Rare earth manganese zirconium composite catalytic material, preparation method thereof and catalyst

Abstract

The invention discloses a rare earth manganese zirconium composite catalytic material, a preparation method thereof and a catalyst, the rare earth manganese zirconium composite catalytic material comprises crystalline rare earth zirconium oxide and amorphous manganese oxide, the chemical general formula of the rare earth manganese zirconium composite catalytic material is REaMnbZrcLdO (2-delta) D beta, RE is a rare earth element; l is a cation doping element, and D is an anion doping element; wherein in terms of mole number, 0.10 < = a < = 0.85, 0.05 < = b < = 0.25, 0.10 < = c < = 0.85, 0 < d < = 0.20, 0 < = delta < = 0.30, 0 < = beta < = 0.10, and d = 1-a-b-c. The dispersity of active manganese is enhanced and the utilization rate of manganese atoms is increased by utilizing the interaction of manganese oxide and rare earth zirconium-based oxide; the catalyst has high catalytic activity to NO at a low temperature and high durability, the use amount of platinum group metals is reduced, and the oxidation rate of NO is increased by increasing the concentration of oxygen vacancies, so that the catalyst has high catalytic activity to NO at a low temperature and is relatively high in durability.

Description

Technical Field

[0001] The invention relates to the technical field of environmental protection, and in particular to a rare earth manganese zirconium composite catalytic material and a preparation method and a catalyst thereof. Background Art

[0002] Diesel exhaust contains a large amount of nitrogen oxides (NOx), hydrocarbons (HCs), and particulate matter PM, which not only seriously harm the human respiratory system, but also cause air pollution. With the increasingly stringent emission regulations, how to effectively remove NOx, HCs, and PM in engine exhaust has become a research hotspot in environmental catalysis. At present, diesel exhaust aftertreatment mainly consists of oxidation catalyst (DOC), selective catalyst (SCR), particulate filter (DPF), ammonia slip catalyst (ASC), etc. Among them, DOC is crucial for the removal of NOx, HCs, and PM.

[0003] The core of DOC (diesel oxidation catalyst) lies in its coating material, which undertakes the key catalytic task of efficiently converting NO into NO2; DOC catalysts usually use precious metal-loaded alumina as active ingredients. At present, the amount of precious metals used in DOC catalysts usually exceeds 25g / ft3, which is relatively expensive; at the same time, with the continuous tightening of global emission regulations, more stringent requirements are placed on the performance of DOC catalysts. On the one hand, the inlet operating temperature of the catalyst needs to be significantly reduced to adapt to a wider range of operating conditions; on the other hand, catalytic efficiency and durability must also reach new heights. Simply relying on increasing the loading of precious metals to improve catalyst performance can meet performance requirements to a certain extent, but it will cause a sharp increase in costs and is not a sustainable solution. Summary of the invention

[0004] The purpose of the embodiments of the present invention is to provide a rare earth manganese zirconium composite catalytic material and a preparation method and catalyst thereof. By including crystalline rare earth zirconium oxide and amorphous manganese oxide in the rare earth manganese zirconium composite catalytic material, the catalyst has higher low-temperature NO oxidation performance, improved durability, high catalytic activity for NO at low temperatures and high durability, reducing the use of platinum group metals and improving the NO oxidation rate.

[0005] In order to solve the above technical problems, the first aspect of the embodiment of the present invention provides a rare earth manganese zirconium composite catalytic material, wherein the rare earth manganese zirconium composite catalytic material comprises crystalline rare earth zirconium oxide and amorphous manganese oxide, and its chemical formula is RE a Mn b Zr c L d O (2-δ) D β , RE is a rare earth element; L is a cation doping element, and D is an anion doping element;

[0006] Wherein, in terms of moles, 0.10≤a≤0.85, 0.05≤b≤0.25, 0.10≤c≤0.85, 0<d≤0.20, 0≤δ≤0.30, 0≤β≤0.10, d=1-abc.

[0007] Furthermore, the amorphous manganese oxide comprises: at least one of Mn3O4, Mn2O3, MnO2, REMn2O5 and REMnO3, preferably at least one of REMn2O5, Mn3O4 and Mn2O3.

[0008] Furthermore, the crystalline rare earth zirconium oxide includes: a tetragonal phase and / or a cubic phase.

[0009] Furthermore, the amorphous manganese oxide is located on the surface and / or grain boundary of the crystalline rare earth zirconium oxide.

