CN112481643B - Lead tetroxide catalyst with different morphologies as well as preparation method and application thereof - Google Patents
Lead tetroxide catalyst with different morphologies as well as preparation method and application thereof Download PDFInfo
- Publication number
- CN112481643B CN112481643B CN202011354756.8A CN202011354756A CN112481643B CN 112481643 B CN112481643 B CN 112481643B CN 202011354756 A CN202011354756 A CN 202011354756A CN 112481643 B CN112481643 B CN 112481643B
- Authority
- CN
- China
- Prior art keywords
- lead
- catalyst
- reaction
- temperature
- ozone
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B1/00—Electrolytic production of inorganic compounds or non-metals
- C25B1/01—Products
- C25B1/13—Ozone
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G21/00—Compounds of lead
- C01G21/02—Oxides
- C01G21/10—Red lead (Pb3O4)
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
Abstract
The invention discloses a lead tetroxide catalyst with different morphologies as well as a preparation method and application thereof, wherein the preparation process of the catalyst comprises the following steps: preparing a lead salt aqueous solution, adding inorganic base into the lead salt aqueous solution, adding a sodium hypochlorite solution after ultrasonic stirring uniformly to generate a brownish red turbid substance, and stirring to uniformly disperse the turbid substance to form a turbid liquid. And carrying out hydrothermal reaction on the obtained suspension at the temperature of 90-150 ℃ for 20-50 hours, cooling to room temperature after the reaction is finished, filtering, cleaning, carrying out suction filtration, placing the obtained product in a vacuum drying oven, drying at the temperature of 60-80 ℃ for 20-24 hours, and finally roasting and activating in a tubular furnace to obtain the lead tetroxide catalyst with different morphologies. The lead tetroxide catalyst prepared by the invention has the advantages of low cost and simple process, is applied to the reaction of preparing ozone by low-pressure electrolyzed water, and has high catalytic activity and stability.
Description
Technical Field
The invention belongs to the technical field of electrocatalysis, and relates to a lead tetroxide catalyst with different morphologies, a preparation method and an application thereof.
Background
Ozone is an allotrope of oxygen, has strong oxidizing power, and can be used as a strong oxidant and a disinfectant. Because the ozone can not leave secondary pollution, and the residual ozone can be decomposed into oxygen in a short time, the ozone-containing ozone can be widely applied to the fields of sterilization and disinfection, sewage treatment, air dust removal, bleaching and decoloring, food industry, microelectronic industry and the like, and has very wide application prospect.
At present, a plurality of methods for synthesizing ozone exist, and a low-voltage electrolysis method, a corona discharge method, an ultraviolet irradiation method and a radiochemical method are main ways for artificially producing ozone. The radiochemical method for generating ozone has the advantages of cheap and easily available raw materials, high utilization rate and high concentration of generated ozone, but the method has low safety and high cost of radioactive sources, and cannot meet the requirement of industrial mass production. Currently, radiochemical methods have been largely eliminated. The ultraviolet radiation method is that air or oxygen generates ozone under the ultraviolet radiation, and the method has the advantages of low ozone yield, complex structure and difficult control of wavelength, and is not suitable for large-scale preparation of ozone. The corona discharge method uses dried oxygen or air as raw material, and comprises two electrodes and a dielectric body with a certain distance, wherein a voltage of 5000-. The method has the advantages of high voltage, low concentration of generated ozone, huge scale production equipment, inconvenient movement and complex operation, and more importantly, a large amount of nitrogen oxides are generated in the process of generating ozone, thus causing harm to the environment and human bodies.
To this end, researchers have proposed methods of generating ozone using low-pressure electrolysis. In the low-pressure electrolysis method, ozone is generated by electrolysis of water. The low-voltage electrolysis method for generating ozone has low requirement on equipment, simple equipment, convenient movement, contribution to on-site preparation in different places, low investment cost, higher concentration, environmental protection and no pollution. In the process of preparing ozone by an electrolytic method, the anode generates ozone and oxygen, the cathode generates hydrogen, and the selection of anode materials with high overpotential can better inhibit the oxygen from being separated out on the anode, thereby improving the current efficiency of generating ozone. Therefore, the research of the electrochemical method for preparing ozone at home and abroad mainly focuses on the selection of anode materials, namely Pt, Au and PbO2And the like have been used for anode materials for low-pressure electrochemical processes for producing ozone. In commercial products, lead dioxide with high oxygen evolution potential and low price is generally selected as an anode material. And whether low-valent lead oxide such as lead tetraoxide has excellent performance of preparing ozone by electrolyzing water is not reported, so that the preparation of lead tetraoxide with different shapes and the application of the lead tetraoxide in a low-voltage electrolysis ozone generator are worthy of research.
Disclosure of Invention
Aiming at the technical problems in the prior art, the invention aims to provide a lead tetroxide catalyst with different morphologies as well as a preparation method and application thereof. The preparation method of the lead tetroxide catalyst with different shapes is simple, the lead tetroxide with different shapes can be prepared by controlling the using amount of sodium hypochlorite, the hydrothermal temperature and time and the roasting treatment conditions, and the lead tetroxide with different shapes obtained by the invention is used as the catalyst in the reaction of preparing ozone by electrolyzing water, and has higher catalytic activity and stability.
