阅读说明：本技术 一种原位合成α-Bi2O3/CuBi2O4异质结光催化材料的制备方法及应用 (In-situ synthesis of α -Bi2O3/CuBi2O4Preparation method and application of heterojunction photocatalytic material ) 是由 饶永芳 陈倩 黄宇 于 2020-04-08 设计创作，主要内容包括：本发明公开了一种原位合成α-Bi<Sub>2</Sub>O<Sub>3</Sub>/CuBi<Sub>2</Sub>O<Sub>4</Sub>异质结光催化材料的制备方法及应用,并将其应用于光催化去除氮氧化物。通过CuBi<Sub>2</Sub>O<Sub>4</Sub>纳米颗粒原位生长在类棒状α-Bi<Sub>2</Sub>O<Sub>3</Sub>上而形成的α-Bi<Sub>2</Sub>O<Sub>3</Sub>/CuBi<Sub>2</Sub>O<Sub>4</Sub>异质结光催化材料具有紧密的界面接触,有利于减少光生载流子的传输阻力。当煅烧温度为400℃时获得的α-Bi<Sub>2</Sub>O<Sub>3</Sub>/CuBi<Sub>2</Sub>O<Sub>4</Sub>异质结在可见光下30min内对NO的去除率高达30％,比纯相α-Bi<Sub>2</Sub>O<Sub>3</Sub>和P25分别提高了13％和15％,同时几乎没有有毒副产物NO<Sub>2</Sub>的生成。在光催化去除NO中表现出较高的催化活性和稳定性。细胞毒性实验表明本发明制备的催化剂具有极低的吸入毒性。因此,原位合成的α-Bi<Sub>2</Sub>O<Sub>3</Sub>/CuBi<Sub>2</Sub>O<Sub>4</Sub>异质结光催化材料是高效、稳定、成本低廉、易于制备和低毒性的光催化剂,在光催化净化空气方面具有潜在的应用价值。(The invention discloses an in-situ synthesis of α -Bi 2 O 3 /CuBi 2 O 4 A preparation method and application of a heterojunction photocatalytic material are provided, and the heterojunction photocatalytic material is applied to photocatalysis to remove nitrogen oxides. By CuBi 2 O 4 The nano particles grow in situ in a rod-like α -Bi 2 O 3 α -Bi formed above 2 O 3 /CuBi 2 O 4 The heterojunction photocatalytic material has close interface contact, and is favorable for reducing the transmission resistance of photon-generated carriersα -Bi obtained when the calcination temperature is 400 DEG C 2 O 3 /CuBi 2 O 4 The heterojunction has a NO removal rate as high as 30% within 30min under visible light, and is pure phase α -Bi 2 O 3 And P25 by 13% and 15%, respectively, with little toxic by-product NO 2 The catalyst prepared by the method has extremely low inhalation toxicity, so that the α -Bi synthesized in situ 2 O 3 /CuBi 2 O 4 The heterojunction photocatalytic material is a photocatalyst which is efficient, stable, low in cost, easy to prepare and low in toxicity, and has potential application value in the aspect of photocatalytic air purification.)

1. In-situ synthesis of α -Bi₂O₃/CuBi₂O₄The preparation method of the heterojunction photocatalytic material is characterized by comprising the following steps of:

step 1, adding Bi (NO)₃)₃·5H₂Adding O into the methanol solution to obtain Bi³⁺A solution; adding Cu (NO)₃)₂·3H₂Adding O into deionized water to obtain Cu²⁺A solution; 1,3, 5-trimesic acid (H)₃BTC) was added to N, N-Dimethylformamide (DMF) to give H₃A BTC solution;

step 2, adding Cu in the step 1²⁺The solution is dripped into Bi³⁺Stirring the solution at room temperature to be uniform to obtain a mixed solution;

step 3, H in the step 1₃Dropwise adding the BTC solution into the mixed solution obtained in the step (2), stirring at room temperature, reacting, washing with deionized water and absolute ethyl alcohol, and drying to obtain a precursor;

step 4, calcining the precursor obtained in the step 3 to obtain α -Bi₂O₃/CuBi₂O₄A heterojunction photocatalytic material.

2. The in situ synthesis of α -Bi according to claim 1₂O₃/CuBi₂O₄The preparation method of the heterojunction photocatalytic material is characterized in that Bi (NO) is prepared in the step 1₃)₃·5H₂0.97g methanol 10m L, Cu (NO) in step 1₃)₂·3H₂And O, 0.2416g of deionized water, 10m L, and 1g of N, N-dimethylformamide as 1,3, 5-trimesic acid in the step 1, 15m L.

3. The in situ synthesis of α -Bi according to claim 1₂O₃/CuBi₂O₄The preparation method of the heterojunction photocatalytic material is characterized in that the stirring time in the step 3 is 1-2 hours, the reaction temperature is 120 ℃, and the reaction time is 24 hours.

