A nanosheet catalyst for CO oxidation catalysis, and a preparation method and application thereof
By growing a nanosheet-like composite of copper oxide and cobalt tetroxide on nickel foam, the stability and catalytic performance issues of existing CO elimination catalysts were solved, achieving rapid and complete CO elimination and reducing preparation costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- LIAONING TECHNICAL UNIVERSITY
- Filing Date
- 2024-03-25
- Publication Date
- 2026-07-21
AI Technical Summary
Existing CO elimination catalysts, such as precious metal catalysts and hogallat agents, are expensive and prone to deterioration. Non-precious metal catalysts, such as cobalt tetroxide, have catalytic performance affected by environmental factors and have a slow catalytic rate, making it difficult to achieve rapid CO elimination.
The catalyst is prepared by growing a composite of copper oxide and cobalt tetroxide on nickel foam to improve its stability and catalytic performance. The catalyst is also prepared by hydrothermal reaction and sintering heat treatment to form a nanostructure to increase the specific surface area.
This method achieves rapid and complete CO elimination at lower temperatures, improving catalyst stability and CO elimination capacity while reducing preparation costs.
Smart Images
Figure CN118237027B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of catalytic materials technology, and in particular to a nanosheet catalyst for CO oxidation catalysis, its preparation method, and its application. Background Technology
[0002] my country boasts some of the world's largest coal reserves, and coal dominates its energy structure, accounting for 56.2%. With continuous economic development, coal mining intensity and operating depth are increasing, leading to various safety hazards, among which carbon monoxide (CO) exceeding limits has attracted considerable attention from researchers. CO exceeding limits often results in accidents causing casualties and making rescue operations extremely difficult. Therefore, finding efficient CO removal methods is of great significance for ensuring the safety of coal mine production and the occupational safety of workers during mine disaster emergency rescue. Among CO removal technologies, catalytic oxidation of CO to CO2 is a highly efficient and stable method.
[0003] Currently, the main CO elimination catalysts studied are noble metal catalysts and horgalactose catalysts, but they still suffer from drawbacks such as high cost and susceptibility to degradation. Non-noble metal catalysts exhibit higher catalytic activity and are significantly cheaper than noble metal catalysts, thus attracting widespread attention from researchers. Among them, cobalt tetroxide (Co3O4) has advantages such as low cost, abundant reserves, and stable chemical structure, and its use as a CO elimination catalyst has been gradually developed in recent years. However, its catalytic performance is affected by many factors such as synthesis temperature and reaction environment temperature and humidity, and its catalytic CO elimination reaction rate is relatively slow, failing to achieve rapid CO elimination. Summary of the Invention
[0004] In view of this, the purpose of this invention is to provide a nanosheet catalyst for CO oxidation catalysis, its preparation method, and its application. The catalyst provided by this invention has good stability and strong CO elimination ability.
[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:
[0006] The present invention provides a nanosheet catalyst for CO oxidation catalysis, comprising nickel foam and metal oxides grown on the nickel foam, wherein the metal oxides are copper oxide and cobalt tetroxide, and the copper oxide and cobalt tetroxide are in the form of nanosheets.
[0007] Preferably, the mass ratio of copper oxide to cobalt tetroxide is (2-4):1.
[0008] This invention provides a method for preparing the catalyst described in the above technical solution, comprising the following steps:
[0009] A copper salt, cobalt salt, urea, and solvent are mixed to obtain an active component precursor solution; the solvent is a mixture of ethylene glycol and water.
[0010] Nickel foam was added to the precursor solution of the active component, and the mixture was subjected to hydrothermal reaction and sintering heat treatment in sequence to obtain the catalyst.
[0011] Preferably, the copper salt is copper nitrate and the cobalt salt is cobalt nitrate.
[0012] Preferably, the mass ratio of the copper salt, cobalt salt and urea is (8-10):(3-5):(5-10).
[0013] Preferably, the volume ratio of ethylene glycol to water in the mixed solvent is 1:(9-11).
[0014] Preferably, the hydrothermal reaction is carried out at a temperature of 100–160°C for 2–6 hours.
[0015] Preferably, the sintering heat treatment is performed at a temperature of 300–400°C for 2–4 hours.
[0016] This invention provides the application of the catalyst described in the above technical solutions or the catalyst prepared by the above technical solutions in the catalytic oxidation of CO to CO2.
[0017] Preferably, the oxidation temperature is 150–180°C.
[0018] This invention provides a nanosheet catalyst for CO oxidation catalysis, comprising nickel foam and metal oxides grown on the nickel foam, wherein the metal oxides are copper oxide and cobalt tetroxide, and the copper oxide and cobalt tetroxide are in the form of nanosheets. This invention introduces copper oxide into cobalt tetroxide to form a composite, which improves the catalyst's resistance to environmental humidity and thermal stability, thus enhancing its catalytic performance while maintaining good stability. Furthermore, this invention grows the active metal oxide components on nickel foam, giving it a nanostructure, which greatly increases the catalyst's specific surface area and significantly improves its CO elimination capacity. Therefore, the catalyst provided by this invention has good stability and strong CO elimination capacity. Example results show that the catalyst provided by this invention, when used for CO oxidation catalysis, can eliminate CO at relatively low temperatures, achieving rapid and complete CO elimination at around 170°C.
[0019] This invention provides a method for preparing the catalyst described in the above technical solution. The preparation method provided by this invention is low in cost, simple in process, and highly reliable. Attached Figure Description
[0020] Figure 1The images shown are SEM images of the catalyst prepared in Example 1 at different magnifications. Figure 1 In the middle, (a), (b), and (c) are SEM images with magnifications of 500, 10000, and 30000, respectively;
[0021] Figure 2 The graphs show the CO elimination performance of the catalysts prepared in Examples 1-3 at different temperatures. Detailed Implementation
[0022] The present invention provides a nanosheet catalyst for CO oxidation catalysis, comprising nickel foam and metal oxides grown on the nickel foam, wherein the metal oxides are copper oxide and cobalt tetroxide, and the copper oxide and cobalt tetroxide are in the form of nanosheets.
[0023] In this invention, the mass ratio of copper oxide to cobalt tetroxide is preferably (2-4):1, more preferably 3:1.
[0024] In this invention, copper oxide and cobalt tetroxide are each combined in the form of nanocrystals to grow into a nanosheet structure.
[0025] This invention incorporates copper doping into cobalt tetroxide, which improves the stability and catalytic performance of the catalyst. Furthermore, this invention grows the active metal oxide component on nickel foam, giving it a nanostructure, which greatly increases the specific surface area of the catalyst and significantly enhances its ability to eliminate CO.
[0026] The catalyst with a nanosheet structure provided by this invention has the advantages of large specific surface area, high catalytic activity, and long lifetime.
[0027] This invention provides a method for preparing the catalyst described in the above technical solution, comprising the following steps:
[0028] A copper salt, cobalt salt, urea, and solvent are mixed to obtain an active component precursor solution; the solvent is a mixture of ethylene glycol and water.
[0029] Nickel foam was added to the precursor solution of the active component, and the mixture was subjected to hydrothermal reaction and sintering heat treatment in sequence to obtain the catalyst.
[0030] Unless otherwise specified, all raw materials involved in this invention are commercially available products well known in the art.
[0031] This invention mixes copper salt, cobalt salt, urea, and a solvent to obtain a precursor solution of the active component. In this invention, the copper salt is preferably copper nitrate, and the cobalt salt is preferably cobalt nitrate. In embodiments of this invention, the copper nitrate and cobalt nitrate are added in the form of copper nitrate trihydrate and cobalt nitrate hexahydrate, respectively. In this invention, the urea is used as a precipitant. In this invention, the particle size of the copper salt, cobalt salt, and urea is preferably 3–15 μm. In this invention, the solvent is a mixture of ethylene glycol and water, preferably deionized water, and the volume ratio of ethylene glycol to water in the mixed solvent is preferably 1:(9–11). In this invention, the ethylene glycol is a polar solvent, with a polarity greater than ethanol but less than water. By adding ethylene glycol, the polarity of the solvent can be changed, affecting the growth process of the material on nickel foam, thereby affecting the morphology of the product.
[0032] In this invention, the preferred mass ratio of the copper salt, cobalt salt, and urea is (8-10):(3-5):(5-10), more preferably 10:4:5. In this invention, the preferred ratio of the total mass of the copper salt, cobalt salt, and urea to the volume of the solvent is 1 g:(69-73) mL.
[0033] In this invention, the mixing is preferably carried out by stirring. This invention does not have special requirements for the stirring conditions, as long as the components are mixed evenly.
[0034] After obtaining the active component precursor solution, the present invention adds nickel foam to the active component precursor solution, and performs hydrothermal reaction and sintering heat treatment sequentially to obtain the catalyst. The present invention does not have special requirements for the nickel foam; any nickel foam well-known to those skilled in the art can be used. Before use, the present invention preferably soaks, cleans, and dries the nickel foam sequentially with hydrochloric acid; the concentration of the hydrochloric acid is preferably 3 mol / L, the soaking is preferably performed under ultrasonic conditions, and the soaking time is preferably 20 min; the cleaning preferably includes sequential rinsing with deionized water, ultrasonic cleaning with deionized water, and ultrasonic cleaning with ethanol, and the ultrasonic cleaning times with deionized water and ethanol are each preferably 15 min; the drying temperature is preferably 80℃, and the drying time is preferably 12 h. The present invention does not have special requirements for the amount of the active component precursor solution; it is sufficient to completely submerge the nickel foam.
[0035] In this invention, the active component precursor solution is preferably transferred to a reaction vessel with a polytetrafluoroethylene liner, nickel foam is added to the solution, and then the reaction vessel is transferred to an oven for hydrothermal reaction.
[0036] In this invention, the temperature of the hydrothermal reaction is preferably 100–160°C, more preferably 140–160°C, and the time is preferably 2–6 h, more preferably 2–4 h. In this invention, the possible chemical reaction during the hydrothermal reaction is: Co(NO3)2 + Cu(NO3)2 + CO(NH2)2 → Co2(OH)2CO3 + Cu2(OH)2CO3 + NH4NO3.
[0037] After the hydrothermal reaction is completed, the resulting nickel foam material is preferably cleaned and dried sequentially before undergoing sintering heat treatment. In this invention, the cleaning is preferably performed using deionized water and ethanol to thoroughly rinse the obtained nickel foam material; the drying temperature is preferably 90°C, and the drying time is determined by complete drying.
[0038] In this invention, the sintering heat treatment temperature is preferably 300–400°C, more preferably 300–350°C, and the time is preferably 2–4 hours, more preferably 2–3 hours. The sintering heat treatment is preferably carried out in a muffle furnace under an air atmosphere. During the sintering heat treatment, the possible reaction is: Co₂(OH)₂CO₃ + Cu₂(OH)₂CO₃ + O₂ → Co₃O₄ / CuO + H₂O + CO₂.
[0039] After the sintering heat treatment is completed, the resulting material is cooled to room temperature to obtain the catalyst.
[0040] This invention provides the application of the catalyst prepared by the preparation method described above in the catalytic oxidation of CO to CO2.
[0041] In this invention, the oxidation temperature is preferably 150–180°C, more preferably 150–170°C. In an embodiment of this invention, in a simple atmosphere (gas ratio of 85% N2 + 14.5% O2 + 0.5% CO) simulation test with a CO concentration of 5000 ppm and a gas flow rate of 100 mL / min, the catalyst can achieve complete CO elimination at around 170°C.
[0042] In this invention, the catalyst can be used to eliminate CO in coal mines, thus protecting the health of workers in coal mines.
[0043] To further illustrate the present invention, the nanosheet catalyst for CO oxidation catalysis provided by the present invention, its preparation method and application are described in detail below with reference to examples, but these should not be construed as limiting the scope of protection of the present invention.
[0044] Example 1
[0045] A nanosheet catalyst for CO oxidation catalysis is prepared as follows:
[0046] Cut the nickel foam into 3cm×7cm pieces (1.6mm thick), immerse them in 3mol / L hydrochloric acid and sonicate for 20min, then rinse with deionized water, and sonicate in deionized water and ethanol for 15min each; finally, place the nickel foam in a vacuum drying oven and vacuum dry at 80℃ for 12h.
[0047] 0.7284 g of copper nitrate trihydrate, 0.2910 g of cobalt nitrate hexahydrate, and 0.3604 g of urea were dissolved in a mixed solution of 8 mL of ethylene glycol and 88 mL of deionized water, and stirred continuously until homogeneous. The resulting solution was then transferred to a 100 mL stainless steel reactor lined with polytetrafluoroethylene (PTFE), and one piece of the pretreated nickel foam was added. The reactor was then transferred to an oven and heated at 140 °C for 4 h. After the reaction was complete, the mixture was cooled to room temperature, and the precipitate was thoroughly washed with deionized water and ethanol, and then dried at 90 °C for 12 h. Subsequently, the obtained precursor was calcined in a muffle furnace at 350 °C for 2 h (i.e., sintering heat treatment). After the reaction was complete, the mixture was cooled to room temperature to obtain the catalyst (the catalyst loading per unit area of nickel foam was 1.955 × 10⁻⁶). -3 g / cm -2 ).
[0048] Figure 1 The images shown are SEM images of the catalyst prepared in Example 1 at different magnifications. Figure 1 Images (a), (b), and (c) are SEM images magnified to 500, 10000, and 30000 magnifications, respectively. Figure 1 Image (a) shows that the catalyst grows on a nickel foam framework, while images (b) and (c) show that the catalyst material exhibits a distinct nanosheet morphology. XRD characterization confirmed that the product contains only Co3O4 (JCPDS 42-1467) and CuO (JCPDS 48-1548), with no other impurities.
[0049] Example 2
[0050] A nanosheet catalyst for CO oxidation catalysis is prepared as follows:
[0051] 5.7985 g of copper nitrate trihydrate, 2.3280 g of cobalt nitrate hexahydrate, and 2.8832 g of urea were dissolved in a mixed solution of 64 mL of ethylene glycol and 704 mL of deionized water, and stirred continuously until homogeneous. The resulting solution was then transferred to a 100 mL stainless steel reactor lined with polytetrafluoroethylene (PTFE), and one piece of pretreated nickel foam (same as in Example 1) was added. The reactor was then transferred to an oven and heated at 140 °C for 2 h. After the reaction was complete, the mixture was cooled to room temperature, and the precipitate was thoroughly washed with deionized water and ethanol, and then dried at 90 °C for 12 h. Subsequently, the obtained precursor was calcined in a muffle furnace at 300 °C for 3 h, and after the reaction was complete, it was cooled to room temperature to obtain the catalyst.
[0052] Example 3
[0053] A nanosheet catalyst for CO oxidation catalysis is prepared as follows:
[0054] 1.44 g of copper nitrate trihydrate, 0.58 g of cobalt nitrate hexahydrate, and 0.72 g of urea were dissolved in a mixture of 20 mL of ethylene glycol and 180 mL of deionized water, and stirred continuously until homogeneous. The resulting solution was then transferred to a 100 mL stainless steel reactor lined with polytetrafluoroethylene (PTFE), and one piece of pretreated nickel foam (same as in Example 1) was added. The reactor was then transferred to an oven and heated at 160 °C for 4 h. After the reaction was complete, the mixture was cooled to room temperature, and the precipitate was thoroughly washed with deionized water and ethanol, and then dried at 90 °C for 12 h. Subsequently, the obtained precursor was calcined in a tube furnace at 300 °C for 2 h, and after the reaction was complete, cooled to room temperature to obtain the catalyst.
[0055] The catalytic performance of the catalysts prepared in Examples 1-3 was tested for CO oxidation. The test method was as follows: The mass of the catalyst used in the test was 0.5 g (excluding the mass of nickel foam). Based on the mass of catalyst supported on nickel foam per unit area, several nickel foam discs with a diameter of 1.9 cm were calculated and cut. These discs were placed in a tube furnace, and a mixed gas with a CO concentration of 5000 ppm and a gas flow rate of 100 mL / min (gas ratio of 85% N2 + 14.5% O2 + 0.5% CO) was introduced. The reaction temperature was controlled using a programmed temperature rise method, and the CO concentration in the tail gas was measured in real time using a gas analyzer to calculate the CO elimination rate. The test results are as follows: Figure 2 As shown, the corresponding CO elimination data are shown in Table 1.
[0056] Table 1. Effect of catalysts prepared in Examples 1-3 on CO elimination at different temperatures.
[0057]
[0058]
[0059] As can be seen from Table 1, the catalysts prepared in Examples 1 to 3 have good CO elimination performance. They can completely eliminate CO at around 170°C, and CO is undetectable in the exhaust gas at the outlet of the tubular furnace, thus achieving rapid CO elimination.
[0060] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. The application of a nanosheet catalyst in the catalytic oxidation of CO to CO2; wherein the oxidation temperature is 150~180℃; wherein the nanosheet catalyst comprises nickel foam and metal oxides grown on the nickel foam, wherein the metal oxides are copper oxide and cobalt tetroxide, and the morphology of the copper oxide and cobalt tetroxide is nanosheet; The method for preparing the catalyst includes the following steps: A copper salt, cobalt salt, urea, and solvent are mixed to obtain an active component precursor solution; the solvent is a mixture of ethylene glycol and water; the mass ratio of the copper salt, cobalt salt, and urea is (8~10):(3~5):(5~10); the volume ratio of ethylene glycol to water in the mixed solvent is 1:(9~11). Nickel foam was added to the precursor solution of the active component, and the catalyst was obtained by sequentially performing a hydrothermal reaction and a sintering heat treatment. The hydrothermal reaction was carried out at a temperature of 100~160℃ for 2~6h. The sintering heat treatment was carried out at a temperature of 300~400℃ for 2~4h.
2. The application according to claim 1, characterized in that, The mass ratio of copper oxide to cobalt tetroxide is (2~4):
1.
3. The application according to claim 1, characterized in that, The copper salt is copper nitrate, and the cobalt salt is cobalt nitrate.