The preparation method of the lead tetroxide catalyst with different morphologies is characterized by comprising the following steps:
1) dissolving lead salt in deionized water, adding inorganic base to adjust the pH value to 12-14, and performing ultrasonic dispersion uniformly to obtain a precursor solution;
2) adding a sodium hypochlorite solution into the precursor solution obtained in the step 1), generating a brownish red turbid substance in the mixed solution, and stirring for 1-3 minutes to uniformly disperse the brownish red turbid substance to obtain a turbid liquid;
3) transferring the suspension obtained in the step 2) into a polytetrafluoroethylene lining, carrying out hydrothermal reaction at the temperature of 90-150 ℃ for 20-50 hours, cooling to room temperature after the reaction is finished, and filtering to obtain a crude product precipitate; washing the obtained crude product precipitate with anhydrous ethanol and deionized water for 3-5 times respectively, vacuum filtering, and drying the filter residue in a vacuum drying oven at 60-80 deg.C for 20-24 hr;
4) grinding the dried solid obtained in the step 3), placing the ground solid in a porcelain boat, placing the porcelain boat in a tubular furnace for roasting, heating the porcelain boat to a roasting temperature of 250-450 ℃ in the environment of high-purity gas, keeping the roasting temperature for 3-10h, and cooling the porcelain boat to room temperature, wherein the heating rate is controlled to be 1-5 ℃/min, so as to obtain the lead tetroxide catalyst.
The preparation method of the lead tetroxide catalyst with different morphologies is characterized in that in the step 1), the lead salt is lead acetate, lead nitrate, lead chloride or lead bromide; the inorganic base is sodium hydroxide, potassium hydroxide, lithium hydroxide or ammonia water.
The preparation method of the lead tetroxide catalyst with different morphologies is characterized in that in the step 2), the effective chlorine concentration of the sodium hypochlorite solution is 2% -10%; the molar ratio of the available chlorine to the lead salt in the sodium hypochlorite solution is 1: 1-6: 1, preferably 2: 1.
The preparation method of the lead tetroxide catalyst with different morphologies is characterized in that the hydrothermal reaction temperature in the step 3) is 100-140 ℃, and the reaction time is 24-48 hours.
The preparation method of the lead tetroxide catalyst with different morphologies is characterized in that the roasting temperature in the step 4) is 280-450 ℃, and the holding time at the roasting temperature is 4-8 hours.
The preparation method of the lead tetroxide catalyst with different morphologies is characterized in that in the step 4), the high-purity gas is hydrogen or nitrogen with the purity of more than 99%.
The lead tetroxide catalyst with different shapes is prepared by the method.
The lead tetroxide catalyst with different morphologies is applied to the reaction of preparing ozone by electrocatalytic decomposition of water.
The application of the lead tetroxide catalyst with different shapes in the reaction of preparing ozone by electrocatalytic decomposition of water is characterized in that a solid polymer electrolyte ozone generator is adopted as a reactor; the lead tetroxide catalyst is used as an anode material, the platinum-carbon catalyst with 5-10% of platinum content is used as a cathode material, the anode material and the cathode material are respectively coated on an anode surface and a cathode surface of a proton exchange membrane, a cathode chamber and an anode chamber of the reactor are separated by the proton exchange membrane, deionized water is used as electrolyte, the current is 5A-20A, the cell voltage is 3V-5V, and the electrolytic reaction is carried out at the temperature of 20-50 ℃ to prepare the ozone product.
The application of the lead tetroxide catalyst with different morphologies in the reaction of preparing ozone by electrocatalytic decomposition of water is that the proton exchange membrane is NafionN117, NafionN115, NafionD520, NafionNRE211, NafionNRE212 or NafionHP, preferably NafionHP or NafionD 520.
By adopting the technology, compared with the prior art, the invention has the following beneficial effects:
1) the invention synthesizes the lead tetroxide catalyst with different shapes by a simple method, and the shape of the finally prepared lead tetroxide catalyst is different along with the rise of the hydrothermal reaction temperature in the preparation process of the catalyst. Referring to the content of the embodiment of the invention, the shape of the lead tetraoxide generated by the reaction at 100 ℃ is cube; the lead tetraoxide generated by the reaction at 110 ℃ is in a cube structure; when the temperature is raised to 120 ℃, the overall appearance of the lead tetraoxide generated by the reaction is cuboid, and the length-width ratio is about 2: 1; lead tetraoxide generated at 130 ℃ is in a uniform cube shape; the catalyst appeared to be cuboid with an aspect ratio of about 5:2 as the reaction temperature increased to 140 ℃; in the preparation process of the lead tetroxide catalyst, the effect of regulating the morphology of catalyst particles is achieved by regulating and controlling the temperature, time and roasting condition of hydrothermal reaction;
2) the method is characterized in that the lead tetroxide prepared by the method is compared with commercial lead tetroxide and commercial lead dioxide catalysts for electrolyzing water to prepare ozone under different conditions, the catalytic performance of the lead tetroxide catalyst is superior to that of the commercial lead tetroxide, the lead tetroxide catalyst with different shapes is superior to that of the commercial lead dioxide in the reaction of preparing ozone by catalyzing electrolyzed water, the stability of the catalyst is superior to that of the commercial lead dioxide, and the catalytic activity is not obviously reduced after long-time electrifying work;
3) the electrocatalysis process uses deionized water as electrolyte, so the cost is lower, the electrolysis process is green and pollution-free, the control is easy, and the method is suitable for popularization and application.