[0010] Furthermore, the Mn comprises Mn 2+ , Mn 3+ and Mn 4+ At least one of;

[0011] Mn 4+ and (Mn 2+ +Mn 3+ )The molar ratio range is 0.2:1 to 2:1.

[0012] Furthermore, the RE includes at least one of La, Ce, Pr, Nd, Sm, Eu, Gd, Yb and Y.

[0013] Further, the cationic doping element L includes: at least one of alkaline earth metals, transition metals, aluminum and silicon, preferably at least one of Fe, Co, Ni, Cu, Zn, V, Ti, Cr, Mo, W, Sn, Nb, Al, Si, Ga, Ge, In, Hf, Ba, Sr, Mg and Ca;

[0014] The anion doping element D includes at least one of anions N, P, F and S.

[0015] Furthermore, the pore size range of the rare earth manganese zirconium composite catalytic material is concentrated in: 1nm to 4nm and 15nm to 25nm;

[0016] The pore volume range of the rare earth manganese zirconium composite catalyst material is: 0.2cm 3 / g~0.6cm 3 / g.

[0017] Accordingly, a second aspect of an embodiment of the present invention provides a rare earth manganese zirconium composite catalytic material for preparing the rare earth manganese zirconium composite catalytic material, comprising the following steps:

[0018] S1. Mixing aqueous solutions of all zirconium compounds, part of RE compounds and part of L compounds, adding alkaline substances for precipitation reaction, filtering, washing, drying and calcining to obtain rare earth zirconium oxide containing RE and L;

[0019] S2, mixing all the manganese compounds, the remaining RE compounds and the remaining L compounds with the rare earth zirconium oxide obtained in step S1 to obtain a composite compound precursor;

[0020] S3. After heat treatment of the composite compound precursor obtained in step S2, a rare earth manganese zirconium composite catalytic material containing amorphous manganese oxide is obtained.

[0021] Accordingly, a third aspect of an embodiment of the present invention provides a rare earth manganese zirconium composite catalytic material for preparing the rare earth manganese zirconium composite catalytic material, comprising the following steps:

[0022] S1. Mixing aqueous solutions of all zirconium compounds, part of RE compounds and all L compounds, adding alkaline substances for precipitation reaction, filtering, washing, drying and calcining to obtain rare earth zirconium oxide containing RE and L;

[0023] S2, mixing all the manganese compounds and the remaining RE compounds with the rare earth zirconium oxide obtained in step S1 to obtain a composite compound precursor;

[0024] S3. After heat treatment of the composite compound precursor obtained in step S2, a rare earth manganese zirconium composite catalytic material containing amorphous manganese oxide is obtained.

[0025] Furthermore, the method for preparing the rare earth manganese zirconium composite catalytic material further comprises:

[0026] The compound of the anion doping element D is added during the precipitation process of step S1 and / or the mixing process of step S2.

[0027] Further, the manganese compound includes: at least one of chloride, nitrate, sulfate, permanganate and acetate, preferably manganese nitrate;

[0028] The zirconium compound comprises: at least one of oxychloride, nitrate, sulfate, acetate and citrate, preferably zirconium oxynitrate;

[0029] The compound of the cationic doping element L and the compound of the rare earth element RE include: a molten salt or aqueous solution of at least one of chloride, nitrate, sulfate, acetate, citrate, amino acid salt, and organosilicon compound, preferably nitrate;

[0030] The compound of the anion doping element D includes: at least one of nitrate, fluoride, phosphate and sulfate. Preferably, the anion doping element D includes: nitrate and / or sulfate;

[0031] The alkaline substance includes: at least one of urea, hydroxide, ammonia water, carbonate and bicarbonate; the bicarbonate includes: at least one of ammonium, potassium, sodium and magnesium; the hydroxide includes: at least one of ammonium, sodium, potassium and magnesium; preferably, the alkaline substance includes: at least one of sodium hydroxide, urea, ammonia water and ammonium bicarbonate.

[0032] Further, the pH value range during the precipitation process of step S1 is 4.5 to 14, preferably 5 to 11;

[0033] The precipitation endpoint pH value of step S1 ranges from 8 to 13, preferably from 9 to 11;

[0034] The temperature during the precipitation process of step S1 is 5°C to 120°C, preferably 20°C to 80°C.

[0035] Further, the calcination temperature of step S1 ranges from 500°C to 1000°C, preferably from 600°C to 900°C;

[0036] The heat treatment temperature range of step S3 is 300°C to 900°C, preferably 400°C to 800°C;

[0037] The calcination and heat treatment are carried out under a preset atmosphere, and the preset atmosphere includes: at least one of air, O2, CO, CO2 and N2.

