Oxygen vacancy adjustable catalyst for synergistically removing nitrogen oxides and volatile organic compounds as well as preparation method and application thereof

Abstract

The invention provides an oxygen vacancy adjustable catalyst for synergistically removing nitrogen oxides and volatile organic compounds as well as a preparation method and application of the oxygen vacancy adjustable catalyst. The catalyst takes natural ore as a raw material, main active components are MnO2 and Fe2O3, and an inert component is mainly SiO2. The catalyst with different oxygen vacancy concentrations is obtained by regulating and controlling the ratio of the active components and the calcining atmosphere, and the catalyst has good catalytic performance of synergistically removing nitrogen oxides and volatile organic compounds. Under the conditions that the volume space velocity (24000 h <-1 >) is high, the concentration of NO and NH3 is 500 ppm, the concentration of toluene is 50 ppm and 5 vol.% O2 / N2, the conversion rate of NO is kept at 80% or above within the range of 90-260 DEG C, and the conversion rate of toluene reaches 50% at the temperature of 114 DEG C and reaches 90% at the temperature of 224 DEG C. The simple preparation method is utilized, ores are selected as active components, the catalyst with the adjustable oxygen vacancy is prepared, and the catalyst is suitable for collaborative purification of NOx and VOCs in flue gas in the industries of coal-fired power plants, cement, metallurgy and the like.

Description

Technical Field

[0001] This invention belongs to the field of catalytic materials technology, specifically relating to an oxygen vacancy-tunable catalyst for the synergistic removal of nitrogen oxides and volatile organic compounds, its preparation method, and its application. Background Technology

[0002] Nitrogen oxides (NOx) and volatile organic compounds (VOCs) are the main components of PM2.5. 2.5 NOx and VOCs are important precursors to ozone and major contributors to environmental problems such as haze, secondary aerosols, and photochemical smog. Selective catalytic reduction (NH3-SCR) and catalytic oxidation are the mainstream technologies for industrial NOx and VOCs removal, respectively. However, using separate units to remove NOx and VOCs has drawbacks such as high equipment investment, large footprint, and high operating costs. Given the current need for synergistic control of multiple pollutants, achieving synergistic removal of NOx and VOCs within an SCR unit is a more energy-efficient and cost-effective approach.

[0003] Currently, vanadium-titanium-based catalysts are the most widely used denitrification catalysts due to their excellent denitrification performance and resistance to poisoning, and are widely used in NOx emission control from stationary sources such as coal-fired power plants. Although vanadium-titanium-based catalysts have high denitrification efficiency, their active component, V₂O₅, has a certain degree of toxicity and can easily cause secondary pollution after disposal. Furthermore, the production cost of this type of catalyst is relatively high, and its activity temperature window is narrow, only 300–400 °C, limiting its application range. Meanwhile, V₂O₅-WO₃ / TiO₂ catalysts have poor VOCs removal performance and are prone to generating organic byproducts. Therefore, improving the low-temperature catalytic activity of catalysts is one of the key challenges in achieving efficient and synergistic removal of NOx and VOCs.

[0004] Transition metal oxides (especially Mn and Fe-based oxides) have shown great potential for application in low-temperature NOx reduction and VOCs oxidation due to their excellent redox properties and variable valence state characteristics. Natural manganese ore, iron ore, and ferromanganese ore are rich in Mn and Fe oxides and are inexpensive, making them promising environmentally friendly catalysts. Existing research shows that these natural ore catalysts have good catalytic activity for NO, but their optimal activity temperature ranges for NO and VOCs differ. Therefore, if they are used for the synergistic removal of NO and VOCs from coal-fired flue gas, the key is to enhance the catalytic activity of the ore catalysts for VOCs, enabling them to maintain high catalytic efficiency for both pollutants simultaneously under low-temperature conditions. Summary of the Invention

[0005] To address the problems of existing technologies, the present invention aims to overcome the shortcomings of existing technologies and provide a catalyst with adjustable oxygen vacancy for the synergistic removal of nitrogen oxides and volatile organic compounds, as well as its preparation method and application. By using natural iron, manganese, or iron-manganese ore as raw materials, a MnOx-FeOx redox active phase system is constructed, and combined with a calcination atmosphere control strategy, oxygen vacancy defects are introduced on the catalyst surface to enhance the low-temperature catalytic activity of the catalyst, thereby achieving efficient synergistic removal of NOx and VOCs in the medium and low temperature range.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: This invention provides a catalyst with adjustable oxygen vacancy, comprising an active component accounting for 30-70 wt% of the total mass of the catalyst; wherein the active component is MnOx and FeOx in a mass ratio of 3:1 to 1:3. It is understood that in this catalyst, MnOx and FeOx together constitute an active phase system capable of undergoing redox cycles. By controlling the relative content of MnOx and FeOx and adjusting the calcination atmosphere, an oxygen vacancy defect structure with adjustable concentration is formed on the catalyst surface, thereby achieving the synergistic removal of nitrogen oxides and volatile organic compounds in the medium- and low-temperature range.

[0007] Furthermore, the catalyst is prepared from natural iron ore, manganese ore, or iron-manganese ore, wherein Mn and Fe exist in the form of oxides; wherein Mn is mainly in the form of Mn 4+ The main component is Fe, which is mainly Fe 3+ The catalyst is primarily composed of an inert component, which is native SiO2 from the raw material. Specifically, the MnOx and FeOx in the active components are MnO2 and Fe2O3.

[0008] The present invention also provides a method for preparing the above-mentioned oxygen vacancy-tunable catalyst, the method comprising: preparing a raw material powder by using natural ore as raw material according to the proportion of active components and the ratio of MnOx to FeOx in the catalyst; adding a dispersant to the raw material powder and then subjecting it to spheroidal graphite treatment and drying treatment in sequence to obtain an intermediate powder; calcining the intermediate powder under different atmospheres at a heating rate of 2℃ / min to 10℃ / min to 300℃ to 600℃ for 3h to 5h to obtain the oxygen vacancy-tunable catalyst.

[0009] Furthermore, the preparation method specifically includes the following steps: a. Crush, grind, and sieve the natural ore to obtain ore powder with the target particle size; then, according to the proportion of active ingredients in the catalyst and the ratio of MnOx to FeOx, prepare the raw material powder, and dry it for later use. b. Place the raw material powder in a ball mill jar, add a dispersant, place the ball mill jar in a high-energy ball mill, and ball mill at a speed of 300~600 rpm for 0.5~1.0 hours. Take out the powder and dry it in a vacuum drying oven at 80℃ for 6~12 hours to obtain intermediate powder. c. The intermediate powder is placed in a tube furnace and calcined under different atmospheres, with the temperature increased to 300℃~600℃ at a heating rate of 2℃ / min~10℃ / min, and calcined for 3~5 hours to obtain the oxygen vacancy-tunable catalyst.

[0010] Furthermore, in step a, the natural ore is crushed by a crusher for 20-40 minutes and then screened using a 40-60 mesh screen.

[0011] Furthermore, in step b, the ball mill jar is one of stainless steel, zirconium oxide, agate, or tungsten carbide alloy, and the ball-to-material ratio is 2:1 to 10:1; the dispersant is one of anhydrous ethanol, acetic acid, or citric acid.

[0012] Furthermore, in step c, the calcination atmosphere is one of nitrogen, air, or argon.

[0013] Furthermore, the calcination atmosphere is argon, the calcination time is 4-5 hours, and the calcination temperature is controlled at 400℃-500℃.

[0014] The present invention also provides the application of the above-mentioned oxygen vacancy-tunable catalyst in the synergistic removal of nitrogen oxides and volatile organic compounds.

[0015] Furthermore, the volumetric space velocity is not less than 24,000 h⁻¹. -1 Under an O2 / N2 atmosphere with NO and NH3 concentrations not less than 500 ppm, toluene concentration not less than 50 ppm, and oxygen volume fraction not more than 5 vol.%, the catalyst with adjustable oxygen vacancies achieves a conversion rate of not less than 80% for nitrogen oxides within a temperature window of 90~260℃, and a conversion rate of not less than 90% for toluene at temperatures above 230℃.

[0016] Preferably, the catalyst can be applied to the industrial waste gas purification process in industries such as coal-fired power plants, cement, and metallurgy to achieve synergistic control of multiple pollutants.

[0017] Compared with the prior art, the present invention has at least the following advantages: This invention provides an oxygen vacancy-tunable catalyst for the synergistic removal of nitrogen oxides and volatile organic compounds, its preparation method, and its applications. By adjusting the MnOx-FeOx ratio and the calcination atmosphere, this invention achieves controllable construction of the oxygen vacancy concentration on the catalyst surface, significantly improving the adsorption, activation, and conversion efficiency of the reactants. Due to the synergistic effect of the Mn-Fe redox active centers and oxygen vacancy defects, the reduction of nitrogen oxides and the oxidation of volatile organic compounds are achieved simultaneously, broadening the effective reaction temperature window of the catalyst and exhibiting excellent synergistic removal performance and good stability under medium and low temperature conditions.

[0018] The raw materials for the preparation of this catalyst can be natural iron, manganese and iron-manganese ore, which are widely available and inexpensive; the preparation method is simple, the process is controllable and has good reproducibility, and the resulting catalyst is suitable for large-scale preparation and has broad prospects for industrial application. Attached Figure Description

[0019] Figure 1 The X-ray diffraction pattern of manganese iron ore; Figure 2 Conversion curves for the synergistic removal of NO and toluene by the catalysts provided in Example 1 and Comparative Examples 1 and 2; Figure 3 Conversion curves for the synergistic removal of NO and toluene by the catalysts provided in Examples 1, 2 and 3; Figure 4 EPR spectra of the catalysts provided in Examples 1, 2 and 3; Figure 5 XPS O1s spectra of the catalysts provided in Examples 1, 2 and 3. Detailed Implementation

[0020] The inventors discovered that oxygen vacancy defects on the catalyst surface play a crucial role in promoting the adsorption, activation, and electron transfer of reactant molecules, and are key to enhancing the catalytic activity of VOCs. Therefore, the core of enhancing the VOCs activity of mineral catalysts lies in constructing suitable oxygen vacancies. However, research on catalytic systems based on natural minerals that achieve the synergistic removal of NOx and VOCs by regulating oxygen vacancies remains limited.

[0021] In view of this, the present invention aims to develop a low-cost, structurally stable, oxygen vacancy-tunable, and suitable synergistic removal catalyst for medium and low temperature conditions.

[0022] To further illustrate the methods and effects of this invention, the technical solution of this invention will be clearly and completely described below in conjunction with experiments.

[0023] Example 1 In this embodiment, an oxygen vacancy-tunable catalyst and its preparation method are provided. The preparation method is as follows: a. Natural iron-manganese ore is selected as raw material, mechanically crushed, then ground using a ball mill, and sieved through a 40-60 mesh screen to obtain ore powder with uniform particle size. Chemical composition analysis shows that both manganese and iron in the ore exist in oxide form, with manganese mainly in the form of Mn. 4+ Iron exists primarily as Fe. 3+ Form exists, such as Figure 1 As shown. Based on the actual content of MnOx and FeOx in the ore, the ore powder was formulated to achieve a mass ratio of MnOx to FeOx of 3:1, with the total mass of active components (MnOx and FeOx) accounting for 50 wt% of the total catalyst mass. The prepared powder was placed in a drying oven and dried at 80 ℃ for later use.

[0024] b. Place 2 g of the dried powder in a stainless steel ball mill jar, add 0.5 mL of anhydrous ethanol as a dispersant, and control the ball-to-powder ratio at 5:1. Then place the ball mill jar in a high-energy ball mill and ball mill at 400 r / min for 0.5 hours. After ball milling, remove the powder and dry it in a vacuum drying oven at 80 ℃ for 8 hours to remove residual dispersant.

[0025] c. The dried powder was placed in a tube furnace and calcined under a nitrogen atmosphere, with the temperature increased to 450 °C at a rate of 5 °C / min, and held at this temperature for 4 hours. After calcination, it was naturally cooled to room temperature to obtain a catalyst with a MnOx to FeOx mass ratio of 3:1, denoted as 3Mn1FeOx-N. The obtained catalyst was pressed into tablets, crushed, and sieved to 40-60 mesh for later use.

[0026] Catalytic performance test 0.5 mL of the tableted and sieved catalyst was placed in a fixed-bed quartz tube reactor. The reaction temperature was adjusted using a temperature controller, increasing from 60 °C to 300 °C at a rate of 2 °C / min, and holding at each temperature for 10 min. After the outlet NO and toluene concentrations reached a stable state, the outlet gas was analyzed. The gas hourly space velocity (GHSV) was set to 24,000 h⁻¹. -1 The inlet gas composition was: 5 vol% O2, 50 ppm toluene, 500 ppm NH3, and 500 ppm NO, with N2 as the balance gas. The NO and NH3 concentrations at the fixed bed outlet were analyzed using Fourier transform infrared spectroscopy, and the toluene concentration was analyzed using gas chromatography. Under these test conditions, the catalyst denitrification efficiency and VOCs conversion efficiency were as follows: Figure 2 As shown, the NO conversion rate can be kept stable at over 70% within the range of 93~282 ℃, with a maximum conversion efficiency close to 80%, while the conversion efficiency of toluene can reach over 90% when the temperature is above 255℃.

[0027] Comparative Example 1 The raw materials, preparation method and process conditions used in Comparative Example 1 are exactly the same as those in Example 1. The only difference is that in the ore powder proportioning stage, iron ore is added to adjust the mass ratio of MnOx to FeOx to 1:1, and the other conditions remain unchanged to obtain the catalyst of Comparative Example 1, which is denoted as 1Mn1FeOx-N.

[0028] Catalytic performance test The obtained catalyst was also sieved to 40-60 mesh and its catalytic performance was tested under the same reaction conditions as in Example 1. (Continue to refer to...) Figure 2 The results showed that, within the temperature range of 100~275 °C, the overall NO conversion rate was lower than that in Example 1, with the maximum NO conversion rate being only 66%, while the toluene conversion rate reached 90% at 282 °C.

[0029] Comparative Example 2 The raw materials, preparation method and process conditions used in Comparative Example 1 are exactly the same as those in Example 1. The only difference is that in the ore powder proportioning stage, the mass ratio of MnOx to FeOx is adjusted to 1:3 using iron ore, while the other conditions remain unchanged, to obtain the catalyst of Comparative Example 2, denoted as 1Mn3FeOx-N.

[0030] Catalytic performance test Its catalytic performance was evaluated under the same reaction conditions. (Continue to refer to...) Figure 2 The results showed that the synergistic removal performance of the catalyst for NOx and toluene was further reduced within the test temperature range. The NOx conversion rate was below 50% in most temperature ranges, and the conversion efficiency of toluene was significantly insufficient below 250 °C. This indicates that an excessively high proportion of FeOx is not conducive to the effective construction of oxygen vacancy structures and the exertion of the Mn-Fe redox synergistic effect.

[0031] The experimental results from Example 1 and Comparative Examples 1 and 2 show that, under the condition of the same total content of active components, the reasonable control of the mass ratio of MnOx to FeOx has a significant impact on the oxygen vacancy concentration on the catalyst surface and its synergistic removal performance. When the mass ratio of MnOx to FeOx is 3:1, the constructed Mn-Fe redox active system exhibits the most significant synergistic effect with the oxygen vacancy defect structure, demonstrating the best synergistic removal performance of NOx and VOCs.

[0032] Example 2 The catalyst prepared in this embodiment is consistent with that in Example 1 in terms of raw material selection, MnOx to FeOx mass ratio, ball milling conditions, and active component content. The only difference is the atmosphere used in the calcination stage. The specific preparation method is as follows: a. Following the method of Example 1, natural iron-manganese ore was crushed, ground, and sieved, and the mass ratio of MnOx to FeOx in the resulting powder was adjusted to 3:1, with the total mass of the active component accounting for 50 wt% of the total mass of the catalyst. The powder was then dried at 80 °C for later use.

[0033] b. Place 2 g of the dried powder in a stainless steel ball mill jar, add 0.5 mL of anhydrous ethanol as a dispersant, and control the ball-to-powder ratio at 5:1. Then place the ball mill jar in a high-energy ball mill and ball mill at 400 r / min for 0.5 hours. After ball milling, remove the powder and dry it in a vacuum drying oven at 80 ℃ for 8 hours to remove residual dispersant.

[0034] c. The dried powder was placed in a tube furnace and calcined in air atmosphere. The temperature was increased to 450 °C at a rate of 5 °C / min and held at this temperature for 4 hours. After calcination, it was naturally cooled to room temperature to obtain an oxygen vacancy-tunable catalyst calcined in air atmosphere, denoted as 3Mn1FeOx-A. The obtained catalyst was tableted, crushed, and sieved, and 40-60 mesh particles were used for catalytic performance evaluation.

[0035] Catalytic performance test Performance tests were conducted under the same reaction conditions as in Example 1. The results showed that the 3Mn1FeOx-A catalyst achieved a NO conversion rate of over 70% in the temperature range of 100–273 °C, with a maximum NO conversion rate of 75%. The 90% toluene conversion temperature was 270 °C. Overall, the low-temperature catalytic activity was inferior to that of Example 1, indicating that the number of oxygen vacancies formed under air calcination was limited, resulting in relatively insufficient activation capacity for the reactants.

[0036] Example 3 This embodiment is based on Example 1, except that the calcination atmosphere is adjusted. All other preparation conditions are completely the same. The specific steps are as follows: a. Using the same natural iron-manganese ore raw material as in Example 1, after crushing, grinding and sieving, the mass ratio of MnOx to FeOx was adjusted to 3:1, the total mass of the active component accounted for 50 wt% of the total mass of the catalyst, and it was dried at 80 °C for later use.

[0037] b. Place 2g of the dried powder into a stainless steel ball mill jar, add 0.5 mL of anhydrous ethanol as a dispersant, and control the ball-to-powder ratio at 5:1. Then place the ball mill jar in a high-energy ball mill and ball mill at 400 r / min for 0.5 hours. After ball milling, remove the powder and dry it in a vacuum drying oven at 80 ℃ for 8 hours to remove residual dispersant.

[0038] c. The dried powder was placed in a tube furnace and calcined under an argon atmosphere. The temperature was increased to 450 °C at a rate of 5 °C / min and held at this temperature for 4 hours. After calcination, it was naturally cooled to room temperature to obtain an oxygen vacancy-tunable catalyst calcined under an argon atmosphere, denoted as 3Mn1FeOx-Ar. The obtained catalyst was tableted, crushed, and sieved, and 40-60 mesh particles were used for catalytic performance evaluation.

[0039] Catalytic performance test Performance tests were conducted under the same reaction conditions as in Examples 1 and 2. The results showed that the conversion rate of nitrogen oxides was not less than 80% within a temperature window of 90–260 °C, and the highest conversion rate of NO was 91%. At temperatures above 230 °C, the conversion rate of toluene was not less than 90%, demonstrating excellent low-temperature activity and wide temperature window characteristics.

[0040] Comparing the experimental results of Examples 1, 2 and 3, it can be seen that under the condition of the same mass ratio of MnOx to FeOx, the calcination atmosphere has a significant impact on the oxygen vacancy structure on the catalyst surface and its synergistic removal performance.

[0041] Compared to calcination in an air atmosphere, calcination in an inert atmosphere (especially argon) is more conducive to suppressing the excessive oxidation of active components, promoting the formation and stabilization of oxygen vacancy defects, and thus enhancing the redox cycle capability of Mn-Fe. Figure 3 As shown in the figure, the catalyst obtained by calcination in an argon atmosphere exhibits the best synergistic removal performance of NOx and VOCs, fully verifying the technical effect of this invention in improving catalytic activity by regulating the oxygen vacancy structure through the calcination atmosphere.

[0042] To further perform qualitative and quantitative analysis of the oxygen vacancy content, the catalyst was characterized by EPR and O1sXPS, respectively.

[0043] EPR test results are as follows Figure 4 As shown, 3Mn1FeOx-Ar exhibits the strongest paramagnetic signal at g=2.003, indicating that it has the richest oxygen vacancy concentration.

[0044] O 1s XPS spectrum as shown Figure 5 As shown, after peak fitting, two characteristic peaks are displayed: lattice oxygen (O) latt529.7~529.8 eV) and surface chemically adsorbed oxygen (O ads (532.1~532.5 eV). Quantitative analysis showed that the O in 3Mn1FeOx-Ar... ads / O latt The ratio reached 0.76, significantly higher than that of 3Mn1FeOx-N (0.73) and 3Mn1FeOx-A (0.68). These characterization results confirm that during calcination in an argon atmosphere with low oxygen partial pressure, the escape of oxygen from the manganese-iron ore lattice forms a large number of oxygen vacancies. These oxygen vacancies can not only directly participate in the catalytic reaction as active sites, but also promote the adsorption and activation of gaseous oxygen molecules, generating more highly reactive O. ads This significantly improves the low-temperature activity and synergistic removal efficiency of the catalyst by introducing specific species.

[0045] In summary, this invention provides an oxygen vacancy-tunable catalyst for the synergistic removal of nitrogen oxides and volatile organic compounds, its preparation method, and its applications. By constructing a MnOx-FeOx redox active phase system using natural iron, manganese, and iron-manganese ore as raw materials, and combining this with a calcination atmosphere control strategy, oxygen vacancy defect structures are introduced on the catalyst surface to enhance the catalyst's low-temperature catalytic activity, thereby achieving highly efficient synergistic removal of nitrogen oxides and volatile organic compounds under medium- and low-temperature conditions.

[0046] The catalyst preparation process provided by this invention is simple, the raw materials are widely available, and the cost is low. The resulting catalyst has good synergistic removal performance, a wide reaction temperature window, and high stability. It is suitable for various industrial flue gas purification scenarios such as coal-fired power plants, cement plants, and metallurgical plants, and has significant engineering application value and promotion prospects.

[0047] It should be noted that the specific embodiments of the present invention described above are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention. Any equivalent modifications or improvements made by those skilled in the art to the structural form, preparation parameters, or application conditions without departing from the technical concept of the present invention should fall within the scope of protection of the present invention.

Claims

1. A catalyst with tunable oxygen vacancy for the synergistic removal of nitrogen oxides and volatile organic compounds, characterized in that, It includes an active component comprising 30-70 wt% of the total mass of the catalyst; wherein the active component is MnOx and FeOx in a mass ratio of 3:1 to 1:

3.

2. The oxygen vacancy-tunable catalyst according to claim 1, characterized in that, The catalyst is prepared from natural iron ore, manganese ore, or iron-manganese ore, wherein Mn and Fe exist in the form of oxides in the raw materials; The catalyst also includes an inert component, which is native SiO2 from the raw material.

3. A method for preparing an oxygen vacancy-tunable catalyst according to claim 1 or 2, characterized in that, The preparation method includes: According to the proportion of active components in the catalyst and the ratio of MnOx to FeOx, a raw material powder is prepared using natural ore as raw material. After adding a dispersant to the raw material powder, spherical ink treatment and drying treatment are performed sequentially to obtain intermediate powder; The intermediate powder was calcined under different atmospheres at a heating rate of 2℃ / min to 10℃ / min to 300℃ to 600℃ for 3 h to 5 h to obtain the oxygen vacancy tunable catalyst.

4. The method for preparing the oxygen vacancy-tunable catalyst according to claim 3, characterized in that, The preparation method specifically includes the following steps: a. Crush, grind, and sieve the natural ore to obtain ore powder with the target particle size; then, according to the proportion of active ingredients in the catalyst and the ratio of MnOx to FeOx, prepare the raw material powder, and dry it for later use. b. Place the raw material powder in a ball mill jar, add a dispersant, place the ball mill jar in a high-energy ball mill, and ball mill at a speed of 300~600 rpm for 0.5~1.0 hours. Take out the powder and dry it in a vacuum drying oven at 80℃ for 6~12 hours to obtain intermediate powder. c. The intermediate powder is placed in a tube furnace and calcined under different atmospheres, with the temperature increased to 300℃~600℃ at a heating rate of 2℃ / min~10℃ / min, and calcined for 3~5 hours to obtain the oxygen vacancy-tunable catalyst.

5. The method for preparing the oxygen vacancy-tunable catalyst according to claim 4, characterized in that, In step a, the natural ore is crushed by a crusher for 20-40 minutes and then screened using a 40-60 mesh screen.

6. The method for preparing the oxygen vacancy-tunable catalyst according to claim 4, characterized in that, In step b, the grinding jar is one of stainless steel, zirconium oxide, agate, or tungsten carbide, with a ball-to-material ratio of 2:1 to 10:

1. The dispersant is selected from anhydrous ethanol, acetic acid, and citric acid.

7. The method for preparing the oxygen vacancy-tunable catalyst according to claim 4, characterized in that, In step c, the calcination atmosphere is one of nitrogen, air, or argon.

8. The method for preparing the oxygen vacancy-tunable catalyst according to claim 7, characterized in that, The calcination atmosphere is argon, the calcination time is 4-5 hours, and the calcination temperature is controlled at 400℃-500℃.

9. The application of an oxygen vacancy-tunable catalyst according to claim 1 or 2 in the synergistic removal of nitrogen oxides and volatile organic compounds.

10. The application according to claim 9, characterized in that, Volume hourly space velocity not less than 24,000 h -1 Under an O2 / N2 atmosphere with NO and NH3 concentrations not less than 500 ppm, toluene concentration not less than 50 ppm, and oxygen volume fraction not more than 5 vol.%, the catalyst with adjustable oxygen vacancies achieves a conversion rate of not less than 80% for nitrogen oxides within a temperature window of 90~260℃, and a conversion rate of not less than 90% for toluene at temperatures above 230℃.

Images