Drawings
FIG. 1a is a schematic view of a transmission electron microscope of a rectangular parallelepiped-shaped lead tetraoxide obtained in example 1 at 1 μm;
FIG. 1b is a scanning electron microscope depiction of the lead tetraoxide obtained in example 1 at 2 μm;
FIG. 2a is a schematic transmission electron microscope of a lead tetraoxide in a tetragonal form at 1 μm obtained in example 2;
FIG. 2b is a scanning electron microscope representation of the particulate lead tetroxide obtained in example 2 at 20 μm;
FIG. 3a is a schematic transmission sub-microscope view at 1 μm of a lead tetraoxide cube obtained in example 3;
FIG. 3b is a scanning electron microscope representation of the lead tetraoxide obtained in example 3 at 5 μm;
FIG. 4a is a schematic transmission electron microscope of a lead tetraoxide in the form of a cube obtained in example 4 at 1 μm;
FIG. 4b is a scanning electron microscope depiction of the lead tetraoxide obtained in example 4 at 5 μm;
FIG. 5a is a schematic view of a transmission electron microscope of a rectangular parallelepiped-shaped lead tetraoxide obtained in example 5 at 1 μm;
FIG. 5b is a schematic transmission electron microscope of lead tetraoxide obtained in example 5 at 10 μm;
FIG. 6 shows the lead tetraoxide catalyst (120 ℃ C. -Pb) obtained in example 13O4) The XRD results of (a) are compared to the standard cards.
FIG. 7 is a graph showing the results of long-term reactions in the production of ozone by electrolyzing water using the lead tetraoxide catalyst and commercial lead dioxide obtained in example 1.
FIG. 8 is a graph showing the reaction performance of the lead tetraoxide catalyst obtained in example 1 and the reaction performance of the commercial lead tetraoxide catalyst for producing ozone by electrolyzing water, respectively.
Detailed Description
The present invention is further illustrated by the following examples, which should not be construed as limiting the scope of the invention.
Example 1: the preparation method of the cuboid-shaped lead tetraoxide catalyst comprises the following steps:
1) adding 1.0g of lead acetate and 20mL of deionized water into a beaker, performing ultrasonic treatment for 5 minutes, and stirring to form a uniform solution;
2) adding 0.8g of sodium hydroxide solid into the uniform solution obtained in the step 1), adjusting the pH value to 13, carrying out ultrasonic treatment for 5 minutes, and continuously stirring to obtain a uniform precursor solution;
3) adding 12 mL of sodium hypochlorite solution (with the effective chlorine content of 5%) into the precursor solution obtained in the step 2) to generate a brownish red turbid substance, and stirring for 3 minutes to uniformly disperse the brownish red turbid substance to obtain a turbid liquid;
4) transferring the suspension obtained in the step 3) into a polytetrafluoroethylene lining, carrying out hydrothermal reaction at 120 ℃ for 36 hours, cooling to room temperature after the reaction is finished, and filtering to obtain a crude product precipitate;
5) washing the crude product precipitate obtained in the step 4) with absolute ethyl alcohol and deionized water for 4 times respectively, performing suction filtration, and drying filter residues in a vacuum drying oven at the temperature of 60 ℃ for 20 hours;
6) placing the dried product obtained in the step 5) in a porcelain boat, introducing high-purity nitrogen at normal temperature, and keeping for 30 min. Setting the heating rate to be 2 ℃/min, heating to 300 ℃, keeping for 6 hours, keeping continuously introducing nitrogen, naturally cooling to room temperature after roasting is finished, taking out a sample, and grinding to obtain the lead tetroxide catalyst.
The XRD test shows that the catalyst obtained in example 1 is lead tetraoxide, and the XRD test result is shown in fig. 6. As shown in FIGS. 1a and 1b, respectively, a schematic diagram of a transmission electron microscope and a schematic diagram of a Scanning Electron Microscope (SEM) of 2 μm at 1 μm of the catalyst show that the lead tetraoxide catalyst particles are rectangular parallelepiped and have an aspect ratio of about 2:1 as seen in FIGS. 1a and 1 b.
The lead tetroxide catalyst of example 1 was applied to the ozone production experiment by electrolysis of water:
firstly, preparing a membrane electrode material, namely respectively coating the anode surface and the cathode surface of a Nafion HP membrane with the lead oxide catalyst prepared in the example 1 as an anode material and the platinum-carbon catalyst with the platinum content of 10% as a cathode material, wherein the preparation process comprises the following steps:
preparing a membrane electrode cathode: 400mg of a 10% commercial platinum-carbon catalyst (platinum loading of 10 wt%) and 200mg of a 5wt% Nafion solution were dispersed in 10ml of ethanol, and the cathode material was evaporated to a viscous state by heating in an oil bath to obtain a cathode material slurry, which was coated on the cathode surface of a Nafion HP membrane.
Preparing a membrane electrode anode: 500mg of the lead tetraoxide catalyst prepared in example 1 and 500mg of a 5wt% Nafion solution were dispersed in 20ml of ethanol, and the anode material was evaporated to a viscous state by oil bath heating to obtain anode material slurry, which was coated on the anode surface of a Nafion HP membrane.
Hot pressing treatment: and respectively coating the cathode and anode materials on two sides of the Nafion HP membrane, setting the hot pressing temperature to be 150 ℃, and carrying out hot pressing treatment to enable the cathode and anode materials to be respectively and tightly adhered to two sides of the Nafion HP membrane, so that the membrane electrode is prepared.
