60~100 DEG C, filtration, washing, drying, to obtain the photocatalytic material of Cu-Au nano alloy coupling PHI.

[0013] Further, the hydrothermal reaction time is 8~16 h;Preferably, the hydrothermal reaction temperature is 90 DEG C, and the hydrothermal reaction time is 12 h.

[0014] Further, the reducing agent is one of ascorbic acid, sodium citrate or hydroxylamine hydrochloride.

[0015] Further, the mass ratio of PHI, Cu-Au nano alloy and reducing agent is 0.5~2:0.12~0.48:0.3~1.2;Preferably, the mass ratio of PHI, Cu-Au nano alloy and reducing agent is 1:0.24:0.6.

[0016] Preferably, the preparation method of the Cu-Au nano-alloy is: adding a surfactant, a copper precursor, a gold precursor and a reducing agent into water to form a mixed solution A; additionally adding a surfactant, a reducing agent and ammonia water into water to form a mixed solution B; uniformly mixing the solution A and the solution B, reacting at 60-100 ℃ for 1-4 h, and freeze-drying to obtain the Cu-Au nano-alloy; the mass fraction of the ammonia water is 37% (wt%), which is mainly to provide an alkaline environment.

[0017] Further, the copper precursor is one of CuCl2, Cu(NO3)2 or CuSO4; and the gold precursor is HAuCl4.

[0018] Further, the reducing agent in the mixed solution A is NaBr, and the pH value of the solution is adjusted to prevent copper ions from forming a precipitate; the reducing agent in the mixed solution B is one of ascorbic acid, sodium citrate or hydroxylamine hydrochloride, which is to prevent copper ions from being oxidized.

[0019] Further, the surfactant in the mixed solution A and the mixed solution B is one of cetyltrimethylammonium bromide (CTAB), N-hydroxysuccinimide (HAD) or polyvinylpyrrolidone K30 (PVP).

[0020] Further, the mass ratio of the surfactant, the copper precursor, the gold precursor and the reducing agent in the mixed solution A is 1:0.001-0.004:0.004-0.001:2.7-12.9; and the mass ratio of the surfactant and the reducing agent in the mixed solution B is 1:2.7-4.3.

[0021] In addition, the application also protects the application of the photocatalytic material in photocatalytic elimination of organic waste gas.

[0022] Preferably, the photocatalytic material in the application removes organic waste gas under the conditions of simulated sunlight irradiation and environmental humidity, and the organic waste gas can be one or more of Cl-VOCs, S-VOCs, NO x , aromatic compounds or olefins.

[0023] The principle is specifically manifested as follows: under the irradiation of sunlight, the photocatalytic material absorbs the photon energy of sunlight to be excited to generate an electron-hole pair, the Cu-Au nano-alloy as an external "electron pump" can quickly pump the photo-generated electrons PHI out to the surface of the photocatalyst, thereby inhibiting the recombination of the electron-hole pair in the bulk phase and the surface of the photocatalyst, and the electrons successfully pumped out and migrated to the surface of the Cu-Au nano-alloy further activate the adsorbed small molecules such as O2 and H2O at the Au site to generate a large amount of active oxygen species (•OH, •O2 - , 1O2), and then attacks the organic waste gas molecules adsorbed by the Cu site (the organic waste gas molecules have higher affinity with the metal Cu site), so that the organic waste gas molecules are deeply oxidized and converted into non-toxic and harmless small molecules (SO4 ).

[0024] Meanwhile, the application also protects a continuous flow photocatalytic organic waste gas elimination system containing the photocatalytic material.

[0025] The application has the following beneficial effects:

[0026] 1. The Cu-Au nanometer alloy used in the application has deep D-orbital cross-linking, and can effectively pump out photo-generated electrons generated by excitation as an external "electron pump", so as to improve the separation efficiency and utilization rate of the carriers. In addition, the Cu-Au nanometer alloy provides a bimetallic active site, the Au site can effectively adsorb and activate small molecules such as O2 and H2O, and generate a large amount of active oxygen species (•OH, •O2 - , 1 O2), and the Cu site can adsorb organic waste gas molecules, avoiding the competitive adsorption of the two in the same system, so that the organic waste gas molecules are finally deeply oxidized to generate SO4 2- , CO3 2- , CO2, H2O and other non-toxic and harmless small molecule substances;

[0027] 2. The photocatalytic material provided by the application has a suitable band gap structure, excellent absorption and response ability to sunlight, and can improve the utilization rate of sunlight, so as to improve the generation ability of intrinsic photo-generated carriers;

[0028] 3. The preparation method of the photocatalytic material provided by the application is simple, the material source is widely available, the structure has good stability, and the photocatalytic material has excellent activity in removing organic waste gas. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a scanning electron microscope graph of PHI-melamine prepared in Example 1.

[0030] Figure 2 It is a scanning electron microscope graph of Cu8Au2 nanometer alloy prepared in Example 3.

[0031] Figure 3 It is an element composition graph of Cu8Au2 nanometer alloy prepared in Example 3.

[0032] Figure 4 It is a scanning electron microscope graph of Cu8Au2-PHI photocatalytic material prepared in Example 4.

[0033] Figure 5Photocatalytic degradation curve of CH3SH by the photocatalytic material prepared in Example 1-2 and Comparative Example 1-2.

[0034] Figure 6 Photocatalytic degradation curve of CH3SH by the photocatalytic material prepared in Example 4-9.

[0035] Figure 7 Photocatalytic degradation curve of CH3SH by the photocatalytic material prepared in Comparative Example 3-4. DETAILED DESCRIPTION

[0036] The present application will be further described in conjunction with the accompanying drawings and specific examples, but the examples do not limit the present application in any form. Unless otherwise specified, the reagents, methods and equipment used in the present application are the conventional reagents, methods and equipment in the technical field.

[0037] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0038] Example 1 Preparation of polyheptazine imide-melamine (PHI-melamine)

[0039] Take 6.0 g of melamine and add it to a quartz crucible, pyrolyze in a tube furnace at 550 ℃ for 4 h (5 °C / min) in a nitrogen atmosphere (nitrogen flow rate is 500 mL / min) to generate a light yellow powder, after cooling to room temperature, take 0.6 g of light yellow powder in a mixed alkali salt of 3.3 g of KCl and 2.7 g of LiCl and grind thoroughly, then continue to pyrolyze at 550 ℃ for 4 h in a nitrogen atmosphere, wash the solid product with a large amount of deionized water, and dry to obtain PHI-melamine. The scanning electron microscope SEM image is shown in Figure 1 From the figure, it can be seen that the photocatalytic material (PHI) presents an agglomerate structure aggregated by one-dimensional nanowires, which has a rough surface and a large size of about 4.0 μm due to the random polymerization of one-dimensional nanowires, which indicates that the PHI photocatalytic material prepared by the molten salt method is different from the typical bulk structure of traditional C3N4, and the rough surface of the structure is more conducive to responding and absorbing sunlight, and also conducive to adsorbing gaseous pollutants and accelerating mass transfer.

[0040] Example 2 Preparation of polyheptazine imide-urea (PHI-urea)

[0041] Take 6.0 g urea added to a quartz crucible, in a tube furnace, pyrolysis at 550 ℃ for 4 h (5 °C / min) in a nitrogen atmosphere (nitrogen flow rate of 500 mL / min), to generate a light yellow powder, after cooling to room temperature, take 0.6 g light yellow powder in the mixed alkali salt of 3.3 g KCl and 2.7 g LiCl grinding thoroughly, then continue to pyrolysis at 550 ℃ for 4 h in a nitrogen atmosphere, the solid product is washed with a large amount of deionized water, dry to obtain PHI-urea.

[0042] Example 2, compared with example 1, only melamine is replaced by urea, the rest of the experimental steps are consistent.

