阅读说明：本技术 一种石墨烯修饰Er掺杂CeO2-BiOBr异质结的光催化降解材料 (Graphene modified Er doped CeO2Photocatalytic degradation material of BiOBr heterojunction ) 是由 庞焕林 于 2020-06-30 设计创作，主要内容包括：本发明涉及光催化技术领域,且公开了一种石墨烯修饰Er掺杂CeO<Sub>2</Sub>-BiOBr异质结的光催化降解材料,以硼氢化钠为还原剂,得到还原氧化石墨烯,有效还原含氧基团,以硝酸铈、硝酸铒为原料,得到梭型Er掺杂草酸铈,经过煅烧,形成大量孔隙结构,得到多孔梭型Er掺杂CeO<Sub>2</Sub>,增大与太阳光的接触面积,铒离子取代铈离子格位,在晶格中产生氧空位缺陷,可作为光生电子捕捉陷阱,延缓光生电子-空穴的复合,以硝酸铋为铋源,得到石墨烯修饰花瓣状BiOBr,花瓣状BiOBr是由片堆积而成,存在大量的狭缝状空洞,Er掺杂CeO<Sub>2</Sub>与BiOBr形成异质结结构,有效抑制光生电子-空穴的复合,使得石墨烯修饰Er掺杂CeO<Sub>2</Sub>-BiOBr异质结具有优异的光催化降解四环素的性能。(The invention relates to the technical field of photocatalysis, and discloses graphene modified Er doped CeO 2 ‑BiThe photocatalytic degradation material of the OBr heterojunction takes sodium borohydride as a reducing agent to obtain reduced graphene oxide, effectively reduces oxygen-containing groups, takes cerium nitrate and erbium nitrate as raw materials to obtain shuttle-type Er doped cerium oxalate, and forms a large number of pore structures through calcination to obtain the porous shuttle-type Er doped CeO 2 The contact area with sunlight is increased, erbium ions replace cerium ion lattice sites, oxygen vacancy defects are generated in crystal lattices, the crystal lattices can be used as photo-generated electrons to capture traps, the recombination of photo-generated electrons and holes is delayed, bismuth nitrate is used as a bismuth source, graphene modified petal-shaped BiOBr is obtained, the petal-shaped BiOBr is formed by stacking sheets, a large number of slit-shaped holes exist, and Er is doped with CeO 2 A heterojunction structure is formed with the BiOBr, so that the recombination of photo-generated electrons and holes is effectively inhibited, and the graphene modified Er doped with CeO 2 The BiOBr heterojunction has excellent performance of photocatalytic degradation of tetracycline.)

1. Graphene modified Er doped CeO₂-a photocatalytic degradation material of a BiOBr heterojunction, characterized in that: the graphene modified Er doped with CeO₂The preparation method of the photocatalytic degradation material of the BiOBr heterojunction comprises the following steps:

(1) adding deionized water and graphene oxide into a beaker to prepare a colloidal solution, dropwise adding a sodium carbonate aqueous solution, adjusting the pH to 8-10, adding a reducing agent sodium borohydride, wherein the mass ratio of the graphene oxide to the sodium borohydride is 15-25:100, placing the beaker into a water bath device, carrying out heat treatment at 70-90 ℃ for 30-90min, filtering, washing and drying to obtain reduced graphene oxide;

(2) adding deionized water, ethylene glycol, cerium nitrate, erbium nitrate and polyvinylpyrrolidone into a beaker, performing ultrasonic treatment for 5-10min to disperse uniformly, adding oxalic acid, performing ultrasonic reaction for 2-6h, centrifuging, washing and drying to obtain shuttle-type Er-doped cerium oxalate;

(3) placing the shuttle-shaped Er doped cerium oxalate in a tubular furnace, and calcining to obtain the porous shuttle-shaped Er doped CeO₂；

(4) Adding ethylene glycol and reduced graphene oxide into a beaker, performing ultrasonic treatment for 1-3h to disperse uniformly, adding hexadecyl trimethyl ammonium bromide, bismuth nitrate and urea, performing ultrasonic treatment for 30-90min to disperse uniformly, adding potassium bromide, stirring uniformly, placing in a reaction kettle, reacting at 140-180 ℃ for 6-18h, cooling, centrifuging, washing and drying to obtain graphene modified petal-shaped BiOBr;

(5) adding deionized water and porous shuttle-shaped Er-doped CeO into a beaker₂Carrying out ultrasonic dispersion for 2-4h, standing for 4-8h, centrifuging, washing and drying to obtain graphene modified Er doped CeO₂-photocatalytic degradation material of the BiOBr heterojunction.

2. The graphene-modified Er-doped CeO composite material of claim 1₂-a photocatalytic degradation material of a BiOBr heterojunction, characterized in that: the water bath device in the step (1) comprises a main body, wherein a positioning block is movably connected to the left side of the main body, a roller is movably connected to the middle of the positioning block, an arc-shaped clamping plate is movably connected to the rear side of the positioning block, a screw rod is movably connected to the right side of the arc-shaped clamping plate, a nut is movably connected to the top of the screw rod, a heating coil is movably connected to the middle of the main body, a temperature sensor is movably connected to the bottom of the main body, and a.

3. The graphene-modified Er-doped CeO composite material of claim 1₂-a photocatalytic degradation material of a BiOBr heterojunction, characterized in that: in the step (2), the mass ratio of the cerium nitrate to the erbium nitrate to the polyvinylpyrrolidone to the oxalic acid is 100:1-5:160-200: 50-65.

4. The graphene-modified Er-doped CeO composite material of claim 1₂-a photocatalytic degradation material of a BiOBr heterojunction, characterized in that: the calcination process in the step (3) is roasting at the temperature of 350-1-3h。

5. The graphene-modified Er-doped CeO composite material of claim 1₂-a photocatalytic degradation material of a BiOBr heterojunction, characterized in that: in the step (4), the mass ratio of the reduced graphene oxide to the hexadecyl trimethyl ammonium bromide to the bismuth nitrate to the urea to the potassium bromide is 1-6:70-80:100:65-75: 55-65.

6. The graphene-modified Er-doped CeO composite material of claim 1₂-a photocatalytic degradation material of a BiOBr heterojunction, characterized in that: the porous shuttle type Er doped CeO in the step (5)₂And the mass ratio of the graphene modified petal-shaped BiOBr is 10-20: 100.

Technical Field

The invention relates to the technical field of photocatalysis, in particular to graphene modified Er doped CeO₂-photocatalytic degradation material of the BiOBr heterojunction.

Background

The usage amount of antibiotics in China is very large, so that a large amount of wastewater containing antibiotics can be generated every year to cause environmental pollution, a large amount of antibiotics can be detected in water environments with different matrixes, most of the antibiotics have biotoxicity and are difficult to degrade by adopting a biological method, drug-resistant and drug-resistant genes can be generated in the environment, the treatment difficulty of diseases is increased, the health and ecological safety of human beings are seriously threatened, and the tetracycline is very large in usage amount and is widely applied to the medical industry and the breeding industry, so that the chemical property is stable, the toxicity is strong, great influences can be easily generated on human beings and organisms, and the antibiotics must be treated.

At present, common treatment technologies of antibiotics include a biological method, a photocatalytic oxidation method, an adsorption method and the like, wherein the photocatalytic oxidation method has the advantages of utilizing sunlight, thoroughly treating pollutants, recycling materials and the like, and can treat antibiotic wastewater relatively in an environment-friendly manner.

Among numerous photocatalysts, BiOBr has the advantages of proper forbidden band width, capability of being excited by visible light, simple preparation process, good chemical stability and the like, and is widely applied to the aspects of hydrogen production by water photolysis and organic matter photocatalytic degradation and the like, but the photoproduction electron-hole recombination speed of single BiOBr is too high, the quantum efficiency is very low, and the efficiency of organic pollutants such as tetracycline and the like photocatalytic degradation is low, therefore, the graphene modified Er doped with CeO is adopted₂The method of the BiOBr heterojunction overcomes the above drawbacks.

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a graphene modified Er doped CeO₂The material is a photocatalytic degradation material of a BiOBr heterojunction, and solves the problems that the photo-generated electrons and holes of BiOBr photocatalysis are easy to compound and the photocatalytic activity is greatly reduced.

(II) technical scheme

In order to achieve the purpose, the invention provides the following technical scheme: graphene modified Er doped CeO₂-photocatalytic degradation material of BiOBr heterojunction, said graphene modified Er doped CeO₂The preparation method of the photocatalytic degradation material of the BiOBr heterojunction comprises the following steps:

(1) adding deionized water and graphene oxide into a beaker to prepare a colloidal solution, dropwise adding a sodium carbonate aqueous solution, adjusting the pH to 8-10, adding a reducing agent sodium borohydride, wherein the mass ratio of the graphene oxide to the sodium borohydride is 15-25:100, placing the beaker into a water bath device, carrying out heat treatment at 70-90 ℃ for 30-90min, filtering, washing and drying to obtain reduced graphene oxide;

(2) adding deionized water, ethylene glycol, cerium nitrate, erbium nitrate and polyvinylpyrrolidone into a beaker, performing ultrasonic treatment for 5-10min to disperse uniformly, adding oxalic acid, performing continuous ultrasonic treatment for 2-6h to react, centrifuging, washing and drying to obtain shuttle-type Er-doped cerium oxalate;

(3) placing the shuttle-shaped Er doped cerium oxalate in a tubular furnace, and calcining to obtain the porous shuttle-shaped Er doped CeO₂；

(4) Adding ethylene glycol and reduced graphene oxide into a beaker, performing ultrasonic treatment for 1-3h to disperse uniformly, adding hexadecyl trimethyl ammonium bromide, bismuth nitrate and urea, performing ultrasonic treatment for 30-90min to disperse uniformly, adding potassium bromide, stirring uniformly, placing in a reaction kettle, reacting at 140-180 ℃ for 6-18h, cooling, centrifuging, washing and drying to obtain graphene modified petal-shaped BiOBr;

(5) adding deionized water and porous shuttle-shaped Er-doped CeO into a beaker₂Carrying out ultrasonic dispersion for 2-4h, standing for 4-8h, centrifuging, washing and drying to obtain graphene modified Er doped CeO₂-photocatalytic degradation material of the BiOBr heterojunction.

Preferably, the water bath device in the step (1) comprises a main body, wherein a positioning block is movably connected to the left side of the main body, a roller is movably connected to the middle of the positioning block, an arc-shaped clamping plate is movably connected to the rear side of the positioning block, a screw rod is movably connected to the right side of the arc-shaped clamping plate, a nut is movably connected to the top of the screw rod, a heating coil is movably connected to the middle of the main body, a temperature sensor is movably connected to the bottom of the main body, and a control.

Preferably, the mass ratio of the cerium nitrate, the erbium nitrate, the polyvinylpyrrolidone and the oxalic acid in the step (2) is 100:1-5:160-200: 50-65.

Preferably, the calcination process in the step (3) is roasting at 350-450 ℃ for 1-3h in an air atmosphere.

Preferably, the mass ratio of the reduced graphene oxide, the hexadecyl trimethyl ammonium bromide, the bismuth nitrate, the urea and the potassium bromide in the step (4) is 1-6:70-80:100:65-75: 55-65.

Preferably, the porous shuttle-type Er is doped with CeO in the step (5)₂And the mass ratio of the graphene modified petal-shaped BiOBr is 10-20: 100.

(III) advantageous technical effects

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

the graphene modified Er doped CeO₂The photocatalytic degradation material of the BiOBr heterojunction takes sodium borohydride as a reducing agent to obtain reduced graphene oxide, effectively reduces oxygen-containing groups, has no impurity atoms introduced, effectively improves the conductivity, takes cerium nitrate as a cerium source and erbium nitrate as an erbium source, obtains shuttle-shaped Er doped cerium oxalate under the action of polyvinylpyrrolidone and oxalic acid, and the shuttle-shaped Er doped cerium oxalate is calcined to escape lost gaseous water and carbon dioxide to form a large number of pore structures to obtain porous shuttle-shaped Er doped CeO₂The specific surface area is obviously increased, the contact area with sunlight is improved, the photocatalytic efficiency is enhanced, the radius of cerium ions is close to that of erbium ions, the erbium ions replace lattice sites of the cerium ions, oxygen vacancy defects are generated in crystal lattices, the cerium ions can be used as capture traps of photoproduction electrons, the combination of the photoproduction electrons and holes is delayed, and the photocatalytic efficiency is effectively improved.

The graphene modified Er doped CeO₂-photocatalytic degradation material of BiOBr heterojunction, using bismuth nitrate as bismuth source, adding reduced graphene oxide, and performing hydrothermal reaction to obtain graphene-modified petal-shaped BiOBr, wherein the petal-shaped BiOBr is formed by stacking sheets and storingIn a large number of slit-shaped cavities, the surfaces of petals are not smooth, the structure is favorable for infiltration of tetracycline solution, the efficiency of degrading tetracycline by photocatalysis is improved, and the n-type semiconductor Er is doped with CeO₂Forming a p-n heterojunction structure with a p-type semiconductor BiOBr, CeO₂The photo-generated electrons on the conduction band are transferred to the BiOBr conduction band, and the holes on the BiOBr valence band are transferred to CeO with lower potential₂On the valence band, the recombination of photogenerated electrons and holes is effectively inhibited, and the Er is modified to be doped with CeO₂Graphene on the surface of the BiOBr heterojunction can be used as a photo-generated electron capture center of a catalyst, photo-generated electrons are continuously transferred to the graphene, the separation of the photo-generated electrons and holes is accelerated, the recombination of the photo-generated electrons and holes is delayed, holes generated by electron transition, the photo-generated electrons and O in a solution are delayed₂The generated superoxide anions can effectively perform oxidation-reduction reaction with tetracycline to perform a degradation process, so that graphene modified Er doped CeO₂The BiOBr heterojunction has excellent performance of photocatalytic degradation of tetracycline.

Drawings

FIG. 1 is a schematic sectional view of a water bath apparatus from above;

fig. 2 is a schematic view of a screw structure.

1. A main body; 2. positioning blocks; 3. a roller; 4. an arc-shaped splint; 5. a screw; 6. a nut; 7. a heating coil; 8. a temperature sensor; 9. and a control module.

Detailed Description

To achieve the above object, the present invention provides the following embodiments and examples: graphene modified Er doped CeO₂-photocatalytic degradation material of BiOBr heterojunction, said graphene modified Er doped CeO₂The preparation method of the photocatalytic degradation material of the BiOBr heterojunction comprises the following steps:

(1) adding deionized water and graphene oxide into a beaker to prepare a colloidal solution, dropwise adding a sodium carbonate aqueous solution, adjusting the pH to 8-10, adding a reducing agent sodium borohydride, wherein the mass ratio of the graphene oxide to the sodium borohydride is 15-25:100, the beaker is placed in a water bath device, the water bath device comprises a main body, the left side of the main body is movably connected with a positioning block, the middle of the positioning block is movably connected with a rolling shaft, the rear side of the positioning block is movably connected with an arc-shaped clamping plate, the right side of the arc-shaped clamping plate is movably connected with a screw rod, the top of the screw rod is movably connected with a nut, the middle of the main body is movably connected with a heating coil, the bottom of the main body is movably connected with a, carrying out heat treatment at 70-90 ℃ for 30-90min, filtering, washing and drying to obtain reduced graphene oxide;

(2) adding deionized water, ethylene glycol, cerium nitrate, erbium nitrate and polyvinylpyrrolidone into a beaker, performing ultrasonic treatment for 5-10min to uniformly disperse, adding oxalic acid, wherein the mass ratio of the cerium nitrate to the erbium nitrate to the polyvinylpyrrolidone to the oxalic acid is 100:1-5:160 and 200:50-65, continuing the ultrasonic treatment for 2-6h for reaction, centrifuging, washing and drying to obtain shuttle-type Er-doped cerium oxalate;

(3) placing the shuttle-type Er doped cerium oxalate in a tubular furnace for calcination, wherein the calcination process is to calcine the mixture for 1 to 3 hours at the temperature of 350-₂；

(4) Adding ethylene glycol and reduced graphene oxide into a beaker, performing ultrasonic treatment for 1-3 hours to uniformly disperse, then adding hexadecyl trimethyl ammonium bromide, bismuth nitrate and urea, performing ultrasonic treatment for 30-90 minutes to uniformly disperse, then adding potassium bromide, wherein the mass ratio of the reduced graphene oxide to the hexadecyl trimethyl ammonium bromide to the bismuth nitrate to the urea to the potassium bromide is 1-6:70-80:100:65-75:55-65, stirring uniformly, then placing into a reaction kettle, reacting for 6-18 hours at 140-180 ℃, cooling, centrifuging, washing and drying to obtain graphene modified petal-shaped BiOBr;

(5) adding deionized water and porous shuttle-shaped Er-doped CeO into a beaker₂The graphene modified petal-shaped BiOBr is dispersed uniformly by ultrasonic for 2-4h at a mass ratio of 10-20:100, and then is kept stand for 4-8h, centrifuged, washed and dried to obtain the graphene modified Er doped CeO₂-photocatalytic degradation material of the BiOBr heterojunction.