阅读说明：本技术 Pt单原子ZnO压电多孔陶瓷、其制法及高效制氢 (Pt monatomic ZnO piezoelectric porous ceramic, preparation method thereof and efficient hydrogen production ) 是由 金向华 王新喜 徐聪 于 2020-12-29 设计创作，主要内容包括：本发明提供一种Pt单原子ZnO压电多孔陶瓷、其制法与自供能高效制氢中的应用。该压电多孔陶瓷包括ZnO压电多孔陶瓷基体以及均匀分散于压电多孔陶瓷基体表面及孔道内的Pt单原子,所述Pt单原子的质量分数为0.01wt％-0.1wt％。本发明提供的一种Pt单原子ZnO压电多孔陶瓷材料中Pt的含量低,同时具有较高的压电催化活性,降低了贵金属的使用,从而大大降低了生产成本。该Pt单原子ZnO压电多孔陶瓷材料可用为氢燃料电池提供氢源,制氢效率高、纯度高,不含一氧化碳、硫化氢、磷化氢、氯离子等使燃料电池中毒的气体,且制备方法简单易行、绿色环保,不排放对环境有害物质。(The invention provides a Pt monatomic ZnO piezoelectric porous ceramic, a preparation method thereof and application thereof in self-powered high-efficiency hydrogen production. The piezoelectric porous ceramic comprises a ZnO piezoelectric porous ceramic matrix and Pt monoatomic atoms uniformly dispersed on the surface and in pore channels of the piezoelectric porous ceramic matrix, wherein the mass fraction of the Pt monoatomic atoms is 0.01-0.1 wt%. The Pt monatomic ZnO piezoelectric porous ceramic material provided by the invention is low in Pt content, has high piezoelectric catalytic activity, and reduces the use of noble metals, so that the production cost is greatly reduced. The Pt monatomic ZnO piezoelectric porous ceramic material can be used for providing a hydrogen source for a hydrogen fuel cell, has high hydrogen production efficiency and high purity, does not contain gases which can poison the fuel cell, such as carbon monoxide, hydrogen sulfide, phosphine, chloride ions and the like, and has the advantages of simple and easy preparation method, environmental protection and no emission of harmful substances to the environment.)

1. The Pt monatomic ZnO piezoelectric porous ceramic is characterized by comprising a ZnO piezoelectric porous ceramic matrix and Pt monatomics uniformly dispersed on the surface of the piezoelectric porous ceramic;

wherein the mass fraction of the Pt monoatomic atoms is 0.01 wt% -0.1 wt%;

the aperture of the ZnO piezoelectric porous ceramic is 0.01 mm-0.1 mm.

2. The Pt monatomic ZnO piezoelectric porous ceramic according to claim 1, wherein the Pt monatomic is further dispersed on the ZnO piezoelectric porous ceramic cell wall surface; wherein the oxygen atom may be replaced by a negative divalent anion.

3. A method for preparing the Pt monatomic ZnO piezoelectric porous ceramic according to any one of claims 1 to 2, characterized by comprising the steps of:

(1) preparation of Zn (OH)₂And (3) particle: reacting the zinc salt with a base to form Zn (OH)₂Particles;

(2) and (3) granulation: to the Zn (OH) prepared in the step (1)₂Adding 1.0-10.0 wt% of starch and a certain amount of polyvinyl alcohol solution into the granules respectively, and ball-milling and granulating;

(3) preparing a greenware: the Zn (OH) prepared in the step (2)₂Adding the granules into a mould with a certain size, and pressing into a greenware by a film pressing machine under the pressure of 10-30 MPa;

(4) pore-forming and degumming: heating the ceramic blank to 350-450 ℃, and keeping the temperature for 1-2 h; continuously heating for degumming treatment;

(5) molding: treating for 0.5-2 h at 1150-1350 ℃ after degumming, and cooling to obtain ZnO porous ceramic;

(6) and (3) polarization treatment: polarizing the ZnO porous ceramic sheet for 20-60min at a voltage of 3-5 KV/mm, and standing for 24h to obtain ZnO piezoelectric porous ceramic;

(7) preparing Pt monatomic ZnO piezoelectric porous ceramic: putting ZnO piezoelectric porous ceramics in H₂PtCl₆Carrying out ultrasonic treatment in the solution to obtain the Pt monogenThe ZnO piezoelectric porous ceramic.

4. The method for preparing Pt monatomic ZnO piezoelectric porous ceramic according to claim 3, wherein the zinc salt is selected from ZnCl₂、Zn(Ac)₂、ZnSO₄、Zn(NO₃)₂At least one of;

preferably, the base is selected from NaOH, KOH, NH₃·H₂At least one of O.

5. The method for preparing Pt monatomic ZnO piezoelectric porous ceramic according to claim 3, wherein the mass concentration of the polyvinyl alcohol (PVA) solution is 5.0 wt% to 8.0 wt%.

6. The preparation method of the Pt monatomic ZnO piezoelectric porous ceramic according to claim 3, wherein the temperature of the degumming treatment is 500-600 ℃.

7. The preparation method of the Pt monatomic ZnO piezoelectric porous ceramic according to claim 3, wherein the ultrasonic treatment time is 30-80 min, and the ultrasonic treatment frequency is 20-60 KHz.

8. Use of a Pt monatomic ZnO piezoelectric porous ceramic as described in any of claims 1 to 2 or as prepared in any of claims 3 to 7 for self-powered hydrogen production.

9. Use according to claim 8, wherein the ultrasonic waves have a frequency of 10-60 KHz.

10. Use according to claim 8, wherein the Pt monatomic ZnO piezoelectric porous ceramic is used in on-board self-powered hydrogen production.

Technical Field

The invention relates to a Pt monatomic ZnO piezoelectric porous ceramic, in particular to a Pt monatomic ZnO piezoelectric porous ceramic material, a preparation method thereof and application thereof in vehicle-mounted self-powered high-efficiency hydrogen production, belonging to the field of energy materials.

Background

With the development of economic society of China, the energy consumption of China is more and more, and the petroleum import amount of China currently accounts for about 70 percent of the total crude oil consumption. On the one hand, the method consumes petroleum resources, and on the other hand, the greenhouse gas emitted by using crude oil pollutes the environment. Therefore, the government of China is provided with a policy to encourage the development of new energy vehicles. In particular, new energy vehicles driven by hydrogen fuel cells are a direction of development that is preferentially encouraged.

However, the electrode material of the hydrogen fuel cell is easily poisoned by impurities such as carbon monoxide, hydrogen sulfide, phosphine, and chloride ions mixed in the hydrogen gas, thereby affecting the service life of the hydrogen fuel cell. Therefore, the preparation of high-purity hydrogen has important application value for developing hydrogen fuel cells and new energy automobile industries. In addition, although the noble metal can be used as a catalyst to produce hydrogen, the noble metal is expensive and has limited resources, thereby limiting the wide application of the noble metal. Therefore, how to prepare high-purity hydrogen by using a material with low quality of precious metal and high catalytic activity is an urgent problem to be solved.

Disclosure of Invention

Most of the existing hydrogen sources are derived from chemical hydrogen production, and the existing hydrogen sources contain gaseous substances such as carbon monoxide, hydrogen sulfide, phosphine, chloride ions and the like which are easy to poison electrode materials of fuel cells. The invention aims to provide a Pt monatomic ZnO piezoelectric porous ceramic material, a preparation method thereof and application thereof in vehicle-mounted self-powered high-efficiency hydrogen production, so as to overcome the defects in the prior hydrogen production technology and overcome the defects of high cost caused by low utilization rate and low catalytic activity of noble metal Pt in the prior art.

In order to achieve the purpose, the technical scheme adopted by the invention comprises the following steps:

the Pt monatomic ZnO piezoelectric porous ceramic comprises a ZnO piezoelectric porous ceramic matrix and Pt monatomics uniformly dispersed on the surface of the piezoelectric porous ceramic matrix;

wherein the mass fraction of the Pt monoatomic atoms is 0.01-0.1 wt%;

the aperture of the ZnO piezoelectric porous ceramic matrix is 0.01 mm-0.1 mm.

Optionally, the Pt monoatomic atoms are also dispersed on the surfaces of the pores of the ZnO piezoelectric porous ceramic matrix.

Alternatively, a sulfur atom is partially substituted for an oxygen atom in the ZnO piezoelectric porous ceramic matrix.

Sulfur

The preparation method of the Pt monatomic ZnO piezoelectric porous ceramic comprises the following steps:

(1) preparation of Zn (OH)₂And (3) particle: reacting the zinc salt with a base to form Zn (OH)₂Particles;

(2) and (3) granulation: to the Zn (OH) prepared in the step (1)₂Adding 1.0-10.0 wt% of starch and a certain amount of polyvinyl alcohol solution into the granules respectively, and ball-milling and granulating;

(3) preparing a greenware: the Zn (OH) prepared in the step (2)₂Adding the granules into a mould with a certain size, and pressing into a greenware by a film pressing machine under the pressure of 10-30 MPa;

(4) pore-forming and degumming: heating the ceramic blank to 350-450 ℃, and keeping the temperature for 1-2 h; continuously heating for degumming treatment;

(5) molding: treating for 0.5-2 h at 1150-1350 ℃ after degumming, and cooling to obtain ZnO porous ceramic;

(6) and (3) polarization treatment: polarizing the ZnO porous ceramic sheet for 20-60min at a voltage of 3-5 KV/mm, and standing for 24h to obtain ZnO piezoelectric porous ceramic;

(7) preparing Pt monatomic ZnO piezoelectric porous ceramic: putting ZnO piezoelectric porous ceramics in H₂PtCl₆And carrying out ultrasonic treatment in the solution to obtain the Pt monatomic ZnO piezoelectric porous ceramic.

Optionally, the temperature of the degumming treatment is 500-.

Alternatively, the zinc salt is selected from ZnCl₂、Zn(Ac)₂、ZnSO₄、Zn(NO₃)₂At least one of (1).

Optionally, the step ofStep (1) preparation of Zn (OH)₂The process of the particles further comprises adding a negative divalent anion to the zinc salt.

Optionally, the negative divalent anion is a sulfide ion. Sulfur

Optionally, the ZnO particles are made of ZnCl₂And NaOH solution.

Alternatively, the concentration of the NaOH solution is in the range of 0.1-1.0 mol/L.

Optionally, the ZnO particles are made of ZnCl₂And NH₃·H₂And O reaction.

Alternatively, the NH₃·H₂The concentration range of O is 0.1-2.0 mol/L.

Optionally, the ZnO particles are made of Zn (Ac)₂And NaOH solution.

Optionally, the ZnO particles are made of Zn (Ac)₂And NH₃·H₂And O reaction.

Optionally, the starch is 1.0 wt% by mass.

Optionally, the starch is present in an amount of 2.0 wt%.

Optionally, the starch is 3.0 wt% by mass.

Optionally, the starch is 4.0 wt% by mass.

Optionally, the starch is 5.0 wt% by mass.

Optionally, the starch is 6.0 wt% by mass.

Optionally, the starch is 7.0 wt% by mass.

Optionally, the starch is 8.0 wt% by mass.

Optionally, the starch is 9.0 wt% by mass.

Optionally, the mass concentration of the polyvinyl alcohol (PVA) solution is 5.0-8.0 wt%.

Optionally, the polyvinyl alcohol (PVA) solution has a mass concentration of 6.0 wt%.

Optionally, the polyvinyl alcohol (PVA) solution has a mass concentration of 7.0 wt%.

Optionally, the temperature of the pore-forming treatment is 350 ℃, 380 ℃, 400 ℃ and 450 ℃;

optionally, the temperature of the degumming treatment is 450 ℃, 500 ℃, 550 ℃ and 600 ℃;

optionally, the ultrasonic treatment time is 30-80 min, and the ultrasonic treatment frequency is 20-60 KHz.

Optionally, the upper limit of the ultrasonic treatment time is 40min, 50min, 60min, 70min, 80 min; the lower limit of the ultrasonic treatment time is 30min, 40min, 50min, 60min and 70 min.

The Pt monatomic ZnO piezoelectric porous ceramic is applied to self-powered high-efficiency hydrogen production.

Preferably, the frequency of the ultrasonic wave is 10-60 KHz.

Preferably, the upper limit of the frequency of the ultrasonic wave is 20KHz, 30KHz, 40KHz, 50KHz and 60 KHz; the lower limit of the frequency of the ultrasonic wave is 10KHz, 20KHz, 30KHz, 40KHz and 50 KHz.

Preferably, the Pt monatomic ZnO piezoelectric porous ceramic is applied to vehicle-mounted self-powered hydrogen production.

Optionally, under the condition that the temperature is 1-95 ℃, mechanical vibration or ultrasonic vibration is applied to a hydrogen production reaction system formed by the Pt monatomic ZnO piezoelectric porous ceramic material and ammonia borane aqueous solution to realize the preparation of hydrogen.

Alternatively, a self-powered piezo-catalytic hydrogen production method, comprising the steps of:

(1) putting ammonia borane aqueous solution into a catalytic hydrogen production reactor, adding a Pt monatomic ZnO piezoelectric porous ceramic material into the ammonia borane aqueous solution to form a hydrogen production reaction system, and then sealing the reactor;

(2) adjusting the temperature of the reactor to 1-95 ℃, then pumping the system to vacuum, and adjusting the temperature in the reactor to 20-30 ℃ after the reactor reaches a vacuum state;

(3) and applying ultrasonic waves to a hydrogen production reaction system in the reactor to enable the hydrogen production reaction system to react and produce hydrogen.

The piezoelectric material can convert mechanical energy into electric energy, and the action principle is that the material is asymmetric in structure, and the original material with neutral electricity generates non-coincidence positive and negative charge centers under the action of external force, so that two ends or two surfaces of the material have different charges. The mechanical vibration or the ultrasonic vibration realizes the conversion of mechanical energy and electric energy.

The reaction mechanism of the piezoelectric catalytic hydrogen production provided by the application is that NH is carried out in the presence of a proper catalyst₃BH₃Hydrogen may be released by solvolysis or thermal decomposition, as shown in formula (I) below:

NH₃BH₃(aq)+2H₂O(l)＝NH₄ ⁺(aq)+BO₂ ^-(aq)+3H₂(g) formula (I)

In the invention, the Pt monatomic ZnO piezoelectric porous ceramic material is a catalyst with piezoelectric effect. The catalyst generates piezoelectric effect in ultrasonic oscillation, and forms self-establishing electric field in the material to make the electrons move directionally, so that the generated electrons and protons H in water⁺Reacting to generate hydrogen, generating positive hole and negative hydrogen ion H^-The combination produces hydrogen.

The hydrogen prepared by the method is high-purity hydrogen, and does not contain carbon monoxide, hydrogen sulfide and other pollutants which poison fuel cell electrode materials.

In a specific embodiment, the Pt monatomic ZnO piezoelectric porous ceramic material hydrogen production system prepared by the invention is applied to a running automobile, the vibration energy in the running process of the automobile is converted into electric energy, and hydrogen is prepared by piezoelectric catalytic reaction and used as automobile fuel to realize self-powered hydrogen production.

In a specific embodiment, the Pt monatomic ZnO piezoelectric porous ceramic material hydrogen production system prepared by the invention is applied to a production workshop with high noise, and sound waves generated in the production of the workshop are converted into electric energy, so that the self-powered hydrogen production is realized.

Compared with the prior art, the invention has the advantages that:

(1) the Pt monatomic ZnO piezoelectric porous ceramic material provided by the invention has low Pt content and high catalytic activity, reduces the use of noble metals, and greatly reduces the production cost.

(2) The preparation method of the Pt monatomic ZnO piezoelectric porous ceramic material provided by the invention is simple and easy to implement, is green and environment-friendly, and does not discharge harmful substances to the environment.

(3) The Pt monatomic ZnO piezoelectric porous ceramic material provided by the invention can provide high-purity hydrogen for a hydrogen fuel cell, and does not contain gases which poison the fuel cell, such as carbon monoxide, hydrogen sulfide, phosphine, chloride ions and the like.

Detailed Description

In view of the deficiencies in the prior art, the inventors of the present invention have made extensive studies and extensive practices to provide technical solutions of the present invention. The technical solution, its implementation and principles, etc. will be further explained as follows.

The technical solution of the present invention is further explained below with reference to several examples.

The medicines used in the examples of the application are all commercially available.

Example 1

The preparation method of the Pt monatomic ZnO piezoelectric porous ceramic comprises the following steps:

(1) preparation of Zn (OH)₂And (3) particle: reacting zinc acetate with sodium hydroxide to form Zn (OH)₂Particles;

(2) and (3) granulation: to the Zn (OH) prepared in the step (1)₂Adding 8 wt% of starch and a certain amount of polyvinyl alcohol solution into the granules respectively, and ball-milling and granulating;

(3) preparing a greenware: the Zn (OH) prepared in the step (2)₂Adding the granules into a mold with the diameter of 20mm multiplied by 20mm, and pressing the granules into a greenware by a film pressing machine under the pressure of 10 MPa;

(4) pore-forming and degumming: heating the greenware to 350 ℃, and keeping the temperature for 1 h; continuously heating to 500 ℃ for degumming treatment;

(5) molding: treating for 0.5h at 1150 ℃ after degumming, and cooling to obtain ZnO porous ceramic;

(6) and (3) polarization treatment: polarizing the ZnO porous ceramic sheet for 20min under the voltage of 3KV/mm, and standing for 24h to obtain ZnO piezoelectric porous ceramic;

(7) preparing Pt monatomic ZnO piezoelectric porous ceramic: pressing ZnOPlacing the electric porous ceramic in H with the solubility of 0.1mol/L₂PtCl₆And carrying out ultrasonic treatment in the solution to obtain the Pt monatomic ZnO piezoelectric porous ceramic.

The hydrogen production reaction is as follows:

the method comprises the following steps: providing 100mL of NH at a concentration of 0.05mol/L₃BH₃Putting the solution into a reactor, adding the self-energized piezoelectric porous ceramic into the solution, covering a quartz glass plate, and sealing the reactor;

step two: connecting the hydrogen production system and the low-temperature constant-temperature tank in the first step, sealing, controlling the temperature of the low-temperature constant-temperature tank to be 1 ℃, then pumping the system to be vacuum, and controlling the temperature of the system to be 25 ℃ through the low-temperature constant-temperature tank after the system reaches a vacuum state;

step three: and (3) placing the reactor in a 28KHz ultrasonic cleaner, turning on the ultrasonic, adjusting the hydrogen production system to a system circulation state, performing an experiment, and detecting the hydrogen yield of each hour by a gas chromatograph every other hour.

Example 2

The preparation method of the Pt monatomic ZnO piezoelectric porous ceramic comprises the following steps:

(1) preparation of Zn (OH)₂And (3) particle: reacting zinc chloride with KOH to form Zn (OH)₂Particles;

(2) and (3) granulation: to the Zn (OH) prepared in the step (1)₂Adding 1.0 wt% of starch and a certain amount of polyvinyl alcohol solution into the granules respectively, and ball-milling and granulating;

(3) preparing a greenware: the Zn (OH) prepared in the step (2)₂Adding the granules into a mold with the diameter of 20mm, and pressing into a greenware by a film pressing machine under the pressure of 20 MPa;

(4) pore-forming and degumming: heating the greenware to 400 ℃, and keeping the temperature for 1 h; continuously heating to 550 ℃ for degumming treatment;

(5) molding: treating for 1.0h at 1200 ℃ after degumming, and cooling to obtain ZnO porous ceramic;

(6) and (3) polarization treatment: polarizing the ZnO porous ceramic sheet for 30min at the voltage of 4KV/mm, and standing for 24h to obtain ZnO piezoelectric porous ceramic;

(7) preparing Pt monatomic ZnO piezoelectric porous ceramic: putting ZnO piezoelectric porous ceramic in 0.5mol/LH₂PtCl₆And carrying out ultrasonic treatment in the solution to obtain the Pt monatomic ZnO piezoelectric porous ceramic.

The hydrogen production reaction is as follows:

the method comprises the following steps: providing 100mL of NH at a concentration of 0.05mol/L₃BH₃Putting the solution into a reactor, adding the self-energized piezoelectric porous ceramic into the solution, covering a quartz glass plate, and sealing the reactor;

step two: connecting the hydrogen production system and the low-temperature constant-temperature tank in the first step, sealing, controlling the temperature of the low-temperature constant-temperature tank to be 1 ℃, then pumping the system to be vacuum, and controlling the temperature of the system to be 25 ℃ through the low-temperature constant-temperature tank after the system reaches a vacuum state;

step three: and (3) placing the reactor in a 28KHz ultrasonic cleaner, turning on the ultrasonic, adjusting the hydrogen production system to a system circulation state, performing an experiment, and detecting the hydrogen yield of each hour by a gas chromatograph every other hour.

Example 3

The preparation method of the Pt monatomic ZnO piezoelectric porous ceramic comprises the following steps:

(1) preparation of Zn (OH)₂And (3) particle: reacting zinc chloride with NaOH and ammonia water to generate Zn (OH)₂Particles;

(2) and (3) granulation: to the Zn (OH) prepared in the step (1)₂Adding 1.5 wt% of starch and a certain amount of polyvinyl alcohol solution into the granules respectively, and ball-milling and granulating;

(3) preparing a greenware: the Zn (OH) prepared in the step (2)₂Adding the granules into a mold with the diameter of 20mm multiplied by 20mm, and pressing the granules into a greenware by a film pressing machine under the pressure of 25 MPa;

(4) pore-forming and degumming: heating the greenware to 450 ℃, and keeping the temperature for 1 h; continuously heating to 500 ℃ for degumming treatment;

(5) molding: treating for 1h at 1300 ℃ after degumming, and cooling to obtain ZnO porous ceramic;

(6) and (3) polarization treatment: polarizing the ZnO porous ceramic sheet for 40min at the voltage of 4KV/mm, and standing for 24h to obtain ZnO piezoelectric porous ceramic;

(7) preparing Pt monatomic ZnO piezoelectric porous ceramic: putting ZnO piezoelectric porous ceramic into 1.0mol/LH₂PtCl₆And carrying out ultrasonic treatment in the solution to obtain the Pt monatomic ZnO piezoelectric porous ceramic.

The hydrogen production reaction is as follows:

the method comprises the following steps: providing 100mL of NH at a concentration of 0.05mol/L₃BH₃Putting the solution into a reactor, adding the self-energized piezoelectric porous ceramic into the solution, covering a quartz glass plate, and sealing the reactor;

step two: connecting the hydrogen production system and the low-temperature constant-temperature tank in the first step, sealing, controlling the temperature of the low-temperature constant-temperature tank to be 1 ℃, then pumping the system to be vacuum, and controlling the temperature of the system to be 25 ℃ through the low-temperature constant-temperature tank after the system reaches a vacuum state;

step three: and (3) placing the reactor in a 28KHz ultrasonic cleaner, turning on the ultrasonic, adjusting the hydrogen production system to a system circulation state, performing an experiment, and detecting the hydrogen yield of each hour by a gas chromatograph every other hour.

Example 4

The preparation method of the Pt monatomic ZnO piezoelectric porous ceramic comprises the following steps:

(1) preparation of Zn (OH)₂And (3) particle: reacting zinc sulfate with potassium hydroxide and ammonia water to generate Zn (OH)₂Particles;

(2) and (3) granulation: to the Zn (OH) prepared in the step (1)₂Adding 2.5 wt% of starch and a certain amount of polyvinyl alcohol solution into the granules respectively, and ball-milling and granulating;

(3) preparing a greenware: the Zn (OH) prepared in the step (2)₂Adding the granules into a mold with the diameter of 20mm, and pressing into a greenware by a film pressing machine under the pressure of 20 MPa;

(4) pore-forming and degumming: heating the greenware to 400 ℃, and keeping the temperature for 1 h; continuously heating to 500 ℃ for degumming treatment;

(5) molding: treating for 2h at 1350 ℃ after degumming, and cooling to obtain ZnO porous ceramic;

(6) and (3) polarization treatment: polarizing the ZnO porous ceramic sheet for 60min at the voltage of 4KV/mm, and standing for 24h to obtain ZnO piezoelectric porous ceramic;

(7) preparing Pt monatomic ZnO piezoelectric porous ceramic: putting ZnO piezoelectric porous ceramic in 0.5mol/LH₂PtCl₆And carrying out ultrasonic treatment in the solution to obtain the Pt monatomic ZnO piezoelectric porous ceramic. The hydrogen production reaction is as follows:

the method comprises the following steps: providing 100mL of NH at a concentration of 0.05mol/L₃BH₃Putting the solution into a reactor, adding the self-energized piezoelectric porous ceramic into the solution, covering a quartz glass plate, and sealing the reactor;

step two: connecting the hydrogen production system and the low-temperature constant-temperature tank in the first step, sealing, controlling the temperature of the low-temperature constant-temperature tank to be 1 ℃, then pumping the system to be vacuum, and controlling the temperature of the system to be 25 ℃ through the low-temperature constant-temperature tank after the system reaches a vacuum state;

step three: and (3) placing the reactor in a 28KHz ultrasonic cleaner, turning on the ultrasonic, adjusting the hydrogen production system to a system circulation state, performing an experiment, and detecting the hydrogen yield of each hour by a gas chromatograph every other hour.

Example 5

The preparation method of the Pt monatomic ZnO piezoelectric porous ceramic comprises the following steps:

(1) preparation of Zn (OH)₂And (3) particle: reacting zinc chloride, a small amount of sodium sulfide and NaOH to generate sulfur-substituted Zn (OH)₂Particles, wherein the atomic ratio of zinc chloride to sodium sulfide is 95-98: 5-2;

(2) and (3) granulation: to the sulfur-substituted Zn (OH) prepared in step (1)₂Respectively adding 3.5 wt% of starch and a certain amount of polyvinyl alcohol solution into the granules, and ball-milling and granulating;

(3) preparing a greenware: the sulfur-substituted Zn (OH) prepared in the step (2)₂Adding the granules into a mold with the diameter of 20mm multiplied by 20mm, and pressing the granules into a greenware by a film pressing machine under the pressure of 30 MPa;

(4) pore-forming and degumming: heating the greenware to 450 ℃, and keeping the temperature for 2 hours; continuously heating to 550 ℃ for degumming treatment;

(5) molding: treating for 0.5h at 1350 ℃ after degumming, and cooling to obtain sulfur-substituted ZnO porous ceramic;

(6) and (3) polarization treatment: polarizing the sulfur-substituted ZnO porous ceramic sheet for 60min at the voltage of 4KV/mm, and standing for 24h to obtain the sulfur-substituted ZnO piezoelectric porous ceramic;

(7) preparing Pt monatomic ZnO piezoelectric porous ceramic: the sulfur-substituted ZnO piezoelectric porous ceramic is placed at 0.5mol/L H₂PtCl₆And carrying out ultrasonic treatment in the solution to obtain the Pt monatomic ZnO piezoelectric porous ceramic. The hydrogen production reaction is as follows:

the method comprises the following steps: providing 100mL of NH at a concentration of 0.05mol/L₃BH₃Putting the solution into a reactor, adding the self-energized piezoelectric porous ceramic into the solution, covering a quartz glass plate, and sealing the reactor;

step two: connecting the hydrogen production system and the low-temperature constant-temperature tank in the first step, sealing, controlling the temperature of the low-temperature constant-temperature tank to be 1 ℃, then pumping the system to be vacuum, and controlling the temperature of the system to be 25 ℃ through the low-temperature constant-temperature tank after the system reaches a vacuum state;

step three: and (3) placing the reactor in a 28KHz ultrasonic cleaner, turning on the ultrasonic, adjusting the hydrogen production system to a system circulation state, performing an experiment, and detecting the hydrogen yield of each hour by a gas chromatograph every other hour.

Example 6

The hydrogen gas produced by the Pt monatomic ZnO piezoelectric porous ceramics produced in examples 1 to 5 was dried and analyzed and detected in a gas chromatograph, and the impurity gases such as carbon monoxide, hydrogen sulfide, phosphine, and chloride ions were not detected.

It should be understood that the above-mentioned embodiments are merely illustrative of the technical concepts and features of the present invention, and are intended to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.