Normal-temperature high-water-resistance ozonolysis catalyst as well as preparation method and application thereof

Abstract

The invention relates to a normal-temperature high-water-resistance ozonolysis catalyst and a preparation method and application thereof, the catalyst is of a composite oxide-heterojunction structure of Ni < 1-x > CexO-CeO2, and 0 lt; xlt; and 0.1. Dissolving soluble Ce salt and Ni salt in water to obtain a mixed solution, dropwise adding the obtained mixed solution and a precipitant into a reactor together, maintaining the constant pH value to be 9-11, and aging at a constant temperature to obtain a mixed precipitate; and filtering, washing and drying the obtained mixed precipitate, and then calcining in an air atmosphere to obtain the Ni < 1-x > CexO-CeO2 catalyst. Compared with the prior art, the catalyst is simple to prepare, high in water resistance, good in stability, good in ozone purification effect and suitable for large-scale industrial production. The catalyst can be applied to the fields of near-surface low-concentration ozone pollution purification or ozone decomposition in a closed space and the like.

Description

Technical Field

[0001] The present invention relates to the fields of catalyst technology and environmental catalysis, and relates to a room-temperature high-water-resistance ozone decomposition catalyst, a preparation method and application thereof, and can be used in the field of air pollution control. Background Art

[0002] 90% of the ozone in the atmosphere is in the stratosphere, which protects the Earth's surface organisms from ultraviolet radiation and provides protection for Earth's life. However, near-surface ozone is a major air pollutant and has surpassed PM2.5 to become my country's primary pollutant. Its strong oxidizing properties can have a significant impact on the ecosystem, environment and human health. According to my country's "Ambient Air Quality Standard" (GB3095-2012), the first and second level standards are an average ozone concentration of no more than 0.16 and 0.20 mg / m3 within one hour, respectively. 3 (about 80ppb and 100ppb), while the "Healthy Standard for Ozone in Indoor Air" (GB / T 18883-2002) stipulates that the average ozone concentration in indoor air within 1 hour shall not exceed 0.16mg / m 3 (approximately 80 ppb). Therefore, effectively eliminating ozone pollution has become a hot topic of research. Catalytic decomposition, with its advantages of high purification efficiency, environmental friendliness, low cost, and safety, is considered the most effective method for decomposing ozone pollution. The development of highly active, water-resistant, and stable catalysts is central to this technology.

[0003] Depending on the active components of the catalyst, it can be divided into precious metal catalysts and metal oxide catalysts. Among them, metal oxide catalysts are widely used in ozone decomposition catalysts due to their good redox ability, stability, economy and environmental protection.

[0004] Patent CN107456978A discloses a method for preparing a manganese-based composite oxide ozone decomposition catalyst. The catalyst comprises a carrier and an active component. The carrier is activated carbon particles and the active component is manganese copper, manganese iron or manganese ruthenium composite oxide. The catalyst is prepared by soaking the manganese activated carbon catalyst in a ferric chloride solution, a copper acetate solution or a ruthenium chloride solution and drying it for more than half a day. This series of catalysts catalyzes the decomposition of ozone at a space velocity of 40,000 h / min. -1 , under the condition of ozone concentration of 100ppm, the ozone decomposition efficiency is 90%, and the catalytic performance is relatively low.

[0005] Patent CN108339546A discloses a supported manganese-based ozone decomposition catalyst, its preparation method, and application. The formed support is mixed with a manganese source solution, and a reducing agent and an oxidizing agent are added according to the valence state of manganese. After sufficient impregnation, the catalyst is dried, then baked and calcined. The initial conversion rate of the catalyst for catalytic decomposition of ozone is 100%, but it gradually loses activity as the reaction proceeds, has poor stability, and is complex to prepare.

[0006] Patent CN1018435160A discloses a cerium-manganese catalyst for decomposing ozone under a wide temperature and high space velocity range, a preparation method, and a method for use thereof. A solution containing a cerium source and a manganese source is mixed with an excess of urea, reacted, and the resulting precipitated product is washed, dried, and calcined to obtain a cerium-manganese catalyst. The catalyst exhibits significant variations in ozone decomposition activity under different relative humidity conditions and exhibits poor water resistance.

[0007] Patent CN111097420B discloses a nickel-based ozone decomposition catalyst, its preparation method, and use. A water-soluble nickel source and a complexing agent are dissolved in water to prepare a mixed solution, and the pH is adjusted. The solution is heated to obtain a gel, and the gel is then dried, ground, and heat-treated to obtain a Ni / NiO heterojunction catalyst. Under conditions of an ozone concentration of 1000 ppm and a space velocity of 240,000 mL / (g·h), the catalyst has an ozone decomposition efficiency of ≥90%, demonstrating good ozone decomposition efficiency. However, the preparation process is complex, the test space velocity is low, and the stability is poor.

[0008] In summary, it is still difficult to obtain an ozone decomposition catalyst that is both highly active and stable under high space velocity and high humidity conditions. Furthermore, the catalyst preparation process is relatively cumbersome, making it unsuitable for current industrial applications. Therefore, developing an ozone decomposition catalyst that is simple to prepare, highly active, and highly water-resistant is of great practical significance. Summary of the Invention

[0009] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a high-activity and reaction stability ozone decomposition catalyst for room temperature and high water resistance and its preparation and application, which catalyzes the decomposition of ozone under room temperature and high relative humidity conditions, has a high ozone decomposition conversion rate, good stability and strong water resistance.

[0010] The purpose of the present invention can be achieved by the following technical solutions: The purpose of the present invention is to provide a catalyst for ozone decomposition at room temperature with high water resistance, wherein the catalyst is Ni 1-x Ce x O-CeO2 composite oxide-heterojunction structure, where 0 <x<0.1。

[0011] Ce is an additive, CeO2 nanoparticles and Ni 1-xCe x O exists in the form of composite oxides; Ni is the active component, with Ni 1-x Ce x O exists in the form of composite oxides.

[0012] Furthermore, the Ni 1-x Ce x The O-CeO2 catalyst has a crystal size of 2~10nm and a specific surface area of ​​50~200m 2 ·g -1 ; the Ni 1-x Ce x The CeO2 grain size in O-CeO2 catalyst is 2~10nm.

[0013] The present invention also provides a method for preparing a room-temperature, highly water-resistant ozone decomposition catalyst, comprising the following steps: Step (1): dissolving soluble Ce salt and Ni salt in water to obtain a mixed solution; Step (2): adding the mixed solution obtained in step (1) and the precipitant dropwise into a reactor while maintaining a constant pH of 9 to 11, and aging at a constant temperature to obtain a mixed precipitate; Step (3): The mixed precipitate obtained in step (2) is filtered, washed, dried, and then calcined in air to obtain Ni 1-x Ce x O-CeO2 catalyst.

[0014] Furthermore, the molar ratio of the soluble Ce salt and the Ni salt in step (1) is 0.1-0.5:1; the purpose of controlling the molar ratio of the soluble Ce salt and the Ni salt to be 0.1-0.5:1 is to form Ni 1-x Ce x O-CeO2 composite metal oxide - heterojunction structure, when Ce doped NiO exceeds the lattice tolerance, Ce forms CeO2 particles and Ni 1-x Ce x O-CeO2 forms a composite metal oxide heterojunction structure. The strong interaction and defect formation at the heterojunction interface are conducive to providing active sites for ozone decomposition. When the Ce content is low, the heterojunction cannot form, while when the Ce content is high, the CeO2 grain size is too large and covers the active sites.

[0015] The concentration of Ce ions in the mixed solution is 0.01-2 mol / L.

[0016] Furthermore, the soluble Ce salt includes any one or more of cerium nitrate hexahydrate, cerium sulfate tetrahydrate, cerium chloride heptahydrate, and cerium acetate.

[0017] Furthermore, the soluble Ni salt includes any one or more of nickel nitrate hexahydrate, nickel sulfate hexahydrate, nickel chloride hexahydrate, and nickel acetate tetrahydrate.

[0018] Furthermore, the precipitant in step (2) includes any one or more of sodium carbonate, sodium hydroxide, ammonia water, and ammonium carbonate; The concentration of the precipitant is 0.2-2 mol / L.

[0019] Furthermore, the aging temperature in step (2) is 20-60°C, and the aging time is 6-24 hours. The purpose of controlling the aging temperature of the mixed precipitate to 20-60°C and the aging time to 6-24 hours is to regulate the grain growth and specific surface area of ​​the precipitate. When the aging temperature is low and the aging time is short, grain growth is inhibited and the crystallinity is poor. When the aging temperature is high and the aging time is long, crystallization is accelerated, large grains are generated, and the specific surface area is reduced.

[0020] Furthermore, the calcination temperature in step (3) is 350-550°C and the calcination time is 3-7h. The purpose of controlling the calcination temperature of the mixed precipitate to 350-550°C and the calcination time to 3-7h is to decompose the precursor to form oxides, Ni 2+ With O 2- Combined to form cubic NiO, part of Ce replaces Ni 2+ After entering the NiO lattice, the excess Ce exceeds the tolerance of the NiO lattice and is dispersed in the NiO lattice in the form of cubic fluorite structure CeO2. 1-x Ce x O surface, forming Ni 1-x Ce x O-CeO2 forms a composite metal oxide heterojunction structure. If the calcination temperature is too low or the calcination time is too short, the precursor will not be fully decomposed and the catalyst will exist in an amorphous structure. If the calcination temperature is too high or the calcination time is too long, the catalyst grain size will be too large, the specific surface area and surface defects will be reduced, and the amount of CeO2 precipitation and the enlarged grain size will cover the surface active sites.

[0021] The present invention also provides an application of a catalyst for ozone decomposition with high water resistance at room temperature, wherein the catalyst is used for ozone decomposition with high water resistance at room temperature.

[0022] Compared with the prior art, the present invention has the following beneficial effects: 1. During the preparation of the catalyst of the present invention, the Ce / Ni molar ratio, aging temperature, aging time and calcination temperature and time selection will have a great influence on the crystal size, specific surface area and structure of the catalyst. Different crystal sizes, crystallinity, and structures have a significant effect on the ozone decomposition activity. The present invention has selected Ni-based catalysts through a large number of experiments. 1-x Cex O-CeO2 composite metal oxide-heterojunction structure catalyst with excellent ozone decomposition activity. On the one hand, the auxiliary agent Ce is doped into the active component Ni to form Ni 1-x Ce x O composite oxides increase the surface oxygen vacancy concentration as the ozone decomposition reaction site, while Ni 1-x Ce x CeO2 particles on the surface of NiO 1-x Ce x O produces a strong interaction, regulating Ni 1-x Ce x The chemical state of the O surface.

[0023] 2. The catalyst of the present invention is prepared by co-precipitation method, the aging temperature of the precipitate is between 20~60℃, the aging time is 6~24h, during the aging period, the amorphous precursor gradually transitions to the crystalline state, the average particle size increases, after the aging is completed, the Ce-Ni composite precipitate is filtered, washed, dried, and then calcined at 350~550℃ for 3~7h. After calcination, the precursor gradually decomposes, Ce replaces Ni to form Ni 1-x Ce x O solid solution, additional oxygen vacancies are generated due to charge imbalance. At the same time, part of Ce is in the form of CeO2 particles on Ni 1-x Ce x O solid solution precipitates on the surface to form Ni 1-x Ce x O-CeO2 composite metal oxide-heterojunction structure, CeO2 and Ni 1-x Ce x The strong interaction between the NiO interfaces regulates the 1-x Ce x O surface chemical state and create additional defect sites at the interface.

[0024] 3. The catalyst of the present invention is Ni 1-x Ce x O-CeO2 composite metal oxide-heterojunction structure is synthesized in one step by co-precipitation method. After Ce is added to the active component NiO, the crystallinity and grain size are significantly reduced and the specific surface area is greatly increased, providing more active sites for ozone decomposition. Ce that exceeds the tolerance of NiO lattice is precipitated in NiO in the form of CeO2 particles. 1- x Ce x O surface, and with Ni 1-x Ce xO2 interacts strongly with the catalyst, altering its surface chemistry. Furthermore, more active sites are created at the heterojunction interface, significantly increasing the catalyst's ozone decomposition efficiency. The catalyst achieves a nearly 100% conversion rate for 200 ppm ozone at room temperature and high relative humidity, and this conversion rate remains stable for 60 consecutive hours. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The reaction stability of the catalysts obtained in Examples 1 to 3.

[0026] Figure 2 This is the X-ray diffraction pattern of the ozone decomposition catalyst prepared in the present invention.

[0027] Figure 3 This is a Raman spectrum of the ozone decomposition catalyst prepared by the present invention.

[0028] Figure 4 This is a transmission electron microscope image of the ozone decomposition catalyst prepared in the present invention. DETAILED DESCRIPTION

[0029] The following examples further illustrate the ozone decomposition catalyst and its preparation method according to the present invention. It should be noted that the following examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. Simple modifications or substitutions to the catalyst preparation methods, steps, or conditions described herein are within the scope of the present invention without departing from the spirit and substance of the present invention. Unless otherwise specified, the basic operations used in the examples are conventional methods well known to those skilled in the art. The catalyst's ozone decomposition activity was evaluated in a fixed-bed reactor at an ozone concentration of 200 ppm, a relative humidity of 90%, and a balance of a 1 / 4 oxygen / nitrogen mixture at a mass space velocity of 1,000,000 mL / (g·h).

[0030] Example 1: 5.8 g Ni(NO3)2⋅6H2O and 0.95 g Ce(NO3)3⋅6H2O were dissolved in 50 mL deionized water and stirred to fully dissolve to form a mixed solution. Then, 0.2 M sodium carbonate solution and the mixed solution were added to the beaker at a uniform rate under vigorous stirring. The pH was controlled at 9 during the addition process and aged at 20 ° C for 6 hours. The obtained mixed precipitate was filtered, washed, dried, and then calcined at 350 ° C for 3 hours to obtain Ni 1-x Ce x O-CeO2 catalyst.

[0031] The X-ray diffraction pattern of the catalyst obtained in this example is as follows Figure 2 As shown by Figure 2It can be seen that the obtained catalyst contains Ni 1-x Ce x Compared with the NiO standard card, the characteristic diffraction peak of NiO shifts to a higher angle after Ce addition, proving that Ce addition to NiO forms NiO. 1-x Ce x O composite oxide, and the characteristic diffraction peak of CeO2 can be observed, indicating the presence of CeO2 particles. The Raman spectrum of the catalyst obtained in this example is shown in FIG. Figure 3 As shown in the figure, the symmetry of NiO changes significantly after Ce addition, making Ni 1-x Ce x The Raman shift of the O composite oxide is significantly blue-shifted compared to pure NiO. At the same time, the Raman peak of CeO2 can be clearly observed, which indicates the presence of CeO2 particles. Figure 4 The TEM image of the catalyst obtained in this example shows that the NiO interplanar spacing after Ce incorporation is 2.44Å and 2.07Å respectively. Compared with the NiO standard card, the interplanar spacing increases, proving that Ni 1- x Ce x O composite oxide. In addition, the interplanar spacing of CeO2 can be observed, indicating that part of Ce exists in the form of CeO2 particles, which is consistent with the Figure 2 and Figure 3 The results correspond.

[0032] Example 2: 5.8 g Ni(NO3)2⋅6H2O and 0.95 g Ce(NO3)3⋅6H2O were dissolved in 50 mL deionized water and stirred to fully dissolve to form a mixed solution. Then, 0.2 M sodium carbonate solution and the mixed solution were added dropwise into the beaker at a uniform rate under vigorous stirring. The pH was controlled at 9 during the addition process and aged at 40 ° C for 6 hours. The obtained mixed precipitate was filtered, washed, dried, and then calcined at 350 ° C for 3 hours to obtain Ni 1-x Ce x O-CeO2 catalyst.

[0033] Example 3: 5.8 g Ni(NO3)2⋅6H2O and 0.95 g Ce(NO3)3⋅6H2O were dissolved in 50 mL deionized water and stirred to fully dissolve to form a mixed solution. Then, 0.2 M sodium carbonate solution and the mixed solution were added dropwise into the beaker at a uniform rate under vigorous stirring. The pH was controlled at 9 during the addition process and aged at 60 ° C for 6 hours. The obtained mixed precipitate was filtered, washed, dried, and then calcined at 350 ° C for 3 hours to obtain Ni 1-x Ce x O-CeO2 catalyst.

[0034] Example 4: 5.8 g Ni(NO3)2⋅6H2O and 0.95 g Ce(NO3)3⋅6H2O were dissolved in 50 mL deionized water and stirred to fully dissolve to form a mixed solution. Then, 0.2 M sodium carbonate solution and the mixed solution were uniformly added to the beaker under vigorous stirring. The pH was controlled at 9 during the addition process. The mixture was aged at 20 ° C for 12 hours. The obtained mixed precipitate was filtered, washed, dried, and then calcined at 350 ° C for 3 hours to obtain Ni 1-x Ce x O-CeO2 catalyst.

[0035] Example 5: 5.8 g Ni(NO3)2⋅6H2O and 0.95 g Ce(NO3)3⋅6H2O were dissolved in 50 mL deionized water and stirred to fully dissolve to form a mixed solution. Then, 0.2 M sodium carbonate solution and the mixed solution were added to the beaker at a uniform rate under vigorous stirring. The pH was controlled at 9 during the addition process. The mixture was aged at 20 ° C for 24 hours. The obtained mixed precipitate was filtered, washed, dried, and then calcined at 350 ° C for 3 hours to obtain Ni 1-x Ce x O-CeO2 catalyst.

[0036] Example 6: 5.8 g Ni(NO3)2⋅6H2O and 0.95 g Ce(NO3)3⋅6H2O were dissolved in 50 mL deionized water and stirred to fully dissolve to form a mixed solution. Then, 0.2 M sodium carbonate solution and the mixed solution were uniformly added to the beaker under vigorous stirring. The pH was controlled at 9 during the addition process and aged at 20 ° C for 6 hours. The obtained mixed precipitate was filtered, washed, dried, and then calcined at 350 ° C for 5 hours to obtain Ni 1-x Ce x O-CeO2 catalyst.

[0037] Example 7: 5.8 g Ni(NO3)2⋅6H2O and 0.95 g Ce(NO3)3⋅6H2O were dissolved in 50 mL deionized water and stirred to fully dissolve to form a mixed solution. Then, 0.2 M sodium carbonate solution and the mixed solution were uniformly added to the beaker under vigorous stirring. The pH was controlled at 9 during the addition process. The mixture was aged at 20 ° C for 6 hours. The obtained mixed precipitate was filtered, washed, dried, and then calcined at 350 ° C for 7 hours to obtain Ni 1-x Ce x O-CeO2 catalyst.

[0038] Example 8: 5.8 g Ni(NO3)2⋅6H2O and 0.95 g Ce(NO3)3⋅6H2O were dissolved in 50 mL deionized water and stirred to fully dissolve to form a mixed solution. Then, 0.2 M sodium carbonate solution and the mixed solution were added dropwise into the beaker at a uniform rate under vigorous stirring. The pH was controlled at 9 during the addition process and aged at 20 ° C for 6 hours. The obtained mixed precipitate was filtered, washed, dried, and then calcined at 450 ° C for 3 hours to obtain Ni 1-x Ce x O-CeO2 catalyst.

[0039] Example 9: 5.8 g Ni(NO3)2⋅6H2O and 0.95 g Ce(NO3)3⋅6H2O were dissolved in 50 mL deionized water and stirred to fully dissolve to form a mixed solution. Then, 0.2 M sodium carbonate solution and the mixed solution were added dropwise into the beaker at a uniform rate under vigorous stirring. The pH was controlled at 9 during the addition process and aged at 20 ° C for 6 hours. The obtained mixed precipitate was filtered, washed, dried, and then calcined at 550 ° C for 3 hours to obtain Ni 1-x Ce x O-CeO2 catalyst.

[0040] Example 10: 5.8 g Ni(NO3)2⋅6H2O and 0.95 g Ce(NO3)3⋅6H2O were dissolved in 50 mL deionized water and stirred to fully dissolve to form a mixed solution. Then, 0.2 M sodium carbonate solution and the mixed solution were added dropwise into the beaker at a uniform rate under vigorous stirring. The pH was controlled at 10 during the addition process and aged at 20 ° C for 6 hours. The obtained mixed precipitate was filtered, washed, dried, and then calcined at 350 ° C for 3 hours to obtain Ni 1-x Ce x O-CeO2 catalyst.

[0041] Example 11: 5.8 g Ni(NO3)2⋅6H2O and 0.95 g Ce(NO3)3⋅6H2O were dissolved in 50 mL deionized water and stirred to fully dissolve to form a mixed solution. Then, 0.2 M sodium carbonate solution and the mixed solution were uniformly added to the beaker under vigorous stirring. The pH was controlled at 11 during the addition process and aged at 20 ° C for 6 hours. The obtained mixed precipitate was filtered, washed, dried, and then calcined at 350 ° C for 3 hours to obtain Ni 1-x Ce x O-CeO2 catalyst.

[0042] Example 12: 5.8 g Ni(NO3)2⋅6H2O and 2.17 g Ce(NO3)3⋅6H2O were dissolved in 50 mL deionized water and stirred to fully dissolve to form a mixed solution. Then, 0.2 M sodium carbonate solution and the mixed solution were uniformly added to the beaker under vigorous stirring. The pH was controlled at 9 during the addition process and aged at 20 ° C for 6 hours. The obtained mixed precipitate was filtered, washed, dried, and then calcined at 350 ° C for 3 hours to obtain Ni 1-x Ce x O-CeO2 catalyst.

[0043] Example 13: 5.8 g Ni(NO3)2⋅6H2O and 3.47 g Ce(NO3)3⋅6H2O were dissolved in 50 mL deionized water and stirred to fully dissolve to form a mixed solution. Then, 0.2 M sodium carbonate solution and the mixed solution were uniformly added to the beaker under vigorous stirring. The pH was controlled at 9 during the addition process. The mixture was aged at 20 ° C for 6 hours. The obtained mixed precipitate was filtered, washed, dried, and then calcined at 350 ° C for 3 hours to obtain Ni 1-x Ce x O-CeO2 catalyst.

[0044] Comparative Example 1: 5.8 g of Ni(NO3)2⋅6H2O was dissolved in 50 mL of deionized water and stirred to fully dissolve to form a solution. The solution was then added dropwise into a beaker at a uniform rate with vigorous stirring together with a 0.2 M sodium carbonate solution. The pH was controlled at 9 during the addition process and the mixture was aged at 30°C for 6 hours. The obtained mixed precipitate was filtered, washed, dried, and then calcined at 350°C for 3 hours to obtain a NiO catalyst.

[0045] Comparative Example 2: 5.8 g Ni(NO3)2⋅6H2O and 0.45 g Ce(NO3)3⋅6H2O were dissolved in 50 mL deionized water and stirred to fully dissolve to form a mixed solution. Then, 0.2 M sodium carbonate solution and the mixed solution were added to the beaker at a uniform rate under vigorous stirring. The pH was controlled at 9 during the addition process and aged at 30 ° C for 6 hours. The obtained mixed precipitate was filtered, washed, dried, and then calcined at 350 ° C for 3 hours to obtain Ni 1-x Ce x O catalyst.

[0046] Comparative Example 3: 5.8 g Ni(NO3)2⋅6H2O and 10.85 g Ce(NO3)3⋅6H2O were dissolved in 50 mL deionized water and stirred to fully dissolve to form a mixed solution. Then, 0.2 M sodium carbonate solution and the mixed solution were added to the beaker at a uniform rate under vigorous stirring. The pH was controlled at 9 during the addition process and aged at 30 ° C for 6 hours. The obtained mixed precipitate was filtered, washed, dried, and then calcined at 350 ° C for 3 hours to obtain Ni 1-x Ce x O-CeO2 catalyst.

[0047] Comparative Example 4: 5.8 g Ni(NO3)2⋅6H2O and 0.45 g Ce(NO3)3⋅6H2O were dissolved in 50 mL deionized water and stirred to fully dissolve. Then, 0.2 M sodium carbonate solution and the stirred precursor salt solution were uniformly added to the beaker under vigorous stirring. The pH was controlled at 9 and aged at 30 ° C for 12 hours. The obtained precipitate was filtered, washed, dried and calcined at 350 ° C for 4 hours to obtain Ni 1-x Ce x O composite oxide support. Then the support powder was impregnated in 4 mL of 0.031 g Ce / mL Ce(NO3)3⋅6H2O aqueous solution, and then dried and calcined at 350℃ in air atmosphere for 3 hours to obtain CeO2 / Ni 1-x Ce x O catalyst.

[0048] Comparative Example 5: 5.8 g Ni(NO3)2⋅6H2O and 0.45 g Ce(NO3)3⋅6H2O were dissolved in 50 mL deionized water and stirred to fully dissolve. Then, 0.2 M sodium carbonate solution and the stirred precursor salt solution were uniformly added to the beaker under vigorous stirring. The pH was controlled at 9 and aged at 30 ° C for 12 hours. The obtained precipitate was filtered, washed, dried and calcined at 350 ° C for 4 hours to obtain Ni 1-x Ce x O composite oxide support. Then the support powder was impregnated in 4 mL of 0.107 g Ce / mL Ce(NO3)3⋅6H2O aqueous solution, and then dried and calcined at 350℃ in air atmosphere for 3 hours to obtain CeO2 / Ni 1-x Ce x O catalyst.

[0049] The catalysts obtained in Examples 1 to 13 and Comparative Examples 1 to 4 were tested for ozone decomposition activity. The ozone decomposition activity of each catalyst was evaluated in a fixed-bed reactor (quartz tube, inner diameter 6 mm) at atmospheric pressure. The catalyst mass was 0.60 g, the ozone concentration was 200 ppm, the balance gas was an O₂ / N₂ volume ratio of 1 / 4, the relative humidity was 30 / 90%, and the mass space velocity was 1,000,000 mL·g. -1 ·h -1 The catalyst bed temperature was maintained at 30°C. The ozone concentration at the inlet and outlet was monitored online using an ozone detector (2B Model 202). The ozone conversion rate was calculated using the following formula: Conversion rate = (C in -C out ) / C in ×100%. Among them, C in with C out The ozone decomposition activities of the catalysts obtained in various examples and comparative examples are shown in Table 1.

[0050] Table 1. Catalytic Ozone Decomposition Activity of Catalysts Obtained from Examples 1 to 8 and Comparative Examples 1 to 4 catalyst Ce / Ni molar ratio Ozone conversion rate / % (RH=30%) Ozone conversion rate / %(RH=90%) Stability / h Example 1 <![CDATA[Ni 1-x What x O-CeO2]]> 0.1 99.9 99 60 Example 2 <![CDATA[Ni 1-x What x O-CeO2]]> 0.1 99.9 99 60 Example 3 <![CDATA[Ni 1-x What x O-CeO2]]> 0.1 99.9 99 60 Example 4 <![CDATA[Ni 1-x What x O-CeO2]]> 0.1 99.9 99 60 Example 5 <![CDATA[Ni 1-x What x O-CeO2]]> 0.1 99.9 99 60 Example 6 <![CDATA[Ni 1-x What x O-CeO2]]> 0.1 99.9 99 60 Example 7 <![CDATA[Ni 1-x What x O-CeO2]]> 0.1 99.9 99 60 Example 8 <![CDATA[Ni 1-x What x O-CeO2]]> 0.1 99.9 99 60 Example 9 <![CDATA[Ni 1-x What x O-CeO2]]> 0.1 99.9 99 60 Example 10 <![CDATA[Ni 1-x What x O-CeO2]]> 0.1 99 93 60 Example 11 <![CDATA[Ni 1-x What x O-CeO2]]> 0.1 91 82 60 Example 12 <![CDATA[Ni 1-x What x O-CeO2]]> 0.25 99 96 60 Example 13 <![CDATA[Ni 1-x What x O-CeO2]]> 0.5 99 92 60 Comparative Example 1 NiO 0 67 55 12 Comparative Example 2 <![CDATA[Ni 1-x What x Oh]]> 0.05 86 74 12 Comparative Example 3 <![CDATA[Ni 1-x What x O-CeO2]]> 1.25 34 30 12 Comparative Example 4 <![CDATA[CeO2 / Ni 1-x What x Oh]]> 0.11 71 62 8 Comparative Example 5 <![CDATA[CeO2 / Ni 1-x What x Oh]]> 0.25 67 56 8 As can be seen from Table 1, the Ni of Examples 1 to 9 were synthesized in one step by coprecipitation. 1-x Ce x The O-CeO2 catalyst has excellent ozone decomposition activity and stability, and the ozone conversion rate hardly decreases when the relative humidity increases from 30% to 90%, proving that it has excellent water resistance and can maintain a conversion rate of nearly 100% for 200 ppm ozone. The catalysts prepared by changing the aging temperature, aging time, pH and calcination time during the catalyst preparation process have almost exactly the same ozone decomposition activity, which is beneficial to the industrial production and application of this catalyst. For Examples 10 to 11, an increase in the calcination temperature will cause the catalyst specific surface area to decrease, resulting in a decrease in the catalyst's ozone decomposition activity. For Examples 12 to 13, when the Ce / Ni molar ratio increases, due to the increase in the amount of CeO2 precipitated, the size of the CeO2 crystals formed increases, covering some active sites, causing the ozone conversion rate to decrease slightly, but it can still maintain an ozone conversion rate of more than 90% and no deactivation for 60h. Comparative Example 1 is pure NiO, and its ozone conversion rate and stability are much lower than those of the catalyst modified with the additive Ce. In Comparative Example 2, the Ce / Ni molar ratio is low and Ni cannot be formed. 1- x Ce xO-CeO2 composite metal oxide-heterojunction structure lacks interfacial interaction and cannot form interfacial defect sites. In the comparative example 3 catalyst, the Ce / Ni molar ratio is too high and the CeO2 grain size is too large, covering a large number of active sites, resulting in a serious decrease in ozone conversion rate. 1-x Ce x O catalyst, CeO2 and Ni 1-x Ce x The interaction between O and O is not strong, and the ozone conversion rate and stability are greatly reduced compared with the examples with the same Ce / Ni molar ratio.

[0051] Table 2. Crystalline size and specific surface area of ​​catalysts obtained in Examples 1 to 13 and Comparative Examples 1 to 4 catalyst Ce / Ni molar ratio Grain size / nm <![CDATA[Specific surface area / m 2 ·g -1 > Example 1 <![CDATA[Ni 1-x What x O-CeO2]]> 0.1 3.10 155 Example 2 <![CDATA[Ni 1-x What x O-CeO2]]> 0.1 3.06 163 Example 3 <![CDATA[Ni 1-x What x O-CeO2]]> 0.1 3.11 160 Example 4 <![CDATA[Ni 1-x What x O-CeO2]]> 0.1 3.08 151 Example 5 <![CDATA[Ni 1-x What x O-CeO2]]> 0.1 3.05 148 Example 6 <![CDATA[Ni 1-x What x O-CeO2]]> 0.1 3.12 152 Example 7 <![CDATA[Ni 1-x What x O-CeO2]]> 0.1 3.13 160 Example 8 <![CDATA[Ni 1-x What x O-CeO2]]> 0.1 3.09 159 Example 9 <![CDATA[Ni 1-x What x O-CeO2]]> 0.1 3.06 156 Example 10 <![CDATA[Ni 1-x What x O-CeO2]]> 0.1 3.52 131 Example 11 <![CDATA[Ni 1-x What x O-CeO2]]> 0.1 3.96 102 Example 12 <![CDATA[Ni 1-x What x O-CeO2]]> 0.25 3.34 99 Example 13 <![CDATA[Ni 1-x What x O-CeO2]]> 0.5 3.56 73 Comparative Example 1 NiO 0 6.22 70 Comparative Example 2 <![CDATA[Ni 1-x What x Oh]]> 0.05 3.72 151 Comparative Example 3 <![CDATA[Ni 1-x What x O-CeO2]]> 1.25 4.85 38 Comparative Example 4 <![CDATA[CeO2 / Ni 1-x What x Oh]]> 0.11 3.83 86 Comparative Example 5 <![CDATA[CeO2 / Ni 1-x What x Oh]]> 0.25 4.09 54 From Table 2, it can be seen that the Ni 1- x Ce x O-CeO2 catalyst has smaller crystal size and larger specific surface area, which is beneficial for providing active sites for decomposing ozone. In the process of catalyst preparation, the calcination temperature is adjusted to increase, the catalyst crystal size increases, and the specific surface area decreases slightly. Adjusting the Ce / Ni molar ratio to increase, more and larger CeO2 particles are formed to cover part of the surface, resulting in an increase in crystal size and a decrease in surface area. Since Ce doping reduces the crystallinity of NiO, the Ni in Comparative Example 2 1-x Ce x The specific surface area of ​​CeO2 / NiO catalyst is much larger than that of NiO in Comparative Example 1. 1-x Ce x O, the specific surface area is much smaller than that of Ni with the same Ce / Ni molar ratio 1-x Ce x O-CeO2.

[0052] The stability test was conducted on the highly active catalysts (Example 1 to Example 3). The test conditions were 30°C, ozone concentration 200 ppm, relative humidity 90%, and mass space velocity 1,000,000 mL·g -1 ·h -1 The ozone decomposition stability of the catalysts obtained in Examples 1 to 3 is as follows: Figure 1 The catalyst maintained an ozone conversion rate of nearly 100% for 60 hours of continuous reaction. This catalyst has stable ozone decomposition performance and has practical application value.

[0053] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A high water resistance ozone decomposition catalyst for room temperature, characterized in that: The catalyst is Ni 1-x Ce x O-CeO2 composite oxide-heterojunction structure, where 0 <x<0.1。 2. The catalyst for ozone decomposition at room temperature with high water resistance according to claim 1, characterized in that: The Ni 1-x Ce x The O-CeO2 catalyst has a crystal size of 2~10nm and a specific surface area of ​​50~200m 2 ·g -1 ; The Ni 1-x Ce x The CeO2 grain size in O-CeO2 catalyst is 2~10nm.

3. A method for preparing a room-temperature high-water-resistance ozone decomposition catalyst according to claim 1 or 2, characterized in that: The following steps are involved: Step (1): dissolving soluble Ce salt and Ni salt in water to obtain a mixed solution; Step (2): adding the mixed solution obtained in step (1) and the precipitant dropwise into a reactor while maintaining a constant pH of 9 to 11, and aging at a constant temperature to obtain a mixed precipitate; Step (3): The mixed precipitate obtained in step (2) is filtered, washed, dried, and then calcined in air to obtain Ni 1-x Ce x O-CeO2 catalyst.

4. The method for preparing a room-temperature high-water-resistance ozone decomposition catalyst according to claim 3, characterized in that: The molar ratio of the soluble Ce salt to the Ni salt in step (1) is 0.1-0.5:1; The concentration of Ce ions in the mixed solution is 0.01-2 mol / L.

5. The method for preparing a room-temperature high-water-resistance ozone decomposition catalyst according to claim 3, characterized in that: The soluble Ce salt includes any one or more of cerium nitrate hexahydrate, cerium sulfate tetrahydrate, cerium chloride heptahydrate, and cerium acetate.

6. The method for preparing a room-temperature high-water-resistance ozone decomposition catalyst according to claim 3, characterized in that: The soluble Ni salt includes any one or more of nickel nitrate hexahydrate, nickel sulfate hexahydrate, nickel chloride hexahydrate, and nickel acetate tetrahydrate.

7. The method for preparing a room-temperature high-water-resistance ozone decomposition catalyst according to claim 3, characterized in that: The precipitant in step (2) includes any one or more of sodium carbonate, sodium hydroxide, ammonia water, and ammonium carbonate; The concentration of the precipitant is 0.1-2 mol / L.

8. The method for preparing a room-temperature high-water-resistance ozone decomposition catalyst according to claim 3, characterized in that: The aging temperature in step (2) is 20-60°C; the aging time is 6-24 hours.

9. The method for preparing a room-temperature high-water-resistance ozone decomposition catalyst according to claim 3, characterized in that: The calcination temperature in step (3) is 350-550° C., and the calcination time is 3-7 hours.

10. A use of a catalyst for ozone decomposition at room temperature with high water resistance as claimed in claim 1 or 2, characterized in that: The catalyst is used for ozone decomposition with high water resistance at room temperature.

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