B-site regulation LaBO3 perovskite catalyst with high-purity hierarchical pore structure as well as preparation method and application of B-site regulation LaBO3 perovskite catalyst
A high-purity, hierarchical porous LaBO3 perovskite catalyst was prepared by a simple process of dissolution, complexation, evaporation, and calcination, which solved the problems of complex preparation and high cost in the existing technology and realized the preparation and application of the catalyst with high efficiency and low cost.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- PINGXIANG UNIV
- Filing Date
- 2025-12-08
- Publication Date
- 2026-04-17
AI Technical Summary
The existing LaBO3 perovskite catalysts have complex and costly preparation processes, making it difficult to achieve large-scale industrial applications.
A high-purity LaBO3 perovskite catalyst with a hierarchical porous structure was prepared by using simple steps such as dissolution, complexation, gel evaporation, aging, and calcination, and by controlling the molar ratio of La to B-site metal ions, the amount of complexing agent, and calcination parameters.
The efficient preparation of high-purity, hierarchical porous LaBO3 catalysts has been achieved. The catalysts are low-cost, suitable for large-scale industrial production, and exhibit excellent catalytic performance, making them suitable for the catalytic combustion degradation of volatile organic compounds.
Smart Images
Figure CN121869338A_ABST
Abstract
Description
Technical Field
[0001] This disclosure belongs to the field of catalytic material preparation and environmental protection technology, specifically relating to a high-purity, multi-level porous structure, B-site regulated LaBO3 perovskite catalyst and its preparation method. Background Technology
[0002] Volatile organic compounds (VOCs) are key precursors to the formation of ozone (O3) and fine particulate matter (PM2.5), posing a serious threat to the ecological environment and human health. With the acceleration of industrialization, VOC emissions continue to rise, and their efficient control has become a core task in air pollution prevention and control.
[0003] Catalytic combustion technology is considered the most promising VOCs treatment technology due to its advantages such as high purification efficiency, low energy consumption, and no secondary pollution. Its core lies in the development of high-performance catalysts. Currently, commonly used catalysts are mainly divided into noble metal catalysts and non-noble metal oxide catalysts: noble metal catalysts (such as Rh, Pt, and Pd) have excellent activity, but suffer from high cost and susceptibility to poisoning and deactivation, limiting large-scale industrial applications; non-noble metal oxide catalysts are inexpensive and have good stability, gradually becoming a research hotspot.
[0004] Perovskite oxides (ABO3), as typical non-noble metal catalysts, possess unique crystal structures, excellent redox properties, and tunable chemical compositions. Among them, the LaBO3 system (La representing a rare earth element at the A-site and B representing a transition metal element) is the most widely used. The A-site ions primarily stabilize the crystal structure, while the B-site ions, as active centers, directly determine the catalyst's surface acidity, oxygen species activity, and redox properties through their type, valence state, and electronic configuration, thereby regulating the catalytic combustion activity of VOCs. Furthermore, high purity and hierarchical porous structures can further enhance the catalytic performance of LaBO3 perovskite catalysts. Therefore, developing a simple, low-cost, high-purity LaBO3 perovskite catalyst preparation method with a hierarchical porous structure has significant technological value and application prospects. Summary of the Invention
[0005] This disclosure aims to at least solve one of the technical problems of complex processes and high costs in the prior art, and provides a high-purity, multi-level porous structure B-site regulated LaBO3 perovskite catalyst, its preparation method, and its application.
[0006] One aspect of this disclosure provides a method for preparing a high-purity, hierarchical porous B-site-controlled LaBO3 perovskite catalyst, the preparation method comprising: Weigh out La(NO3)3 6H2O and the corresponding B-site metal nitrate were added to ultrapure water and magnetically stirred until completely dissolved, and then stirring was continued to obtain a homogeneous solution. Add a complexing agent to the homogeneous solution, stir magnetically until completely dissolved, and continue stirring to form a homogeneous complexing solution; The homogeneous complex solution was heated to a gel state and then dried to obtain the precursor. The precursor was crushed and placed in a crucible, then calcined in a muffle furnace and naturally cooled to obtain the LaBO3 perovskite catalyst.
[0007] Optionally, the B-site metal nitrate is selected from Co(NO3)2. 6H2O, Fe(NO3)3 9H2O, Mn(NO3)2 aqueous solution, Al(NO3)3 One of the components of 9H2O.
[0008] Alternatively, La(NO3)3 6H2O and B-site metal nitrate were weighed according to a 1:1 molar ratio of La to B-site metal ions.
[0009] Optionally, the complexing agent is citric acid monohydrate.
[0010] Optionally, the amount of the complexing agent added is 1.1-1.3 times the total number of moles of metal ions in the homogeneous solution.
[0011] Optionally, the heating temperature for heating the homogeneous complex solution to a gel state is 75-85°C, and the drying temperature is 110-130°C.
[0012] Optionally, the precursor is crushed, placed in a crucible, and calcined in a muffle furnace at a temperature of 450-550°C for 3-5 hours.
[0013] Optionally, the LaBO3 perovskite catalyst has an ABO3-type pure-phase perovskite structure with a hierarchical porous structure.
[0014] In another aspect of this disclosure, a high-purity, hierarchical porous structure B-site regulated LaBO3 perovskite catalyst is proposed, wherein the LaBO3 perovskite catalyst is prepared using the preparation method described above.
[0015] Another aspect of this disclosure proposes the application of a high-purity, hierarchical porous B-site controlled LaBO3 perovskite catalyst, which is used in the catalytic combustion degradation of volatile organic compounds.
[0016] This disclosure provides a high-purity, hierarchical porous structure, B-site-controlled LaBO3 perovskite catalyst, its preparation method, and its application. The preparation method of the B-site-controlled LaBO3 perovskite catalyst includes: weighing La(NO3)3... 6H₂O and the corresponding B-site metal nitrate are added to ultrapure water and magnetically stirred until completely dissolved, then stirring is continued to obtain a homogeneous solution. A complexing agent is added to the homogeneous solution, and magnetically stirred until completely dissolved, then stirring is continued to form a homogeneous complex solution. The homogeneous complex solution is heated to a gel state, dried, and a precursor is obtained. The precursor is crushed, placed in a crucible, calcined in a muffle furnace, and naturally cooled to obtain a LaBO₃ perovskite catalyst. This disclosure achieves the efficient preparation of a pure-phase, highly active, and hierarchically porous LaBO₃ catalyst. The preparation method is simple to operate, has controllable parameters, and is low in cost, solving the problems of complex and high-cost traditional precious metal catalyst preparation processes. It is suitable for large-scale industrial production, and the prepared catalyst can be widely used in VOCs catalytic combustion treatment. Attached Figure Description
[0017] Figure 1 This is a flowchart illustrating the LaBO3 catalyst preparation method according to a specific embodiment of this disclosure; Figure 2 The XRD patterns of the LaBO3 catalysts prepared in Examples 1-4 of this disclosure are shown below. Figure 3 The SEM images are of the LaBO3 catalysts prepared in Examples 1-4 of this disclosure; Figure 4 The BJH pore size distribution diagrams of the LaBO3 catalysts prepared in Examples 1-4 of this disclosure are shown. Figure 5 The O2-TPD spectra of the LaBO3 catalysts prepared in Examples 1-4 of this disclosure are shown. Figure 6 The NH3-TPD spectra of the LaBO3 catalysts prepared in Examples 1-4 of this disclosure are shown. Figure 7 The toluene catalytic combustion activity curves of the LaBO3 catalysts prepared in Examples 1-4 of this disclosure are shown. Detailed Implementation
[0018] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain this disclosure and represent a part of the embodiments of this disclosure, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the protection scope of this disclosure.
[0019] As shown in Figure 1, one aspect of this disclosure provides a method S100 for preparing a high-purity, hierarchical porous structure B-site regulated LaBO3 perovskite catalyst, specifically including the following steps S110~S140: S110, Raw material ratio and dissolution: Weigh out La(NO3)3 according to a 1:1 molar ratio of La to B-site metal ions. Add 6H2O and the corresponding B-site metal nitrate to 100 mL of ultrapure water, stir magnetically until completely dissolved, and continue stirring for 10-20 min to obtain a homogeneous solution.
[0020] In step S110, the B-site metal nitrate is selected from Co(NO3)2. 6H2O, Fe(NO3)3 9H2O, Mn(NO3)2 aqueous solution, Al(NO3)3 One of the components of 9H2O.
[0021] In step S110, a metal nitrate with a purity of ≥98% is selected as the ion source, wherein Mn is used in the form of a 50 wt% aqueous solution. The high purity metal nitrate avoids the introduction of impurity ions, reduces impurity oxides in the subsequent calcination process from the source, and ensures ion activity; the ultrapure water is deionized to avoid interference from impurities.
[0022] S120, Complexation reaction: Add a complexing agent equal to 1.2 times the total number of metal ions to the above homogeneous solution, stir magnetically until completely dissolved, and continue stirring for 10-20 minutes to ensure complete complexation reaction and formation of homogeneous complex solution.
[0023] In step S120, the complexing agent is citric acid monohydrate. The amount of the complexing agent added is 1.1-1.3 times the total number of moles of metal ions in the homogeneous solution, for example, preferably 1.2 times. The citric acid complex aggregate can serve as a template for forming a hierarchical porous structure. Furthermore, the citric acid complex aggregate can be completely decomposed by calcination without the need for additional template removal, thus avoiding pore blockage or impurity introduction caused by template residue.
[0024] This disclosure ensures a complete complexation reaction and avoids impurity formation by strictly controlling the molar ratio of La to B-site ions to 1:1 and using a complexing agent amount of approximately 1.2 times the total metal ions. Secondly, it employs a two-stage stirring process (continuing stirring for approximately 15 minutes after dissolution) to ensure sufficient complexation between the metal ions and citric acid, forming a homogeneous and stable complex solution. Simultaneously, the citric acid complex aggregates can serve as templates for forming a hierarchical porous structure.
[0025] S130, Evaporation and Aging: The complexation solution is placed in a constant temperature water bath at 75-85℃ and continuously evaporated until it becomes gel-like (about 2-3 hours) to avoid local clumping. Then it is transferred to an oven at 110-130℃ and aged overnight (aged for more than 12 hours) to obtain a loose foam-like precursor.
[0026] It should be noted that the constant temperature water bath evaporation process in step S130 requires continuous stirring to avoid local overheating and uneven gelation; the oven aging process requires ventilation to ensure that the moisture evaporates fully.
[0027] This disclosure employs a synergistic treatment of 80 ℃ constant temperature water bath evaporation followed by 120 ℃ overnight aging. The 120 ℃ high-temperature aging further removes residual free water and some organic volatiles from the gel, transforming the gel skeleton from "flexible" to "rigid and loose foamy". At the same time, the complexation bonds are further strengthened during the aging process, preventing the collapse of pores due to skeleton shrinkage during subsequent calcination and ensuring the complete preservation of the multi-level pore structure. This not only ensures uniform gel formation but also achieves precursor structure stability through sufficient dehydration.
[0028] S140, calcination and molding: The precursor is crushed into particles and placed in a crucible. The crucible is placed in a muffle furnace and heated to 450-550℃ in air at a heating rate of 5℃ / min. The temperature is kept constant for 3-5 hours and then cooled to room temperature to obtain the LaBO3 perovskite catalyst.
[0029] This disclosure employs a uniform heating rate of 5℃ / min followed by a holding temperature of 500℃ for 4 hours to avoid excessively rapid heating that could lead to crystal structure defects, thus ensuring the formation of pure-phase perovskite and the integrity of its hierarchical porous structure. Simultaneously, high-temperature calcination transforms the perovskite crystal structure from a "metastable state" to a "stable state," improving lattice integrity and reducing interference from crystal defects on active sites. During crystal growth, the valence distribution of B-site metal ions becomes more uniform, enhancing the generation and release of reactive oxygen species and providing sufficient active centers for catalytic reactions.
[0030] In this embodiment, La 3+ The A-site is used to fix the ion, and Co is selected at the B-site. 2+ Fe 3+ Mn 2+ Al 3+ One method involves the precise control of raw material ratios, complexation conditions, evaporation-aging processes, and calcination parameters via a sol-gel method to achieve the efficient synthesis of a pure-phase hierarchical porous LaBO3 perovskite structure. This preparation method is simple to operate, has controllable parameters, and is low in cost. The LaCoO3 catalyst can achieve complete toluene conversion at 275℃. This method solves the problems of complex and high-cost traditional precious metal catalyst preparation processes and is suitable for large-scale industrial production.
[0031] In this embodiment, the prepared LaBO3 perovskite catalyst has an ABO3-type pure-phase perovskite structure with a hierarchical porous structure and a pore size range of 16-150 nm. The prepared catalyst can be widely used in the catalytic combustion treatment of VOCs.
[0032] Another aspect of this disclosure is to propose a high-purity, hierarchical porous structure, B-site-controlled LaBO3 perovskite catalyst, which is prepared by the method described above. For details, please refer to the above description and will not be repeated here.
[0033] Another aspect of this disclosure proposes the application of a high-purity, hierarchical porous B-site controlled LaBO3 perovskite catalyst, which is used in the catalytic combustion degradation of volatile organic compounds.
[0034] The catalyst preparation process disclosed herein is simple and controllable, low in cost, and exhibits excellent catalytic performance. The prepared catalyst can be widely used for the synergistic purification or individual treatment of VOCs and carbon monoxide in industrial exhaust gases, resulting in significant environmental and economic benefits.
[0035] The preparation method of high-purity, hierarchical porous structure, B-site regulated LaBO3 perovskite catalyst will be further explained below with reference to specific embodiments: Example 1 This example illustrates a method for preparing a LaCoO3 catalyst: 1. Raw material weighing: Weigh La(NO3)3 according to the molar ratio of La to Co of 1:1. 6H2O (98% purity) and Co(NO3)2 Add 6H2O (98% purity) to 100 mL of ultrapure water; 2. Solution preparation: Stir magnetically until the raw materials are completely dissolved, continue stirring for 15 minutes, add citric acid at 1.2 times the total number of metal ions, stir until dissolved, and then stir for another 15 minutes; 3. Gel preparation: Evaporate in an 80 ℃ constant temperature water bath until gel-like, then age in a 120 ℃ oven overnight to obtain a foam-like precursor; 4. Calcination and shaping: The precursor is crushed, placed in a crucible, heated to 500 °C in a muffle furnace at 5 °C / min, calcined for 4 h, and then cooled to obtain the LaCoO3 catalyst.
[0036] 5. Performance Testing: A fixed-bed reactor was used, with a toluene concentration of 1000 ppm, a flow rate of 30 mL / min, a catalyst dosage of 60 mg, and a space velocity of 30000 mL / (h). (g). Test results show that the catalyst exhibits optimal catalytic activity at T10=220℃, T50=245℃, and T100=275℃.
[0037] like Figure 2 As shown, the LaCoO3 catalyst prepared in this embodiment was confirmed by XRD characterization to be a high-purity ABO3 perovskite structure with no impurity oxide peaks.
[0038] like Figure 3 As shown in the figure, SEM characterization revealed that the LaCoO3 catalyst prepared in this embodiment has a distinct hierarchical porous structure with pore sizes ranging from tens of nanometers to several micrometers.
[0039] like Figure 4 As shown, the BJH pore size distribution results further demonstrate that the LaCoO3 catalyst has a nanoscale hierarchical pore structure, and the mesoporous peaks of the LaCoO3 catalyst are mainly concentrated in the 16-74 nm range.
[0040] like Figure 5 and Figure 6 As shown, O2-TPD characterization results indicate that two strong desorption peaks appear at 200-400℃ (surface adsorbed oxygen) and 450-600℃ (bulk lattice oxygen), with the largest peak areas, indicating the highest content of active oxygen species and a high proportion of surface adsorbed oxygen, providing a sufficient active oxygen source for the rapid oxidation of toluene. NH3-TPD characterization results show that the catalyst exhibits two strong desorption peaks at 200-300℃ (weakly acidic) and 350-450℃ (medium acidic), with the largest peak areas, indicating the highest content of weak / medium acidic sites on its surface, which can effectively adsorb toluene (basic organic matter) and activate CH bonds, providing an "adsorption-activation" basis for the oxidation reaction. Therefore, the LaCoO3 catalyst contains abundant active oxygen species and surface acidic sites.
[0041] like Figure 7 As shown, the curve is plotted with "reaction temperature" on the x-axis and "toluene conversion rate" on the y-axis. The temperature at which the toluene conversion rate reaches 10% is T. 10 The temperature at which toluene conversion reaches 50% is T. 50 The temperature at which toluene conversion reaches 100% is T. 100 Performance test results show that the T of the LaCoO3 catalyst is... 10 =220 ℃, T 50 =245 ℃, T 100 =275 ℃.
[0042] Example 2 This example illustrates a method for preparing a LaMnO3 catalyst: This example follows the preparation method of Example 1, using Co(NO3)2 The LaMnO3 catalyst was obtained by replacing 6H2O with an aqueous solution of Mn(NO3)2 (50wt%) and keeping the other steps unchanged.
[0043] like Figure 2 As shown, the LaMnO3 catalyst prepared in this embodiment was confirmed by XRD characterization to be a high-purity ABO3 perovskite structure with no impurity oxide peaks.
[0044] like Figure 3 As shown in the figure, SEM characterization revealed that the LaMnO3 catalyst prepared in this embodiment has a distinct hierarchical porous structure with pore sizes ranging from tens of nanometers to several micrometers.
[0045] like Figure 4 As shown, the BJH pore size distribution results further demonstrate that the LaMnO3 catalyst has a nanoscale hierarchical pore structure, and the mesoporous peak of the LaCoO3 catalyst is mainly concentrated in the 50-100 nm range.
[0046] like Figure 5 and Figure 6 As shown, O2-TPD characterization results indicate that the LaMnO3 catalyst exhibits desorption peaks at 250-400℃ and 500-650℃, with the second largest peak area, and its active oxygen content is lower than that of the LaCoO3 catalyst. NH3-TPD characterization results show that the LaMnO3 catalyst exhibits desorption peaks at 220-320℃ and 380-480℃, with the second largest peak area, and its acidic site content is lower than that of LaCoO3. Therefore, the LaMnO3 catalyst contains abundant active oxygen species and surface acidic sites.
[0047] like Figure 7 As shown, the performance test results indicate that the T of the LaMnO3 catalyst... 10 =219 ℃, T 50 =267 ℃, T 100 =313℃.
[0048] Example 3 This example illustrates a method for preparing a LaFeO3 catalyst: This example follows the preparation method of Example 1, using Co(NO3)2 6H2O is replaced with Fe(NO3)3 9H2O (98% purity) was added, and the remaining steps remained unchanged to obtain the LaFeO3 catalyst.
[0049] like Figure 2 As shown, the LaFeO3 catalyst prepared in this embodiment was confirmed by XRD characterization to be a high-purity ABO3 perovskite structure with no impurity oxide peaks.
[0050] like Figure 3 As shown in the figure, SEM characterization revealed that the LaFeO3 catalyst prepared in this embodiment has a distinct hierarchical porous structure with pore sizes ranging from tens of nanometers to several micrometers.
[0051] like Figure 4 As shown, the BJH pore size distribution results further demonstrate that the LaFeO3 catalyst has a nanoscale hierarchical pore structure, and the mesoporous peak of the LaFeO3 catalyst is mainly concentrated in the range of 80-150 nm.
[0052] like Figure 5 and Figure 6 As shown, the O2-TPD characterization results indicate that the LaFeO3 catalyst exhibits weak desorption peaks at 300-450℃ and 600-700℃, indicating a low content of active oxygen. The NH3-TPD characterization results indicate that the LaFeO3 catalyst only exhibits a weak desorption peak at 250-350℃, indicating a low content of acidic sites.
[0053] like Figure 7 As shown, the performance test results indicate that the LaFeO3 catalyst T 10 =238 ℃, T 50 =334 ℃, T 100 =400℃.
[0054] Example 4 This example illustrates a method for preparing a LaAlO3 catalyst: This example follows the preparation method of Example 1. Following the preparation method of Example 1, Co(NO3)2... 6H2O is replaced with Al(NO3)3 9H2O (purity 98%), with the remaining steps unchanged, yields the LaAlO3 catalyst. like Figure 2 As shown, the LaAlO3 catalyst prepared in this embodiment was confirmed by XRD characterization to be a high-purity ABO3 perovskite structure with no impurity oxide peaks.
[0055] like Figure 3 As shown in the figure, SEM characterization revealed that the LaAlO3 catalyst prepared in this embodiment has a distinct hierarchical porous structure with pore sizes ranging from tens of nanometers to several micrometers.
[0056] like Figure 4 As shown, the BJH pore size distribution results further reveal that the LaAlO3 catalyst has a nanoscale hierarchical pore structure, and the mesoporous peak of the LaAlO3 catalyst is mainly concentrated in the range of 80-150 nm.
[0057] like Figure 5 and Figure 6 As shown, the O2-TPD characterization results indicate that the desorption peak of the LaAlO3 catalyst is the weakest and the peak position is at a relatively high temperature (350-500℃, 650-800℃), indicating that its active oxygen binding strength is high and its release is difficult, resulting in the lowest content of active oxygen actually participating in the reaction. The NH3-TPD characterization results indicate that the desorption peak of the LaAlO3 catalyst is the weakest and is dominated by medium-to-strong acidic sites (400-500℃), with insufficient weak acidic sites (the main sites for toluene adsorption), resulting in poor toluene adsorption and activation capabilities.
[0058] like Figure 7 As shown, the performance test results indicate that the T of the LaAlO3 catalyst... 10 =T 10 =365 ℃, T 50 =450 ℃, T 100 =565 ℃.
[0059] In summary, based on the XRD results of Examples 1-4, all four catalysts—LaCoO3, LaMnO3, LaFeO3, and LaAlO3—exhibited characteristic diffraction peaks of the ABO3 perovskite structure. These peaks were sharp and free of impurities, confirming that the product obtained through the preparation method described in this embodiment possesses a high-purity perovskite structure with excellent crystal structure integrity and stability. The catalysts with different B-site ions (Co, Mn, Fe, Al) showed slight differences in the positions of their characteristic diffraction peaks, consistent with the influence of B-site ion substitution on lattice parameters in the perovskite structure, further verifying the effectiveness of B-site regulation.
[0060] Secondly, according to the SEM results of Examples 1-4, all four catalysts exhibit a loose and porous microstructure, without a distinct dense blocky structure, and a hierarchical pore distribution characteristic of "micron-sized macropores + nano-sized mesopores / micropores" can be observed. The catalysts with different B-site ions show slight differences in the details of their porous structure: LaCoO3 and LaMnO3 have more uniform pore distribution and more concentrated pore sizes; LaFeO3 and LaAlO3 have slightly coarser pores, but still maintain a hierarchical pore structure. Furthermore, based on the pore size distribution results of Examples 1-4, it can be seen that all four catalysts exhibit multi-peak pore size distribution: mainly concentrated in the mesoporous range of 2-50 nm, accompanied by a small number of macropores of 100-1000 nm, which perfectly matches the "hierarchical pore structure" observed by SEM.
[0061] Furthermore, based on the O2-TPD and NH3-TPD spectra results of Examples 1-4, it can be seen that the synergistic effect of "high reactive oxygen + high acidic sites" of LaCoO3 is the key to its optimal catalytic activity; while LaAlO3 has the worst catalytic activity due to "low reactive oxygen + low acidic sites", which further reveals the core logic of "active site regulation" proposed in this embodiment.
[0062] Furthermore, according to the toluene catalytic combustion activity curves of Examples 1-4, the toluene conversion rate of all four catalysts gradually increases with increasing temperature. The conversion rates of LaCoO3 and LaMnO3 rise rapidly in the 200-300℃ range, while LaFeO3 and LaAlO3 require temperatures above 300℃ to enter the rapid conversion rate increase stage, further demonstrating the decisive influence of B-site ions on catalytic activity. In summary, the preparation method of this embodiment can stably produce a pure-phase, porous catalyst. Furthermore, through the synergistic effect of B-site ion regulation and process optimization, the content of active oxygen species and surface acidic sites in the product is significantly improved. This core characteristic not only ensures its high activity in the catalytic combustion of toluene, but also highly matches the reaction mechanism of carbon monoxide catalytic oxidation, providing a solid theoretical and structural foundation for expanding to multi-pollutant treatment scenarios.
[0063] This disclosure presents a high-purity, hierarchical porous structure, B-site-controlled LaBO3 perovskite catalyst, its preparation method, and its applications. Compared with existing technologies, it has the following advantages: First, the preparation process disclosed herein involves only five steps: dissolution, complexation, gelation, aging, and calcination. It is simple to operate, requires no complex equipment, and the parameters are precisely controllable, making it suitable for large-scale industrial production. Second, this disclosure achieves the efficient synthesis of LaBO3 perovskite catalyst by optimizing the raw material ratio and standardizing the process parameters, using the sol-gel method. The product is a pure phase perovskite structure with no impurity phase generated, high product purity, and excellent crystal structure stability. Third, the catalyst prepared in this disclosure has a porous structure and a high content of active oxygen and acidic sites working synergistically. The LaCoO3 catalyst can achieve complete conversion of toluene at 275℃. Fourth, the raw materials used in the preparation process disclosed herein are readily available, require no precious metals, have low energy consumption, and offer high cost-effectiveness.
[0064] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.
Claims
1. A method for preparing a high-purity multi-level pore structure B-site regulated LaBO3 perovskite catalyst, characterized in that, The preparation method include: Weigh out La(NO3)3 6H2O and the corresponding B-site metal nitrate were added to ultrapure water and magnetically stirred until completely dissolved, and then stirring was continued to obtain a homogeneous solution. Add a complexing agent to the homogeneous solution, stir magnetically until completely dissolved, and continue stirring to form a homogeneous complexing solution; The homogeneous complex solution was heated to a gel state and then dried to obtain the precursor. The precursor was crushed and placed in a crucible, then calcined in a muffle furnace and naturally cooled to obtain the LaBO3 perovskite catalyst.
2. The preparation method according to claim 1, characterized in that, The B-site metal nitrate is selected from Co(NO3)2. 6H2O, Fe(NO3)3 9H2O, Mn(NO3)2 aqueous solution, Al(NO3)3 One of the components of 9H2O.
3. The preparation method according to claim 1, characterized in that, La(NO3)3 6H2O and B-site metal nitrate were weighed according to a 1:1 molar ratio of La to B-site metal ions.
4. The preparation method according to claim 1, characterized in that, The complexing agent is citric acid monohydrate.
5. The preparation method according to claim 1, characterized in that, The amount of complexing agent added is 1.1-1.3 times the total number of moles of metal ions in the homogeneous solution.
6. The preparation method according to claim 1, characterized in that, The heating temperature for heating the homogeneous complex solution to a gel state is 75-85℃, and the drying temperature is 110-130℃.
7. The preparation method according to claim 1, characterized in that, The precursor is crushed, placed in a crucible, and calcined in a muffle furnace at a temperature of 450-550℃ for 3-5 hours.
8. The preparation method according to claim 1, characterized in that, The LaBO3 perovskite catalyst has an ABO3-type pure-phase perovskite structure with a hierarchical porous structure.
9. A high-purity, hierarchical porous structure, B-site-controlled LaBO3 perovskite catalyst, characterized in that... The LaBO3 perovskite catalyst was prepared by the preparation method according to any one of claims 1 to 8.
10. The application of a high-purity, hierarchical porous structure, B-site-controlled LaBO3 perovskite catalyst, characterized in that... The LaBO3 perovskite catalyst described in claim 9 is used in the catalytic combustion degradation of volatile organic compounds.