Multi-heterogeneous cobalt-based sulfide catalyst and preparation method and application thereof
Through the preparation method of multi-heterogeneous cobalt-based sulfide catalyst, the problem of insufficient activity and stability of cobalt-based sulfide catalysts is solved, efficient electrocatalytic performance and stability are achieved, and the industrialization of electrocatalytic water decomposition technology has been promoted.
Patent Information
- Application Number
- CN202510328023.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-19
- Publication Date
- 2025-06-06
AI Technical Summary
The existing cobalt-based sulfides have insufficient activity and stability when used as oxygen evolution catalysts and the complex preparation process.
The preparation method of a multi-heterogeneous cobalt-based sulfide catalyst was used to prepare a multi-heterogeneous interface catalyst with three phases coexisting by hydrothermal reaction and high-temperature calcination.
The high electrocatalytic activity and excellent stability of the catalyst are achieved, with an overpotential below 300 mV, showing its excellent potential in electrocatalytic applications.
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Figure CN120099579A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of hydrogen production by water electrolysis, and specifically relates to a multi-heterogeneous cobalt-based sulfide catalyst and a preparation method thereof and application thereof in oxygen evolution by water electrolysis. Background Art
[0002] Hydrogen, with its high combustion calorific value and zero carbon emission, is widely regarded as one of the ideal choices for achieving sustainable energy transformation. Water electrolysis technology, as a green hydrogen production route, shows its potential in sustainable energy solutions through the action of efficient electrocatalysts. However, due to the slow kinetics of the four-electron transfer process involving proton coupling, the oxygen evolution reaction (OER) has become a major limiting factor in the electrocatalytic water splitting process. Therefore, the development of OER catalysts that are both efficient and stable is crucial to promote the commercialization and large-scale application of this technology.
[0003] Although noble metal catalysts such as ruthenium dioxide (RuO 2 ), iridium dioxide (IrO 2 ) and platinum (Pt) show excellent OER activity, but their scarcity and corresponding high cost have become the main obstacles to their widespread application. Therefore, researchers are working hard to find or design new non-precious metal catalysts in order to reduce costs and improve resource sustainability while maintaining high catalytic activity.
[0004] Transition metal sulfides, especially cobalt-based sulfides, have attracted widespread attention due to their excellent catalytic performance. These materials show great potential in the field of catalysis, but in-depth research and development are still needed to realize their application on an industrial scale. Morphology regulation, interface regulation, and defect regulation are effective means to improve catalyst performance. These strategies have been widely studied and applied to catalyst modification. Therefore, achieving multi-strategy regulation of cobalt-based sulfide catalysts to obtain the best catalytic effect is expected to play an important role in the field of electrocatalysis and promote the industrialization of related technologies. Summary of the invention
[0005] The purpose of the present invention is to solve the problems of insufficient activity and stability and complicated preparation process when the existing cobalt-based sulfide is used as an oxygen evolution catalyst. To this end, the present invention provides a multi-heterogeneous cobalt-based sulfide catalyst and a preparation method thereof and an application in electrolysis of water for oxygen evolution, wherein the electrocatalyst not only has high electrocatalytic activity but also exhibits excellent stability.
[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows: A method for preparing a multi-heterogeneous cobalt-based sulfide catalyst, the steps of which are as follows: (1) Prepare a mixed solution of cobalt source and sulfur source, transfer it to a reactor for hydrothermal reaction, and after natural cooling, rinse it with deionized water and ethanol respectively, place it in a drying oven for drying, and obtain cobalt disulfide (CoS 2 ); (2) Prepare CoS 2 The catalyst is placed in a tubular furnace with an inert atmosphere and calcined at a temperature of 400-600° C. to obtain a multi-heterogeneous cobalt-based sulfide catalyst.
[0007] Preferably, in step (1), the cobalt source is one of cobalt chloride, cobalt sulfate, and cobalt nitrate; and the sulfur source is one of sodium thiosulfate, thiourea, and thioacetamide.
[0008] Preferably, in step (1), the molar ratio of the cobalt source to the sulfur source is 2:5.
[0009] Preferably, in step (1), the hydrothermal reaction temperature is 160-200 °C, and the reaction time is 10-15 h. In this preparation step, the hydrothermal reaction temperature has little effect on the preparation and performance of the catalyst. CoS can be synthesized within the set temperature range of 160-200 °C. 2 .
[0010] Preferably, in step (1), the vacuum drying temperature is 60-80°C and the time is 8-12 h.
