阅读说明：本技术 一种催化剂负载合金钢电极板的制备方法 (Preparation method of catalyst-loaded alloy steel electrode plate ) 是由 魏世忠 潘昆明 赵阳 夏梁彬 吴宏辉 徐流杰 张玢 于华 张程 陈冲 毛丰 周 于 2020-12-30 设计创作，主要内容包括：本发明涉及一种催化剂负载合金钢电极板的制备方法,称取合金钢粉、镍粉和钼酸铵,将其逐一加入盛有蒸馏水的烧杯中搅拌,对烧杯加热并持续搅拌使水完全蒸发得到干燥固体粉末,对该固体粉末在真空下热处理,冷却后将其倒入石墨模具中并进行烧结处理,然后再放入通有硫化氢气体的管式炉内进行热处理,得到催化剂负载合金钢电极板。本发明通过温度控制、流量控制、浓度控制、高温烧结等,使得到的合金钢基体呈现多孔疏松的微观结构,有利于提供更多催化剂反应的场所,从而优化材料的催化效率。本发明步骤简单、原料成本低,过程可控,所得成品电极兼具稳定的催化活性和良好的导电性,一定程度上可完成机械加工制成各种形状,有望实现规模化生产。(The invention relates to a preparation method of a catalyst-loaded alloy steel electrode plate, which comprises the steps of weighing alloy steel powder, nickel powder and ammonium molybdate, adding the alloy steel powder, the nickel powder and the ammonium molybdate into a beaker filled with distilled water one by one, stirring, heating the beaker, continuously stirring to completely evaporate water to obtain dry solid powder, carrying out heat treatment on the solid powder under vacuum, cooling, pouring the solid powder into a graphite mold, carrying out sintering treatment, and then putting the graphite mold into a tubular furnace filled with hydrogen sulfide gas for heat treatment to obtain the catalyst-loaded alloy steel electrode plate. According to the invention, through temperature control, flow control, concentration control, high-temperature sintering and the like, the obtained alloy steel matrix presents a porous and loose microstructure, so that more catalyst reaction places are provided, and the catalytic efficiency of the material is optimized. The method has the advantages of simple steps, low raw material cost and controllable process, and the obtained finished electrode has stable catalytic activity and good conductivity, can be machined to be made into various shapes to a certain extent, and is expected to realize large-scale production.)

1. The preparation method of the catalyst-supported alloy steel electrode plate is characterized by comprising the following steps of:

step one, weighing alloy steel powder, nickel powder and ammonium molybdate according to the required size of a final product, and selecting a proper graphite die for later use;

step two, slowly adding the three kinds of powder in the step one into a beaker filled with distilled water one by one, and fully stirring;

step three, heating the beaker in the step two, and continuously stirring in the heating process until the water is completely evaporated, wherein all the inside of the beaker is dry solid powder;

step four, carrying out heat treatment on the dried solid powder obtained in the step three under a vacuum condition, cooling to room temperature, and taking out the powder;

step five, slowly pouring the cooled powder in the step four into the graphite mould in the step one, and then placing the graphite mould into a discharge plasma sintering furnace to sinter the powder;

taking out the sintered sample from the spark plasma sintering furnace, and then putting the sintered sample into a tubular furnace filled with hydrogen sulfide gas for heat treatment; and taking out the sample after the heat treatment is finished, and obtaining the final product, namely the catalyst-loaded alloy steel electrode plate.

2. The preparation method of the catalyst-supported alloy steel electrode plate according to claim 1, characterized in that: in the first step, the mass ratio of the alloy steel powder, the nickel powder and the ammonium molybdate is 15-40: 2-10: 1.

3. The preparation method of the catalyst-supported alloy steel electrode plate according to claim 1 or 2, characterized in that: the alloy steel powder adopts DT 300.

4. The preparation method of the catalyst-supported alloy steel electrode plate according to claim 1, characterized in that: in the third step, the heating temperature is 60-80 ℃.

5. The preparation method of the catalyst-supported alloy steel electrode plate according to claim 1, characterized in that: in the fourth step, the temperature of the heat treatment is 400-600 ℃, and the time is 1-3 h.

6. The preparation method of the catalyst-supported alloy steel electrode plate according to claim 1, characterized in that: in the fifth step, the sintering temperature is 400-800 ℃, the heating rate is 50-100 ℃/min, and the sintering condition is non-vacuum sintering.

7. The preparation method of the catalyst-supported alloy steel electrode plate according to claim 1, characterized in that: in the sixth step, the flow rate of the hydrogen sulfide gas is 10-30 sccm, the heat treatment temperature is 440-600 ℃, and the time is 1-3 h.

8. The preparation method of the catalyst-supported alloy steel electrode plate according to claim 1, characterized in that: the obtained catalyst-loaded alloy steel electrode plate is used for hydrogen production by catalytic water decomposition.

9. The preparation method of the catalyst-supported alloy steel electrode plate according to claims 1 to 7, wherein the preparation method comprises the following steps: other substances with catalytic properties are loaded on the metal substrate by the method to prepare the electrode material with catalytic properties.

10. The preparation method of the catalyst-supported alloy steel electrode plate according to claim 9, wherein the preparation method comprises the following steps: other materials with catalytic properties are tungsten sulphide, nickel sulphide, cobalt sulphide.

Technical Field

The invention relates to the technical field of preparation of catalytic materials, in particular to a preparation method of a catalyst-loaded alloy steel electrode plate, and belongs to a technical application of preparing catalytic materials by a powder metallurgy method.

Background

Today, where the world economy has developed vigorously, the industry has pushed the progress of human civilization, but has also led to a dramatic increase in energy consumption, with fossil energy still being the most dominant energy source in use today. On the one hand, fossil energy reserves are limited and non-renewable; on the other hand, fossil energy consumption brings ecological environment pollution. With the gradual shortage of petroleum resources and the increasing serious environmental pollution, the healthy life of human beings is threatened. Therefore, the search for clean and sustainable energy sources to reduce environmental pollution is urgent. Hydrogen energy is considered as the most promising clean energy, and how to produce hydrogen gas with low cost and high efficiency becomes a research hotspot which is concerned. The hydrogen production by catalytic water decomposition is an old and mature technology, but the existing high-efficiency catalyst is mainly a noble metal material, so that the large-batch industrial application of the catalyst is severely restricted, and the development of a low-cost non-noble metal catalyst has important significance.

The main problems of the research on non-noble metal catalysts at home and abroad can be summarized as follows: 1. the conductivity was poor. The catalyst prepared in the laboratory is mainly powder, lacks the current collector of electricity, hardly gives full play to the catalytic performance of the material. The obtained performance is only small-scale performance, but if the method is applied to engineering, the large-scale catalytic effect cannot be quantitatively calculated based on the small scale; 2. the scale is small. The catalyst prepared in the laboratory is mainly prepared in small batches, the process is fine and complex, the dominant phase such as 1T phase is slightly interfered by external conditions, but the stability of the catalyst in the engineering production is difficult to ensure; 3. the mechanical strength is poor. Although the research on the self-supporting electrode is available at present, the adopted carrier is a carbon material or a flexible conductive material, so that the mechanical strength is poor, the operation and the processing are not facilitated, and the carrier is not suitable for engineering production.

Disclosure of Invention

In order to solve the technical problems, the invention provides a preparation method of a catalyst-loaded alloy steel electrode plate, which has the advantages of simple steps, low raw material cost and controllable process, and the prepared finished electrode has stable catalytic activity and good conductivity, can be machined to be made into various shapes to a certain extent, and is expected to realize large-scale production.

The invention provides a preparation method of a catalyst-loaded alloy steel electrode plate, which comprises the following steps:

step one, weighing alloy steel powder, nickel powder and ammonium molybdate according to the required size of a final product, and selecting a proper graphite die for later use;

step two, slowly adding the three powders in the step one into a beaker filled with distilled water one by one, and fully stirring to ensure that the three powders are completely fused;

step three, heating the beaker in the step two, and continuously stirring in the heating process until the water is completely evaporated, wherein all the inside of the beaker is dry solid powder;

step four, carrying out heat treatment on the dried solid powder obtained in the step three under a vacuum condition, cooling to room temperature, and taking out the powder;

step five, slowly pouring the cooled powder in the step four into the graphite mould in the step one, and then placing the graphite mould into a discharge plasma sintering furnace to sinter the powder;

taking out the sintered sample from the spark plasma sintering furnace, and then putting the sintered sample into a tubular furnace filled with hydrogen sulfide gas for heat treatment; and taking out the sample after the heat treatment is finished, and obtaining the final product, namely the catalyst-loaded alloy steel electrode plate.

Preferably, in the first step, the mass ratio of the alloy steel powder, the nickel powder and the ammonium molybdate is 15-40: 2-10: 1.

Preferably, DT300 is selected as the alloy steel powder.

Preferably, in the third step, the heating temperature is 60 ℃ to 80 ℃.

Preferably, in the fourth step, the temperature of the heat treatment is 400-600 ℃ and the time is 1-3 h.

Preferably, in the fifth step, the sintering temperature is 400-800 ℃, the heating rate is 50-100 ℃/min, and the sintering condition is non-vacuum sintering.

Preferably, in the sixth step, the flow rate of the hydrogen sulfide gas is 10-30 sccm, the heat treatment temperature is 440-600 ℃, and the time is 1-3 h.

Preferably, the obtained catalyst-supported alloy steel electrode plate is used for catalyzing water decomposition to produce hydrogen.

Furthermore, the main body of the catalytic phase of the catalyst-supported alloy steel electrode plate obtained by the invention is molybdenum disulfide, but other substances with catalytic properties (such as tungsten sulfide, nickel sulfide, cobalt sulfide and the like) can be supported on a metal substrate by the method provided by the invention to prepare the electrode material with catalytic properties.

The molybdenum source is in-situ precipitated on the surface of the metal powder through liquid phase mixing, and then is sintered with the metal powder, and the forming condition is controlled, so that the product is porous as much as possible to expose more reaction sites. And then, the metal oxide in the catalyst is converted into metal sulfide by adopting an in-situ vulcanization process to form a heterogeneous structure of various sulfides, so that the catalytic activity of the product is enhanced. According to the invention, in the preparation process, through temperature control, flow control, concentration control and the like, the obtained alloy steel matrix presents a porous and loose microstructure, so that more catalyst reaction sites can be provided, the contact area of the material and the electrolyte can be greatly increased, and the catalytic reaction can be carried out more fully. In addition, hydrogen and oxygen which are water decomposition products easily escape from the pores of the material, so that the catalytic efficiency of the material is further optimized.

Compared with the existing smelting method, the preparation process has the advantages of lower cost, more convenient operation and stronger applicability. The prepared catalyst-loaded alloy steel electrode plate has high catalytic activity, good conductivity and certain mechanical property and machinability, can be used as a catalyst and a current collector, can be particularly directly used as an electrode for catalyzing water decomposition, and has wide industrial production prospect.

Drawings

FIG. 1 is a photograph of a sample of a catalyst-supported alloy steel electrode plate prepared in example 1;

FIG. 2 is an SEM electron micrograph of the catalyst-supported alloy steel electrode plate prepared in example 1;

FIG. 3 is an SEM electron micrograph of the catalyst-supported alloy steel electrode plate prepared in example 2;

FIG. 4 is an SEM electron micrograph of the catalyst-supported alloy steel electrode plate prepared in example 3;

FIG. 5 is a graph showing the electrocatalytic water splitting performance of the catalyst-supported alloy steel electrode plate prepared in example 3.

Detailed Description

The technical solution of the present invention will be further explained and explained in detail with reference to the drawings and the specific embodiments.

A preparation method of a catalyst-loaded alloy steel electrode plate mainly comprises the following steps:

step one, selecting a proper graphite die according to the required size of a final product, and weighing a certain amount of alloy steel powder, nickel powder and ammonium molybdate for later use.

For example, according to the size of a final product, determining volume and shape parameters, selecting a graphite mold with a proper size, estimating the mass of required powder (alloy steel powder, nickel powder and ammonium molybdate) by the product of the volume and the powder density, and meeting the requirement that the mass ratio of the alloy steel powder, the nickel powder and the ammonium molybdate is steel powder: nickel powder: 15-40: 2-10: 1 ammonium molybdate, wherein DT300 can be selected as the alloy steel powder. In the application, steel is the main body of the material, nickel plays the role of connecting and bridging iron and molybdenum elements, the molybdenum salt amount needs to be strictly controlled, and if the molybdenum salt amount is too small, the product catalytic phase MoS is generated₂The precipitation is not obvious, and the excessive precipitation affects the sintering property of the product and is not easy to form.

And step two, slowly adding the three powders in the step one into a beaker filled with distilled water one by one, and fully stirring to ensure that the three powders are completely fused.

The amount of distilled water used here is preferably such that ammonium molybdate is completely dissolved.

And step three, heating the beaker obtained in the step two, and continuously stirring in the heating process until the water is completely evaporated, wherein the inside of the beaker is completely dry solid powder.

The stirring here may be mechanical paddle stirring or manual glass rod stirring, with no strict requirement, in order to evaporate the water in the powder and to precipitate ammonium molybdate uniformly on the metal powder particles. The heating temperature is 60-80 ℃, the precipitation efficiency is influenced by too low temperature, and the operation difficulty is increased by too high temperature.

And step four, carrying out heat treatment on the dried solid powder obtained in the step three under a vacuum condition. After cooling to room temperature, the powder was taken out.

The heat treatment temperature is 400-600 ℃, and the time is 1-3 h. The purpose is to attach ammonium molybdate [ (NH) to the metal powder particles₄)₂Mo₄O₁₃]Decomposition into molybdenum trioxide [ MoO₃]To obtain a metal particle mixed powder to which molybdenum trioxide is attached. The vacuum condition ensures the rapid removal of the reaction products of ammonia and water, and greatly improves the reaction efficiency. The relevant reaction equation is as follows:

(NH₄)₂Mo₄O₁₃＝2NH₃+4MoO₃+H₂O

and step five, slowly pouring the cooled powder in the step four into the graphite mold in the step one, and then placing the graphite mold into an SPS discharge plasma sintering furnace to sinter the mixed powder.

The SPS sintering temperature is 400-800 ℃, and the heating rate is 50-100 ℃/min. The temperature and the heating rate need to be strictly controlled, if the temperature is too low, the forming degree is poor, and the pulverization is easy; if the temperature is too high, the density of the formed sample is high, and the sample has no porous structure, so that the adhesion and the function of the catalyst are not favorably exerted. Similarly, the rate of temperature increase also affects the size of the product pores. More importantly, the SPS sintering is different from the ordinary SPS sintering, and a hearth of the SPS sintering cannot be vacuumized. The principle is that dense oxides can be formed at the point where the sample is in contact with air during sintering. The method aims to be beneficial to the formation of a porous loose structure of a sample on the one hand and reduce the difficulty of subsequent vulcanization on the other hand.

Taking out the sintered sample from the discharge plasma sintering furnace after cooling, and then putting the sample into a tubular furnace filled with hydrogen sulfide gas for heat treatment; and taking out the sample after the heat treatment is finished, and obtaining the final product, namely the catalyst-loaded alloy steel electrode plate.

The flow rate of the hydrogen sulfide gas is 10-30 sccm, the heat treatment temperature is 440-600 ℃, and the time is 1-3 h. The method aims to ensure that metal oxides on the surface of a sample and in micropores are completely converted into metal sulfides, the reaction is insufficient when the temperature is too low, the generated elemental sulfur is difficult to completely remove, and the particles of the generated metal sulfides are large when the temperature is too high, so that the improvement of the catalytic activity is not facilitated. The relevant reaction equation is as follows:

MoO₃+3H₂S＝MoS₂+3H₂O+S

NiO+H₂S＝NiS+H₂O

Fe₂O₃+3H₂S＝Fe₂S₃+3H₂O

example 1:

(1) 3g of DT300 alloy steel powder, 0.4g of nickel powder and 0.2g of ammonium molybdate are weighed, and a graphite die with the diameter of phi 20mm is selected for standby.

(2) Slowly adding the three powders in the step (1) into a beaker filled with distilled water one by one, and fully stirring to ensure that the three powders are completely fused.

(3) And (3) heating the beaker in the step (2) at the heating temperature of 60 ℃. Stirring is continued during the heating process until the water is completely evaporated and the inside of the beaker is completely dry solid powder.

(4) And (4) carrying out heat treatment on the solid powder obtained in the step (3) under a vacuum condition, wherein the heat treatment temperature is 400 ℃, and the time is 1 h. After cooling to room temperature, the powder was taken out.

(5) And (3) slowly pouring the cooled powder in the step (4) into the graphite mould in the step (1), and then placing the graphite mould into an SPS discharge plasma sintering furnace to sinter the powder. Setting the sintering temperature of the discharge plasma sintering furnace at 400 ℃, the heating rate at 50 ℃/min, and the sintering condition of non-vacuum sintering.

(6) And after cooling, taking out the sintered sample from the SPS sintering furnace, and then putting the sample into a tubular furnace filled with hydrogen sulfide gas for heat treatment. The flow rate of hydrogen sulfide gas is 10sccm, the heat treatment temperature is 440 ℃, and the time is 1 h. And taking out the sample after the heat treatment is finished, and obtaining the final product, namely the catalyst-loaded alloy steel electrode plate.

The finished electrode plate prepared in this example was macroscopically and microscopically characterized, and the results are shown in fig. 1 and 2. As can be seen from fig. 1: the product obtained in this example is in the form of a black disc having a diameter of 20mm and a thickness of 2mm, as can be seen from FIG. 2: the microscopic appearance of the surface of the product is a mixed particle cluster consisting of a large number of nanospheres, nanorods and nanosheets, and the cluster is uniformly distributed on the surface of the material.

Example 2:

(1) 30g of DT300 alloy steel powder, 10g of nickel powder and 1g of ammonium molybdate are weighed, and a graphite die with the diameter of phi 100mm is selected for standby.

(2) Slowly adding the three powders in the step (1) into a beaker filled with distilled water one by one, and fully stirring to ensure that the three powders are completely fused.

(3) And (3) heating the beaker in the step (2) at the heating temperature of 80 ℃. Stirring is continued during the heating process until the water is completely evaporated and the inside of the beaker is completely dry solid powder.

(4) And (4) carrying out heat treatment on the solid powder obtained in the step (3) under a vacuum condition, wherein the heat treatment temperature is 600 ℃, and the time is 3 hours. After cooling to room temperature, the powder was taken out.

(5) And (3) slowly pouring the cooled powder in the step (4) into the graphite mould in the step (1), and then placing the graphite mould into an SPS discharge plasma sintering furnace to sinter the powder. Setting the sintering temperature of the discharge plasma sintering furnace to be 800 ℃, the heating rate to be 100 ℃/min, and the sintering condition to be non-vacuum sintering.

(6) And after cooling, taking out the sintered sample from the SPS sintering furnace, and then putting the sample into a tubular furnace filled with hydrogen sulfide gas for heat treatment. The flow rate of hydrogen sulfide gas is 30sccm, the heat treatment temperature is 600 ℃, and the time is 3 h. And taking out the sample after the heat treatment is finished, and obtaining the final product, namely the catalyst-loaded alloy steel electrode plate.

The finished electrode plate prepared in this example was characterized by SEM electron micrographs, and the results are shown in fig. 3. As can be seen from fig. 3: after the product prepared by the embodiment is amplified by 5 thousand times, the surface of the product is obviously attached with flaky small particles, and the nanosheets uniformly grow out of the relatively flat substrate in situ and have good binding property with the substrate.

Example 3:

(1) weighing 15g of DT300 alloy steel powder, 5g of nickel powder and 1g of ammonium molybdate, and selecting a graphite die with the diameter of phi 50mm for later use.

(2) Slowly adding the three powders in the step (1) into a beaker filled with distilled water one by one, and fully stirring to ensure that the three powders are completely fused.

(3) And (3) heating the beaker in the step (2) at the heating temperature of 70 ℃. Stirring is continued during the heating process until the water is completely evaporated and the inside of the beaker is completely dry solid powder.

(4) And (4) carrying out heat treatment on the solid powder obtained in the step (3) under a vacuum condition, wherein the heat treatment temperature is 500 ℃, and the time is 2 hours. After cooling to room temperature, the powder was taken out.

(5) And (3) slowly pouring the cooled powder in the step (4) into the graphite mould in the step (1), and then placing the graphite mould into an SPS discharge plasma sintering furnace to sinter the powder. Setting the sintering temperature of the discharge plasma sintering furnace as 600 ℃, the heating rate as 800 ℃/min and the sintering condition as non-vacuum sintering.

(6) And after cooling, taking out the sintered sample from the SPS sintering furnace, and then putting the sample into a tubular furnace filled with hydrogen sulfide gas for heat treatment. The flow rate of hydrogen sulfide gas is 20sccm, the heat treatment temperature is 500 ℃, and the time is 2 h. And taking out the sample after the heat treatment is finished, and obtaining the final product, namely the catalyst-loaded alloy steel electrode plate.

The finished electrode plate prepared in this example was characterized by SEM electron micrographs, and the results are shown in fig. 4. As can be seen from fig. 4: after the product prepared in the embodiment is amplified by 1 ten thousand times, a plurality of nano-platelet structures are uniformly attached to the surface of the substrate, and the result shows that the product obtained by the method is a self-supporting catalytic electrode material formed by loading the nano-platelet layers on a metal alloy steel plate.

In order to test the performance of the product prepared by the invention in water electrocatalytic decomposition, an electrochemical workstation can be adopted to demonstrate through an experiment of testing a hydrogen evolution polarization curve by three electrodes. The electrolyte used in the experiment is a 1mol/L KOH solution, the obtained alloy steel plate can be directly used as a working electrode, a graphite rod is used as a counter electrode, and a calomel electrode is used as a reference electrode. And setting a voltage scanning interval to be-1.4-0V to obtain a polarization curve. The results are shown in FIG. 5. As can be seen from fig. 5: the starting potential of the hydrogen evolution catalytic reaction of the alloy steel electrode plate finished product is eta 10-97 mV. The material has excellent electrocatalytic hydrogen evolution performance.

The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention in any way, and any simple modification, equivalent change and modification made by those skilled in the art according to the technical spirit of the present invention are still within the technical scope of the present invention without departing from the technical scope of the present invention.