阅读说明：本技术 镍微米线高负载片状NiCo2O4的HER电催化剂制备方法 (Nickel micron line high load sheet NiCo2O4Preparation method of HER electrocatalyst ) 是由 唐少春 乔清山 张晟 胡立兵 于 2020-10-10 设计创作，主要内容包括：本发明公开了一种镍微米线高负载片状双金属氧化物NiCo-2O-4纳米结构的HER电催化剂,以镍微米线为基体、表面原位生长出片状NiCo-2O-4。制备步骤如下：取一段直径20μm的镍线,先用酸处理除去镍微米线表面的氧化物杂质；随后以硫酸镍、硝酸钴、氟化铵、尿素的混合溶液为原料,利用水热反应制得均匀NiCo-2O-4片状结构包覆镍微米线的纳微复合材料。该材料在高电流密度下催化性能优异,在100mA cm～(-2)的电流密度下过电势仅为85mV。(The invention discloses a nickel micron line high-load sheet-shaped bimetallic oxide NiCo 2 O 4 Nano structured HER electro catalyst, nickel micron line as substrate, sheet NiCo grown in situ on surface 2 O 4 . The preparation steps are as follows: taking a section of nickel wire with the diameter of 20 mu m, and removing oxide impurities on the surface of the nickel micron wire by acid treatment; then, the mixed solution of nickel sulfate, cobalt nitrate, ammonium fluoride and urea is used as a raw material, and a uniform NiCo is prepared by hydrothermal reaction 2 O 4 The nano-micro composite material of the nickel micron wire is coated by the sheet structure. The material has excellent catalytic performance under high current density and the current density is 100mA cm ‑2 The overpotential at current density of (a) is only 85 mV.)

1. Nickel micron line high-load flaky NiCo₂O₄The preparation method of the HER electrocatalyst is characterized in that a commercial nickel wire is sequentially dipped in 1M dilute hydrochloric acid and acetone, taken out, washed with deionized water for several times and dried at room temperature; dissolving nickel sulfate, cobalt nitrate, ammonium fluoride and urea with certain mass in deionized water, and magnetically stirring for 30 min; and transferring 35mL of mixed solution into a 50mL reaction kettle, adding an acidified nickel wire, reacting at 110-150 ℃, washing, and freeze-drying for 10h to obtain a final product.

2. The nickel microwire high load uniform flake NiCo of claim 1₂O₄The method for producing the catalyst is characterized in that the optimum concentrations of the mixed solution prepared from nickel sulfate, cobalt nitrate, ammonium fluoride and urea are 5 to 15mM, 10 to 50mM, 50 to 100mM and 100 to 200mM, respectively.

3. The preparation method according to claim 1, wherein 35mL of the mixed solution is transferred to a 50mL reaction kettle, and an acidified nickel wire with a length of 10-20 cm is added; the hydrothermal reaction temperature is 110-150 ℃, and the reaction time is required to be 1-3 h.

4. The nickel microwire high-load platy NiCo of claim 1₂O₄The method is characterized in that the final product is a nickel wire and NiCo grown on the surface of the nickel wire in situ₂O₄A spinel sheet structure; the sheet structure grows on the nickel wire in an overlapping manner, and the thickness of the coating layer is 4-5 mu m.

5. The nickel microwire high-load platy NiCo of claim 1₂O₄The preparation method is characterized in that the nickel wire after acidification treatment and the product after hydrothermal reaction are washed by deionized water and then freeze-dried, and the drying time is 10 hours.

6. The nickel microwire high-load platy NiCo of claim 1₂O₄Can be directly used for HER electrocatalytic electrodes.

Technical Field

The invention relates to a preparation process of a high-efficiency hydro-electro-catalysis Hydrogen Evolution Reaction (HER) catalyst, which is characterized in that commercial nickel micron lines are subjected to surface modification, and then flaky NiCo grows on the surface of the commercial nickel micron lines in situ through one step of hydrothermal process₂O₄A nanostructure. The method does not need any template, is simple to operate, low in cost, good in repeatability and easy to control.

Background

Hydrogen energy is considered to be 21One of the most promising energy sources in the century. Hydrogen energy is a very superior new energy source, and has the main advantages that: high combustion heat value, cleanness, no pollution, rich resources, wide application range and the like. Hydrogen is stored in vast sea. If the hydrogen is extracted, about 1.4X 10¹⁷Ton, generates 9000 times as much heat as fossil fuels on earth. The key technology for developing hydrogen energy comprises two aspects: on one hand, the problem of hydrogen production is solved; on the other hand, the problem of hydrogen storage and transportation is solved. The selection of the hydrogen production method is crucial to the wide use of hydrogen. The hydrogen production method mainly comprises the steps of water electrolysis hydrogen production, water photolysis hydrogen production, mineral fuel hydrogen production, biomass hydrogen production, hydrogen production by other hydrogen-containing substances, recovery of hydrogen produced by various chemical processes and the like, wherein the hydrogen production by electrocatalytic decomposition of water is the most main way for large-scale hydrogen production.

The nickel catalyst has good hydrogenation activity, and has the advantages of good catalytic activity, high mechanical strength, insensitivity to poison, good thermal conductivity and the like, so that the nickel catalyst is not only applied to hydrogenation of various unsaturated hydrocarbons, but also is a good catalyst in certain conversion processes such as dehydrogenation, oxidative dehalogenation, desulfurization and the like. The nickel-based catalyst has low preparation cost, is easy to obtain, and has potential in industrial application prospect. It has been found that when a nickel-based catalyst is supported on, for example, an inorganic or organic support, the catalyst itself and the support form an ordered whole, which is called a supported nickel-based catalyst, and the activity and stability of the catalyst can be effectively improved. This is because the carrier can increase the activity by interacting with the catalyst, or provide more contact area for the catalyst, etc.

The invention solves the problem that the surface of the nickel wire contains oxide impurities through acid treatment, and the modification enables the load material to easily grow on the substrate; through controlling the reaction kinetics, NiCo with the thickness of 4-5 microns is grown on the surface of the nickel wire₂O₄The sheet stacking structure has a high specific surface area, and the synergistic effect of the nickel and cobalt ions remarkably improves the efficiency of hydrogen production by catalytic water decomposition. And because the load material grows on the nickel wire substrate in situ, the load material and the nickel substrate have strong correlation, thereby enhancing catalysisThe stability of the whole material is improved.

Disclosure of Invention

The purpose of the invention is as follows: this patent proposes a nickel micron line high load slice NiCo₂O₄The material is based on nickel micron line, NiCo grows on the nickel micron line in situ₂O₄A sheet-like structure. The material has excellent catalytic performance under high current density and the current density is 100mA cm^-2The overpotential at current density of (a) is only 85 mV. The preparation method is simple to operate, low in cost and easy to scale; has important significance for designing and preparing HER electrocatalytic materials.

The technical scheme of the invention is as follows: soaking a commercial nickel wire in 1M dilute hydrochloric acid and acetone in sequence, taking out, washing with deionized water for several times, and drying at room temperature; dissolving nickel sulfate, cobalt nitrate, ammonium fluoride and urea with certain mass in deionized water, and magnetically stirring for 30 min; and transferring 35mL of the mixed solution into a 50mL reaction kettle, adding an acidified nickel wire (15 cm in length), reacting at 110-150 ℃, washing, and freeze-drying for 10h to obtain a final product.

As the optimum reaction parameters, the mixed reaction solution is prepared from nickel sulfate, cobalt nitrate, ammonium fluoride and urea, and the respective optimum concentrations are 5-15 mM, 10-50 mM, 50-100 mM and 100-200 mM.

Taking 35mL of the mixed solution as an optimal condition, transferring the mixed solution into a 50mL reaction kettle, and adding an acidified nickel wire (the length is 10-20 cm); the hydrothermal reaction temperature is 110-150 ℃, and the reaction time is required to be 1-3 h.

As an optimal condition, the final product is NiCo grown on the surface of a nickel wire in situ and a nickel wire₂O₄A sheet structure; the sheet structure grows on the nickel wire in an overlapping manner, and the thickness of the coating layer is 4-5 mu m.

As the optimal conditions, the nickel wire after the acidification treatment and the product after the hydrothermal reaction are washed by deionized water, and then freeze-dried, wherein the drying time is 10 hours.

The invention removes the oxide impurities on the surface of the nickel wire by a simple acid treatment method; then using nickel sulfate, cobalt nitrate, ammonium fluoride and urea as raw materialPreparing nickel wire as core and homogeneous NiCo through hydrothermal reaction₂O₄The sheet structure is a nano composite material of the surface layer. The sheet structures are overlapped to form a plurality of cavity structures, so that the specific surface area and the ion exchange rate of the material are increased. The material has excellent catalytic performance under high current density and the current density is 100mA cm^-2The overpotential at current density of (a) is only 85 mV.

The invention has the beneficial effects that:

(1) the invention provides a method for modifying the performance of a commercial nickel micron line;

(2) the material with a specific morphology can be obtained through one-step hydrothermal reaction, the operation is simple and convenient, and the repeatability is good;

(3) the prepared electro-catalytic material shows high-efficiency catalytic performance;

(4) compared with other methods, the preparation method has the following unique advantages:

firstly, the experimental device, experimental conditions and preparation process are very simple and easy to operate;

secondly, the cost is low, the control and the scale are easy, and the method has good industrial application prospect;

and the applicability is strong, and the method can be popularized to the preparation and large-scale production of other electrocatalysis devices.

Drawings

FIG. 1(a) is a raw nickel microwire without any treatment; (b-d) is NiCo of example 1₂O₄SEM images of the/Ni catalyst at different magnifications;

FIGS. 2(a-d) are NiCo of example 2₂O₄SEM images of the/Ni catalyst at different magnifications;

FIG. 3(a) shows how the nickel micron lines are fixed during performance testing; (b) the effect of hydrogen generation during the performance test; (c) linear sweep voltammetry tests of three samples of nickel wire without any treatment, example 1 and example 2. Wherein, the nickel wire represents the original nickel micron line without any treatment, and 0.5mmol represents NiCo prepared by adding nickel sulfate hexahydrate in an amount of 0.5mmol in example 1₂O₄Sample of Ni, 1.0mmol means that the amount of nickel sulfate hexahydrate added in example 2 is1.0mmol of prepared NiCo₂O₄The Ni sample.

Detailed Description

The invention prepares nickel micron line high-load sheet NiCo₂O₄Nanostructured HER electrocatalyst, for further understanding of the present invention, the electrocatalyst composites and their applications provided by the present invention are specifically described below with reference to examples, but the present invention is not limited to these examples, and those skilled in the art who have the teachings of the present invention will make insubstantial modifications and adaptations without departing from the scope of the invention. The specific implementation mode is as follows:

example 1

Nickel micron line high load sheet NiCo₂O₄Preparation of nanostructured HER electrocatalyst: soaking a commercial nickel wire in 1M dilute hydrochloric acid and acetone for 30min in sequence, taking out, washing with deionized water for several times, and drying at room temperature; 0.5mmol nickel sulfate hexahydrate, 1.0mmol cobalt nitrate hexahydrate, 3mmol ammonium fluoride and 6mmol urea were added to a 50ml beaker followed by deionized water to 35 ml; selecting proper magnetons, and magnetically stirring for 30 min; transferring 35mL of the mixed solution into a 50mL reaction kettle, adding an acidified nickel wire with the length of 15cm, reacting at 130 ℃, washing, and freeze-drying for 10h to obtain a final product.

FIG. 1(b-d) is a NiCo of example 1₂O₄SEM images of different magnifications of/Ni catalyst. Statistical analysis with software gave a shell material thickness of 4.8 μm. FIG. (b) is a low-magnification SEM image, and it can be clearly observed that the lamellar structure is uniformly distributed in the outer layer; (c) the overlapped sheet structures can be clearly observed on the graph, the specific surface area of the shell layer material is greatly improved by the formed cavity structure, and the HER catalytic performance is closely related to the specific surface area, so that the electrocatalytic performance of the material can be effectively enhanced; the edge of the formed sheet has a burr shape and is not smooth, so that the performance of the sheet is further improved.

Example 2

FIGS. 2(a-d) are NiCo of example 2₂O₄SEM images of different magnifications of/Ni catalyst. Wherein the addition amount of nickel sulfate hexahydrate is 1.0mmol, and cobalt nitrate hexahydrateThe amount of (2) was 2.0mmol, and other conditions were the same as in example 1. The average thickness of the shell layer material is 5 μm, the loading capacity of the shell layer material is larger than that of the shell layer material in example 1, the growth uniformity is worse than that of the shell layer material in example 1, but the single sheet is more regular, the edge and the surface of the single sheet are smoother and smoother, and the transport of electrons and ions is more facilitated.

Fig. 3(b) clearly shows that a large number of bubbles are generated during the performance test, indicating excellent catalytic performance for HER; there was a gradual improvement in the electrocatalytic HER performance from the linear sweep voltammetry test of (c) from the untreated nickel wire sample, to the 0.5mmol sample of example 1, to the 1.0mmol sample of example 2. At the same time of 100mA cm^-2At the current density of (2), overpotentials corresponding to the nickel wire, 0.5mmol and 1.0mmol of samples are respectively 160mV, 99mV and 85 mV.