An acid-etched 3DOM multi-metal catalyst for photo-thermal catalytic oxidation of Cl-VOCs and a preparation method thereof

Abstract

The application discloses an acid-etched three-dimensional ordered macroporous (3DOM) multi-metal catalyst for photo-thermal catalytic oxidation of chlorinated volatile organic compounds (Cl-VOCs) and a preparation method thereof. 0.9 Al 0.1 MnO3 catalyst, and then the catalyst is subjected to acid etching treatment, so that the obtained catalyst has rich acid sites, redox sites and defect sites, and thus can be used for catalytic oxidation of Cl-VOCs and can exhibit excellent photo-thermal catalytic activity and stability in the catalytic oxidation process.

Description

Technical Field

[0001] This invention belongs to the field of photothermal materials and catalytic oxidation technology, specifically relating to an acid-etched 3DOMLa 0.9 Al 0.1 MnO3 catalysts, their preparation methods, and their application in photothermal catalytic oxidation of Cl-VOCs. Background Technology

[0002] Chlorinated volatile organic compounds (Cl-VOCs) are widely derived from industry, medicine, agriculture, and other fields. Their release into the environment not only easily causes pollution and ecological damage, but also poses a threat to human health due to their high toxicity. Catalytic oxidation is one of the most effective technologies for eliminating Cl-VOCs.

[0003] Catalytic combustion of Cl-VOCs mainly utilizes three types of catalysts: noble metals, zeolites, and transition metal oxides. Noble metal catalysts are expensive and prone to poisoning during Cl-VOC degradation. Zeolites, with their large specific surface area and excellent thermal stability, are widely used as catalyst supports; however, excessively strong acidic sites can lead to sintering and chlorine poisoning on the zeolite surface. Transition metal oxides are low-cost, thermally stable, and have tunable acid-base properties, exhibiting high redox performance and good catalytic activity in the catalytic degradation of Cl-VOCs. However, preventing chlorination and suppressing the formation of polychlorinated byproducts remains a challenge. Furthermore, catalytic combustion requires temperatures between 200 and 500 °C to achieve complete conversion of Cl-VOCs, resulting in high energy consumption. Sunlight irradiation allows catalysts to maximize the collection and absorption of solar radiation energy projected onto their surfaces and convert it into heat energy, replacing external heating and rapidly increasing the temperature of the surface catalytically active sites, thus promoting the catalytic reaction. However, research on fully utilizing the energy of the entire solar spectrum for catalytic degradation of Cl-VOCs is relatively limited. Therefore, there is an urgent need to design a photothermal catalyst with good catalytic activity, high selectivity, good stability, and the ability to suppress the generation of polychlorinated byproducts, so as to provide a new approach for the efficient photothermal degradation of Cl-VOCs. Summary of the Invention

[0004] The purpose of this invention is to provide an acid etching method for photothermal catalytic oxidation of Cl-VOCs using 3DOM La. 0.9 Al 0.1 MnO3 catalyst and its preparation method are proposed to address the shortcomings of existing Cl-VOCs catalytic combustion technology.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0006] Acid etching of 3DOM La for photothermal catalytic oxidation of Cl-VOCs 0.9 Al 0.1The MnO3 catalyst was prepared by first using polymethyl methacrylate (PMMA) as a template and then employing a citric acid-assisted colloidal crystal template method to prepare Al-doped 3DOMLa. 0.9 Al 0.1 The MnO3 catalyst was prepared by acid etching.

[0007] The acid etching 3DOM La 0.9 Al 0.1 The preparation method of MnO3 catalyst includes the following steps:

[0008] (1) La(NO3)3∙6H2O, Al(NO3)3∙6H2O, Mn(NO3)2 and citric acid were dissolved together in a mixed solvent and stirred continuously at room temperature for 1 h to obtain a transparent precursor solution; then PMMA template was added to the precursor solution, impregnated for 4 h, filtered, dried and calcined to obtain 3DOM La 0.9 Al 0.1 MnO3 catalyst;

[0009] (2) After acid etching of the catalyst obtained in step (1) with acid solution, rinse with pure water until the pH of the filtrate is neutral, and then dry to obtain the catalyst.

[0010] Furthermore, the molar ratio of La(NO3)3∙6H2O, Al(NO3)3∙6H2O, and Mn(NO3)2 used in step (1) is 0.9:0.1:1. Furthermore, the molar ratio of citric acid used in step (1) to the total metal ions in the solution is 1:3.

[0011] Furthermore, the mixed solvent mentioned in step (1) is composed of water, methanol and ethylene glycol in a volume ratio of 5:4:2.

[0012] Further, the calcination in step (1) is first heated from room temperature to 300°C at a rate of 1°C / min in an N2 stream and held for 3 h, then cooled to room temperature, then heated from room temperature to 300°C at a rate of 1°C / min in an air stream and held for 1 h, then heated to 750°C and held for 5 h.

[0013] Further, the acid solution mentioned in step (2) includes an aqueous solution of any one of nitric acid, phosphoric acid, acetic acid, citric acid, and boric acid, preferably an aqueous solution of nitric acid.

[0014] Further, the concentration of the acid solution in step (2) is 0.01~2 mol / L, preferably 0.4 mol / L.

[0015] Furthermore, the acid etching treatment in step (2) is carried out by soaking or stirring. Preferably, nitric acid is used for soaking, while phosphoric acid, acetic acid, citric acid and boric acid are used for stirring.

[0016] Furthermore, the acid etching process in step (2) takes 1 to 6 hours, preferably 1 hour.

[0017] The acid etching 3DOM La 0.9 Al 0.1 MnO3 catalysts possess abundant acidic sites, redox sites, and defect sites, providing active sites for the adsorption and degradation of Cl-VOCs, and thus can be used for photothermal catalytic oxidation of Cl-VOCs.

[0018] Furthermore, specifically, sunlight (with an irradiance of 80 mW·cm⁻¹) is introduced into the system for photothermal catalytic oxidation of Cl-VOCs. -2 And use a line-focusing Fresnel lens to concentrate the light.

[0019] The beneficial effects of this invention are as follows:

[0020] (1) In this invention, Al doping and acid etching can generate more oxygen vacancies. The higher lattice oxygen concentration and lattice oxygen mobility are beneficial to the deep oxidation of chlorination intermediates. At the same time, the increase in acidic sites can inhibit the formation of polychlorinated byproducts and reduce the deposition of chlorination byproducts on the catalyst surface. The 3DOM structure is conducive to the diffusion of Cl-VOCs in the channels, and the large specific surface area can effectively promote the high dispersion of acidic sites on the catalyst surface and the full contact between Cl-VOCs and active sites.

[0021] (2) The 3DOM La provided by this invention 0.9 Al 0.1 MnO3 catalyst exhibits strong photothermal conversion capabilities, reaching a temperature of 286 °C within 5 minutes under normal sunlight irradiation, effectively degrading Cl-VOCs. This is particularly effective at a chlorobenzene concentration of 100 ppm and a mass hourly space velocity (WHSV) of 30,000 mL∙h. -1 ∙g -1 Light intensity 62 mW·cm -2 Under conditions of (focusing light with a line-focusing Fresnel lens), its chlorobenzene conversion rate is 100%, and its CO2 yield is 85%; at a light intensity of 80 mW·cm -2 Under conditions of continuous reaction (with the aid of a line-focusing Fresnel lens) for 12 hours, the chlorobenzene conversion rate remained at 97% and the CO2 yield was 79%, demonstrating good stability. Attached Figure Description

[0022] Figure 1 The images show the XRD patterns of the catalysts prepared in Examples 1, 4 and the comparative examples.

[0023] Figure 2 The images show SEM images of the catalysts prepared in Examples 1, 4 and the comparative examples, where a is Example 1, b is Example 4 and c is the comparative example.

[0024] Figure 3 In Test Example 1, different catalysts were used under sunlight with an intensity of 62 mW·cm². -2 The graph shows the conversion rate and CO2 yield of catalytic oxidation of chlorobenzene under concentrated light irradiation.

[0025] Figure 4 The NH3-TPD diagrams are for the catalysts prepared in Examples 1 and 4 and the comparative examples in Test Example 2.

[0026] Figure 5 In Test Example 3, the catalyst prepared in Example 4 and 3DOM TiO2 were used under sunlight with an intensity of 80 mW·cm². -2 Temperature curve under concentrated light illumination.

[0027] Figure 6 This is a stability graph of the catalyst prepared in Example 4 for the catalytic oxidation of chlorobenzene under concentrated light irradiation of different solar light intensities, as used in Test Example 4.

[0028] Figure 7 The catalyst prepared in Example 4 was used in Test Example 4 under sunlight intensity of 80 mW·cm². -2 Stability diagram of switching lights on and off under focused light illumination.

[0029] Figure 8 In Test Example 5, the catalyst prepared in Example 4 was used under sunlight with an intensity of 80 mW·cm². -2 Water resistance diagram under concentrated light illumination.

[0030] Figure 9 The activity graph shows the conversion rate of chlorobenzene and the yield of CO2 using the catalyst prepared in Example 4 in Test Example 6 under sunlight and pure heating to the same temperature. Detailed Implementation

[0031] Acid etching of 3DOM La for photothermal catalytic oxidation of Cl-VOCs 0.9 Al 0.1 The preparation of the MnO3 catalyst includes the following steps:

[0032] (1) La(NO3)3∙6H2O, Al(NO3)3∙6H2O, and Mn(NO3)2 were added to a mixed solvent consisting of water, methanol, and ethylene glycol in a volume ratio of 5:4:2 at a molar ratio of 0.9:0.1:1. Citric acid was added at a molar ratio of 1:3 to the total metal ions in the solution. The mixture was stirred continuously at room temperature for 1 h to obtain a transparent precursor solution. Subsequently, a PMMA template was added to the precursor solution and impregnated for 4 h. The excess liquid was filtered out using a vacuum filter and dried overnight in a 60 ℃ forced-air drying oven. The resulting powder was then heated from room temperature to 300 ℃ at a rate of 1 ℃ / min in an N2 stream (350 mL / min) and held for 3 h. It was then cooled to room temperature and heated from room temperature to 300 ℃ at a rate of 1 ℃ / min in an air stream (400 mL / min) and held for 1 h. The temperature was then further increased to 750 ℃ ​​and held for 5 h to obtain 3DOM La. 0.9 Al 0.1 MnO3 catalyst;

[0033] (2) The catalyst obtained in step (1) is soaked or stirred in an acid solution of 0.01~2 mol / L for 1~6 h, rinsed with pure water until the pH of the filtrate is neutral, and then dried overnight in an oven at 100 ℃ to obtain the catalyst.

[0034] The acid solution used is an aqueous solution of any one of nitric acid, phosphoric acid, acetic acid, citric acid, boric acid, etc.

[0035] To make the content of this invention easier to understand, the technical solution of this invention will be further described below with reference to specific embodiments, but this invention is not limited thereto.

[0036] Example 1

[0037] 3.9365 g La(NO3)3∙6H2O, 0.3785 g Al(NO3)3∙6H2O, 2.324 mL Mn(NO3)2 (50wt%), and 1.4010 g citric acid were dissolved in 5 mL pure water, 4 mL methanol, and 2 mL ethylene glycol. The mixture was stirred continuously at room temperature for 1 h to obtain a transparent precursor solution. Subsequently, 2.0 g PMMA template agent was added to the above precursor solution, and after impregnation for 4 h, excess liquid was filtered using a vacuum filter. The solution was then dried overnight in a 60 °C forced-air drying oven. The resulting powder was then placed in a tube furnace and heated from room temperature to 300 °C at a rate of 1 °C / min in an N2 stream (350 mL / min) and held for 3 h. The solution was then cooled to room temperature, and subsequently heated from room temperature to 300 °C at a rate of 1 °C / min in an air stream (400 mL / min) and held for 1 h. Heating to 750 °C at a rate of °C / min and holding for 5 h yields 3DOM La. 0.9 Al 0.1 MnO3.

[0038] Example 2

[0039] 0.1 g of the 3DOM La prepared in Example 1 was used. 0.9 Al 0.1 MnO3 was soaked in 2 mL of 0.05 mol / L dilute nitric acid (66-68%) solution for 1 h, then the catalyst was rinsed with pure water until the pH of the filtrate was neutral, and dried overnight in an oven at 100 °C to obtain acid-etched 3DOM La. 0.9 Al 0.1 MnO3-0.05 HNO3.

[0040] Example 3

[0041] 0.1 g of the 3DOM La prepared in Example 1 was used. 0.9 Al 0.1 MnO3 was soaked in 2 mL of 0.2 mol / L dilute nitric acid (66-68%) solution for 1 h, then the catalyst was washed with pure water until the pH of the filtrate was neutral, and dried overnight in an oven at 100 °C to obtain acid-etched 3DOM La. 0.9 Al 0.1 MnO3-0.2 HNO3.

[0042] Example 4

[0043] 0.1 g of the 3DOM La prepared in Example 1 was used. 0.9 Al 0.1MnO3 was soaked in 2 mL of 0.4 mol / L dilute nitric acid (66–68%) solution for 1 h, then the catalyst was washed with pure water until the pH of the filtrate was neutral, and dried overnight in an oven at 100 °C to obtain acid-etched 3DOM La. 0.9 Al 0.1 MnO3-0.4 HNO3.

[0044] Example 5

[0045] 0.1 g of the 3DOM La prepared in Example 1 was used. 0.9 Al 0.1 MnO3 was stirred in 5 mL of 0.1 mol / L phosphoric acid solution for 1 h, then the catalyst was washed with pure water until the pH of the filtrate was neutral, and dried overnight in an oven at 100 °C to obtain acid-etched 3DOMLa. 0.9 Al 0.1 MnO3-H3PO4.

[0046] Example 6

[0047] 0.1 g of the 3DOM La prepared in Example 1 was used. 0.9 Al 0.1 MnO3 was stirred in 5 mL of 0.2 mol / L acetic acid solution for 1 h, then the catalyst was washed with pure water until the pH of the filtrate was neutral, and dried overnight in an oven at 100 °C to obtain acid-etched 3DOMLa. 0.9 Al 0.1 MnO3-HAc.

[0048] Example 7

[0049] 0.1 g of the 3DOM La prepared in Example 1 was used. 0.9 Al 0.1 MnO3 was stirred in 10 mL of 0.1 mol / L citric acid solution for 1 h, then the catalyst was washed with pure water until the pH of the filtrate was neutral, and dried overnight in an oven at 100 °C to obtain acid-etched 3DOMLa. 0.9 Al 0.1 MnO3-CA.

[0050] Example 8

[0051] 0.1 g of the 3DOM La prepared in Example 1 was used. 0.9 Al 0.1 MnO3 was stirred in 5 mL of 0.1 mol / L boric acid solution for 1 h, then the catalyst was washed with pure water until the pH of the filtrate was neutral, and dried overnight in an oven at 100 °C to obtain acid-etched 3DOMLa. 0.9 Al 0.1 MnO3-H3BO4.

[0052] Comparative Example 1

[0053] Compared with Example 1, the difference is that the amount of La(NO3)3∙6H2O added was adjusted to 4.1551 g, and Al(NO3)3∙6H2O was not added, so the catalyst obtained was 3DOM LaMnO3.

[0054] Figure 1 The figures show the XRD patterns of the catalysts prepared in Examples 1, 4, and the comparative examples. As can be seen from the figures, the crystal phase of the prepared catalysts is LaMnO3, and no other components were detected. This indicates that Al cations may be incorporated into the LaMnO3 lattice or may be highly dispersed on the catalyst surface in the form of Al2O3.

[0055] Figure 2 The images show SEM images of the catalysts prepared in Examples 1, 4, and the comparative examples. As can be seen from the images, the catalysts exhibit a high-quality three-dimensional ordered macroporous structure with a regular pore distribution. The three-dimensional ordered macroporous structure framework remains intact even under acid etching with low-concentration acid solutions.

[0056] Test Example 1

[0057] The catalysts prepared in the examples and comparative examples were subjected to performance tests for photothermal synergistic catalytic oxidation of chlorobenzene. The tests used a PLS-SXE 300 xenon lamp from Beijing Pofila Technology Co., Ltd. as the light source to simulate sunlight, and a 15 cm diameter line-focusing Fresnel lens was used for focusing (the light intensity before focusing was 62 mW·cm). -2 The light intensity after focusing is 1200 mW / cm². 2 The initial concentration of chlorobenzene was 100 ppm, the flow rate was 12.8 mL / min, and the mass hourly space velocity (WHSV) was 30,000 mL·g. -1 ·h -1 The concentrations of chlorobenzene and CO2 during the reaction were detected online using a GC 9160 gas chromatograph. The results are as follows: Figure 3 As shown.

[0058] Depend on Figure 3 It can be seen that 3DOM La 0.9 Al 0.1 MnO3 exhibits higher activity than 3DOM LaMnO3, and the catalytic performance of the catalyst after acid etching with a certain concentration of acid is higher than that of the untreated catalyst. Specifically, 3DOM LaMnO3 treated with 0.4 mol / L dilute nitric acid shows superior catalytic performance. 0.9 Al 0.1 The conversion rate of chlorobenzene by MnO3-0.4 HNO3 can reach 100%, and the CO2 yield is 85% (100 min).

[0059] Test Example 2

[0060] To evaluate the relationship between the catalytic performance of Cl-VOCs and the surface acidity of the catalyst prepared in this invention, NH3-TPD analysis was performed. The experimental method is as follows: 0.1 g of catalyst was pretreated in N2 (30 mL / min) at 300 °C for 1 h, and then cooled to 50 °C; subsequently, NH3 (30 mL / min) was introduced into the reactor for 45 min, and then purged with N2 (30 mL / min) for 1 h to remove physically adsorbed NH3; finally, the catalyst was heated from 50 °C to 900 °C at a rate of 10 °C / min.

[0061] NH3 desorption spectra can represent surface acidity of varying strengths, mainly categorized as weak, moderate, and strong acids, with temperatures ranging from 0 to 280 °C, 280 to 450 °C, and 450 to 600 °C, respectively. For example... Figure 4 As shown, the original 3DOM LaMnO3 exhibits a distinct desorption peak at 170 °C, indicating that the catalyst is weakly acidic. After the introduction of Al, the desorption peak area at 140 °C significantly increases, and the peak area further increases after acid etching, indicating that Al doping and acid etching increase the number of weak acid sites in the catalyst.

[0062] Test Example 3

[0063] The catalyst prepared in Example 4 and 3DOM TiO2 were tested at 80 mW·cm⁻¹. -2 The change of catalyst surface temperature over time under concentrated light intensity is shown in the following results. Figure 5 As shown.

[0064] Depend on Figure 5 It can be seen that, under the same light intensity, the 3DOM La prepared in Example 4... 0.9 Al 0.1 The MnO3-0.4HNO3 and 3DOMTiO2 catalysts exhibited the same temperature change trend, and both reached the required 286 °C for the catalytic reaction within 5 minutes of illumination, indicating that the catalysts possess excellent photothermal conversion capabilities. After the light was turned off, the catalysts were also able to recover to room temperature within a short time.

[0065] Test Example 4

[0066] Study on 3DOM La under different light intensities 0.9 Al 0.1 Stability of chlorobenzene catalytic oxidation by MnO3-0.4HNO3. The experimental method is as follows: chlorobenzene concentration was 100 ppm, and the mass hourly space velocity (WHSV) was 30000 mL·g. -1 ·h -1The total air flow rate was 12.8 mL / min, and the light intensity was adjusted to 62 mW·cm by regulating the height between the xenon lamp and the T-shaped reactor. -2 70 mW·cm -2 and 80 mW·cm -2 The result is as follows Figure 6 As shown.

[0067] Depend on Figure 6 It can be seen that under the same light intensity focusing, 3DOM La 0.9 Al 0.1 The catalytic activity of MnO3-0.4HNO3 for chlorobenzene remained relatively unchanged over 12 h; however, with increasing light intensity, the conversion rate of chlorobenzene and the CO2 yield of the catalyst increased. At 80 mW·cm⁻¹ -2 Even after 12 hours of concentrated light irradiation, the chlorobenzene conversion rate still reached 97%, and the CO2 yield was 79%, indicating that 3DOM La 0.9 Al 0.1 MnO3-0.4HNO3 exhibits good stability.

[0068] Five rounds of switching the lights on and off were also conducted (sunlight intensity was 80 mW·cm²). -2 To further verify the stability of the obtained catalyst, the results are as follows: Figure 7 As shown. From Figure 7 As can be seen, after five rounds of switching the lights on and off, the chlorobenzene conversion rate and CO2 yield were close to 98% and 77% respectively, with no significant difference, further proving that the catalyst prepared in this invention has good stability.

[0069] Test Example 5

[0070] Study on the effect of water vapor on 3DOM La 0.9 Al 0.1 The effect of MnO3-0.4HNO3 on catalytic activity. The experimental method is as follows: chlorobenzene concentration was 100 ppm, and sunlight intensity was 80 mW·cm⁻¹. -2 The reaction space velocity was 30,000 mL·g -1 ·h -1 The total air flow rate was 12.8 mL / min, of which the chlorobenzene purge gas was 0.2 mL / min and the equilibrium gas was 12.6 mL / min. The equilibrium gas was passed through a bubbler containing water, and the relative humidity of the water in the reaction gas was ensured by adjusting the temperature of the water in the bubbler (calculated to be 50% and 100% when the water was at 4 ℃ and 15 ℃, respectively).

[0071] Figure 8 For 3DOM La 0.9 Al 0.1MnO3-0.4 HNO3 in simulated sunlight intensity of 80 mW·cm -2 The water resistance diagram under concentrated light irradiation is shown. As can be seen from the figure, under dry conditions, the conversion rate of chlorobenzene remained around 97% and the CO2 yield was approximately 83% after 12 hours of light irradiation. When the relative humidity was 50%, the conversion rate of chlorobenzene increased to 100% and the CO2 yield increased to 92%. When the relative humidity was 100%, the conversion rate of chlorobenzene was 98% and the CO2 yield was 93%. When returning to dry conditions, the conversion rate of chlorobenzene recovered to 96%, and the CO2 yield decreased to 73%. These results indicate that the addition of water vapor promotes the catalytic activity of the catalyst. This may be because the abundant H atoms provided by water promote dechlorination, and the hydroxyl groups promote the deep oxidation of intermediates. Furthermore, under humid conditions, the migration of Cl is promoted, reducing the polychlorinated byproducts deposited on the surface. Therefore, 3DOMLa... 0.9 Al 0.1 MnO3-0.4H has good water resistance.

[0072] Test Example 6

[0073] To understand the effect of sunlight on the catalytic activity of the catalyst, the catalyst was heated to different temperatures using a fixed bed and then irradiated to the corresponding temperatures using concentrated light. The catalytic activity of the catalyst in the oxidation of chlorobenzene was then measured, and the results are as follows: Figure 9 As shown.

[0074] Depend on Figure 9 It is evident that the photothermal catalytic activity is close to that of the thermocatalytic activity at 120–200 °C; at >200 °C, the photothermal catalytic activity is significantly higher than that of pure heating; and at 280 °C, chlorobenzene is completely converted. This result demonstrates that sunlight greatly promotes the catalytic oxidation of chlorobenzene.

[0075] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. An acid etching method for photothermal catalytic oxidation of Cl-VOCs using 3DOM La 0.9 Al 0.1 MnO3 catalyst, characterized in that... It first uses PMMA as a template and then prepares 3DOM La using a citric acid-assisted colloidal crystal template method. 0.9 Al 0.1 The MnO3 catalyst is prepared by acid etching; its preparation specifically includes the following steps: (1) La(NO3)3∙6H2O, Al(NO3)3∙6H2O, Mn(NO3)2 and citric acid were dissolved together in a mixed solvent and stirred continuously at room temperature for 1 h to obtain a transparent precursor solution; then PMMA template was added to the precursor solution, impregnated for 4 h, filtered, dried and calcined to obtain 3DOM La 0.9 Al 0.1 MnO3 catalyst; (2) After acid etching the catalyst obtained in step (1) with acid solution, rinse it with pure water until the pH of the filtrate is neutral, and then dry it to obtain the catalyst. The molar ratio of citric acid used in step (1) to the total metal ions in the solution is 1:3; the calcination is first heated from room temperature to 300 ℃ at a rate of 1 ℃ / min in a N2 stream and held for 3 h, then cooled to room temperature, then heated from room temperature to 300 ℃ at a rate of 1 ℃ / min in an air stream and held for 1 h, then heated to 750 ℃ ​​and held for 5 h; The concentration of the acid solution in step (2) is 0.01~2 mol / L.

2. The acid-etched 3DOM La according to claim 1 0.9 Al 0.1 MnO3 catalyst, characterized in that... The molar ratio of La(NO3)3∙6H2O, Al(NO3)3∙6H2O and Mn(NO3)2 used in step (1) is 0.9:0.1:

1.

3. The acid-etched 3DOM La according to claim 1 0.9 Al 0.1 MnO3 catalyst, characterized in that... The mixed solvent mentioned in step (1) is composed of water, methanol and ethylene glycol in a volume ratio of 5:4:

2.

4. The acid-etched 3DOM La according to claim 1 0.9 Al 0.1 MnO3 catalyst, characterized in that... The acid solution mentioned in step (2) includes an aqueous solution of any one of nitric acid, phosphoric acid, acetic acid, citric acid, and boric acid.

5. The acid-etched 3DOM La according to claim 1 0.9 Al 0.1 MnO3 catalyst, characterized in that... The acid etching process in step (2) takes 1 to 6 hours.

6. An acid-etched 3DOM La as described in claim 1 0.9 Al 0.1 Application of MnO3 catalyst in photothermal catalytic oxidation of Cl-VOCs.

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