Photocatalyst and preparation method and application thereof
阅读说明：本技术 一种光催化剂及其制备方法和应用 (Photocatalyst and preparation method and application thereof ) 是由 杨应昌 石维 冷森林 于 2020-07-20 设计创作，主要内容包括：本发明涉及环境化工光催化水处理及新能源利用技术领域,具体而言,涉及一种光催化剂及其制备方法和应用。一种Bi<Sub>12</Sub>O<Sub>17</Sub>Br<Sub>2</Sub>光催化剂的制备方法,包括以下步骤：将阴极和阳极置于含有四烷基溴化物的有机溶液中,施加直流电,收集沉淀并进行热处理；所述阴极为金属铋；所述阳极为惰性电极。本发明的Bi<Sub>12</Sub>O<Sub>17</Sub>Br<Sub>2</Sub>光催化剂的制备方法工序简单,无需铋盐前驱体,经济环保。得到的Bi<Sub>12</Sub>O<Sub>17</Sub>Br<Sub>2</Sub>光催化剂对有机污染物的降解表现出了良好的响应能力,对水污染处理和太阳能利用具有重要意义。(The invention relates to the technical field of environmental chemical photocatalytic water treatment and new energy utilization, and particularly relates to a photocatalyst and a preparation method and application thereof. Bi 12 O 17 Br 2 The preparation method of the photocatalyst comprises the following steps: placing the cathode and the anode in an organic solution containing tetraalkyl bromide, applying direct current, collecting the precipitate and performing heat treatment; the cathode is metal bismuth; the anode is an inert electrode. Bi of the present invention 12 O 17 Br 2 The preparation method of the photocatalyst has simple process, does not need a bismuth salt precursor, and is economicalAnd (5) protecting. The obtained Bi 12 O 17 Br 2 The photocatalyst shows good response capability to the degradation of organic pollutants, and has important significance to water pollution treatment and solar energy utilization.)
1. Bi12O17Br2The preparation method of the photocatalyst is characterized by comprising the following steps:
placing the cathode and the anode in an organic solution containing tetraalkyl bromide, applying direct current, collecting the precipitate and performing heat treatment;
the cathode is metal bismuth;
the anode is an inert electrode.
2. The Bi according to claim 112O17Br2The preparation method of the photocatalyst is characterized in that the inert electrode comprises a platinum sheet;
preferably, the shape of the cathode comprises a block or a rod.
3. The Bi according to claim 112O17Br2The preparation method of the photocatalyst is characterized in that the tetraalkyl bromide comprises at least one of tetramethylammonium bromide, tetraethylammonium bromide, tetrabutylammonium bromide and tetraheptylammonium bromide;
preferably, the organic solvent in the organic solution comprises at least one of acetonitrile, N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, propylene carbonate, dimethyl carbonate and diethyl carbonate.
4. The Bi according to claim 112O17Br2The preparation method of the photocatalyst is characterized in that the distance between the cathode and the anode is 1.8-2.2 cm, and preferably 2 cm.
5. The Bi according to claim 112O17Br2The preparation method of the photocatalyst is characterized in that the voltage of the direct current is 6-100V, and the time for applying the direct current is 1.5-2.5 h.
6. The Bi according to claim 112O17Br2The preparation method of the photocatalyst is characterized in that the precipitate is collected by a centrifugal treatment mode;
preferably, the rotating speed of the centrifugation is 4900-5100 r/min, and the time of the centrifugation is 2.5-3.5 min.
7. The Bi according to claim 112O17Br2The preparation method of the photocatalyst is characterized in that the temperature of the heat treatment is 380-410 ℃ and the time is 1.8-2.2 h.
8. The Bi according to any one of claims 1 to 712O17Br2Bi prepared by preparation method of photocatalyst12O17Br2A photocatalyst.
9. A method for degrading organic pollutants, which comprises using the Bi of claim 812O17Br2A photocatalyst.
10. A method of degrading organic pollutants according to claim 9, comprising the steps of:
the Bi is added12O17Br2Carrying out light treatment on the mixed solution of the photocatalyst and the organic pollutants;
preferably, the Bi12O17Br2The dosage of the photocatalyst is 0.5-2 g/L;
preferably, the illumination adopts a xenon lamp;
preferably, the power of the xenon lamp is 450-550W, and the illumination intensity is 110-130 klx;
preferably, the distance between the xenon lamp and the reaction interface is 18-22 cm;
preferably, the wavelength of the illumination is 200-800 nm;
preferably, the Bi12O17Br2The mixed solution of the photocatalyst and the organic pollutants is subjected to light-shielding treatment for 8-12 min before being subjected to light treatment;
preferably, the organic contaminants comprise bisphenol a and/or resorcinol.
Technical Field
The invention relates to the technical field of environmental chemical photocatalytic water treatment and new energy utilization, and particularly relates to a photocatalyst and a preparation method and application thereof.
Background
The photocatalytic degradation of pollutants is a process of degrading pollutants in water into harmless substances completely by utilizing free radicals with extremely strong activity generated in a reaction system by solar radiation and a photocatalyst and through the processes of addition, substitution, electron transfer and the like between the free radicals and organic pollutants. The method directly utilizes green energy solar energy, and is an economical and practical water pollution treatment method. Among them, the performance of the photocatalyst has a decisive role for the treatment capacity of the contaminants. Bismuth has excellent electron energy level and energy level orbital effect, so bismuth-based semiconductor catalyst materials become hot spots in research and application fields.
Bismuth-based catalyst materials reported so far are bismuth oxide, bismuth oxometalate, bismuth oxycarbonate and bismuth oxyhalide. Bi12O17Br2Is a non-integral bismuth oxyhalide, has a very suitable band gap structure (the valence band position is 2.89eV, and the conduction band position is-0.18 eV), and is more suitable for being used as a photocatalyst for degrading pollutants in water bodies.
Preparation of Bi at present12O17Br2The catalyst mainly comprises a hydrothermal reaction method, a bismuth salt hydrolysis method, an alcoholysis method and the like. The hydrothermal decomposition method requires a high-temperature and high-pressure environment and has high requirements on equipment; the bismuth salt hydrolysis method and the alcoholysis method have simple and few processes, but have high requirements on raw materials, harsh preparation conditions and high difficulty in separating and purifying products, so how to find a simple, economic and environment-friendly preparation method for obtaining high-purity Bi12O17Br2The catalyst has important practical significance.
In view of the above, the present invention is particularly proposed.
Disclosure of Invention
An object of the present invention is to provide a Bi12O17Br2The preparation method of the photocatalyst has simple process, does not need a bismuth salt precursor, and is economic and environment-friendly.
Another object of the present invention is to provide the above Bi12O17Br2Bi obtained by preparation method of photocatalyst12O17Br2The photocatalyst has excellent performance of degrading organic pollutants.
Another object of the present invention is to provide a method for degrading organic pollutants using Bi as defined above12O17Br2A photocatalyst. The catalyst shows good response capability to the degradation of organic pollutants, and has important significance to water pollution treatment and solar energy utilization.
In order to achieve the above purpose of the present invention, the following technical solutions are adopted:
bi12O17Br2The preparation method of the photocatalyst comprises the following steps:
placing the cathode and the anode in an organic solution containing tetraalkyl bromide, applying direct current, collecting the precipitate and performing heat treatment;
the cathode is metal bismuth;
the anode is an inert electrode.
Preferably, the inert electrode comprises a platinum sheet;
preferably, the shape of the cathode comprises a block or a rod.
Preferably, the tetraalkylammonium bromide comprises at least one of tetramethylammonium bromide, tetraethylammonium bromide, tetrabutylammonium bromide, and tetraheptylammonium bromide;
preferably, the organic solvent in the organic solution comprises at least one of acetonitrile, N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, propylene carbonate, dimethyl carbonate and diethyl carbonate.
Preferably, the distance between the cathode and the anode is 1.8-2.2 cm, and preferably 2 cm.
Preferably, the voltage of the direct current is 6-100V, and the time for applying the direct current is 1.5-2.5 h.
Preferably, collection by means of centrifugation;
preferably, the rotating speed of the centrifugation is 4900-5100 r/min, and the time of the centrifugation is 2.5-3.5 min.
Preferably, the temperature of the heat treatment is 380-410 ℃, and the time is 1.8-2.2 h.
Bi as described above12O17Br2Bi prepared by preparation method of photocatalyst12O17Br2A photocatalyst.
A method for degrading organic pollutants by adopting the Bi12O17Br2A photocatalyst.
Preferably, the method for degrading organic pollutants comprises the following steps:
the Bi is added12O17Br2Carrying out light treatment on the mixed solution of the photocatalyst and the organic pollutants;
preferably, the Bi12O17Br2The dosage of the photocatalyst is 0.5-2 g/L;
preferably, the illumination adopts a xenon lamp;
preferably, the power of the xenon lamp is 450-550W, and the illumination intensity is 110-130 klx;
preferably, the distance between the xenon lamp and the reaction interface is 18-22 cm;
preferably, the wavelength of the illumination is 200-800 nm;
preferably, the Bi12O17Br2The mixed solution of the photocatalyst and the organic pollutants is subjected to light-shielding treatment for 8-12 min before being subjected to light treatment;
preferably, the organic contaminants comprise bisphenol a and/or resorcinol.
Compared with the prior art, the invention has the beneficial effects that:
(1) bi of the present invention12O17Br2The preparation method of the photocatalyst has simple process, does not need a bismuth salt precursor, and is economic and environment-friendly.
(2) Bi obtained by the present invention12O17Br2The photocatalyst is of a lamellar structure, so that the contact between the catalyst and pollutant molecules can be increased, and the catalysis efficiency is improved.
(3) The method for degrading organic pollutants of the present invention employs the method as described aboveOf Bi12O17Br2A photocatalyst. The degradation of the organic pollutants of the catalyst shows good response capability, and has important significance for water pollution treatment and solar energy utilization.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 shows a photocatalytic material Bi obtained in example 112O17Br2An XRD pattern of (a);
FIG. 2 shows a photocatalytic material Bi obtained in example 112O17Br2A TEM image of (B);
FIG. 3 shows the photocatalytic material Bi obtained in example 212O17Br2A TEM image of (B);
FIG. 4 shows a photocatalytic material Bi obtained in example 312O17Br2A TEM image of (a).
Detailed Description
Embodiments of the present invention will be described in detail below with reference to examples, but it will be understood by those skilled in the art that the following examples are only illustrative of the present invention and should not be construed as limiting the scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.
Bi12O17Br2The preparation method of the photocatalyst comprises the following steps:
placing the cathode and the anode in an organic solution containing tetraalkyl bromide, applying direct current, collecting the precipitate and performing heat treatment;
the cathode is metal bismuth;
the anode is an inert electrode.
Preferably, the inert electrode comprises a platinum sheet;
preferably, the shape of the cathode comprises a block or a rod.
Bi of the present invention12O17Br2The preparation method of the photocatalyst has simple process, does not need a bismuth salt precursor, is economic and environment-friendly, and bismuth nanosheet stripped from the cathode reacts with bromine molecules generated by anodic oxidation to generate Bi12O17Br2Precipitating and heat treating to obtain Bi12O17Br2A photocatalyst.
Preferably, the concentration of the tetraalkyl bromide in the organic solution containing the tetraalkyl bromide is 0.02-2 mol/L.
In one embodiment, the concentration of the tetraalkyl bromide is 0.02 to 2mol/L, and optionally 0.05mol/L, 0.1mol/L, 0.2mol/L, 0.3mol/L, 0.4mol/L, 0.5mol/L, 0.6mol/L, 0.7mol/L, 0.8mol/L, 0.9mol/L, 1mol/L, 1.2mol/L, 1.5mol/L, 1.7mol/L, 1.8mol/L, or 2 mol/L.
Preferably, the tetraalkylammonium bromide comprises at least one of tetramethylammonium bromide, tetraethylammonium bromide, tetrabutylammonium bromide, and tetraheptylammonium bromide.
Preferably, the organic solvent in the organic solution comprises at least one of acetonitrile, N-Dimethylformamide (DMF), dimethyl sulfoxide, N-methylpyrrolidone, propylene carbonate, dimethyl carbonate, and diethyl carbonate.
Preferably, the distance between the cathode and the anode is 1.8-2.2 cm, and preferably 2 cm.
In one embodiment, the distance between the cathode and the anode is 1.8-2.2 cm, and may be 1.9cm, 2cm or 2.1 cm. The bismuth nanosheet stripped from the cathode can react with bromine molecules generated by anodic oxidation to generate Bi more favorably by adopting the bipolar distance in a specific range12O17Br2And (4) precipitating.
Preferably, the voltage of the direct current is 6-100V, and the time for applying the direct current is 1.5-2.5 h.
In one embodiment, the voltage of the direct current is 6-100V, and may be selected from 6V, 10V, 15V, 20V, 25V, 30V, 35V, 40V, 45V, 50V, 55V, 60V, 65V, 70V, 75V, 80V, 85V, 90V, 95V, or 100V.
In one embodiment, the time for applying the direct current is 1.5-2.5 h, and may be selected from 1.6h, 1.7h, 1.8h, 1.9h, 2h and 2.1 h.
According to the invention, the voltage of the direct current is set to be 6-100V, and the time for applying the direct current is 1.5-2.5 h, so that the obtained Bi can be better improved12O17Br2The catalytic ability of the photocatalyst is more beneficial to degrading organic pollutants.
Preferably, collection by means of centrifugation;
preferably, the rotating speed of the centrifugation is 4900-5100 r/min, and the time of the centrifugation is 2.5-3.5 min.
In one embodiment, the rotation speed of the centrifugation is 4900-5100 r/min, and 4900r/min, 4910r/min, 4920r/min, 4930r/min, 4940r/min, 4950r/min, 4960r/min, 4970r/min, 4980r/min, 4990r/min, 5000r/min, 5010r/min, 5020r/min, 5030r/min, 5040r/min, 5050r/min, 5060r/min, 5070r/min, 5080r/min, 5090r/min or 5100r/min can be selected.
In one embodiment, the centrifugation time is 2.5-3.5 min, and may be 2.6min, 2.7min, 2.8min, 2.9min, 3min, 3.1min, 3.2min, 3.3min, 3.4min or 3.5 min.
Preferably, the temperature of the heat treatment is 380-410 ℃, and the time of the heat treatment is 1.8-2.2 h.
The invention limits the heat treatment temperature to 380-410 ℃ and the heat treatment time to 1.8-2.2 h, and is more beneficial to obtaining Bi12O17Br2The photocatalyst can catalyze efficiently and is beneficial to the photodegradation of organic pollutants. Bi which is not favorable to be obtained if the temperature is too high or too low12O17Br2The catalytic performance of the photocatalyst and the degradation effect on organic pollutants.
In one embodiment, the temperature of the heat treatment is 380 to 410 ℃, and 385 ℃, 387 ℃, 390 ℃, 392 ℃, 395 ℃, 397 ℃, 400 ℃, 402 ℃, 405 ℃, 407 ℃ or 410 ℃ can be selected.
In one embodiment, the time of the heat treatment is 1.8 to 2.2 hours, and 1.8 hours, 1.9 hours, 2 hours, 2.1 hours or 2.2 hours can be selected.
Bi as described above12O17Br2Bi prepared by preparation method of photocatalyst12O17Br2A photocatalyst.
Bi obtained by the present invention12O17Br2The photocatalyst has excellent performance of degrading organic pollutants.
A method for degrading organic pollutants by adopting the Bi12O17Br2A photocatalyst.
The method for degrading organic pollutants of the invention adopts Bi as described above12O17Br2A photocatalyst. The degradation of the organic pollutants of the catalyst shows good response capability, and has important significance for water pollution treatment and solar energy utilization.
Preferably, the method for degrading organic pollutants comprises the following steps:
the Bi is added12O17Br2And carrying out light treatment on the mixed solution of the photocatalyst and the organic pollutants.
Preferably, the Bi12O17Br2The dosage of the photocatalyst is 0.5-2 g/L;
in one embodiment, the Bi12O17Br2The amount of the photocatalyst is 0.5-2 g/L, and 0.5g/L, 0.6g/L, 0.7g/L, 1g/L, 1.2g/L, 1.4g/L, 1.5g/L, 1.6g/L, 1.8g/L or 2g/L can be selected.
Preferably, the illumination adopts a xenon lamp;
preferably, the power of the xenon lamp is 450-550W, and the illumination intensity is 110-130 klx;
in one embodiment, the power of the xenon lamp is 450-550W, and 450W, 455W, 460W, 465W, 470W, 475W, 480W, 485W, 490W, 495W, 500W, 505W, 510W, 515W, 520W, 525W, 530W, 535W, 540W, 545W or 550W can be selected.
In one embodiment, the illuminance is 110 to 130klx, and 111klx, 112klx, 113klx, 114klx, 115klx, 116klx, 117klx, 118klx, 119klx, 120klx, 121klx, 122klx, 123klx, 124klx, 125klx, 126klx, 127klx, 128klx, 129klx or 130klx may be selected.
Preferably, the distance between the xenon lamp and the reaction interface is 18-22 cm.
The distance between the xenon lamp and the reaction interface refers to the distance between the photocatalytic light source and the catalyzed organic matter solution.
In one embodiment, the distance between the xenon lamp and the reaction interface is 18-22 cm, and 18cm, 19cm, 20cm, 21cm or 22cm can be selected.
Preferably, the wavelength of the illumination is 200-800 nm.
In one embodiment, the wavelength of the illumination is 200 to 800nm, and may be 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, 550nm, 600nm, 650nm, 700nm, 750nm or 800 nm.
Preferably, the Bi12O17Br2And (3) carrying out light-shielding treatment for 8-12 min before carrying out illumination treatment on the mixed solution of the photocatalyst and the organic pollutants.
In one embodiment, the Bi12O17Br2And (3) carrying out light-shielding treatment on the mixed liquid of the photocatalyst and the organic pollutants for 8-12 min before carrying out illumination treatment, and optionally carrying out light-shielding treatment for 8.5min, 9min, 9.5min, 10min, 10.5min, 11min, 11.5min or 12 min.
Preferably, the organic contaminants comprise bisphenol a and/or resorcinol.
The invention will be further explained with reference to specific examples.