A Solid Polymer Electrolyte (SPE) ozone generator was used, the volume of the electrolysis chamber was 3L (the volume of the cathode chamber and the anode chamber was 1.5L each), deionized water was added to the electrolysis chamber, and the cathode chamber and the anode chamber were separated by a proton exchange membrane Nafion HP membrane prepared as described above. The current of the electrolysis reaction is 5A, the cell voltage is 3.5V, and the electrolysis reaction is carried out at the temperature of 25 ℃. Electrolytically synthesized O3Through the anode gas outlet and ozone detectionConnector connection, O3The concentration can be detected immediately. After the electrolytic reaction time is 48 hours, the O is detected by an ozone detector3The volume mass concentration is 162.84 g/m3。
In order to verify the catalytic stability of the nano-lead tetroxide catalyst prepared in example 1, the above ozone generator was operated for 200 hours, and the results are shown in fig. 7. As can be seen from FIG. 7, the ozone concentration was substantially stable after 72 hours of reaction, and there was no significant decrease in ozone concentration with time within 200 hours. The lead tetroxide catalyst is proved to have better stability.
Comparative example 1 commercial lead dioxide of over 97% purity available from mcelin reagent net was applied to an electrolyzed water ozone production experiment:
first, a membrane electrode material was prepared, and the commercial lead dioxide of comparative example 1 and a platinum-carbon catalyst having a platinum content of 10% were coated on both sides of a Nafion HP membrane as an anode material and a cathode material, respectively.
Preparation of membrane electrode material of comparative example 1 was repeated except that: the catalyst of example 1 was replaced with an equal mass of commercial lead dioxide of comparative example 1, and the remaining preparation process of the membrane electrode material was the same as in example 1.
A Solid Polymer Electrolyte (SPE) ozone generator was used, the volume of the electrolysis chamber was 3L (the volume of the cathode chamber and the anode chamber was 1.5L each), deionized water was added to the electrolysis chamber, and the cathode chamber and the anode chamber were separated by a proton exchange membrane Nafion HP membrane prepared as described above. The current of the electrolysis reaction was 5A, the cell voltage was 3.4V, and the electrolysis experiment was carried out at a temperature of 25 ℃. Electrolytically synthesized O3Connected to an ozone detector to detect O3And (4) concentration.
In order to verify the catalytic stability of the nano-lead tetroxide catalyst prepared in comparative example 1, the above ozone generator was operated for 200 hours, and the results are shown in fig. 7. As can be seen from FIG. 7, after 36 hours of reaction, the ozone concentration reached the maximum and then decreased all the way down. The commercial lead dioxide catalyst proved to be less stable.
By comparing the reaction stability of lead tetraoxide with commercial lead dioxide in example 1, it is presumed that since the lead dioxide has a higher valence relative to lead tetraoxide, it is easily reduced in the electrolytic water reaction system to cause a decrease in valence, and the performance during the reaction is unstable.
Comparative example 2 commercial lead tetroxide with a purity of 98% or more, available from jiding chemical network, was applied to an experiment for preparing ozone by electrolyzing water:
the lead tetroxide catalyst prepared in example 1 and commercial lead tetroxide were used to prepare catalyst slurries, respectively, as follows: weighing 8 mg of catalyst, adding 900 mu L of ethanol, and carrying out ultrasonic treatment for 0.5 hour to completely disperse the catalyst in the ethanol, thereby obtaining uniform catalyst slurry. Cutting the carbon cloth with the specification of 2 cm multiplied by 2 cm, uniformly dripping the dispersed catalyst slurry on the carbon cloth, and drying to be used as a working electrode.
The working electrodes were fabricated and formed according to the above-described method for the lead tetroxide catalyst prepared in example 1 and the commercial lead tetroxide, respectively, and the electrocatalytic properties thereof were verified according to the following experiments, respectively:
the voltage and current are controlled by a constant current instrument, and an H-shaped electrolytic bath is adopted for reaction. In the anode chamber, a working electrode is used; in the cathode chamber, a platinum sheet is used as a counter electrode, and the electrolyte is saturated potassium sulfate aqueous solution. One end of the H-shaped electrolytic cell is connected with an ozone detector to detect the generation condition of ozone in real time. When the electro-catalysis is used for preparing ozone, the current is controlled to be 200mA, the cell voltage is controlled to be 2-10V, and the reaction time is 3.5 hours. The concentration of ozone produced by the electrocatalytic reaction as the reaction proceeded is shown in figure 8. As can be seen from fig. 8, as the reaction proceeded, the ozone concentration gradually increased, and the ozone concentration at the working electrode fabricated using the catalyst of example 1 reached 6700 ppb; the concentration of ozone correspondingly generated by the commercial lead tetroxide can reach 5500 ppb, which proves that the catalytic activity of the lead tetroxide catalyst prepared in example 1 is superior to that of the commercial lead tetroxide.
By comparing the reactivity of the catalyst of example 1 with commercial lead tetroxide, it is hypothesized that the specific crystal face of the lead tetroxide with specific morphology prepared in example 1 is directionally exposed, thereby having a good influence on the ozone generation performance.