4. The in situ synthesis of α -Bi according to claim 1₂O₃/CuBi₂O₄The preparation method of the heterojunction photocatalytic material is characterized in that the drying temperature in the step 3 is 60-80 ℃.

5. The in situ synthesis of α -Bi according to claim 1₂O₃/CuBi₂O₄The preparation method of the heterojunction photocatalytic material is characterized in that the calcination temperature in the step 4 is T, T is more than or equal to 400 ℃ and less than 800 ℃, the calcination time is 3h, and the temperature rise rate is 2 ℃/min.

6. The in-situ synthesis of α -Bi according to any one of claims 1 to 5₂O₃/CuBi₂O₄Application of a heterojunction photocatalytic material in photocatalytic removal of NO.

7. The in situ synthesis of α -Bi according to claim 6₂O₃/CuBi₂O₄The application of the heterojunction photocatalytic material in the photocatalytic removal of NO is characterized in that the photocatalytic removal of NO is carried out in a continuous flow reaction device, the initial concentration of NO is 400ppb, and N is₂The gas flow rate is 3L/min as equilibrium gas, the catalyst dosage is 0.1g, the light source is a xenon lamp, the wavelength is more than 420nm, and the light source irradiation time is 15-60 min.

Technical Field

The invention belongs to the technical field of photocatalysis, and relates to in-situ synthesis of α -Bi₂O₃/CuBi₂O₄A preparation method and application of a heterojunction photocatalytic material.

Background

Nitrogen Oxides (NO) in the atmosphere_x) Not only is one of important precursors for forming haze and secondary organic aerosol, but also can generate great harm to human health. The traditional technology such as selective catalytic reduction, three-way catalysis, absorption, adsorption and the like can effectively remove high-concentration nitrogen oxides generated by the combustion of fossil fuel, but can be used for removing low-concentration NO in the atmosphere_x(ppb level) is not applicable. Therefore, for low concentrations of NO_xNew techniques need to be taken to avoid its constant accumulation in the atmosphere. Recently, the photocatalytic technology has attracted much attention due to its advantages of simple operation, mild reaction conditions, no secondary pollution, and the like, and can realize deep purification of low-concentration pollutants.

Bismuth-based semiconductors have been studied in large numbers because of their advantages of visible light response, readily available raw materials, non-toxicity, and harmlessness. Wherein, Bi₂O₃As a simple bismuth-based material, the bismuth-based material has α, β, gamma and four main crystal phases, and a monoclinic phase α -Bi with a band gap ranging from 2.1eV to 2.8 eV.₂O₃The photocatalyst is stable at normal temperature and normal pressure, can absorb visible light in solar energy and has a positive valence band position, but the photocatalytic activity of the photocatalyst is greatly reduced by the rapid recombination of photon-generated carriers. Single component photocatalystIt is often difficult to achieve the desired photocatalytic performance and constructing a heterojunction by coupling two or more semiconductors is currently one of the most feasible ways to overcome the above problems. In general, the construction of a heterojunction requires a stepwise procedure, i.e. one of the catalysts is first prepared and then attached to the surface of the other catalyst. Due to compatibility problems and differences in preparation conditions between different components, the step-by-step synthesis method is difficult to realize uniform distribution of the catalyst, and may increase the transport resistance of charges at the interface, affecting the effective separation of the photo-generated electron-hole pairs. Wang in the publication of surface radial-based photo-Fenton reaction derivative by CuBi₂O₄and its composites withα-Bi₂O₃under vision irradation, Catalyst surface, performance and reaction mechanism, CuBi is prepared by sol-gel method₂O₄/α-Bi₂O₃The composite material is applied to a sulfate radical photo-Fenton reaction under the assistance of visible light to remove rhodamine B dye in a liquid phase; under the irradiation of only visible light, CuBi₂O₄/α-Bi₂O₃The composite material has no effect of removing rhodamine B, and the preparation method of the catalyst is α -Bi during high-temperature calcination₂O₃To CuBi₂O₄The transformation process is not obvious, and the shape change of the material is irregular.

Disclosure of Invention

The invention aims to solve the problems of poor compatibility between different components and large interface transmission resistance in the process of synthesizing a heterojunction material in the prior art, and provides in-situ synthesis α -Bi₂O₃/CuBi₂O₄A preparation method and application of a heterojunction photocatalytic material.

In order to achieve the purpose, the invention adopts the following technical scheme to realize the purpose:

in-situ synthesis of α -Bi₂O₃/CuBi₂O₄The preparation method of the heterojunction photocatalytic material comprises the following steps:

step 1, adding Bi (NO)₃)₃·5H₂O adding methanolIn the solution to obtain Bi³⁺A solution; adding Cu (NO)₃)₂·3H₂Adding O into deionized water to obtain Cu²⁺A solution; 1,3, 5-trimesic acid (H)₃BTC) was added to N, N-Dimethylformamide (DMF) to give H₃A BTC solution;

step 2, adding Cu in the step 1²⁺The solution is dripped into Bi³⁺Stirring the solution at room temperature to be uniform to obtain a mixed solution;

step 3, H in the step 1₃Dropwise adding the BTC solution into the mixed solution obtained in the step (2), stirring at room temperature, reacting, washing with deionized water and absolute ethyl alcohol, and drying to obtain a precursor;

step 4, calcining the precursor obtained in the step 3 to obtain α -Bi₂O₃/CuBi₂O₄A heterojunction photocatalytic material.

The invention is further improved in that:

step 1 Bi (NO)₃)₃·5H₂0.97g methanol 10m L, Cu (NO) in step 1₃)₂·3H₂And O, 0.2416g of deionized water, 10m L, and 1g of N, N-dimethylformamide as 1,3, 5-trimesic acid in the step 1, 15m L.

In the step 3, the stirring time is 1-2 h, the reaction temperature is 120 ℃, and the reaction time is 24 h.

And in the step 3, the drying temperature is 60-80 ℃.

In the step 4, the calcining temperature is T, T is more than or equal to 400 ℃ and less than 800 ℃, the calcining time is 3h, and the heating rate is 2 ℃/min.

In-situ synthesis of α -Bi₂O₃/CuBi₂O₄Application of a heterojunction photocatalytic material in photocatalytic removal of NO. The photocatalytic removal of NO is carried out in a continuous flow reaction device with an initial NO concentration of 400ppb, N₂The gas flow rate is 3L/min as equilibrium gas, the catalyst dosage is 0.1g, the light source is a xenon lamp, the wavelength is more than 420nm, and the light source irradiation time is 15-60 min.

Compared with the prior art, the invention has the following beneficial effects:

the inventionDiscloses an in-situ synthesis of α -Bi₂O₃/CuBi₂O₄α -Bi with close contact interface is prepared by utilizing coordination between metal ions and organic ligands through solvothermal method and high-temperature calcination₂O₃/CuBi₂O₄The invention regulates α -Bi in the heterojunction photocatalytic material by changing the calcination temperature₂O₃And CuBi₂O₄By the ratio of (A) to (B) when calcined at 400 ℃ by CuBi₂O₄The nano particles grow in situ in a rod-like α -Bi₂O₃α -Bi formed above₂O₃/CuBi₂O₄The heterojunction photocatalytic material has close interface contact, and is favorable for reducing the transmission resistance of photon-generated carriers.

The invention discloses an in-situ synthesis of α -Bi₂O₃/CuBi₂O₄The application of the heterojunction photocatalytic material in photocatalytic NO removal has the highest NO removal rate reaching 30% under visible light irradiation, and is compared with pure phase α -Bi₂O₃And P25 increased by 13% and 15%, respectively; and hardly any NO is produced during the photocatalytic removal of NO₂The toxic by-product is inhibited, and the cytotoxicity experiment shows α -Bi₂O₃/CuBi₂O₄The composite photocatalytic material has low toxicity and high biocompatibility, and the α -Bi protected by the invention₂O₃/CuBi₂O₄The compound has high catalytic activity, stability, selectivity and biocompatibility, shows excellent photocatalytic performance in the fields of gas-phase low-concentration pollutants and liquid-phase organic micro-pollutant degradation, and has potential application prospects.

Drawings

FIG. 1 shows pure phase CuBi of comparative example 1 of the present invention₂O₄Comparative example 2 pure phase α -Bi₂O₃α -Bi different from examples 1 to 4₂O₃/CuBi₂O₄Heterojunction photocatalysisXRD spectrum of the material;

FIG. 2 is SEM images of different catalytic materials in comparative example 2, examples 1 to 4 and comparative example 1 of the present invention, respectively, (a) pure phase α -Bi₂O₃(BO-400), (b) BO/CBO-400, (c) BO/CBO-500, (d) BO/CBO-600, (e) BO/CBO-700, and (f) phase-pure CuBi₂O₄(CBO-800)；

FIG. 3 is a transmission electron micrograph (a) of a BO/CBO-400 heterojunction photocatalytic material in example 1 of the present invention, (b) a TEM image, and (c) an HRTEM image;

FIG. 4 is a graph of pure phase CuBi in comparative example 1, comparative example 2 and examples 1-4 of the present invention₂O₄Pure phase α -Bi₂O₃And different α -Bi₂O₃/CuBi₂O₄Activity test chart of material under visible light, (a) NO removal efficiency chart, (b) NO₂A production amount schematic diagram;

FIG. 5 is a graph showing the measurement of the cyclic activity of the BO/CBO-400 heterojunction photocatalytic material for removing NO under visible light in example 1 of the present invention;

FIG. 6 is a graph showing the activity of the BO/CBO-400 heterojunction photocatalytic material in degrading DCF under visible light in example 1 of the present invention;

FIG. 7 shows pure phase α -Bi of different concentrations in comparative example 2 and example 1 of the present invention₂O₃(BO-400) and BO/CBO-400.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments, and are not intended to limit the scope of the present disclosure.

The invention is described in further detail below with reference to the accompanying drawings: