Preparation method and application of hydrogen evolution catalytic material Pt-CoP
阅读说明：本技术 一种氢析出催化材料Pt-CoP的制备方法和应用 (Preparation method and application of hydrogen evolution catalytic material Pt-CoP ) 是由 商超群 林琴 王新 于 2020-12-24 设计创作，主要内容包括：本发明属于电解水产氢制备技术领域,公开了一种氢析出材料Pt-CoP的制备方法和应用,是以MoF为框架,采用自模板法,P化,氩气中高温煅烧,还原,最终得到骰子状空心结构。这种结构有效的增大了电化学活性表面积,有利于材料与电解质的接触,和加快了传质速率,有效的提升催化性能。本发明制备出骰子状的空心CoP载体,极大的增加了电解液与活性位点的接触面积,加快了传质速率。Pt的引入不仅降低了贵金属的含量,而且修饰了电子结构,导致电子从Pt转移到CoP载体。Pt与CoP两者之间的协同作用提高了材料催化性能。在酸性溶液中,Pt-CoP展现了优秀的氢析出性能和稳定性,适用于电解水产氢。(The invention belongs to the technical field of hydrogen preparation of electrolyzed water, and discloses a preparation method and application of a hydrogen evolution material Pt-CoP. The structure effectively increases the electrochemical active surface area, is beneficial to the contact of materials and electrolyte, accelerates the mass transfer rate and effectively improves the catalytic performance. The dice-shaped hollow CoP carrier prepared by the method greatly increases the contact area of the electrolyte and the active site, and accelerates the mass transfer rate. The introduction of Pt not only reduces the content of noble metal but also modifies the electronic structure, resulting in the transfer of electrons from Pt to the CoP support. The synergistic effect between the Pt and the CoP improves the catalytic performance of the material. In an acid solution, Pt-CoP shows excellent hydrogen evolution performance and stability, and is suitable for hydrogen production by electrolyzing water.)
1. A preparation method of a hydrogen evolution material Pt-CoP is characterized by comprising the following steps:
s1, quickly pouring the aqueous solution of polyvinylpyrrolidone and squaric acid into the methanol solution of cobalt nitrate, carrying out ultrasonic treatment, standing for 72 hours, centrifuging, washing and drying to obtain powder 1;
s2, calcining the powder 1 under the protection of inert gas to obtain powder 2;
s3, calcining the powder 2 and sodium dihydrogen phosphate according to a certain ratio to obtain CoP;
s4, dispersing the CoP into a mixed solution of water and isopropanol, respectively adding chloroplatinic acid and sodium borohydride in sequence, mixing, stirring, reducing, separating and drying to obtain the Pt-CoP.
2. The method for the preparation of a hydrogen evolving material, Pt-CoP, according to claim 1, wherein the molar ratio of squaric acid and cobalt nitrate in S1 is 1.2: 1.
3. the method for the preparation of a hydrogen evolving material Pt-CoP according to claim 1, characterized in that the calcination in S2 is carried out at a temperature rise rate of 1 ℃/min, at a temperature rise of 400 ℃ and for a holding time of 2 h.
4. The method for the preparation of a hydrogen evolving material Pt-CoP according to claim 1, wherein the calcination in S3 is carried out at a temperature rise rate of 5 ℃/min, a temperature rise of 350 ℃ and a holding time of 2 h.
5. The method for the preparation of a hydrogen evolving material, Pt-CoP, according to claim 1, characterized in that the molar ratio of sodium borohydride to chloroplatinic acid in S4 is 5: 1.
6. the method for preparing a hydrogen evolution material, Pt-CoP, according to claim 1, wherein the operations of adding chloroplatinic acid and sodium borohydride in S4 in the following order are: firstly adding chloroplatinic acid, stirring for 10h, then adding sodium borohydride, and stirring for 3 h.
7. The method for the preparation of a hydrogen evolving material Pt-CoP according to claim 6, wherein the time of sonication in S1 is 1 min.
8. A hydrogen evolving material Pt-CoP obtainable by the process for the preparation of a hydrogen evolving material Pt-CoP according to any one of claims 1 to 7.
9. A catalyst for the electrolysis of water to produce hydrogen, characterized in that it comprises the hydrogen evolving material Pt-CoP according to claim 8.
10. Use of the hydrogen evolving material Pt-CoP according to claim 8 in the electrolysis of water to produce hydrogen.
Technical Field
The invention belongs to the technical field of hydrogen preparation by electrolyzing water, and particularly relates to a preparation method and application of a hydrogen evolution material Pt-CoP.