[0038] Correspondingly, the fourth aspect of an embodiment of the present invention provides a catalyst, including the above-mentioned rare earth manganese zirconium composite catalytic material, which is used for motor vehicle exhaust purification, organic waste gas purification, flue gas denitrification or natural gas catalytic combustion.

[0039] The above technical solution of the embodiment of the present invention has the following beneficial technical effects:

[0040] 1. The rare earth manganese zirconium composite catalytic material contains crystalline rare earth zirconium oxide and amorphous manganese oxide, which improves the NO oxidation performance of the catalyst in a low temperature environment, exhibits excellent low-temperature catalytic activity, significantly enhances the durability of the catalyst, ensures long-term and efficient catalytic effect, and effectively reduces the demand for platinum group metals, achieves cost savings, and simultaneously improves the NO oxidation efficiency;

[0041] 2. The rare earth manganese zirconium composite catalytic material containing amorphous manganese oxide uses the riveting effect of rare earth zirconium oxide in the crystalline phase on amorphous manganese oxide, which is beneficial to improve the thermal stability of amorphous manganese oxide, so that it can still maintain an amorphous structure at high temperatures up to 800°C. In addition, the rich active oxygen and defect structure of rare earth zirconium oxide can be used to quickly transfer oxygen elements and improve redox performance;

[0042] 3. The rare earth manganese zirconium composite catalytic material comprises crystalline rare earth zirconium oxide and amorphous manganese oxide. By utilizing the interaction between manganese oxide and rare earth zirconium-based oxide, the manganese oxide presents an amorphous distribution, thereby enhancing the dispersion of active manganese and improving the utilization rate of manganese atoms; and increasing the concentration of oxygen defects, thereby increasing the amount of active oxygen and improving the catalytic activity of the rare earth manganese zirconium composite catalytic material. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is an XRD diagram of the rare earth manganese zirconium composite catalytic material containing amorphous manganese oxide provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0045] The first aspect of the embodiment of the present invention provides a rare earth manganese zirconium composite catalytic material, the rare earth manganese zirconium composite catalytic material comprises crystalline rare earth zirconium oxide and amorphous manganese oxide, and its chemical formula is RE a Mn b Zr c L d O (2-δ) D β , RE is a rare earth element; L is a cation doping element, and D is an anion doping element; wherein, in terms of molar number, 0.10≤a≤0.85, 0.05≤b≤0.25, 0.10≤c≤0.85, 0<d≤0.20, 0≤δ≤0.30, 0≤β≤0.10, and d=1-abc.

[0046] In the above technical solution, the main catalytic activity of the rare earth manganese zirconium composite catalyst material containing amorphous manganese oxide is concentrated in the amorphous manganese oxide. Compared with crystalline manganese oxide, amorphous manganese oxide has the characteristics of short-range order and long-range disorder. The metal ions in these short-range ordered structures can exert strong atomic-level interactions, enhance the pd electron hybridization between Mn-O, so that the manganese element has a richer valence state and is beneficial to its active Mn 3+ / Mn 4+ redox cycle and improve its redox performance.

[0047] The rare earth manganese zirconium composite catalytic material containing amorphous manganese oxide utilizes the fixing effect of the rare earth zirconium oxide in the crystalline phase on the amorphous manganese oxide, which is beneficial to improve the thermal stability of the amorphous manganese oxide, so that it can still maintain an amorphous structure at high temperatures up to 800°C. In addition, the specific rich active oxygen and defect structure of the rare earth zirconium oxide can be used to quickly transfer oxygen elements and improve redox performance.

[0048] Furthermore, the amorphous manganese oxide comprises at least one of Mn3O4, Mn2O3, MnO2, REMn2O5 and REMnO3, preferably at least one of REMn2O5, Mn3O4 and Mn2O3.

[0049] Furthermore, the crystalline rare earth zirconium oxide includes: a tetragonal phase and / or a cubic phase.

[0050] Furthermore, the amorphous manganese oxide is located on the surface and / or grain boundary of the crystalline rare earth zirconium oxide.

[0051] Furthermore, the Mn comprises Mn 2+ , Mn 3+ , Mn 4+ At least one of: Mn 4+ and (Mn 2+ +Mn 3+ )The molar ratio range is 0.2:1 to 2:1.

[0052] Further, RE includes at least one of La, Ce, Pr, Nd, Sm, Eu, Gd, Yb and Y.

