ZnO/NiO heterojunction piezoelectric ceramic, preparation method thereof and application thereof in self-powered high-efficiency hydrogen production
阅读说明：本技术 ZnO/NiO异质结压电陶瓷、其制法与自供能高效制氢中的应用 (ZnO/NiO heterojunction piezoelectric ceramic, preparation method thereof and application thereof in self-powered high-efficiency hydrogen production ) 是由 金向华 刘守清 李华 于 2021-01-28 设计创作，主要内容包括：本发明提供一种p-n-ZnO/NiO异质结压电陶瓷、其制法与自供能高效制氢中的应用。该异质结压电陶瓷包括n-ZnO压电陶瓷基体以及与之形成异质结的p-NiO材料,所述p-NiO的质量分数为0.1-10wt％。本发明提供的ZnO/NiO异质结压电陶瓷构建了内建电场,电荷的复合率低,压电催化活性高,可利用自然界的水波能、声波能、风能作为驱动力压电催化制氢。且制得的氢气纯度高,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,制备方法简单易行、绿色环保,不排放对环境有害的物质。(The invention provides p-n-ZnO/NiO heterojunction piezoelectric ceramics, a preparation method thereof and application thereof in self-powered high-efficiency hydrogen production. The heterojunction piezoelectric ceramic comprises an n-ZnO piezoelectric ceramic matrix and a p-NiO material forming a heterojunction with the n-ZnO piezoelectric ceramic matrix, wherein the mass fraction of the p-NiO is 0.1-10 wt%. The ZnO/NiO heterojunction piezoelectric ceramic provided by the invention constructs a built-in electric field, has low recombination rate of charges and high piezoelectric catalytic activity, and can be used for producing hydrogen by piezoelectric catalysis by taking water wave energy, sound wave energy and wind energy in the nature as driving forces. The prepared hydrogen has high purity, does not contain carbon monoxide, hydrogen sulfide, phosphine, chloride ions and other gases which poison the fuel cell, has simple and easy preparation method, is green and environment-friendly, and does not discharge substances which are harmful to the environment.)
1. The p-n-ZnO/NiO heterostructure piezoelectric ceramic material is characterized by comprising an n-ZnO piezoelectric ceramic substrate and a p-NiO material forming a heterojunction with the substrate;
wherein the mass fraction of the p-NiO is 0.1-10 wt%;
the thickness of the p-NiO is 0.1-10 μm.
2. The p-n-ZnO/NiO heterostructure piezoceramic material of claim 1, wherein the p-NiO is dispersed on the surface of the n-ZnO piezoceramic;
preferably, the p-NiO is dispersed on one surface of the n-ZnO piezoelectric ceramic.
3. A method for preparing the p-n-ZnO/NiO heterostructure piezoelectric ceramic material of any of claims 1-2, 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 a certain amount of polyvinyl alcohol solution into the granules, and then carrying out ball milling and granulation;
(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) degumming: heating the ceramic blank to 450-DEG C and 500 ℃, and carrying out degumming treatment at constant temperature for 1-2 h;
(5) molding: after degumming, processing for 0.5h-2h at the temperature of 1150-1350 ℃, and cooling to obtain ZnO ceramics;
(6) preparing p-n-ZnO/NiO piezoelectric ceramics: uniformly coating a nickel salt solution on one side of the ZnO piezoelectric ceramic, airing, then uniformly coating a NaOH solution, generating a NiO film on the surface of ZnO, and then sintering at 600 ℃ for 2h to obtain compact and uniform p-n-ZnO/NiO ceramic;
(7) and (3) polarization treatment: polarizing the p-n-ZnO/NiO ceramic plate for 20-60min at the voltage of 3-5 KV/mm, and standing for 24h to obtain the p-n-ZnO/NiO heterojunction piezoelectric ceramic.
4. The method for preparing p-n-ZnO/NiO heterostructure piezoelectric ceramic of 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 NH3·H2At least one of O, NaOH and KOH.
5. The method for preparing the p-n-ZnO/NiO heterojunction piezoelectric ceramic as claimed in claim 3, wherein the mass concentration of the polyvinyl alcohol (PVA) solution is 4.0 wt% to 8.0 wt%.
6. The method for preparing p-n-ZnO/NiO heterojunction piezoelectric ceramic as claimed in claim 3, wherein the nickel salt is selected from NiCl2、NiSO4、Ni(NO3)2、Ni(Ac)2At least one of (1).
7. The method for preparing p-n-ZnO/NiO heterojunction piezoelectric ceramic as claimed in claim 3, wherein the preparation of the NiO film further comprises air drying after uniformly coating NaOH solution, washing the surface with deionized water, and then performing constant temperature treatment at 400-450 ℃ for 20-60min to obtain the NiO film on the surface of ZnO.
8. Use of a p-n-ZnO/NiO heterojunction piezoceramic material 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, characterized by the application of p-n-ZnO/NiO heterojunction piezoceramic materials for on-board self-powered hydrogen production.
Technical Field
The invention relates to a p-n-ZnO/NiO heterojunction piezoelectric ceramic, in particular to a p-n-ZnO/NiO heterojunction piezoelectric ceramic material, a preparation method thereof and application thereof in vehicle-mounted self-powered high-efficiency hydrogen production, and belongs to the field of clean energy materials.
Background
Piezoelectric catalysis is a method of converting mechanical energy into chemical energy, and piezoelectric materials can absorb small mechanical energy such as sound, water waves, vibration and the like to generate charge separation, so that two sides of the piezoelectric materials are charged with different signs. That is, the surface of the piezoelectric material generates positive and negative charges due to external mechanical force, and these charges accelerate the oxidation-reduction reaction of the substance adsorbed on the surface of the piezoelectric material.
However, piezoelectrically generated charges are easily recombined, resulting in poor piezoelectric catalytic efficiency. Therefore, technical means for improving the efficiency of the piezoelectric catalyst are necessary.
Disclosure of Invention
The invention aims to provide a p-n-ZnO/NiO heterojunction piezoelectric ceramic material for improving piezoelectric charge separation efficiency, a preparation method thereof and application of the material in vehicle-mounted self-powered high-efficiency preparation of high-purity hydrogen, so as to overcome the defect of low piezoelectric catalysis efficiency caused by easy recombination of charges generated by piezoelectricity in the prior hydrogen preparation technology.
In order to achieve the purpose, the technical scheme adopted by the invention comprises the following steps:
the p-n-ZnO/NiO heterojunction piezoelectric ceramic material comprises an n-ZnO piezoelectric ceramic matrix and a p-NiO material which forms a heterojunction with the matrix;
wherein the mass fraction of the p-NiO material is 0.1-10 wt%;
the thickness of the p-NiO is 0.1-10 μm.
Optionally, the upper limit of the mass fraction of the p-NiO material is selected from 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%; the lower limit of the mass fraction of the p-NiO material is selected from 0.1 wt%, 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%.
Optionally, the upper thickness limit of the p-NiO material is selected from 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm; the lower limit of the thickness of the p-NiO material is selected from 0.1 μm, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm and 9 μm.
Optionally, the ZnO piezoceramic matrix has dimensions of 20mm × 20mm × 1 mm.
Optionally, the p-NiO is dispersed on the surface of the n-ZnO piezoelectric ceramic.
Optionally, the p-NiO is dispersed on one surface of the n-ZnO piezoelectric ceramic.
The preparation method of the p-n-ZnO/NiO piezoelectric ceramic material 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 a certain amount of polyvinyl alcohol solution into the granules, and then carrying out ball milling and granulation;
(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) degumming: heating the ceramic blank to 450-DEG C and 500 ℃, and carrying out degumming treatment at constant temperature for 1-2 h;
(5) molding: after degumming, processing for 0.5h-2h at the temperature of 1150-1350 ℃, and cooling to obtain ZnO ceramics;
(6) preparing p-n-ZnO/NiO piezoelectric ceramics: uniformly coating a nickel salt solution on one side of the ZnO piezoelectric ceramic, airing, then uniformly coating a NaOH solution, generating a NiO film on the surface of ZnO, and then sintering at 600 ℃ for 2h to obtain compact and uniform p-n-ZnO/NiO ceramic;
(7) and (3) polarization treatment: polarizing the p-n-ZnO/NiO ceramic plate for 20-60min at a voltage of 3-5 KV/mm, and standing for 24h to obtain the p-n-ZnO/NiO piezoelectric ceramic.
Alternatively, the zinc salt is selected from ZnCl2、Zn(Ac)2、ZnSO4、Zn(NO3)2At least one of (1).
Alternatively, the base is selected from NH3·H2At least one of O, NaOH and KOH.
Optionally, the nickel salt is selected from NiCl2、NiSO4、Ni(NO3)2、Ni(Ac)2At least one of (1).
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 mass concentration of the polyvinyl alcohol (PVA) solution is 4.0-8.0 wt%.
Optionally, the polyvinyl alcohol (PVA) solution has a mass concentration of 5.0 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 polarization voltage is 3.0KV/mm, and the polarization time is 60 min.
Optionally, the polarization voltage is 4.0KV/mm, and the polarization time is 50 min.
Optionally, the polarization voltage is 5.0KV/mm, and the polarization time is 40 min.
Optionally, the preparation of the NiO film further comprises the steps of air drying after uniformly coating a NaOH solution, washing the surface of the NiO film with deionized water, and then performing constant temperature treatment at 400-450 ℃ for 20-60min to obtain the NiO film on the ZnO surface.
Optionally, the p-n-ZnO/NiO heterojunction piezoelectric ceramic is applied to vehicle-mounted self-powered hydrogen production.
Optionally, mechanical vibration or ultrasonic vibration is applied to a hydrogen production reaction system formed by the p-n-ZnO/NiO heterojunction piezoelectric ceramic material and ammonia borane aqueous solution at the temperature of 1-95 ℃ to realize the preparation of hydrogen.
Optionally, the ultrasonic vibration frequency is 10-60 KHz.
Optionally, the upper frequency limit of the ultrasonic wave is 20KHz, 30KHz, 40KHz, 50KHz, 60 KHz; the lower limit of the frequency of the ultrasonic wave is 10KHz, 20KHz, 30KHz, 40KHz and 50 KHz.
Optionally, the p-n-ZnO/NiO is a p-n junction constructed from ZnO and NiO.
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 p-n-ZnO/NiO heterojunction piezoelectric 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 p-n-ZnO/NiO heterojunction piezoelectric ceramic material can convert mechanical energy into electric energy, and has the action principle that the positive and negative charge centers of the original material with neutral electricity are not overlapped under the action of external force by utilizing the asymmetry of the structure of the material, 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 invention 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 p-n-ZnO/NiO heterojunction piezoelectric ceramic material is a catalyst with piezoelectric effect. The catalyst generates a piezoelectric effect in ultrasonic oscillation, a self-built electric field is formed in the material, and NiO has the functions of reducing the recombination rate of positive and negative charges and improving the separation efficiency of the positive and negative charges, thereby further improving the hydrogen production efficiency.
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 p-n-ZnO/NiO heterojunction piezoelectric 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 p-n-ZnO/NiO heterojunction piezoceramic material hydrogen production system prepared by the invention is applied to a production workshop with larger noise, and the sound wave generated during the production of the workshop is 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 p-n-ZnO/NiO heterojunction piezoelectric ceramic material provided by the invention does not use a noble metal catalyst, and has high catalytic activity, so that the production cost is reduced, and high-efficiency catalytic activity is maintained.
(2) The p-n-ZnO/NiO heterojunction piezoelectric ceramic material provided by the invention can efficiently prepare high-purity hydrogen by utilizing mechanical energy such as water wave energy, wind energy, sound wave energy and the like in the nature, and realizes the collection and utilization of natural energy.
(3) The preparation method of the p-n-ZnO/NiO heterojunction piezoelectric ceramic material provided by the invention is simple and feasible, green and environment-friendly, and does not discharge harmful substances to the environment.
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 p-n-ZnO/NiO heterojunction piezoelectric ceramic material comprises the following steps:
(1) preparation of Zn (OH)2And (3) particle: reacting zinc chloride with sodium hydroxide to form Zn (OH)2Particles;
(2) and (3) granulation: to the Zn (OH) prepared in the step (1)2Adding 5.0 wt% of polyvinyl alcohol solution into the granules, and then carrying out ball milling and granulation;
(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) degumming: heating the greenware to 520 ℃, and carrying out degumming treatment at constant temperature for 2 hours;
(5) molding: after degumming, treating for 2h at the temperature of 1100 ℃, and cooling to obtain ZnO ceramics;
(6) preparing p-n-ZnO/NiO piezoelectric ceramics: evenly coating NiSO on one side of ZnO piezoelectric ceramics4The solution is dried, then NaOH solution is evenly coated, the surface of the solution is washed by deionized water, then the solution is processed for 20 to 60 minutes at constant temperature of 400-450 ℃, a NiO film is generated on the surface of ZnO, and the NiO film is sintered for 2 hours at the temperature of 620 ℃ to obtain compact and even p-n-ZnO/NiO ceramic;
(7) and (3) polarization treatment: polarizing the p-n-ZnO/NiO ceramic plate for 60min under the voltage of 3KV/mm, and standing for 24h to obtain the p-n-ZnO/NiO heterojunction piezoelectric 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 p-n-ZnO/NiO heterojunction piezoelectric ceramic material 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 p-n-ZnO/NiO heterojunction piezoelectric ceramic material comprises the following steps:
(1) preparation of Zn (OH)2And (3) particle: reacting zinc acetate with ammonia water to generate Zn (OH)2Particles;
(2) and (3) granulation: to the Zn (OH) prepared in the step (1)2Adding 6.0 wt% of polyvinyl alcohol solution into the granules, and then carrying out ball milling and granulation;
(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 15 MPa;
(4) degumming: heating the greenware to 450 ℃, and carrying out degumming treatment at constant temperature for 2 hours;
(5) molding: treating for 1h at the temperature of 1200 ℃ after degumming, and cooling to obtain ZnO ceramics;
(6) preparing p-n-ZnO/NiO piezoelectric ceramics: one side of ZnO piezoelectric ceramic is evenly coated with Ni (Ac)2The solution is dried, then NaOH solution is evenly coated, the surface of the solution is washed by deionized water, then the solution is processed for 20 to 60 minutes at constant temperature of 400-450 ℃, a NiO film is generated on the surface of ZnO, and then the NiO film is sintered for 2 hours at 550 ℃ to obtain compact and even p-n-ZnO/NiO ceramic;
(7) and (3) polarization treatment: polarizing the p-n-ZnO/NiO ceramic plate for 50min under the voltage of 4KV/mm, and standing for 24h to obtain the p-n-ZnO/NiO heterojunction piezoelectric 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 p-n-ZnO/NiO heterojunction piezoelectric ceramic material 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 p-n-ZnO/NiO heterojunction piezoelectric ceramic material comprises the following steps:
(1) preparation of Zn (OH)2And (3) particle: reacting zinc sulfate with potassium hydroxide to form Zn (OH)2Particles;
(2) and (3) granulation: to the Zn (OH) prepared in the step (1)2Adding 7.0 wt% of polyvinyl alcohol solution into the granules, and then carrying out ball milling and granulation;
(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 20 MPa;
(4) degumming: heating the greenware to 500 ℃, and carrying out degumming treatment at constant temperature for 2 hours;
(5) molding: treating for 1h at the temperature of 1150 ℃ after degumming, and cooling to obtain ZnO ceramics;
(6) preparing p-n-ZnO/NiO piezoelectric ceramics: one side of ZnO piezoelectric ceramic is evenly coated with NiCl2The solution is dried, then NaOH solution is evenly coated, the surface of the solution is washed by deionized water, then the solution is processed for 20 to 60 minutes at constant temperature of 400-450 ℃, a NiO film is generated on the surface of ZnO, and then the NiO film is sintered for 2 hours at 550 ℃ to obtain compact and even p-n-ZnO/NiO ceramic;
(7) and (3) polarization treatment: polarizing the p-n-ZnO/NiO ceramic plate for 20min under the voltage of 3KV/mm, and standing for 24h to obtain the p-n-ZnO/NiO heterojunction piezoelectric 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, and adding the p-n-ZnO/NiO heterojunction piezoelectric ceramic into the solutionA ceramic material covering the 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 p-n-ZnO/NiO heterojunction piezoelectric ceramic material comprises the following steps:
(1) preparation of Zn (OH)2And (3) particle: reacting zinc nitrate with ammonia water to produce Zn (OH)2Particles;
(2) and (3) granulation: to the Zn (OH) prepared in the step (1)2Adding 8.0 wt% of polyvinyl alcohol solution into the granules, and then carrying out ball milling and granulation;
(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 20 MPa;
(4) degumming: heating the greenware to 480 ℃, and carrying out degumming treatment at constant temperature for 2 hours;
(5) molding: treating for 1h at the temperature of 1150 ℃ after degumming, and cooling to obtain ZnO ceramics;
(6) preparing p-n-ZnO/NiO piezoelectric ceramics: uniformly coating Ni (NO) on one side of ZnO piezoelectric ceramic3)2The solution is dried, then NaOH solution is evenly coated, the surface of the solution is washed by deionized water, then the solution is processed for 20 to 60 minutes at constant temperature of 400-450 ℃, a NiO film is generated on the surface of ZnO, and then the NiO film is sintered for 2 hours at 600 ℃ to obtain compact and even p-n-ZnO/NiO ceramic;
(7) and (3) polarization treatment: polarizing the p-n-ZnO/NiO ceramic plate for 40min under the voltage of 5KV/mm, and standing for 24h to obtain the p-n-ZnO/NiO heterojunction piezoelectric 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 p-n-ZnO/NiO heterojunction piezoelectric ceramic material 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
After being dried, the hydrogen prepared from the p-n-ZnO/NiO heterojunction piezoelectric ceramic materials prepared in the examples 1 to 4 is analyzed and detected in a gas chromatograph, wherein impurity gases such as carbon monoxide, hydrogen sulfide, phosphine, chloride ions and the like are 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.