Background
With the increasing serious problems of energy and environment, the development and exploration of green and clean new energy are imminent. Since hydrogen has many advantages such as abundant resources, high calorific value, no pollution, etc., it is considered as the most ideal and alternative new energy. At present, the hydrogen production by electrolyzing water draws attention of people due to the advantages of low cost, environmental protection and the like. As a half-reaction for electrolyzing water, a hydrogen evolution reaction requires an electrocatalyst with fast kinetics and low potential. Commercial Pt is the most effective hydrogen production catalyst for electrolysis of water, but the characteristics of high price and resource scarcity severely limit the application. Therefore, it is very important to search for a low-potential, high-performance, low-price, clean and environment-friendly electrocatalytic material.
Therefore, the development of the electrocatalyst with good catalytic performance has important significance and application value.
Disclosure of Invention
The invention aims to overcome the defect and the defect of poor catalytic performance of the traditional electro-catalytic hydrogen production catalyst, and firstly provides a preparation method of a hydrogen evolution material Pt-CoP.
It is a second object of the present invention to provide a hydrogen evolution material Pt-CoP obtained by the above production method.
It is a third object of the present invention to provide an electrolytic water hydrogen production catalyst containing the above Pt-CoP.
It is a fourth object of the present invention to provide the use of the above Pt-CoP.
The purpose of the invention is realized by the following technical scheme:
the invention firstly provides a preparation method of a hydrogen evolution material Pt-CoP, which comprises the following steps:
s1, quickly pouring the aqueous solution of polyvinylpyrrolidone and squaric acid into the methanol solution of cobalt nitrate, carrying out ultrasonic treatment, standing for 72 hours, centrifuging, washing and drying to obtain powder 1;
s2, calcining the powder 1 under the protection of inert gas to obtain powder 2;
s3, calcining the powder 2 and sodium dihydrogen phosphate according to a certain ratio to obtain CoP;
s4, dispersing the CoP into a mixed solution of water and isopropanol, respectively adding chloroplatinic acid and sodium borohydride in sequence, mixing, stirring, reducing, separating and drying to obtain the Pt-CoP.
The method takes MoF as a frame, adopts a self-template method, carries out P-conversion, carries out high-temperature calcination in argon, and reduces to finally obtain the dice-shaped hollow structure. The structure effectively increases the electrochemical active surface area, is beneficial to the contact of materials and electrolyte, accelerates the mass transfer rate and effectively improves the catalytic performance. A small amount of Pt is loaded on a CoP dice-shaped hollow carrier through a chemical reduction method, so that the arrangement of electrons is effectively modified, the migration of the electrons is promoted, the synergistic effect between the two is realized, and the catalytic performance is jointly improved.
In recent years, hollow structures have attracted much attention due to their large specific surface area, large buffer volume, low density, and the like. Hollow structures obtained by the "self-templated" method tend to have advantages over "templated" in that structural integrity can be maintained and no other impurities introduced. Therefore, the invention designs a dice-shaped hollow structure by adopting a self-template method. In addition, the structure is used as a carrier, a small amount of Pt load is introduced, and the catalytic performance is improved through the synergistic effect of Pt modified electronic structure and the hollow carrier of the CoP.
Preferably, in the above method for producing a hydrogen evolution material Pt — CoP, the molar ratio of the squaric acid to the cobalt nitrate in S1 is 1.2: 1.
preferably, the pouring in step S1 is rapid pouring, the ultrasound time is 1min, and the drying manner is freeze drying.
Preferably, in step S2, the heating rate is 1 ℃/min, the temperature is 400 ℃, and the holding time is 2 h.
Preferably, the mass ratio of the black powder to the sodium dihydrogen phosphate in step S3 is 1: 16.
preferably, the calcination procedure in step S3 is: heating to 350 ℃ at the heating rate of 5 ℃/min, and keeping the temperature for 2 h.
Preferably, the volume ratio of water to isopropanol in step S4 is 1: 1.
preferably, the molar ratio of the sodium borohydride and the chloroplatinic acid added in step S4 is 5: 1.
preferably, the step S4 includes the following steps of adding chloroplatinic acid and sodium borohydride in sequence: firstly adding chloroplatinic acid, stirring for 10h, then adding sodium borohydride, and stirring for 3 h.
Preferably, the hydrogen evolution material Pt-CoP is in a dice-shaped hollow structure.
The invention also provides the hydrogen evolution material Pt-CoP obtained by the method.
The invention also provides the application of the hydrogen evolution material Pt-CoP in the hydrogen production by electrolyzing water; the Pt-CoP not only has the performance close to that of Pt/C in an acid solution, but also has good stability.
Compared with the prior art, the invention has the following beneficial effects:
the invention provides a preparation method of a hydrogen evolution material Pt-CoP, which takes MoF as a frame, adopts a self-template method, and adopts the steps of P formation, high-temperature calcination in argon and reduction to finally obtain a dice-shaped hollow structure. The structure effectively increases the electrochemical active surface area, is beneficial to the contact of materials and electrolyte, accelerates the mass transfer rate and effectively improves the catalytic performance. The dice-shaped hollow CoP carrier prepared by the method greatly increases the contact area of the electrolyte and the active site, and accelerates the mass transfer rate. The introduction of Pt not only reduces the content of noble metal but also modifies the electronic structure, resulting in the transfer of electrons from Pt to the CoP support. The synergistic effect between the Pt and the CoP improves the catalytic performance of the material. In an acid solution, Pt-CoP shows excellent hydrogen evolution performance and stability, and is suitable for hydrogen production by electrolyzing water.
Drawings
FIG. 1 is an SEM image of the catalytic material prepared in example 1;
FIG. 2 is an SEM photograph of the catalytic material prepared in comparative example 1;
FIG. 3 is an SEM photograph of the catalytic material prepared in comparative example 2;
FIG. 4 is an SEM photograph of the catalytic material prepared in comparative example 3;
FIG. 5 is a graph of HER polarization curves for example 1, comparative example 1, Pt/C in acidic solution;
figure 6 is a graph of HER polarization in acidic solution for example 1, comparative example 2;
figure 7 is a graph of HER polarization in acidic solution for example 1, comparative example 3.
Detailed Description
The following further describes the embodiments of the present invention. It should be noted that the description of the embodiments is provided to help understanding of the present invention, but the present invention is not limited thereto. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
The test methods used in the following examples and experimental examples are conventional methods unless otherwise specified; the materials, reagents and the like used, unless otherwise specified, are commercially available reagents and materials; the equipment used, unless otherwise specified, is conventional laboratory equipment.
Example 1
The preparation method of the hydrogen evolution electrocatalytic material Pt-CoP comprises the following steps:
(1) quickly pouring 7.5mL of aqueous solution dispersed with 75mg of polyvinylpyrrolidone and 65mg of squaric acid into 2.5mL of methanol solution of 141.2mg of cobalt nitrate, performing ultrasonic treatment for 1min, standing for 72h, washing with water for three times, centrifuging at 8000rpm for 5min, and freeze-drying to obtain pink powder;
(2) putting the pink powder prepared in the step (1) into argon, heating to 400 ℃ at a speed of 1 ℃/min, and preserving heat for 2h to obtain precursor powder;
(3) and (3) placing 0.05g of precursor powder prepared in the step (2) and 0.8g of sodium hypophosphite in argon, and placing the precursor powder at the air outlet of the tubular furnace below the sodium hypophosphite. Then heating to 350 ℃ at the speed of 5 ℃/min, and preserving heat for 2h to obtain black powder CoP;
(4) 25mg of the black powder obtained in (3) was dispersed in 2.5mL of a mixture (volume ratio of water to isopropyl alcohol: 1), followed by addition of 7.5mL of H2PtCl6(0.2mg/mL), stirred for 10h, and then 2.5mL NaH was added2PO2(0.584mg/mL) and stirred for 3 hours. Finally, the mixture is centrifuged to obtain a mixture,drying in a vacuum oven at 60 ℃ to obtain the final product named Pt-CoP.
Comparative example 1
The preparation method of the hydrogen evolution electrocatalytic material CoP comprises the following steps:
(1) quickly pouring 7.5mL of aqueous solution dispersed with 75mg of polyvinylpyrrolidone and 65mg of squaric acid into 2.5mL of methanol solution dissolved in 141.2mg of cobalt nitrate, carrying out ultrasonic treatment for 1min, standing for 72h, washing with water for three times, centrifuging for 5min at the speed of 8000rpm, and freeze-drying to obtain pink powder;
(2) putting the pink powder prepared in the step (1) into argon, heating to 400 ℃ at a speed of 1 ℃/min, and preserving heat for 2h to obtain precursor powder;
(3) and (3) placing 0.05g of precursor powder prepared in the step (2) and 0.8g of sodium hypophosphite in argon, and placing the precursor powder at the air outlet of the tubular furnace below the sodium hypophosphite. Then, the temperature is raised to 350 ℃ at the speed of 5 ℃/min, and the temperature is kept for 2h, so as to obtain black powder CoP.
Comparative example 2
The preparation method of the hydrogen evolution electrocatalytic material solid-Pt-CoP comprises the following steps:
(1) quickly pouring 7.5mL of aqueous solution dispersed with 75mg of polyvinylpyrrolidone and 65mg of squaric acid into 2.5mL of methanol solution dissolved in 141.2mg of cobalt nitrate, performing ultrasonic treatment for 1min, washing with water for three times, centrifuging at 8000rpm for 5min, and freeze-drying to obtain pink powder;
(2) putting the pink powder prepared in the step (1) into argon, heating to 400 ℃ at a speed of 1 ℃/min, and preserving heat for 2h to obtain precursor powder;
(3) and (3) placing 0.05g of precursor powder prepared in the step (2) and 0.8g of sodium hypophosphite in argon, and placing the precursor powder at the air outlet of the tubular furnace below the sodium hypophosphite. Then heating to 350 ℃ at the speed of 5 ℃/min, and preserving heat for 2h to obtain black powder CoP;
(4) 25mg of the black powder obtained in (3) was dispersed in 2.5mL of a mixture (volume ratio of water to isopropyl alcohol: 1), followed by addition of 7.5mL of H2PtCl6(0.2mg/mL), stirred for 10h, and then 2.5mL NaH was added2PO2(0.584mg/mL) and stirred for 3 hours. Last to leaveDrying the core in a vacuum oven at 60 ℃ to obtain the final product which is named solid-Pt-CoP.
Comparative example 3
The preparation method of the hydrogen evolution electrocatalytic material Pt-C comprises the following steps: 25mg of super C was dispersed in 2.5mL of the mixture (1: 1 volume ratio of water to isopropanol), followed by 7.5mL of H2PtCl6(0.2mg/mL), stirred for 10h, and then 2.5mL NaH was added2PO2(0.584mg/mL) and stirred for 3 hours. And finally, centrifuging and drying in a vacuum oven at 60 ℃ to obtain a final product named as Pt-C.
Application examples
The samples obtained in example 1 and comparative examples 1, 2 and 3 were subjected to a performance test.
And (3) morphology testing: as shown in FIGS. 1 and 2, SEM images of Pt-CoP and CoP of example 1 and comparative example 1, respectively. It can be seen from the figure that both are dice-shaped hollow structures. This structure can increase the active surface area, exposing more active sites. FIG. 3 is an SEM image of solid-Pt-CoP of comparative example 2, which is seen to be a solid cubic structure. FIG. 4 is an SEM image of comparative example 3Pt-C from which a structure that is loosely porous and amorphous can be seen.
Electrochemical testing: electrochemical testing the electrochemical test was performed using a three electrode system. The counter electrode was a carbon rod, the reference electrode was a silver chloride electrode, and the working electrode was a catalyst-coated glassy carbon electrode, wherein the catalysts were those prepared in example 1, comparative example 2, comparative example 3, and noble metal Pt/C. The working electrode was prepared as follows: adding 5mg of catalyst into 50uL of 5% Nafion solution and 950uL of water and mixed solution, ultrasonically dispersing for more than 30min, dropping 5uL of uniformly dispersed suspension on a glassy carbon electrode with the diameter of 3mm by using a 10uL liquid transfer gun, and carrying out infrared drying. The electrochemical test performance results are shown in fig. 5, fig. 6 and fig. 7.
As can be seen from FIG. 5, the catalytic performance of the catalytic material Pt-CoP prepared in example 1 is close to that of Pt/C. At a current density of-10 mA cm-2When used, the overpotential was 68.03mV, which is much less than the overpotential (197.09mV) of CoP in comparative example 1. This indicates thatThe introduction of Pt can obviously improve the catalytic activity of CoP. Also as can be seen in FIG. 6, the overpotential of solid-Pt-CoP is significantly larger than that of Pt-CoP, which indicates that the dice-like hollow structure helps to expose more active sites and improve the catalytic performance of the material. It is clear from FIG. 7 that the activity of Pt-CoP is much higher than that of Pt-C, which just demonstrates the superiority of CoP dice-like hollow structure as a carrier.
The embodiments of the present invention have been described in detail, but the present invention is not limited to the described embodiments. It will be apparent to those skilled in the art that various changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, and the scope of protection is still within the scope of the invention.