阅读说明：本技术 一种NiMoSx高效氧析出催化剂的制备方法 (NiMoSxPreparation method of high-efficiency oxygen evolution catalyst ) 是由 李光达 赵凌雪 葛怀云 于 2021-08-30 设计创作，主要内容包括：本发明涉及催化和纳米材料领域,介绍了一种NiMoS-x高效氧析出催化剂的制备方法,可以应用于电解水领域以及金属-空气电池领域。首先六水合硝酸钴,均苯三甲酸,钼酸铵为原料合成了镍钼双金属MOF前驱体,在此基础上,利用水合肼和硫粉水热进行硫化,得到最终产物：钼硫化镍催化剂材料,以其作为氧析出电催化剂表现出优异性能。该催化剂在0.1M的碱性氢氧化钾溶液中进行氧析出性能测试,催化剂材料具有比贵金属催化剂更加小的过电位(180mV),且该催化剂制备过程简单,价格相对较低,过电位低,制备时间短,循环稳定性好等优点。(The invention relates to the field of catalysis and nano materials, and introduces a NiMoS x The preparation method of the high-efficiency oxygen evolution catalyst can be applied to the field of water electrolysis and the field of metal-air batteries. Firstly, cobalt nitrate hexahydrate, trimesic acid and ammonium molybdate are used as raw materials to synthesize a nickel-molybdenum bimetallic MOF precursor, and on the basis, hydrazine hydrate and sulfur powder are used for hydrothermal vulcanization to obtain a final product: molybdenum nickel sulphide catalyst materials, which exhibit excellent performance as oxygen evolution electrocatalysts. The catalyst is tested for oxygen precipitation performance in 0.1M alkaline potassium hydroxide solution,the catalyst material has a smaller overpotential (180mV) than a noble metal catalyst, and the catalyst has the advantages of simple preparation process, relatively low price, low overpotential, short preparation time, good cycle stability and the like.)

1. NiMoS_xThe preparation process of the catalyst material comprises the following steps:

(1)0.25 g of nickel nitrate hexahydrate and 0.2 g of trimesic acid were dissolved in 20 ml of dimethylformamide, and 0.25 g of ammonium molybdate was added thereto and stirred until dissolved. Adding into a reaction kettle with a volume of 50 ml, reacting at 140 ℃ for 12 hours, naturally cooling to room temperature, centrifuging for 3 times by using absolute ethyl alcohol, and drying in an oven at 60 ℃ for 12 hours to obtain a precursor

(2) Weighing 100 mg of precursor, dispersing in 20 ml of deionized water, and continuously stirring and uniformly mixing; dissolving sulfur powder in 10 ml of hydrazine hydrate, then dropwise adding the hydrazine hydrate dissolved with the sulfur powder into the precursor solution, stirring for 3 hours, adding into a reaction kettle, reacting for 12 hours at 140 ℃, after the reaction is finished, respectively centrifuging the obtained product for 3 times by using deionized water and absolute ethyl alcohol, and drying for 12 hours in an oven at 60 ℃.

2. NiMoS_xCatalyst material the catalyst is prepared by the process of claim 1.

Technical Field

The invention belongs to the field of catalysis and nano materials, and particularly relates to NiMoS_xThe preparation method and the application of the high-efficiency Oxygen Evolution (OER) catalyst can be widely applied to the field of electrocatalysis, including the fields of water electrolysis, secondary metal air batteries and the like.

Background

The increasing demand for energy has led to rapid consumption of fossil fuels, stimulating outbreaks of environmental problems. Pressure from energy sources and the environment drives people to continuously seek new energy sources and new energy storageAnd the mode of transformation. Among the many types of energy storage and conversion, electrocatalytic energy conversion and storage technologies have been recognized as one of the most feasible and effective ways to convert and store energy. Four major reactions related to water in electrocatalysis, including Hydrogen Evolution Reaction (HER), Oxygen Evolution Reaction (OER), Oxygen Reduction Reaction (ORR) and Hydrogen Oxidation Reaction (HOR), are widely used in electrolytic cells and fuel cells, and have become the focus of research in recent years. The zinc-air battery has high theoretical energy density (1086Wh kg)^-15 times of commercial lithium batteries), rich raw materials, no pollution, renewable utilization, high cost performance, high safety and the like. Therefore, the invention prepares a high-efficiency oxygen precipitation catalyst by a simple hydrothermal method so as to improve the oxygen precipitation performance of the metal-air battery.

At present, noble metal catalysts such as IrO2/RuO2 catalysts are considered as the best active catalysts for OER. However, the high cost and poor stability of these precious metals has hindered their large-scale commercial application. Therefore, the development of highly efficient catalysts remains a difficult task. Among them, some transition metal chalcogenides exhibit excellent catalytic activity for OER, which can be attributed to the high electronic conductivity and multiple valence states of various metal chalcogenides. In general, atoms that are not sufficiently coordinated at the MS edge have high catalytic activity and can provide more active sites simultaneously. However, these metal sulfides have limited exposed electroactive sites and lack stability, which is not favorable for improving the electrocatalytic activity. Therefore, researchers have employed a series of processes to expose sulfides to more active sites and to modulate their active adsorption energy. Based on the idea, the invention prepares the bimetallic MOF precursor and then carries out vulcanization, and the bimetallic MOF precursor generates more defects and active sites due to the substitution of another metal, so that the vulcanized product has higher performance.

Disclosure of Invention

According to the problems provided by the invention, an idea for preparing the bimetallic MOF and then carrying out vulcanization is designed, and the high-performance oxygen evolution catalyst is prepared.

The specific scheme of the invention is as follows:

(1) dissolving cobalt nitrate hexahydrate and trimesic acid in a certain amount of dimethylformamide, stirring for 30 minutes, adding ammonium molybdate, dissolving, placing into a reaction kettle, reacting for 12 hours at 140 ℃, and centrifugally drying;

(2) dispersing the precursor obtained in the step (1) in 20 ml of deionized water, and continuously stirring and uniformly mixing; dissolving sulfur powder in 10 ml of hydrazine hydrate, then dropwise adding the hydrazine hydrate dissolved with the sulfur powder into the precursor solution, stirring for 3 hours, then placing into a reaction kettle, reacting for 12 hours at 140 ℃, and centrifugally drying.

In the first step, 0.25 g of nickel nitrate hexahydrate and 0.2 g of trimesic acid were dissolved in 20 ml of dimethylformamide, and 0.25 g of ammonium molybdate was added thereto and stirred until dissolved. Adding the mixture into a reaction kettle with the volume of 50 ml, reacting for 12 hours at the temperature of 140 ℃, naturally cooling to room temperature, centrifuging for 3 times by using absolute ethyl alcohol, and drying for 12 hours in an oven at the temperature of 60 ℃ to obtain a precursor.

In the second step, the precursor is weighed to be 100 mg, and hydrazine hydrate is slowly added dropwise in a fume hood. After the reaction in the reaction kettle is completed, respectively centrifuging 3 times by using deionized water and absolute ethyl alcohol, and drying for 12 hours in an oven at the temperature of 60 ℃.

Drawings

FIG. 1 illustrates NiMoS prepared in an example embodiment_xTransmission electron microscopy images of the catalyst material.

FIG. 2 illustrates NiMoS prepared in accordance with an exemplary embodiment_xThe polarization curve of the oxygen evolution reaction of the catalyst measured under 0.1M potassium hydroxide basic conditions is compared to the performance of standard iridium carbon.

Detailed Description

The following detailed description of the present invention is provided in connection with specific examples to provide a further understanding of the present invention, and the following specific examples are not intended to limit the invention to only one experimental embodiment.

Examples

0.25 g of nickel nitrate hexahydrate and 0.2 g of trimesic acid were weighed out and dissolved in 20 ml of dimethylformamide, and 0.25 g of ammonium molybdate was added thereto and stirred until dissolved. Adding the mixture into a reaction kettle with the volume of 50 ml, reacting for 12 hours at the temperature of 140 ℃, naturally cooling to room temperature, centrifuging for 3 times by using absolute ethyl alcohol, and drying for 12 hours in an oven at the temperature of 60 ℃ to obtain a precursor. Weighing 100 mg of precursor, dispersing in 20 ml of deionized water, and continuously stirring and uniformly mixing; dissolving sulfur powder in 10 ml of hydrazine hydrate, then dropwise adding the hydrazine hydrate dissolved with the sulfur powder into the precursor solution, stirring for 3 hours, adding into a reaction kettle, reacting for 12 hours at 140 ℃, after the reaction is finished, respectively centrifuging the obtained product for 3 times by using deionized water and absolute ethyl alcohol, and drying for 12 hours in an oven at 60 ℃.

The electrode manufacturing process comprises the following steps:

weighing 2 mg of NiMoS_xThe catalyst material, 1.5 mg VXC-72 conductive carbon black, 20. mu.l Nafion were dissolved in 480. mu.l isopropanol, sonicated for 40 minutes, 16. mu.l of the slurry was drop-coated onto a glassy carbon electrode (radius 5 mm), and dried at room temperature for 24 hours.

And (3) testing oxygen precipitation performance:

with NiMoS_xThe catalyst material is used for oxygen precipitation performance test and is characterized in that: when oxygen evolution performance analysis is carried out, 0.1M potassium hydroxide solution is used as electrolyte, the rotation speed is 1600r/min for testing, and the scanning speed is 5 mV/s. As shown in FIG. 1, NiMoS_xThe transmission electron microscope image can be used for obtaining NiMoS_xThe composite material is composed of nickel substrate and molybdenum sulfide grown on the surface thereof, and has an oxygen precipitation catalysis curve measured under alkaline condition with current density of 10mA/cm as shown in FIG. 2²The overpotential is only 180 mV.