[0053] Furthermore, the cation doping element L includes: at least one of alkaline earth metals, transition metals, aluminum and silicon elements, preferably at least one of Fe, Co, Ni, Cu, Zn, V, Ti, Cr, Mo, W, Sn, Nb, Al, Si, Ga, Ge, In, Hf, Ba, Sr, Mg and Ca; the anion doping element D includes: at least one of anions N, P, F and S.

[0054] Furthermore, the pore size range of the rare earth manganese zirconium composite catalyst material is concentrated in: 1nm ~ 4nm and 15nm ~ 25nm; the pore volume range of the rare earth manganese zirconium composite catalyst material is: 0.2cm 3 / g~0.6cm 3 / g.

[0055] During the preparation process of traditional manganese oxide amorphous catalytic materials, the calcination temperature and material usage conditions need to be controlled. Otherwise, the manganese oxide will undergo crystallization, particle sintering and agglomeration, thereby reducing the catalytic activity of manganese oxide as an active component of the catalyst, reducing the utilization rate of the active component, and resulting in poor long-term stability of the catalyst.

[0056] Accordingly, a second aspect of an embodiment of the present invention provides a rare earth manganese zirconium composite catalytic material for preparing the rare earth manganese zirconium composite catalytic material, comprising the following steps:

[0057] S1. Mixing aqueous solutions of all zirconium compounds, part of RE compounds and part of L compounds, adding alkaline substances for precipitation reaction, filtering, washing, drying and calcining to obtain rare earth zirconium oxide containing RE and L;

[0058] S2, mixing all the manganese compounds, the remaining RE compounds and the remaining L compounds with the rare earth zirconium oxide obtained in step S1 to obtain a composite compound precursor;

[0059] S3. After heat treatment of the composite compound precursor obtained in step S2, a rare earth manganese zirconium composite catalytic material containing amorphous manganese oxide is obtained.

[0060] Accordingly, a third aspect of an embodiment of the present invention provides a rare earth manganese zirconium composite catalytic material for preparing the rare earth manganese zirconium composite catalytic material, comprising the following steps:

[0061] S1. Mixing aqueous solutions of all zirconium compounds, part of RE compounds and all L compounds, adding alkaline substances for precipitation reaction, filtering, washing, drying and calcining to obtain rare earth zirconium oxide containing RE and L;

[0062] S2, mixing all the manganese compounds and the remaining RE compound with the rare earth zirconium oxide obtained in step S1 to obtain a composite compound precursor;

[0063] S3. After heat treatment of the composite compound precursor obtained in step S2, a rare earth manganese zirconium composite catalytic material containing amorphous manganese oxide is obtained.

[0064] In the above two embodiments, the mixing process in step S2 can make the amorphous manganese oxide be located on the surface and / or grain boundary of the crystalline rare earth zirconium oxide.

[0065] Furthermore, the method for preparing the rare earth manganese zirconium composite catalytic material also includes:

[0066] The compound of the anion doping element D is added during the precipitation process of step S1 and / or the mixing process of step S2.

[0067] Further, the manganese compound includes: at least one of chloride, nitrate, sulfate, permanganate and acetate, preferably manganese nitrate;

[0068] The zirconium compound comprises at least one of oxychloride, nitrate, sulfate, acetate and citrate, preferably zirconium oxynitrate;

[0069] The compound of the cationic doping element L and the compound of the rare earth element RE include: a molten salt or aqueous solution of at least one of chlorides, nitrates, sulfates, acetates, citrates, amino acid salts, and organosilicon compounds, preferably nitrates;

[0070] The compound of the anion doping element D includes: at least one of nitrate, fluoride, phosphate and sulfate. Preferably, the anion doping element D includes: nitrate and / or sulfate;

[0071] The alkaline substance includes: at least one of urea, hydroxide, ammonia water, carbonate and bicarbonate; the bicarbonate includes: at least one of ammonium, potassium, sodium and magnesium; the hydroxide includes: at least one of ammonium, sodium, potassium and magnesium; preferably, the alkaline substance includes: at least one of sodium hydroxide, urea, ammonia water and ammonium bicarbonate.

[0072] Further, the pH value range during the precipitation process of step S1 is 4.5 to 14, preferably 5 to 11;

[0073] The precipitation endpoint pH value of step S1 ranges from 8 to 13, preferably from 9 to 11;

[0074] The temperature during the precipitation process of step S1 is 5°C to 120°C, preferably 20°C to 80°C.

[0075] Further, the calcination temperature of step S1 ranges from 500°C to 1000°C, preferably from 600°C to 900°C;

[0076] The heat treatment temperature range of step S3 is 300°C to 900°C, preferably 400°C to 800°C;

[0077] The calcination and heat treatment are carried out under a preset atmosphere, which includes at least one of air, O2, CO, CO2 and N2.