Example 2: the preparation method of the cube-shaped lead tetroxide catalyst comprises the following steps:
1) adding 1.5g of lead chloride and 20mL of deionized water into a beaker, performing ultrasonic treatment for 5 minutes, and stirring to form a uniform solution;
2) adding 0.4 g of potassium hydroxide into the solution obtained in the step 1) to adjust the pH value to 12, and stirring after carrying out ultrasonic treatment for 3 minutes to obtain a precursor solution;
3) adding 10mL of sodium hypochlorite solution (the effective chlorine concentration is 5%) into the precursor solution obtained in the step 2) to generate a brownish red turbid substance, and stirring for 3 minutes to uniformly disperse the brownish red turbid substance to obtain a turbid liquid;
4) transferring the suspension obtained in the step 3) into a polytetrafluoroethylene lining, carrying out hydrothermal reaction at 100 ℃ for 24 hours, cooling to room temperature after the reaction is finished, and filtering to obtain a crude product;
5) washing the crude product obtained in the step 4) with absolute ethyl alcohol and deionized water for 4 times respectively, performing suction filtration, and drying filter residues in a vacuum drying oven at the temperature of 60 ℃ for 20 hours;
6) placing the dried product obtained in the step 5) in a porcelain boat, introducing high-purity hydrogen at normal temperature, and keeping for 30 min. Setting the heating rate to be 3 ℃/min, heating to 350 ℃, keeping for 8 hours, keeping continuously introducing hydrogen, naturally cooling to room temperature after roasting is finished, taking out a sample, and grinding to obtain the lead tetroxide catalyst.
The schematic drawing of a transmission electron microscope and the schematic drawing of a 20 μm scanning electron microscope at 1 μm of the lead tetraoxide catalyst obtained in example 2 are shown in fig. 2a and 2b, respectively, and it can be seen from fig. 2a and 2b that the lead tetraoxide catalyst particles are in a cube shape.
The lead tetroxide catalyst of example 2 was used in an experiment for electrolysis of water to produce ozone:
first, a membrane electrode material was prepared, and the trilead tetroxide catalyst prepared in example 2 was used as an anode material, and a platinum carbon catalyst having a platinum content of 5% was used as a cathode material to be coated on both sides of a NafionD520 membrane, respectively.
Procedure for preparation of membrane electrode material of example 2 example 1 was repeated except that: the NafionHP membrane was replaced with NafionD520 membrane, the catalyst of example 1 added was replaced with the same mass of catalyst prepared in example 2, and the commercial platinum-on-carbon catalyst of example 1 with a platinum content of 10% was replaced with
The remaining preparation procedure for the membrane electrode material was the same as in example 1 with the same mass of a commercial platinum carbon catalyst having a platinum content of 5%.
A Solid Polymer Electrolyte (SPE) ozone generator was used, the volume of the electrolysis chamber was 3L (the volume of the cathode chamber and the anode chamber was 1.5L each), deionized water was added to the electrolysis chamber, and the cathode chamber and the anode chamber were separated by a proton exchange membrane Nafion D520 membrane prepared as described above. The current of the electrolysis reaction was 10A, the cell voltage was 3.8V, and the electrolysis experiment was carried out at a temperature of 25 ℃. Electrolytically synthesized O3Connected with an ozone detector to detect O3The concentration and the electrolytic reaction time are 48 hours, and then O is detected by an ozone detector3The volume mass concentration is 138.51 g/m3。
Example 3: the preparation method of the cube-shaped lead tetroxide catalyst comprises the following steps:
1) adding 1.5g of lead nitrate and 20mL of deionized water into a beaker, performing ultrasonic treatment for 5 minutes, and stirring to form a uniform solution;
2) adding 30mL of ammonia water (with the concentration of 28% -30%) into the solution obtained in the step 1), adjusting the pH value to 12, and carrying out ultrasonic stirring for 3 minutes to obtain a precursor solution;
3) adding 8mL of sodium hypochlorite solution (the effective chlorine concentration is 5%) into the precursor solution obtained in the step 2) to generate a brownish red turbid substance, and stirring for 3 minutes to uniformly disperse the brownish red turbid substance to obtain a turbid liquid;
4) transferring the suspension obtained in the step 3) into a polytetrafluoroethylene tank, carrying out hydrothermal reaction at the temperature of 110 ℃ for 48 hours, cooling to room temperature after the reaction is finished, and filtering to obtain a crude product precipitate;
5) washing the crude product precipitate obtained in the step 4) with absolute ethyl alcohol and deionized water for 4 times respectively, performing suction filtration, and drying filter residues in a vacuum drying oven at the temperature of 60 ℃ for 20 hours;
6) placing the dried product obtained in the step 5) in a porcelain boat, introducing high-purity nitrogen at normal temperature, and keeping for 30 min. Setting the heating rate to be 4 ℃/min, heating to 400 ℃ for 4 hours, keeping continuously introducing nitrogen, naturally cooling to room temperature after roasting is finished, taking out a sample, and grinding to obtain the lead tetroxide catalyst.
The schematic diagrams of a transmission electron microscope and a scanning electron microscope at 1 μm and 5 μm of the tetragonal lead tetroxide catalyst obtained in example 3 are shown in fig. 3a and 3b, respectively, and it can be seen from fig. 3a and 3b that the tetragonal lead tetroxide catalyst is tetragonal.
The application of the lead tetraoxide catalyst of example 3 to the ozone preparation experiment with electrolyzed water:
first, a membrane electrode material was prepared by coating each of both sides of a NafionHP membrane with the lead tetraoxide catalyst prepared in example 3 as an anode material and a platinum-carbon catalyst having a platinum content of 10% as a cathode material.
Preparation of membrane electrode material for example 3 example 1 was repeated except that: the catalyst of example 1 was replaced with the same quality of the catalyst prepared in example 3, and the remaining preparation process of the membrane electrode material was the same as in example 1.