[0011] Preferably, in step (2), the inert atmosphere introduced into the tubular furnace is argon or a hydrogen-argon mixture, and the gas flow rate is 400 mL / min.
[0012] The purpose of introducing argon or hydrogen-argon mixed gas is, on the one hand, to exclude the air in the furnace, especially the oxygen therein, thereby avoiding oxidation of the sample; on the other hand, argon / hydrogen-argon conditions are conducive to high temperatures, and the sulfur species in the reaction are separated from the reaction area, thereby promoting the reaction to proceed in the direction of forming sulfur vacancies.
[0013] Preferably, in step (2), the calcination temperature in the tubular furnace is 420-590° C., and the calcination time is 1.5-2.5 h.
[0014] CoS 2 Under the condition of heat treatment at 420 ℃, phase transformation occurs and the phase transition is CoS 2 / Co 3 S 4 / CoS three-phase coexistence, CoS around 590 ℃ 2 、Co 3 S 4 Most of the phase changes to CoS.
[0015] In this temperature range, CoS2 It is in the intermediate transition stage to other crystalline phases, neither completely transformed into other sulfides nor maintaining the original CoS 2 crystalline phase, but formed a 2 、Co 3 S 4 and CoS are mixed in three phases. 2 、Co 3 S 4 The crystal structures of CoS and the quartz crystals are similar to each other to a certain extent, which enables them to achieve a certain degree of lattice matching at the crystal interface within this temperature range. At the same time, the thermal expansion and distortion of the lattice caused by temperature are also within a certain range and will not lead to complete destruction of the crystal structure, thus allowing the three phases to coexist under this condition.
[0016] Another object of the present invention is to provide a multi-heterogeneous cobalt-based sulfide catalyst prepared by the above-mentioned preparation method.
[0017] Another object of the present invention is to provide a multi-heterogeneous cobalt-based sulfide catalytic electrode material prepared using the cobalt-based sulfide catalyst.
[0018] Another object of the present invention is to provide a multi-heterogeneous cobalt-based sulfide catalytic electrode material for use in the electrolysis of water for oxygen evolution reaction, wherein the electrolyte is a 1.0 M KOH solution and the current density is 10 mA cm -2 The overpotential of the catalyst is 230 mV.
[0019] Compared with the existing electrocatalytic oxygen evolution catalyst, the present invention has the following beneficial effects: (1) The preparation method of the present invention can realize the preparation of cobalt-based sulfide catalyst by a simple hydrothermal method combined with a high-temperature calcination process. The preparation method is simple and has low cost.
[0020] (2) The present invention achieves the regulation of the catalyst phase by controlling different calcination temperatures. Calcination at high temperature can achieve the dual strategies of defect regulation and interface regulation, effectively increase the catalyst active sites, and improve the catalytic performance of the material.
[0021] (3) The catalysts calcined at different temperatures showed good catalytic activity (10 mAcm -2 Under the condition of calcination at high temperature of 500 °C, the obtained multi-heterogeneous interface structure (CoS 2 / Co 3 S 4 / CoS) exhibited excellent catalytic performance. -2Under the conditions of 40 ℃ and 80 ℃, the overpotential of the catalyst was only 230 mV, showing its excellent potential in electrocatalytic applications. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 CoS prepared in Example 1 of the present invention 2 -500 X-ray diffraction pattern (XRD).
[0023] Figure 2 CoS prepared in Example 1 of the present invention 2 -500 scanning electron microscope (SEM).
[0024] Figure 3 CoS prepared in Example 1 of the present invention 2 -500 transmission electron microscopy (TEM).
[0025] Figure 4 CoS prepared in Example 1 of the present invention 2 -500 high-resolution transmission electron microscopy (HR-TEM).
[0026] Figure 5 CoS prepared in Example 1 of the present invention 2 -500 electron paramagnetic resonance spectrum (EPR).
[0027] Figure 6 The CoS prepared in Example 1 of the present invention 2 -500 electrocatalyst, comparative sample CoS 2 Oxygen evolution polarization curves of electrode material (coated on commercial carbon paper) and commercial carbon paper.
[0028] Figure 7 The CoS prepared in Examples 2-5 of the present invention 2 -400, CoS 2 -600, CoS 2 -700, CoS 2 XRD pattern of the -800 electrocatalyst.
[0029] Figure 8 XRD patterns of the electrocatalysts prepared in Examples 6-13.
[0030] Fig. 9 The CoS prepared in Example 2 of the present invention 2 -400, CoS 2 -600, CoS 2 -700, CoS 2 Oxygen evolution polarization curve of -800 electrocatalyst. DETAILED DESCRIPTION
[0031] The details of the present invention will be further described by combining specific embodiments. It should be noted that the described embodiments do not represent all possible implementations of the present invention, but only a part thereof. Based on these embodiments, those skilled in the art can obviously obtain all other possible embodiments of the present invention without creative work. These embodiments also fall within the protection scope of the present invention.
[0032] Example 1 The preparation steps of the multi-heterogeneous cobalt-based sulfide catalyst are as follows: (1) Prepare 35 mL of a mixed solution containing cobalt nitrate and sodium thiosulfate (the molar ratio of cobalt nitrate to sodium thiosulfate is 2:5), then transfer the solution to a 50 mL reactor, perform a hydrothermal reaction at 180 °C for 12 h, and after natural cooling, rinse with deionized water and alcohol for multiple times, and dry in a drying oven at 60 °C to obtain cobalt disulfide (CoS 2 ); (2) Prepare CoS 2 The catalyst was placed in a tube furnace with argon gas and calcined at 500 °C for 2 h to obtain the desired cobalt-based sulfide catalyst (CoS 2 -500).
[0033] The prepared cobalt-based sulfide catalyst (CoS 2 -500) for characterization analysis: The figure shows the cobalt-based sulfide material CoS 2 -500's XRD spectrum shows that the material has good crystallinity. By comparing the standard PDF cards, they correspond to CoS 2 、Co 3 S 4 and the diffraction peaks of CoS (CoS 2 No: 41-1471, Co 3 S 4 The morphology of the material was further characterized by scanning electron microscopy and transmission electron microscopy. As shown in the figure, the cobalt-based sulfide presents a microsphere morphology formed by the aggregation of nanoparticles. The lattice fringes of 0.319 nm, 0.333 nm and 0.169 nm under high-resolution transmission electron microscopy correspond to CoS 2 (111), Co 3 S 4 (220) and CoS (110) crystal planes, further confirming that CoS 2 / Co 3 S 4 / CoS multi-heterointerface formation. The electron paramagnetic resonance spectrum (EPR) in the figure shows a more obvious paramagnetic absorption signal at g = 2.005, indicating the formation of sulfur vacancies.
[0034] Electrode material preparation and performance testing: Weigh 5 mg of the prepared cobalt-based sulfide electrocatalyst powder (CoS 2 -500) was added to a mixed solution of 480 μL anhydrous ethanol, 480 μL deionized water and 20 μL Nafion solution, and ultrasonically mixed for 30 min to obtain a uniform slurry. 100 μL of the uniform slurry was applied on a 1*1 cm 2 on carbon paper.
[0035] The oxygen evolution reaction of cobalt-based sulfide electrocatalysts was tested using a standard three-electrode system. In the test experiment, carbon paper coated with cobalt-based sulfide electrocatalysts was used as the working electrode, Hg / HgO was used as the reference electrode, platinum mesh was used as the counter electrode, and 1.0 M KOH solution was used as the electrolyte. As shown in the data, CoS 2 The electrocatalyst requires an overpotential of 230 mV at a current density of 10 mA cm², which is much lower than that of the untreated sample CoS 2 (399 mV). This result clearly shows that high-temperature calcination treatment significantly improves the activity of the electrocatalyst in the oxygen evolution reaction.
[0036] Example 2-Example 5 The specific preparation steps of Example 2-5 are different from those of Example 1 in that the cobalt disulfide CoS prepared in Example 2-5 is 2 Heat treatment temperature in different tube furnaces was 400 °C (CoS 2 -400)、600℃(CoS 2 -600)、700℃(CoS 2 -700) and 800 °C (CoS 2 -800). Figure 7 Table 1 shows the XRD patterns of the cobalt-based catalysts obtained at different calcination temperatures. Table 2 shows the catalyst phases and current densities up to 10 mA cm obtained at different heat treatment temperatures. - ²The overpotential required.
[0037] Table 1 Comparison of heat-treated phases and catalyst oxygen evolution performance at different temperatures
[0038] It can be seen from Table 1 that the cobalt-based sulfide catalyst prepared by the method of the present invention generates a catalyst containing CoS at a calcination temperature of 500°C.2 / Co 3 S 4 / CoS three-phase coexistence multi-heterogeneous interface catalyst at a current density of 10 mA cm - ², the required overpotential is 230mV, showing its optimal catalytic performance.
[0039] Example 6-Example 13 Cobalt disulfide will undergo a phase change during the calcination process. The present invention conducts multiple tests at a calcination temperature between 400-600°C to study the calcination temperature at which the phase change occurs. The specific test process is the same as that of Example 1, except that only the calcination temperature of cobalt disulfide is changed.
[0040] The specific preparation steps of Example 6-13 are different from those of Example 1 in that the cobalt disulfide CoS prepared in Example 6-13 is 2 The heat treatment temperatures in different tube furnaces are 420°C, 430°C, 450°C, 470°C, 550°C, 570°C, 580°C, and 590°C, and are compared with Examples 1 and 3.
[0041] Figure 8 The XRD patterns of the cobalt-based catalysts obtained at different calcination temperatures are shown in the figure. 2 Phase transformation occurs under 420℃ heat treatment conditions, and the phase transition is CoS 2 / Co 3 S 4 / CoS three-phase coexistence, CoS around 590 ℃ 2 、Co 3 S 4 Most of the phase changes to CoS, so CoS 2 / Co 3 S 4 The appearance temperature of the CoS / CoS heterostructure is 420~590℃. In this temperature range, the CoS 2 It is in the intermediate transition stage to other crystalline phases, neither completely transformed into other sulfides nor maintaining the original CoS 2 crystalline phase, but formed a 2 、Co 3 S 4 and CoS are mixed in three phases. 2 、Co 3 S 4The crystal structures of CoS and the quartz crystals are similar to each other to a certain extent, which enables them to achieve a certain degree of lattice matching at the crystal interface within this temperature range. At the same time, the thermal expansion and distortion of the lattice caused by temperature are also within a certain range and will not lead to complete destruction of the crystal structure, thus allowing the three phases to coexist under this condition.
Claims
1. A method for preparing a multi-heterogeneous cobalt-based sulfide catalyst, characterized in that: The preparation steps are as follows: (1) preparing a mixed solution of a cobalt source and a sulfur source, transferring it to a reactor for hydrothermal reaction, and after natural cooling, washing it with deionized water and ethanol respectively, placing it in a drying oven for drying, and obtaining cobalt disulfide (CoS2); (2) The prepared CoS2 is placed in a tubular furnace with an inert atmosphere for calcination at a temperature of 400-600°C to obtain a heterogeneous cobalt-based sulfide catalyst.
2. The method for preparing a cobalt-based sulfide catalyst according to claim 1, characterized in that: In the step (1), the cobalt source is one of cobalt chloride, cobalt sulfate and cobalt nitrate; and the sulfur source is one of sodium thiosulfate, thiourea and thioacetamide.
3. The method for preparing a multi-heterogeneous cobalt-based sulfide catalyst according to claim 1, characterized in that: In the step (1), the molar ratio of the cobalt source to the sulfur source is 2:
5.
4. The method for preparing a multi-heterogeneous cobalt-based sulfide catalyst according to claim 1, characterized in that: In the step (1), the hydrothermal reaction temperature is 160-200°C and the reaction time is 10-15 h.
5. The method for preparing a cobalt-based sulfide catalyst according to claim 1, characterized in that: In step (2), the vacuum drying temperature is 60-80°C and the time is 8-12 h.
6. The method for preparing the polyheterogeneous cobalt-based sulfide catalyst according to claim 1, characterized in that: In the step (2), the inert atmosphere introduced into the tubular furnace is argon or a hydrogen-argon mixture, and the gas flow rate is 400 mL / min.
7. The method for preparing a multi-heterogeneous cobalt-based sulfide catalyst according to claim 1, characterized in that: In the step (2), the calcination temperature in the tubular furnace is 420-590° C., and the calcination time is 1.5-2.5 h.
8. A multi-heterogeneous cobalt-based sulfide catalyst, characterized in that: The method according to any one of claims 1 to 7 is used for preparation, and the structure is a multi-heterogeneous interface structure in which three phases of CoS2 / Co3S4 / CoS coexist.
9. A multi-heterogeneous cobalt-based sulfide catalytic electrode material, characterized in that: It is prepared using the cobalt-based sulfide catalyst described in claim 8.
10. The use of the multi-heterogeneous cobalt-based sulfide catalytic electrode material in electrolysis of water for oxygen evolution as claimed in claim 9, characterized in that: The electrolyte was 1.0 M KOH solution and the current density was 10 mA cm -2 The overpotential of the catalyst is 230 mV.