[0043] Example 3 Preparation of Cu8Au2 Nanometer Alloy

[0044] Take 0.35 g CTAB, 0.8 mL CuCl2(5 g / L), 0.2 mL HAuCl4(5 g / L) and 4.52 g NaBr added to 50 mL deionized water, recorded as solution A; 0.35 g CTAB, 1.5 g ascorbic acid, 5 mL ammonia water, added to 45 mL deionized water, recorded as solution B. Then slowly add solution B to solution A, keep at 80 ℃ for 2 h. After cooling to room temperature, freeze-drying to obtain Cu8Au2 nanometer alloy.

[0045] Scanning electron microscope SEM image is shown in Figure 2 From the figure, Cu8Au2 nanometer alloy shows a typical triangular sheet structure, the size is about 2.5 μm, and the surface is relatively smooth, the structure integrity is good.

[0046] Cu8Au2 nanometer alloy element composition analysis results are shown in Figure 3 As shown in the figure: Cu8Au2 nanometer alloy Cu element content is much higher than Au, which may be due to Au 4+ / Au 0 Compared with Cu 2+ / Cu 0 Has higher redox potential, so that the Cu element content of the outer surface is higher, and the formation of such bimetallic alloy can provide multi-center active site, which is conducive to the adsorption of active small molecules (H2O, O2) and organic waste gas molecules.

[0047] Example 4 Preparation of Cu8Au2-PHI

[0048] PHI-melamine 50 mg prepared in Example 1 was weighed into 50 mL of deionized water, then 12 mg of Cu8Au2nano-alloy prepared in Example 3 and 30 mg of ascorbic acid were added, and ultrasonic dispersion was performed until uniform. Then, hydrothermal treatment was performed at 90°C for 12 h, filtration, washing, and drying in a vacuum drying oven at 60°C for 8 h to obtain Cu8Au2-PHI photocatalytic material.

[0049] The scanning electron microscope (SEM) image is shown in Figure 4 As can be seen from the figure, the overall structure of the material is similar to that of Cu8Au2nano-alloy, and presents a triangular sheet morphology. PHI is tightly loaded on the outer surface of Cu8Au2nano-alloy, and this morphology is helpful for absorbing and responding to sunlight, and the charges generated are more easily migrated to the surface active sites.

[0050] Example 5 Preparation of Cu5Au5-PHI

[0051] Preparation of Cu5Au5nano-alloy: Compared with Example 3, the difference is that 0.8 mL of CuCl2(5 g / L) and 0.2 mL of HAuCl4(5 g / L) are replaced by 0.5 mL of CuCl2(5 g / L) and 0.5 mL of HAuCl4(5 g / L), and the other steps remain unchanged.

[0052] Compared with Example 4, the Cu8Au2nano-alloy is replaced by Cu5Au5nano-alloy in the present application, and the other steps remain unchanged, to obtain Cu5Au5-PHI photocatalytic material.

[0053] Example 6 Preparation of Cu2Au8-PHI

[0054] Preparation of Cu2Au8nano-alloy: Compared with Example 3, 0.8 mL of CuCl2(5 g / L) and 0.2 mL of HAuCl4(5 g / L) are replaced by 0.2 mL of CuCl2(5 g / L) and 0.8 mL of HAuCl4(5 g / L), and the other steps remain unchanged.

[0055] Compared with Example 4, the Cu8Au2nano-alloy is replaced by Cu2Au8nano-alloy in the present application, and the other steps remain unchanged, to obtain Cu2Au8-PHI photocatalytic material.

[0056] Example 7 Preparation of Cu8Au2-PHI-urea

[0057] PHI-urea 50 mg prepared in Example 2 was weighed into 50 mL of deionized water, then 12 mg of Cu8Au2 nanoalloy prepared in Example 3 and 30 mg of ascorbic acid were added, and ultrasonic dispersion was performed until uniform dispersion was achieved. Then, hydrothermal treatment was performed at 90 ℃ for 12 h, filtration, washing, and drying in a vacuum drying oven at 60 ℃ for 8 h to obtain a Cu8Au2-PHI-urea photocatalytic material.

[0058] Example 8 Preparation of Cu5Au5-PHI-urea

[0059] Preparation of Cu5Au5 nanoalloy: Compared with Example 3, the difference is that 0.8 mL of CuCl2(5 g / L) and 0.2 mL of HAuCl4(5 g / L) are replaced by 0.5 mL of CuCl2(5 g / L) and 0.5 mL of HAuCl4(5 g / L), and the other steps remain unchanged.

[0060] Compared with Example 7, only the Cu8Au2 nanoalloy is replaced by the Cu5Au5 nanoalloy, and the other steps remain unchanged, to obtain a Cu5Au5-PHI-urea photocatalytic material.

[0061] Example 9 Preparation of Cu2Au8-PHI-urea

[0062] Preparation of Cu2Au8 nanoalloy: Compared with Example 3, 0.8 mL of CuCl2(5 g / L) and 0.2 mL of HAuCl4(5 g / L) are replaced by 0.2 mL of CuCl2(5 g / L) and 0.8 mL of HAuCl4(5 g / L), and the other steps remain unchanged.

[0063] Compared with Example 7, only the Cu8Au2 nanoalloy is replaced by the Cu2Au8 nanoalloy, and the other steps remain unchanged, to obtain a Cu2Au8-PHI-urea photocatalytic material.

[0064] Preparation of block carbon nitride (C3N4-melamine) in Comparative Example 1

[0065] 6.0 g of melamine was added to a quartz crucible, pyrolysis was performed in a tube furnace at 550 ℃ for 4 h (5 °C / min) in a nitrogen (N2) atmosphere, and after the solid product was cooled to room temperature, it was washed with a large amount of deionized water and dried to obtain C3N4.

[0066] Preparation of block carbon nitride (C3N4-melamine) in Comparative Example 1

[0067] Compared with Comparative Example 1, the difference is that 6.0 g of melamine is replaced by 6.0 g of urea in the step, and the remaining steps are the same as those of Comparative Example 1.

[0068] Preparation of Cu-PHI

[0069] Cu nanocrystal preparation: compared with Example 3, 0.8 mL CuCl2(5 g / L) and 0.2 mL HAuCl4(5 g / L) were replaced by 1.0 mL CuCl2(5 g / L), and other steps were unchanged.

[0070] Compared with Example 4, the present application only replaces Cu8Au2nano alloy with Cu nanocrystal, and other steps are unchanged, that is, Cu-PHI photocatalytic material is obtained.

[0071] Preparation of Au-PHI

[0072] Au nanocrystal preparation: compared with Example 3, 0.8 mL CuCl2(5 g / L) and 0.2 mL HAuCl4(5 g / L) were replaced by 1.0 mL HAuCl4(5 g / L), and other steps were unchanged.

[0073] Compared with Example 4, the present application only replaces Cu8Au2nano alloy with Au nanocrystal, and other steps are unchanged, that is, Au-PHI photocatalytic material is obtained.

[0074] Experimental Example 1: photocatalytic removal of CH3SH

[0075] Experimental materials: Examples 1-2 and Comparative Examples 1-2.

[0076] The prepared photocatalyst was used to eliminate CH3SH in a continuous flow system. Specifically, 50 mg of photocatalyst was fixed between two baffles of a photoreactor. 40 ppm CH3SH mixed with air was introduced into the reactor at a total flow rate of 10 mL / min, and the gas mixture passed through the catalyst for 30 min, and then simulated sunlight irradiation was carried out after adsorption equilibrium was reached. A 300 W full-wavelength xenon lamp (12 cm from the quartz reactor window) was used to introduce simulated sunlight into the quartz reactor from the top, and a sensor recorded the CH3SH concentration at the outlet of the reactor every minute. C0is the initial concentration, C is the final concentration, and C / C0represents the degradation rate.

[0077] Figure 5The figure shows the effect of photocatalytic removal of CH3SH in a continuous flow system for Examples 1-2 and Comparative Examples 1-2. The photocatalytic degradation effect of CH3SH by C3N4 prepared from different nitrogen sources (melamine, urea) and PHI is mainly investigated. As can be seen from the figure, under the condition that the nitrogen source is unchanged, the removal effect of CH3SH by the PHI structure material prepared in the examples is much higher than that of the blocky carbon nitride structure prepared in the comparative examples, which is mainly because the PHI prepared by the molten salt method has higher polymerization degree and more ordered in-plane structure, as well as more excellent light absorption capacity and stronger intrinsic carrier excitation capacity. At the same time, under the same experimental conditions, by changing the nitrogen source from melamine to urea, the catalytic activity will also change slightly, and the catalytic activity of the material prepared by taking melamine as the nitrogen source is slightly higher than that of the material prepared by taking urea as the nitrogen source. This shows that the difference of the nitrogen source will affect the polymerization mode and degree of C3N4 and PHI to a certain extent, and then affect its molecular structure, so that the ability of generating carriers by excitation is different, and finally leads to the difference in the effect of photocatalytic removal of CH3SH.

[0078] Experimental Example 2: Photocatalytic removal of CH3SH

[0079] Experimental materials: Examples 4-9, Comparative Examples 3-4.

[0080] The experimental examples of the present application investigate the photocatalytic degradation effect of CH3SH by the photocatalytic material prepared by coupling Cu-Au nanometer alloy (Cu8Au2 nanometer alloy, Cu5Au5 nanometer alloy, Cu2Au8 nanometer alloy) with polyheptazine imide (PHI) and the catalytic material of coupling polyheptazine imide (PHI) with single Cu nanocrystal and single Au nanocrystal. The specific experimental method is consistent with Experimental Example 1.

[0081] The experimental results of the photocatalyst prepared in Examples 4-9 for removing CH3SH are shown in Table Figure 6 The experimental results of the photocatalyst prepared in Comparative Examples 3-4 for removing CH3SH are shown in Table Figure 7 .

[0082] From Figure 6As can be seen, the Cu8Au2-PHI photocatalyst prepared in Example 4 has the highest removal efficiency of CH3SH, and the removal rate reaches 89.8% in 30 min, indicating that the Cu8Au2 nano-alloy has stronger ability to pump out the photo-generated charges excited by PHI, and is more conducive to photocatalytic removal of CH3SH. It is also found by comparison that the photocatalytic degradation efficiency of CH3SH by Cu8Au2-PHI-urea reaches 84.0% in 30 min, which is not much different from that of Cu8Au2-PHI. The catalytic activity of the catalytic materials prepared by different Cu / Au atomic ratios from high to low is Cu8Au2-PHI (Example 4, CH3SH removal rate reaches 89.8%) > Cu8Au2-PHI-urea (Example 7, CH3SH removal rate reaches 84.0%) > Cu5Au5-PHI-urea (Example 8, CH3SH removal rate reaches 79.0%) > Cu5Au5-PHI (Example 5, CH3SH removal rate reaches 73.0%) > Cu2Au8-PHI (Example 6, CH3SH removal rate reaches 69.1%) > Cu2Au8-PHI-urea (Example 9, CH3SH removal rate reaches 61.4%).

[0083] In addition, from Figure 7 As can be seen, the photocatalytic degradation efficiency of Cu-PHI is 56.6% in 30 min, and the photocatalytic degradation efficiency of Au-PHI is 51.1% in 30 min, that is, the catalytic activity of the catalytic materials prepared in Comparative Examples 3 and 4 is much lower than that of the catalytic materials prepared by loading different Cu / Au atomic ratio Cu-Au nano-alloys (Examples 4-9).

[0084] It can be seen from the performance test comparison of the examples and comparative examples that: the PHI material prepared by taking melamine as the nitrogen source has relatively excellent activity in removing CH3SH alone, and the photocatalytic activity is slightly higher than that of the material prepared by taking urea as the nitrogen source. However, after coupling with Cu-Au nano-alloy, the photocatalytic activity is greatly improved, which shows that the Cu-Au nano-alloy as an external "electron pump" has a relatively universal feature and excellent ability to pump out electrons. And by comparing the photocatalytic degradation rates of Comparative Examples 3 and 4, it can be found that the introduction of multiple active sites of Cu-Au nano-alloy has more significant ability to enhance the separation, transfer and utilization of photo-generated carriers, and the effective adsorption and removal of organic waste gas molecules on the surface of the photocatalytic material. The difference in surface formation energy of the nano-alloy will affect the binding strength of small molecules (O2, H2O) and organic waste gas molecules on Cu and Au sites, and then affect the ability of small molecule activation to produce different active oxygen species, resulting in slight differences in photocatalytic efficiency.

[0085] Through performance test comparison of the examples and the comparative examples, it can be known that the photocatalytic material obtained by the application has good application prospect, can be applied to various photocatalytic oxidation scenes under actual conditions, and further realizes efficient removal of single or multi-component organic waste gas (Cl-VOCs, S-VOCs, NOx, aromatic compounds, olefins).

[0086] The above examples are preferred embodiments of the application, but the embodiments of the application are not limited to the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the application should be equivalent replacement methods, and are all included in the protection scope of the application.

Claims

1. A D-Orbit deep cross-linked Cu-Au nano-alloy coupled PHI photocatalytic material, characterized in that, The photocatalytic material is obtained by coupling PHI and a D-orbital deep cross-linked Cu-Au nanometer alloy under hydrothermal conditions, wherein the Cu / Au atomic ratio of the D-orbital deep cross-linked Cu-Au nanometer alloy is 8-2:8-2. The preparation method of the Cu-Au nanometer alloy comprises the following steps: adding a surfactant, a copper precursor, a gold precursor and a reducing agent into water to form a mixed solution A; additionally adding the surfactant, the reducing agent and ammonia water into water to form a mixed solution B; mixing the solution A and the solution B uniformly, and reacting at 60-100 ℃ for 1-4 h, and then freeze-drying to obtain the Cu-Au nanometer alloy.

2. The method of claim 1, wherein the preparation of the D-tracked deep cross-linked Cu-Au nano-alloy coupled PHI photocatalytic material is characterized by, Specifically comprising the following steps: The PHI, the Cu-Au nanometer alloy and the reducing agent are mixed uniformly in water, and then hydrothermal reaction is carried out at 60-100 ℃, followed by filtration, washing and drying to obtain the photocatalytic material of the Cu-Au nanometer alloy coupled with PHI.

3. The preparation method according to claim 2, characterized in that, The hydrothermal reaction time is 8-16 h.

4. The preparation method according to claim 2, characterized in that, The reducing agent is one of ascorbic acid, sodium citrate and hydroxylamine hydrochloride.

5. The preparation method according to claim 2, characterized in that, The mass ratio of the PHI, the Cu-Au nanometer alloy and the reducing agent is 0.5-2:0.12-0.48:0.3-1.

2.

6. The preparation method according to claim 2, characterized in that, The preparation method of the Cu-Au nanometer alloy comprises the following steps: adding a surfactant, a copper precursor, a gold precursor and a reducing agent into water to form a mixed solution A; additionally adding the surfactant, the reducing agent and ammonia water into water to form a mixed solution B; mixing the solution A and the solution B uniformly, and reacting at 60-100 ℃ for 1-4 h, and then freeze-drying to obtain the Cu-Au nanometer alloy.

7. The preparation method according to claim 6, characterized in that, The copper precursor is one of CuCl2, Cu(NO3)2 and CuSO4; and the gold precursor is HAuCl4.

8. The application of the photocatalytic material in claim 1 in photocatalytic elimination of organic waste gas.

9. Use according to claim 8, characterized in that, The organic waste gas is Cl-VOCs, S-VOCs, NO x , aromatic compounds or olefins.

10. A continuous flow photocatalytic organic exhaust gas elimination method, characterized by, The photocatalytic material in claim 1 is contained.

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