A Solid Polymer Electrolyte (SPE) ozone generator is adopted, the volume of an electrolytic chamber is 3L (the volume of a cathode chamber and the volume of an anode chamber are respectively 1.5L), deionized water is added into the electrolytic chamber, and the cathode chamber and the anode chamber are separated by a proton exchange membrane NafionHP membrane. The current of the electrolytic reaction is 15A, the cell voltage is 3.7V, and the electrolytic experiment is carried out at the temperature of 25 ℃. Electrolytic synthesis of O3In the process, the anode gas outlet is connected with an ozone detector to detect O3The concentration and the electrolytic reaction time are 48 hours, and then O is detected by an ozone detector3The volume mass concentration is 132.11 g/m3。
Example 4: the preparation method of the cube-shaped lead tetroxide catalyst comprises the following steps:
1) adding 1.5g of lead chloride and 20mL of deionized water into a beaker, performing ultrasonic treatment for 5 minutes, and stirring to form a uniform solution;
2) adding 0.8g of lithium hydroxide into the solution obtained in the step 1) to adjust the pH value to 12, carrying out ultrasonic treatment for 3 minutes, and stirring to obtain a precursor solution;
3) adding 10mL of sodium hypochlorite solution (the effective chlorine concentration is 5%) into the precursor solution obtained in the step 2) to generate a brownish red turbid substance, and stirring for 3 minutes to uniformly disperse the brownish red turbid substance to obtain a turbid liquid;
4) transferring the suspension obtained in the step 3) into a polytetrafluoroethylene lining, carrying out hydrothermal reaction at the temperature of 130 ℃ for 36 hours, cooling to room temperature after the reaction is finished, and filtering to obtain a crude product precipitate;
5) washing the crude product precipitate obtained in the step 4) with absolute ethyl alcohol and deionized water for 4 times respectively, performing suction filtration, and drying filter residues in a vacuum drying oven at the temperature of 60 ℃ for 20 hours;
6) placing the dried product obtained in the step 5) in a porcelain boat, introducing high-purity hydrogen at normal temperature, and keeping for 30 min. Setting the heating rate to be 1 ℃/min, heating to 300 ℃, keeping for 6 hours, keeping continuously introducing nitrogen, naturally cooling to room temperature after roasting is finished, taking out a sample, and grinding to obtain the lead tetroxide catalyst.
The schematic diagrams of a transmission electron microscope and a scanning electron microscope at 1 μm and 5 μm of the tetragonal lead tetroxide catalyst obtained in example 4 are shown in fig. 4a and 4b, respectively, and it can be seen from fig. 4a and 4b that the tetragonal lead tetroxide catalyst is tetragonal.
The granular tetragonal lead tetroxide catalyst of example 4 was used in the ozone production experiment by electrolyzing water:
first, a membrane electrode material was prepared by coating each of both sides of a NafionD520 membrane with the lead tetroxide catalyst prepared in example 4 as an anode catalyst and a platinum-carbon catalyst having a platinum content of 5% as a cathode material.
Example 4 membrane electrode material preparation procedure example 2 was repeated except that: the catalyst of example 2 was replaced with the same quality of the catalyst prepared in example 4, and the remaining preparation process of the membrane electrode material was the same as in example 2.
Using a Solid Polymer Electrolyte (SPE) ozone generator, the volume of the electrolysis chamber was 3L (of cathode and anode chambers)Volumes were each 1.5L), deionized water was charged into the electrolytic chamber, and the cathode chamber and the anode chamber were separated by a proton exchange membrane Nafion D520 membrane prepared as described above. The current of the electrolysis reaction was 15A, the cell voltage was 3.6V, and the electrolysis experiment was carried out at a temperature of 25 ℃. Electrolytic synthesis of O3In the process, the anode gas outlet is connected with an ozone detector to detect O3The concentration and the electrolytic reaction time are 48 hours, and then O is detected by an ozone detector3The volume mass concentration is 131.85 g/m3。
Example 5: the preparation method of the cuboid plumbous tetroxide catalyst comprises the following steps:
1) adding 1.3g of lead bromide and 20mL of deionized water into a beaker, performing ultrasonic treatment for 5 minutes, and stirring to form a uniform solution;
2) adding 0.6g of sodium hydroxide into the solution obtained in the step 1) to adjust the pH value to 14, and carrying out ultrasonic stirring for 3 minutes to obtain a precursor solution;
3) adding 10mL of sodium hypochlorite solution (the effective chlorine concentration is 5%) into the precursor solution obtained in the step 2) to generate a brownish red turbid substance, and stirring for 3 minutes to uniformly disperse the brownish red turbid substance to obtain a turbid liquid;
4) transferring the suspension obtained in the step 3) into a polytetrafluoroethylene lining, carrying out hydrothermal reaction at the temperature of 140 ℃ for 24 hours, cooling to room temperature after the reaction is finished, and filtering to obtain a crude product precipitate;
5) washing the cuboid lead tetraoxide precipitate obtained in the step 4) with absolute ethyl alcohol and deionized water for 4 times respectively, performing suction filtration, and drying filter residues in a vacuum drying oven at the temperature of 60 ℃ for 20 hours;
6) placing the dried product obtained in the step 5) in a porcelain boat, introducing high-purity hydrogen at normal temperature, and keeping for 30 min. Setting the heating rate to be 2 ℃/min, heating to 400 ℃ for 6 hours, keeping continuously introducing hydrogen, naturally cooling to room temperature after roasting is finished, taking out a sample, and grinding to obtain the lead tetroxide catalyst.
The schematic drawing of the lead tetroxide catalyst obtained in example 5 under a transmission electron microscope at 1 μm and a scanning electron microscope at 10 μm is shown in fig. 5a and 5b, respectively, and it can be seen from fig. 5a and 5b that the lead tetroxide catalyst has a rectangular parallelepiped shape with an aspect ratio of about 5: 2.
The cuboid plumbous tetraoxide catalyst of example 5 was applied to an experiment for preparing ozone by electrolyzing water:
first, a membrane electrode material was prepared by coating each of both sides of a NafionD520 membrane with the lead tetroxide catalyst prepared in example 5 as an anode material and a platinum-carbon catalyst having a platinum content of 10% as a cathode material.
Preparation of membrane electrode material for example 5 example 2 was repeated except that: the catalyst of example 2 was replaced with the same mass of the catalyst prepared in example 5, and the 5% commercial platinum-carbon catalyst of example 2 was replaced with the same mass of a commercial platinum-carbon catalyst having a platinum content of 10%, and the remaining preparation process of the membrane electrode material was the same as in example 2.
A Solid Polymer Electrolyte (SPE) ozone generator is adopted, the volume of an electrolytic chamber is 3L (the volume of a cathode chamber and the volume of an anode chamber are respectively 1.5L), deionized water is added into the electrolytic chamber, and the cathode chamber and the anode chamber are separated by a proton exchange membrane Nafion D520 membrane. The current of the electrolysis reaction was 10A, the cell voltage was 4.0V, and the electrolysis experiment was carried out at a temperature of 25 ℃. Electrolytic synthesis of O3In the process, the anode gas outlet is connected with an ozone detector to detect O3Concentration, electrolytic reaction for 48h, and ozone detector to detect O3The volume mass concentration is 130.27 g/m3。
The statements in this specification merely set forth a list of implementations of the inventive concept and the scope of the present invention should not be construed as limited to the particular forms set forth in the examples.
Claims (10)
1. A preparation method of lead tetroxide catalysts with different morphologies is characterized by comprising the following steps:
1) dissolving lead salt in deionized water, adding inorganic base to adjust the pH value to 12-14, and performing ultrasonic dispersion uniformly to obtain a precursor solution;
2) adding a sodium hypochlorite solution into the precursor solution obtained in the step 1), generating a brownish red turbid substance in the mixed solution, and stirring for 1-3 minutes to uniformly disperse the brownish red turbid substance to obtain a turbid liquid;
3) transferring the suspension obtained in the step 2) into a polytetrafluoroethylene lining, carrying out hydrothermal reaction at the temperature of 90-150 ℃ for 20-50 hours, cooling to room temperature after the reaction is finished, and filtering to obtain a crude product precipitate; washing the obtained crude product precipitate with anhydrous ethanol and deionized water for 3-5 times respectively, vacuum filtering, and drying the filter residue in a vacuum drying oven at 60-80 deg.C for 20-24 hr;
4) grinding the dried solid obtained in the step 3), placing the ground solid in a porcelain boat, placing the porcelain boat in a tubular furnace for roasting, heating the porcelain boat to a roasting temperature of 250-450 ℃ in the environment of high-purity gas, keeping the roasting temperature for 3-10h, and cooling the porcelain boat to room temperature, wherein the heating rate is controlled to be 1-5 ℃/min, so as to obtain the lead tetroxide catalyst;
in the step 2), the effective chlorine concentration of the sodium hypochlorite solution is 2-10%; the molar ratio of the available chlorine to the lead salt in the sodium hypochlorite solution is 1: 1-6: 1;
in step 4), the high-purity gas is hydrogen or nitrogen with the purity of more than 99%.
2. The method for preparing the lead tetroxide catalyst with different morphologies as claimed in claim 1, wherein in step 1), the lead salt is lead acetate, lead nitrate, lead chloride or lead bromide; the inorganic base is sodium hydroxide, potassium hydroxide, lithium hydroxide or ammonia water.
3. The method for preparing the lead tetroxide catalyst with different morphologies as claimed in claim 1, wherein in the step 2), the molar ratio of the available chlorine to the lead salt in the sodium hypochlorite solution is 2: 1.
4. The method for preparing the lead tetroxide catalyst with different morphologies as claimed in claim 1, wherein the hydrothermal reaction temperature in step 3) is 100-140 ℃ and the reaction time is 24-48 hours.
5. The method for preparing the lead tetroxide catalyst with different morphologies as claimed in claim 1, wherein the calcination temperature in the step 4) is 280 ℃ to 450 ℃, and the retention time at the calcination temperature is 4 to 8 hours.
6. The lead tetroxide catalyst of different morphologies prepared by the method of any of claims 1 to 5.
7. The use of the lead tetroxide catalyst of different morphologies as defined in claim 6 in the reaction of electrocatalytic decomposition of water to produce ozone.
8. The use according to claim 7, characterized in that a solid polymer electrolyte ozone generator is used as reactor; the lead tetroxide catalyst is used as an anode material, the platinum-carbon catalyst with 5-10% of platinum content is used as a cathode material, the anode material and the cathode material are respectively coated on an anode surface and a cathode surface of a proton exchange membrane, a cathode chamber and an anode chamber of the reactor are separated by the proton exchange membrane, deionized water is used as electrolyte, the current is 5A-20A, the cell voltage is 3V-5V, and the electrolytic reaction is carried out at the temperature of 20-50 ℃ to prepare the ozone product.
