阅读说明：本技术 一种Pr3+掺杂Bi2MoO6-g-C3N4异质结的光催化降解材料及其制法 (Pr (Pr) powder3+Doping with Bi2MoO6-g-C3N4Heterojunction photocatalytic degradation material and preparation method thereof ) 是由 訾孟涛 于 2020-07-17 设计创作，主要内容包括：本发明涉及光催化降解技术领域,且公开了一种Pr<Sup>3+</Sup>掺杂Bi<Sub>2</Sub>MoO<Sub>6</Sub>-g-C<Sub>3</Sub>N<Sub>4</Sub>异质结的光催化降解材料,包括以下配方原料及组分：三维多孔g-C<Sub>3</Sub>N<Sub>4</Sub>纳米片、聚乙烯吡咯烷酮,葡萄糖、硝酸铋、钼酸钠、硝酸镨。多孔g-C<Sub>3</Sub>N<Sub>4</Sub>纳米片具有超高的比表面积,可以提高对光能的响应性和利用率,以多孔g-C<Sub>3</Sub>N<Sub>4</Sub>纳米片为基底,在表面活性剂聚乙烯吡咯烷酮和葡萄糖水热生成的碳纳米球为模板的体系中,制备得到多孔Pr<Sup>3+</Sup>掺杂Bi<Sub>2</Sub>MoO<Sub>6</Sub>空心微球负载多孔g-C<Sub>3</Sub>N<Sub>4</Sub>纳米片,Pr<Sup>3+</Sup>掺杂Bi<Sub>2</Sub>MoO<Sub>6</Sub>和g-C<Sub>3</Sub>N<Sub>4</Sub>形成Z型异质结,当光辐射在Z型异质结上时,Pr<Sup>3+</Sup>掺杂Bi<Sub>2</Sub>MoO<Sub>6</Sub>价带上的空穴和g-C<Sub>3</Sub>N<Sub>4</Sub>导带上的光生电子可以快速与氧气和水反应,生成的氧负离子自由基和羟基自由基对四环素等有机污染物进行快速降解。(The invention relates to the technical field of photocatalytic degradation and discloses a Pr catalyst 3+ Doping with Bi 2 MoO 6 ‑g‑C 3 N 4 The photocatalytic degradation material for the heterojunction comprises the following formula raw materials and components: three-dimensional porous g-C 3 N 4 Nano-sheets, polyvinylpyrrolidone, glucose, bismuth nitrate, sodium molybdate and praseodymium nitrate. Porous g-C 3 N 4 The nano-sheet has ultra-high specific surface area, can improve the responsiveness and the utilization rate to light energy, and is porous g-C 3 N 4 The nano-sheet is used as a substrate, and polyvinylpyrrolidone and grapes are added into a surfactantPreparing porous Pr in the system with carbon nanometer ball as template produced with sugar water 3+ Doping with Bi 2 MoO 6 Hollow microsphere loaded porous g-C 3 N 4 Nanosheets, Pr 3+ Doping with Bi 2 MoO 6 And g-C 3 N 4 Forming a Z-type heterojunction, Pr when light is radiated at the Z-type heterojunction 3+ Doping with Bi 2 MoO 6 Hole sum g-C in the valence band 3 N 4 The photo-generated electrons on the conduction band can rapidly react with oxygen and water, and the generated oxygen anion free radicals and hydroxyl free radicals rapidly degrade organic pollutants such as tetracycline.)

1. Pr (Pr) powder³⁺Doping with Bi₂MoO₆-g-C₃N₄The photocatalytic degradation material of the heterojunction is characterized in that: comprises the following raw materials and components, three-dimensional porous g-C₃N₄Nano-sheets, polyvinylpyrrolidone, glucose, bismuth nitrate, sodium molybdate and praseodymium nitrate, wherein the mass ratio of the bismuth nitrate to the sodium molybdate to the praseodymium nitrate to the glucose is 97-99.5:50:0.5-3:120-₃N₄The mass ratio of the nano-sheets, the polyvinylpyrrolidone and the glucose is 150-300:100: 10-15.

2. A Pr according to claim 1³⁺Doping with Bi₂MoO₆-g-C₃N₄The photocatalytic degradation material of the heterojunction is characterized in that: the Pr³⁺Doping with Bi₂MoO₆-g-C₃N₄The preparation method of the heterojunction photocatalytic degradation material comprises the following steps:

(1) adding melamine and nano SiO into distilled water solvent₂After ultrasonic dispersion is uniform, heating to 75-85 ℃, stirring until the solvent is evaporated to dryness, fully grinding the mixed product, placing the mixed product in a resistance furnace, heating to 530-In the process, stirring for 20-30h after ultrasonic dispersion is uniform, and etching to remove nano SiO₂Template, filtering, washing to neutrality, ultrasonic peeling the solid product, cooling and thawing in a freeze drier to obtain three-dimensional porous g-C₃N₄Nanosheets;

(2) adding three-dimensional porous g-C into a mixed solvent of distilled water and ethanol₃N₄Uniformly dispersing nanosheets, polyvinylpyrrolidone and glucose by ultrasonic, stirring at room temperature for 2-4h, adding bismuth nitrate, sodium molybdate, praseodymium nitrate and glacial acetic acid, stirring for 12-24h, pouring the solution into a polymerization reaction kettle, placing the polymerization reaction kettle in a reaction kettle heating box, heating to 170-190 ℃, reacting for 6-12h, filtering, washing and drying, calcining in a nitrogen atmosphere to remove a carbon sphere template, and preparing to obtain Pr³⁺Doping with Bi₂MoO₆Hollow microsphere loaded porous g-C₃N₄Nanosheets, as Pr³⁺Doping with Bi₂MoO₆-g-C₃N₄A photocatalytic degradation material of a heterojunction.

3. A Pr according to claim 2³⁺Doping with Bi₂MoO₆-g-C₃N₄The photocatalytic degradation material of the heterojunction is characterized in that: the nano SiO in the step (1)₂Has an average particle diameter of 10-50nm and a mass ratio of 1:2-6 to melamine.

4. A Pr according to claim 2³⁺Doping with Bi₂MoO₆-g-C₃N₄The photocatalytic degradation material of the heterojunction is characterized in that: the freezing-unfreezing treatment in the step (1) comprises the steps of freezing and drying for 8-12h at-25 to-45 ℃, unfreezing at room temperature, freezing and drying for 4-6h at-25 to-45 ℃, unfreezing at room temperature, freezing and drying for 1-3h at-25 to-45 ℃, and unfreezing at room temperature.

5. A Pr according to claim 2³⁺Doping with Bi₂MoO₆-g-C₃N₄Photocatalytic degradation material of heterojunctionThe method is characterized in that: the volume ratio of the distilled water, the ethanol and the glacial acetic acid in the step (2) is 40-50:10:6-10, and the mass fraction of the glucose in the total solution is controlled to be 0.3-0.4%.

6. A Pr according to claim 2³⁺Doping with Bi₂MoO₆-g-C₃N₄The photocatalytic degradation material of the heterojunction is characterized in that: the reation kettle heating cabinet in step (2) includes the air-blast heater, air-blast heater swing joint has the air-blast fan piece, reation kettle heating cabinet bottom fixedly connected with rotary device, rotary device swing joint has the rotation axis, rotation axis upper end fixedly connected with base, the base top is provided with polymerization reaction kettle, base top fixedly connected with bracing piece, bracing piece swing joint has the governing valve, governing valve fixedly connected with carriage release lever, carriage release lever fixedly connected with annular cardboard.

Technical Field

The invention relates to the technical field of photocatalytic degradation, in particular to Pr³⁺Doping with Bi₂MoO₆-g-C₃N₄A photocatalytic degradation material of heterojunction and its preparation method are provided.

Background

Water pollution, noise pollution, air pollution and solid waste pollution are four pollution problems in the contemporary society, the pollution-free problem form of China is severe, the pollutants mainly comprise inorganic pollutants and organic pollutants, the organic pollutants such as phenol, methylene blue, tetracycline and the like, the pollution degree is large, the degradation is difficult, and the existing treatment methods for the organic pollutants mainly comprise a physical adsorption method, an oxidation-reduction method and the like.

The photocatalytic degradation is a new high-efficiency organic pollutant degradation method, and utilizes the light radiation and free radical with strong activity produced by photocatalyst in the reaction system, and utilizes the processes of addition, substitution and electron transfer between free radical and organic pollutant to degrade the pollutant into inorganic substance, and the existent photocatalytic degradation material mainly contains titanium dioxide, transition metal sulfide and bismuthate, etc. and graphite phase carbon nitride g-C₃N₄Has moderate band gap and good optical activity under visible light, is a photocatalytic degradation material with wide application, but g-C₃N₄Has a low specific surface area, a low utilization ratio of light energy, and g-C₃N₄The photoproduction electrons and holes are easy to recombine, and the g-C is greatly reduced₃N₄Photocatalytic degradation activity of (1) g-C₃N₄And transition metal sulfide, bismuthate and the like with suitable band gaps form a heterojunction structure, so that the recombination of photogenerated electrons and holes can be effectively reduced.

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a Pr³⁺Doping with Bi₂MoO₆-g-C₃N₄The photocatalytic degradation material of heterojunction and its preparation method solve the problem of common g-C₃N₄Is not high, and the photogenerated electrons and holes are easily recombined.

(II) technical scheme

In order to achieve the purpose, the invention provides the following technical scheme: pr (Pr) powder³⁺Doping with Bi₂MoO₆-g-C₃N₄The photocatalytic degradation material of the heterojunction is characterized in that: comprises the following raw materials and components, three-dimensional porous g-C₃N₄Nano-sheets, polyvinylpyrrolidone, glucose, bismuth nitrate, sodium molybdate and praseodymium nitrate, wherein the mass ratio of the bismuth nitrate to the sodium molybdate to the praseodymium nitrate to the glucose is 97-99.5:50:0.5-3:120-₃N₄The mass ratio of the nano-sheets, the polyvinylpyrrolidone and the glucose is 150-300:100: 10-15.

Preferably, the Pr is³⁺Doping with Bi₂MoO₆-g-C₃N₄The preparation method of the heterojunction photocatalytic degradation material comprises the following steps:

(1) adding distilled water solvent, melamine and nano SiO into a reaction bottle₂Uniformly dispersing by ultrasonic wave, placing in an oil bath, heating to 75-85 deg.C, stirring at constant speed until the solvent is evaporated to dryness, fully grinding the mixed product, placing in a resistance furnace, heating to 530-₂Template, filtering, washing to neutrality, ultrasonic peeling the solid product, cooling and thawing in a freeze drier to obtain three-dimensional porous g-C₃N₄Nanosheets.

(2) Adding a mixed solvent of distilled water and ethanol and three-dimensional porous g-C into a reaction bottle₃N₄Uniformly dispersing nanosheets, polyvinylpyrrolidone and glucose by ultrasonic, uniformly stirring at room temperature for 2-4h, adding bismuth nitrate, sodium molybdate, praseodymium nitrate and glacial acetic acid, uniformly stirring for 12-24h, pouring the solution into a polymerization reaction kettle, placing the polymerization reaction kettle in a reaction kettle heating box, heating to 190 ℃ at 170 ℃, reacting for 6-12h, filtering the solution to remove the solvent, washing the precipitated product by using distilled water and ethanol, drying, calcining in nitrogen atmosphere to remove a carbon sphere template, and preparing to obtain Pr³⁺Doping with Bi₂MoO₆Hollow microsphere loaded porous g-C₃N₄Nanosheets, as Pr³⁺Doping with Bi₂MoO₆-g-C₃N₄A photocatalytic degradation material of a heterojunction.

Preferably, the nano SiO in the step (1)₂Has an average particle diameter of 10-50nm and a mass ratio of 1:2-6 to melamine.

Preferably, the freeze-thaw treatment in the step (1) is freeze-drying at-25 to-45 ℃ for 8 to 12 hours, thawing at room temperature, freeze-drying at-25 to-45 ℃ for 4 to 6 hours, thawing at room temperature, freeze-drying at-25 to-45 ℃ for 1 to 3 hours, and thawing at room temperature.

Preferably, the volume ratio of the distilled water, the ethanol and the glacial acetic acid in the step (2) is 40-50:10:6-10, and the mass fraction of the glucose in the total solution is controlled to be 0.3-0.4%.

Preferably, the reation kettle heating cabinet in step (2) includes the air-blast heater, and air-blast heater swing joint has the air-blast fan piece, reation kettle heating bottom of the case portion fixedly connected with rotary device, and rotary device swing joint has the rotation axis, rotation axis upper end fixedly connected with base, and the base top is provided with polymerization kettle, base top fixedly connected with bracing piece, bracing piece swing joint has the governing valve, governing valve fixedly connected with carriage release lever, carriage release lever fixedly connected with annular cardboard.

(III) advantageous technical effects

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

the Pr³⁺Doping with Bi₂MoO₆-g-C₃N₄Heterojunction photocatalytic degradation material, regulation and control template agent nanometer SiO₂The prepared porous g-C with rich nano-aperture₃N₄Then the porous g-C is prepared by ultrasonic stripping and freeze drying treatment₃N₄Nanosheets, comparable to ordinary g-C₃N₄Porous g-C₃N₄The nano-sheet has an ultra-high specific surface area, and can improve the responsiveness and the utilization rate to light energy.

The Pr³⁺Doping with Bi₂MoO₆-g-C₃N₄Photocatalytic degradation material of heterojunction with porous g-C₃N₄The nano sheet is taken as a substrate, and porous Pr is prepared in a system with a carbon nano sphere generated by hydrothermal reaction of surfactant polyvinylpyrrolidone and glucose as a template³⁺Doping with Bi₂MoO₆Hollow microsphere loaded porous g-C₃N₄Nanosheets, Pr³⁺Substituted part of Bi³⁺Forms a new donor level, reduces the energy band gap, and enables Pr³⁺Doping with Bi₂MoO₆The light absorption edge of the film generates red shift, the visible light absorption waveband is widened, and meanwhile, the film is Pr³⁺Doping with Bi₂MoO₆And g-C₃N₄Forming a Z-type heterojunction when light is radiated at Pr³⁺Doping with Bi₂MoO₆And g-C₃N₄When in the heterojunction, Pr³⁺Doping with Bi₂MoO₆And g-C₃N₄Both the conduction and valence bands of (2) generate photogenerated electrons and holes, but Pr^{3 +}Doping with Bi₂MoO₆Valence band ratio of g to C₃N₄Correction of valence band, g-C₃N₄Conduction band ratio Pr of³⁺Doping with Bi₂MoO₆The conduction band of (2) is more negative, so that Pr is³⁺Doping with Bi₂MoO₆Electron transition to g-C in the conduction band of₃N₄And recombines with the hole on its valence band to make Pr³⁺Doping with Bi₂MoO₆Hole sum g-C in the valence band₃N₄The photo-generated electrons on the conduction band can rapidly react with oxygen and water to generate a large amount of oxygen anion free radicals and hydroxyl free radicals with strong activity, organic pollutants such as tetracycline and the like are rapidly degraded, and a high-efficiency photocatalytic degradation process is realized through a Z-type heterojunction carrier transmission mechanism.

Drawings

FIG. 1 is a schematic front view of a reactor heating box;

FIG. 2 is a schematic view of the adjustment of the ring clamp;

FIG. 3 is a schematic top view of a polymerization reactor.

1-a reaction kettle heating box; 2-a blast heater; 3-blast fan sheet; 4-a rotating device; 5-a rotating shaft; 6-a base; 7-a polymerization reaction kettle; 8-a support bar; 9-adjusting valve; 10-a moving bar; 11-ring catch plate.

Detailed Description

To achieve the above object, the present invention provides the following embodiments and examples: pr (Pr) powder³⁺Doping with Bi₂MoO₆-g-C₃N₄The photocatalytic degradation material of the heterojunction is characterized in that: comprises the following raw materials and components, three-dimensional porous g-C₃N₄Nano-sheets, polyvinylpyrrolidone, glucose, bismuth nitrate, sodium molybdate and praseodymium nitrate, wherein the mass ratio of the bismuth nitrate to the sodium molybdate to the praseodymium nitrate to the glucose is 97-99.5:50:0.5-3:120-₃N₄The mass ratio of the nano-sheets, the polyvinylpyrrolidone and the glucose is 150-300:100: 10-15.

Pr³⁺Doping with Bi₂MoO₆-g-C₃N₄The preparation method of the heterojunction photocatalytic degradation material comprises the following steps:

(1) adding distilled water solvent, melamine and nano SiO with average grain diameter of 10-50nm into a reaction bottle₂The mass ratio of the two is 2-6:1, the mixture is placed in an oil bath pot after being dispersed evenly by ultrasonic, the mixture is heated to 75-85 ℃, the mixture is stirred at a constant speed until the solvent is evaporated to dryness, the mixture is fully ground and then placed in a resistance furnace, the temperature is raised to 530 ℃ and 560 ℃, the mixture is calcined for 3-5h, the calcined product is placed in hydrofluoric acid solution, the mixture is stirred at a constant speed for 20-30h after being dispersed evenly by ultrasonic, and the nano SiO is removed by etching₂Filtering, washing to neutrality, ultrasonically stripping solid product, cooling and thawing in a freeze drier at-25 deg.c to-45 deg.c for 8-12 hr, thawing at room temperature, freeze drying at-25 deg.c to-45 deg.c for 4-6 hr, thawing at room temperature, freeze drying at-25 deg.c to-45 deg.c for 1-3 hr, thawing at room temperature to obtain three-dimensional porous g-C₃N₄Nanosheets.

(2) Adding a mixed solvent of distilled water and ethanol and three-dimensional porous g-C into a reaction bottle₃N₄Uniformly dispersing the nanosheets, polyvinylpyrrolidone and glucose by ultrasonic, uniformly stirring at room temperature for 2-4h, adding bismuth nitrate, sodium molybdate, praseodymium nitrate and glacial acetic acid, and controlling distilled water, ethanol and glacial ethyl acetateThe volume ratio of the acid is 40-50:10:6-10, the mass fraction of the glucose in the total solution is controlled to be 0.3-0.4%, the solution is stirred at a constant speed for 12-24h, the solution is poured into a polymerization reaction kettle and placed in a reaction kettle heating box, the reaction kettle heating box comprises an air blowing heating machine, the air blowing heating machine is movably connected with an air blowing fan sheet, the bottom of the reaction kettle heating box is fixedly connected with a rotating device, the rotating device is movably connected with a rotating shaft, the upper end of the rotating shaft is fixedly connected with a base, the polymerization reaction kettle is arranged above the base, a supporting rod is fixedly connected above the base, the supporting rod is movably connected with an adjusting valve, the adjusting valve is fixedly connected with a moving rod, the moving rod is fixedly connected with an annular clamping plate, the temperature is 190 ℃ when the solution is heated to 170 ℃, calcining in nitrogen atmosphere to remove the carbon sphere template to prepare the Pr³⁺Doping with Bi₂MoO₆Hollow microsphere loaded porous g-C₃N₄Nanosheets, as Pr³⁺Doping with Bi₂MoO₆-g-C₃N₄A photocatalytic degradation material of a heterojunction.