[0078] The following is a comparative example and an example of a number of preparation methods to specifically describe the preparation process of amorphous manganese oxide rare earth manganese zirconium composite catalyst material, wherein the catalytic performance evaluation conditions are: 500ppm NO, 8% O2, 500ppm CO, 300ppm HC, N2 as the balance gas, space velocity 80000h -1 .

[0079] Comparative Example 1:

[0080] According to La 0.05 Y 0.05 Ce 0.3 Zr 0.55 Nd 0.05 The mixture was prepared according to the molar ratio of La / Y / Ce / Zr / Nd in the rare earth zirconium oxide of 1.5 M O2 to obtain a mixed solution with a total cation concentration of 1.5 M; the mixed solution was added to a 3.0 M NaOH solution at a uniform rate under stirring, the pH value of the precipitation process was 10-14, the end point pH value was 10, and the temperature was controlled at 50°C; the precipitate was filtered, washed, dried, and calcined at 550°C for 8 hours to obtain a tetragonal rare earth zirconium oxide La 0.05 Y 0.05 Ce 0.3 Zr 0.55 Nd 0.05 O2.

[0081] The rare earth zirconium oxide obtained by the preparation method of Comparative Example 1 has a NO conversion rate of 7% at 240° C. through catalytic oxidation, a maximum NO conversion rate of 20%, and a conversion temperature corresponding to the maximum conversion rate of 385° C.

[0082] Comparative Example 2:

[0083] The ingredients were prepared according to the molar ratio of Y / Mn in YMn2O5 rare earth manganese oxide to obtain a mixed solution with a total cation concentration of 1.2M; the mixed solution and 2.8M NaOH solution were added to the reactor at a uniform rate under stirring conditions, the pH of the precipitation process was 9±0.2, the end point pH was 9, the temperature was controlled at 40°C, and Mn was added. 2+ The precipitate was filtered, washed, dried, and calcined at 820°C for 8 hours to obtain the rare earth manganese oxide YMn2O5 in the mullite phase. 4+ and (Mn 2+ +Mn 3+ ) has a molar ratio of 0.2:1.

[0084] The mullite phase rare earth manganese oxide obtained by the preparation method of Comparative Example 2 has a NO conversion rate of 10% at 240° C. in catalytic oxidation, a maximum NO conversion rate of 45%, and a conversion temperature corresponding to the maximum conversion rate of 366° C.

[0085] Comparative Example 3:

[0086] According to Sm 0.12 Mn 0.35 Zr 0.4 Y 0.13 O 1.98 The Sm / Zr / Y in the rare earth manganese zirconium composite catalytic material is prepared according to the molar ratio of 3:40:4 to obtain a mixed solution with a total cation concentration of 1.0M; under stirring, the mixed liquid is added to a 2.0M ammonia solution at a uniform rate, the pH of the precipitation process is 5-9, the end point pH is 8.9, and the temperature is controlled at 60°C; the precipitate is filtered, washed, dried, and calcined at 830°C for 8h to obtain tetragonal rare earth zirconium oxide. The rare earth zirconium oxide is mixed with a 1.8M Mn(NO3)2 solution containing Sm and Y, and then heat-treated at 900°C in air for 13h to obtain a rare earth manganese zirconium composite catalytic material containing tetragonal phase and mullite phase. Among them, the tetragonal phase accounts for 82% and the mullite phase accounts for 18%. Mn 4+ and (Mn 2+ +Mn 3+ ) has a molar ratio of 0.3:1.

[0087] The rare earth manganese oxide containing tetragonal phase and mullite phase obtained by the preparation method of Comparative Example 3 has a NO conversion rate of 13% at 240°C for catalytic oxidation, a maximum NO conversion rate of 50%, and a conversion temperature corresponding to the maximum conversion rate of 360°C.

[0088] Comparative Example 4:

[0089] According to Ce 0.27 Mn 0.43 Zr 0.15 Y 0.15 O 1.98 The Ce / Zr / Y in the rare earth manganese zirconium composite catalyst material is prepared according to the molar ratio of 27:20:3 to obtain a mixed solution with a total cation concentration of 1.0M; under stirring, the mixed liquid is added to a 2.0M NaOH solution at a uniform rate, the pH of the precipitation process is 6-10, the end point pH is 9.8, and the temperature is controlled at 40°C; the precipitate is filtered, washed, dried, and calcined at 600°C for 4h to obtain cubic rare earth zirconium oxide. After the rare earth zirconium oxide is mixed with a 1.2M Y-containing Mn(NO3)2 solution, it is heat treated at 700°C in air for 13h to obtain a rare earth manganese zirconium composite catalyst material containing cubic phase, mullite phase, and Mn3O4 phase. Among them, the cubic phase accounts for 77%, the mullite phase accounts for 20%, and the Mn3O4 phase accounts for 3%. Mn 4+ and (Mn 2+ +Mn 3+ ) has a molar ratio of 0.3:1.

[0090] The rare earth manganese oxide containing tetragonal phase and mullite phase obtained by the preparation method of Comparative Example 3 has a NO conversion rate of 14% at 240° C., a maximum NO conversion rate of 52%, and a conversion temperature corresponding to the maximum conversion rate of 359° C.

[0091] Example 1

[0092] According to Ce 0.06 La 0.05 Y 0.08 Mn 0.21 Zr 0.6 O 1.94 The molar ratio of Ce / La / Y / Zr in the rare earth manganese zirconium composite catalyst material is 6:2:3:60, which is dissolved in water to obtain a mixed solution with a concentration of 1.5M; under stirring conditions, the mixed liquid is added to a 2.1M NaOH solution at a uniform rate, the pH of the precipitation process is 10-14, the end point pH is 10, and the temperature is controlled at 50°C; the precipitate is filtered, washed, and dried, and the dried product is calcined at 800°C for 7h to obtain tetragonal rare earth zirconium oxide. After the rare earth zirconium oxide is mixed with a 1.2M Mn(NO3)2 solution containing La and Y, it is heat treated at 150°C in an oxygen atmosphere for 5h, and then calcined at 500°C in an air atmosphere for 12h to obtain Mn 4+ and (Mn 2+ +Mn 3+ ) has a molar ratio of 0.5:1. Amorphous manganese oxide contains REMn2O5 and Mn3O4, and the pore volume of the compound is 0.3cm 3 / g.

[0093] The rare earth manganese zirconium composite catalytic material containing amorphous manganese oxide obtained by the preparation method of this embodiment of the present invention has a NO conversion rate of 37% at 240°C for catalytic oxidation, a maximum NO conversion rate of 70%, and a conversion temperature corresponding to the maximum conversion rate of 298°C.

[0094] Examples 2-43: Unless otherwise specified below, all are carried out in the same manner as Example 1. The specific phase structure composition and performance test results of the examples are shown in Table 1.

[0095] Specifically, Mn 4+ and (Mn 2+ +Mn 3+ ) was detected by XPS. By performing Gaussian fitting on the spectral peak of Mn 2p, the peak signal of the electron binding energy near 640 eV in the XPS spectrum was attributed to divalent Mn (Mn 2+ ), the peak signal of the electron binding energy near 641.3 eV is attributed to trivalent Mn (Mn 3+ ), and tetravalent Mn (Mn4+ ) characteristic signal, through Mn 4+ Corresponding peak area and Mn 2+ , Mn 3+ The Mn was calculated by the ratio of the corresponding peak areas. 4+ and (Mn 2+ +Mn 3+ ) molar ratio. The phase composition was analyzed by XRD, and the types of amorphous manganese oxides were analyzed by synchrotron radiation.

[0096] Table 1 Comparative Examples and Examples Phase Structure Composition and Performance Test Results

[0097]

[0098]

[0099] Please refer to Table 1. From the contents disclosed in Table 1, it can be seen that the method provided by the present invention can be used to adjust the types, sequence and ratio of the added manganese compound, RE compound and L compound, and adjust the test conditions such as atmosphere and temperature during the preparation process to prepare a compound with the chemical formula RE a Mn b Zr c L d O (2-δ) D β A rare earth manganese zirconium composite catalytic material, wherein the rare earth manganese zirconium composite catalytic material comprises crystalline rare earth zirconium oxide and amorphous manganese oxide, RE is a rare earth element; L is a cation doping element, and D is an anion doping element.

[0100] Figure 1 The XRD structure of the rare earth manganese zirconium composite catalytic material was analyzed, and its physical phase only contained a tetragonal phase of rare earth zirconium oxide, and no manganese oxide crystal phase was detected, indicating that the amorphous rare earth manganese zirconium composite catalytic material was successfully synthesized.

[0101] Correspondingly, the fourth aspect of an embodiment of the present invention provides a catalyst, including the above-mentioned rare earth manganese zirconium composite catalytic material, which is used for motor vehicle exhaust purification, organic waste gas purification, flue gas denitrification or natural gas catalytic combustion.

[0102] The catalyst based on the above rare earth manganese zirconium composite catalytic material can be used to efficiently remove pollutants such as CO, HC, and carbon smoke in automobile exhaust, and is beneficial to the catalytic oxidation of NO to NO2, improving the low-temperature activity of motor vehicle exhaust purification catalysts, and reducing the amount of precious metals in the catalyst.

[0103] The embodiment of the present invention is intended to protect a rare earth manganese zirconium composite catalytic material and a preparation method and catalyst thereof. The rare earth manganese zirconium composite catalytic material comprises crystalline rare earth zirconium oxide and amorphous manganese oxide, and its chemical formula is RE a Mnb Zr c L d O (2-δ) D β , RE is a rare earth element; L is a cation doping element, and D is an anion doping element; wherein, in terms of molar number, 0.10≤a≤0.85, 0.05≤b≤0.25, 0.10≤c≤0.85, 0<d≤0.20, 0≤δ≤0.30, 0≤β≤0.10, d=1-abc. The above technical solution has the following effects:

[0104] 1. By including crystalline rare earth zirconium oxide and amorphous manganese oxide in the rare earth manganese zirconium composite catalytic material, the catalyst has higher low-temperature NO oxidation performance and improved durability. It has high catalytic activity for NO at low temperatures and high durability, reduces the use of platinum group metals, and improves the NO oxidation rate;

[0105] 2. The rare earth manganese zirconium composite catalytic material containing amorphous manganese oxide uses the riveting effect of rare earth zirconium oxide in the crystalline phase on amorphous manganese oxide, which is beneficial to improve the thermal stability of amorphous manganese oxide, so that it can still maintain an amorphous structure at high temperatures up to 800°C. In addition, the rich active oxygen and defect structure of rare earth zirconium oxide can be used to quickly transfer oxygen elements and improve redox performance;

[0106] 3. The rare earth manganese zirconium composite catalytic material comprises crystalline rare earth zirconium oxide and amorphous manganese oxide. By utilizing the interaction between manganese oxide and rare earth zirconium-based oxide, the manganese oxide presents an amorphous distribution, thereby enhancing the dispersion of active manganese and improving the utilization rate of manganese atoms; and increasing the concentration of oxygen defects, thereby increasing the amount of active oxygen and improving the catalytic activity of the rare earth manganese zirconium composite catalytic material.

[0107] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and do not constitute a limitation of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the appended claims, or the equivalent forms of such scope and boundaries.

Claims

1. A rare earth manganese zirconium composite catalytic material, characterized in that: The rare earth manganese zirconium composite catalytic material comprises crystalline rare earth zirconium oxide and amorphous manganese oxide, and its general chemical formula is RE a Mn b Zr c L d O (2-δ) D β , RE is a rare earth element; L is a cation doping element, and D is an anion doping element; Wherein, in terms of moles, 0.10≤a≤0.85, 0.05≤b≤0.25, 0.10≤c≤0.85, 0<d≤0.20, 0≤δ≤0.30, 0≤β≤0.10, d=1-abc.

2. The rare earth manganese zirconium composite catalytic material according to claim 1, characterized in that: The amorphous manganese oxide comprises at least one of Mn3O4, Mn2O3, MnO2, REMn2O5 and REMnO3, preferably at least one of REMn2O5, Mn3O4 and Mn2O3.

3. The rare earth manganese zirconium composite catalytic material according to claim 1, characterized in that: The crystalline rare earth zirconium oxide includes: a tetragonal phase and / or a cubic phase.

4. The rare earth manganese zirconium composite catalytic material according to claim 3, characterized in that: The amorphous manganese oxide is located on the surface and / or grain boundary of the crystalline rare earth zirconium oxide.

5. The rare earth manganese zirconium composite catalytic material according to claim 1, characterized in that: The Mn includes Mn 2+ , Mn 3+ , Mn 4+ At least one of; Mn 4+ and (Mn 2+ +Mn 3+ )The molar ratio range is 0.2:1 to 2:

1.

6. The rare earth manganese zirconium composite catalytic material according to any one of claims 1 to 5, characterized in that: The RE includes at least one of La, Ce, Pr, Nd, Sm, Eu, Gd, Yb and Y.

7. The rare earth manganese zirconium composite catalytic material according to any one of claims 1 to 5, characterized in that: The cationic doping element L comprises: at least one of alkaline earth metals, transition metals, aluminum and silicon, preferably at least one of Fe, Co, Ni, Cu, Zn, V, Ti, Cr, Mo, W, Sn, Nb, Al, Si, Ga, Ge, In, Hf, Ba, Sr, Mg and Ca; The anion doping element D includes at least one of anions N, P, F and S.

8. The rare earth manganese zirconium composite catalytic material according to any one of claims 1 to 5, characterized in that: The pore size range of the rare earth manganese zirconium composite catalyst material is concentrated in: 1nm-4nm and 15nm-25nm; The pore volume range of the rare earth manganese zirconium composite catalyst material is: 0.2cm 3 / g~0.6cm 3 / g.

9. A method for preparing a rare earth manganese zirconium composite catalytic material, characterized in that: The method for preparing the rare earth manganese zirconium composite catalytic material according to any one of claims 1 to 8 comprises the following steps: S1. Mixing aqueous solutions of all zirconium compounds, part of RE compounds and part of L compounds, adding alkaline substances for precipitation reaction, filtering, washing, drying and calcining to obtain rare earth zirconium oxide containing RE and L; S2, mixing all the manganese compounds, the remaining RE compounds and the remaining L compounds with the rare earth zirconium oxide obtained in step S1 to obtain a composite compound precursor; S3. After heat treatment of the composite compound precursor obtained in step S2, a rare earth manganese zirconium composite catalytic material containing amorphous manganese oxide is obtained.

10. A method for preparing a rare earth manganese zirconium composite catalytic material, characterized in that: The method for preparing the rare earth manganese zirconium composite catalytic material according to any one of claims 1 to 8 comprises the following steps: S1. Mixing aqueous solutions of all zirconium compounds, part of RE compounds and all L compounds, adding alkaline substances for precipitation reaction, filtering, washing, drying and calcining to obtain rare earth zirconium oxide containing RE and L; S2, mixing all the manganese compounds and the remaining RE compounds with the rare earth zirconium oxide obtained in step S1 to obtain a composite compound precursor; S3. After heat treatment of the composite compound precursor obtained in step S2, a rare earth manganese zirconium composite catalytic material containing amorphous manganese oxide is obtained.

11. The method for preparing the rare earth manganese zirconium composite catalytic material according to claim 9 or 10, characterized in that: Also includes: The compound of the anion doping element D is added during the precipitation process of step S1 and / or the mixing process of step S2.

12. The method for preparing the rare earth manganese zirconium composite catalytic material according to claim 9 or 10, characterized in that: The manganese compound comprises: at least one of chloride, nitrate, sulfate, permanganate and acetate, preferably manganese nitrate; The zirconium compound comprises: at least one of oxychloride, nitrate, sulfate, acetate and citrate, preferably zirconium oxynitrate; The compound of the cationic doping element L and the compound of the rare earth element RE include: a molten salt or aqueous solution of at least one of chloride, nitrate, sulfate, acetate, citrate, amino acid salt, and organosilicon compound, preferably nitrate; The compound of the anion doping element D includes: at least one of nitrate, fluoride, phosphate and sulfate. Preferably, the anion doping element D includes: nitrate and / or sulfate; The alkaline substance includes: at least one of urea, hydroxide, ammonia water, carbonate and bicarbonate; the bicarbonate includes: at least one of ammonium, potassium, sodium and magnesium; the hydroxide includes: at least one of ammonium, sodium, potassium and magnesium; preferably, the alkaline substance includes: at least one of sodium hydroxide, urea, ammonia water and ammonium bicarbonate.

13. The method for preparing the rare earth manganese zirconium composite catalytic material according to claim 9 or 10, characterized in that: The pH value during the precipitation process of step S1 ranges from 4.5 to 14, preferably from 5 to 11; The precipitation endpoint pH value of step S1 is in the range of 8 to 13, preferably 9 to 11; The temperature during the precipitation process of step S1 is 5°C to 120°C, preferably 20°C to 80°C.

14. The method for preparing the rare earth manganese zirconium composite catalytic material according to claim 9 or 10, characterized in that: The calcination temperature of step S1 is in the range of 500°C to 1000°C, preferably 600°C to 900°C; The heat treatment temperature range of step S3 is 300°C to 900°C, preferably 400°C to 800°C; The calcination and heat treatment are carried out under a preset atmosphere, and the preset atmosphere includes: at least one of air, O2, CO, CO2 and N2.

15. A catalyst, characterized in that The rare earth manganese-zirconium composite catalytic material comprises any one of claims 1 to 8, which is used for motor vehicle exhaust purification, organic waste gas purification, flue gas denitrification or natural gas catalytic combustion.

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