9. Use according to claim 8, wherein the proton exchange membrane is NafionN117, NafionN115, NafionD520, NafionNRE211, NafionNRE212 or NafionHP.
10. Use according to claim 9, wherein the proton exchange membrane is NafionHP or NafionD 520.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011354756.8A CN112481643B (en) | 2020-11-27 | 2020-11-27 | Lead tetroxide catalyst with different morphologies as well as preparation method and application thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011354756.8A CN112481643B (en) | 2020-11-27 | 2020-11-27 | Lead tetroxide catalyst with different morphologies as well as preparation method and application thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112481643A CN112481643A (en) | 2021-03-12 |
| CN112481643B true CN112481643B (en) | 2022-02-15 |
Family
ID=74935872
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011354756.8A Active CN112481643B (en) | 2020-11-27 | 2020-11-27 | Lead tetroxide catalyst with different morphologies as well as preparation method and application thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112481643B (en) |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2597882B2 (en) * | 1988-05-11 | 1997-04-09 | 財団法人生産開発科学研究所 | Method for producing fibrous material coated with PbO 2 |
| CN1171797C (en) * | 2002-01-11 | 2004-10-20 | 清华大学 | Process for synthesizing alpha, beta type lead dioxide and leadleaden oxide naon crystal |
| CN101792176B (en) * | 2010-02-13 | 2011-08-31 | 张保兴 | Preparation method for producing nano-red lead (lead tetraoxide) via dry-wet process technology |
| CN111097402B (en) * | 2019-12-26 | 2022-10-04 | 浙江工业大学 | Nano beta-lead dioxide catalyst, preparation method and application thereof |
| CN111889098A (en) * | 2020-08-05 | 2020-11-06 | 浙江工业大学 | Beta-lead dioxide catalyst with different morphologies as well as preparation method and application thereof |
-
2020
- 2020-11-27 CN CN202011354756.8A patent/CN112481643B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN112481643A (en) | 2021-03-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US10854885B2 (en) | Non-noble metal electrocatalysts for oxygen depolarized cathodes and their application in chlor-alkali electrolysis cells | |
| CN111097402B (en) | Nano beta-lead dioxide catalyst, preparation method and application thereof | |
| CN109289843B (en) | Sea urchin-shaped rutile type titanium dioxide supported ruthenium oxide oxygen precipitation catalyst, and preparation method and application thereof | |
| CN110639593B (en) | Boron and nitrogen doped carbon porous nanotube coated platinum alloy nanoparticle material catalyst and preparation method and application thereof | |
| CN110639592B (en) | Boron and nitrogen doped carbon porous nanosheet supported transition metal nanoparticle material catalyst and preparation method and application thereof | |
| CN113526623A (en) | Preparation method of manganese oxide nano electrode and application of manganese oxide nano electrode in tetracycline hydrochloride wastewater treatment | |
| CN114477320B (en) | Preparation method of PEM water electrolysis oxygen desorption catalyst iridium oxide | |
| CN112481643B (en) | Lead tetroxide catalyst with different morphologies as well as preparation method and application thereof | |
| CN113443610A (en) | Ruthenium selenide nanosphere electrocatalyst and preparation method and application thereof | |
| CN111992215B (en) | Lanthanide perovskite supported lead dioxide catalyst and preparation method and application thereof | |
| CN111889098A (en) | Beta-lead dioxide catalyst with different morphologies as well as preparation method and application thereof | |
| CN114836781B (en) | Preparation method and application of lamellar Cu-based N-doped graphene catalyst | |
| CN110065932B (en) | Lithium insertion type selenium compound, and preparation method and application thereof | |
| CN111939895B (en) | Bismuth oxide supported lead dioxide catalyst with different morphologies and preparation method and application thereof | |
| CN113862716B (en) | Nanometer tin oxide loaded platinum alloy catalyst and preparation method and application thereof | |
| CN115807243A (en) | Silicon dioxide coated cubic lead tetroxide catalyst and preparation method and application thereof | |
| CN110681385A (en) | TiO22Preparation method of neodymium-cuprate nano catalytic powder | |
| CN114804237B (en) | Iridium acid salt nano material with open framework structure, preparation method and application thereof in electrocatalytic pyrolysis of acidic water to produce oxygen | |
| CN115818715A (en) | Oxygen-enriched vacancy niobium pentoxide catalyst with different crystal forms, synthesis method thereof and application thereof in air cathode | |
| CN112391651B (en) | BiOBr/TiO containing oxygen vacancies2Nanotube array composite electrode, preparation method thereof and application of nanotube array composite electrode in photoelectrocatalysis nitrogen fixation | |
| CN115852388B (en) | Nitrogen-doped hollow mesoporous carbon sphere loaded nano platinum electrocatalytic hydrogen evolution material for cathode of PEM (proton exchange membrane) electrolytic cell, preparation and application | |
| CN113106470B (en) | Vanadium-doped titanium dioxide/graphene electrocatalyst suitable for electrochemical nitrogen reduction and preparation method thereof | |
| CN115893531B (en) | La, rh codoped SrTiO 3 Nanotube array and preparation method and application thereof | |
| CN117414816A (en) | Octagonal electrocatalyst and preparation method and application thereof | |
| CN115821293A (en) | Based on WS 2 Hydrogen production method for preparing azofurazan energetic material by coupling of/Pt composite catalyst |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |