Zn-doped ZrO2 bifunctional catalyst as well as preparation method and application thereof

Abstract

The invention discloses a Zn-doped ZrO2 bifunctional catalyst as well as a preparation method and application thereof. The Zn-doped ZrO2 bifunctional catalyst comprises zirconium oxide serving as a carrier and zinc oxide uniformly loaded on the zirconium oxide, zirconium oxide coexists in a tetragonal phase and a monoclinic phase, and zinc oxide is a hexagonal wurtzite crystal phase. The preparation method comprises the following steps: mixing soluble zinc salt with a Zr (OH) 4 precursor, adding an alkaline solution to carry out a first reaction to obtain a precipitate, and calcining to obtain the Zn-doped ZrO2 bifunctional catalyst. The Zn-doped ZrO2 bifunctional catalyst prepared by the preparation method disclosed by the invention is applied to CO2-assisted ethane oxidative dehydrogenation (CO2-ODHE) reaction, has an excellent ethylene generation rate, realizes conversion and utilization of CO2, and has a relatively good application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalysts, and particularly relates to a Zn-doped ZrO2 bifunctional catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] Ethylene is one of the most important light olefins and is mainly used to produce high-value-added chemicals such as polyesters, polyethylene, polyvinyl chloride, chloroethanol, vinyl chloride, styrene, dichloroethane, and vinyl acetate. Currently, industrial production of ethylene is mainly achieved by high-temperature cracking of naphtha or ethane. The entire reaction process needs to be carried out at high temperatures (700 - 900 °C), which inevitably leads to problems such as high energy consumption, large CO x emissions, and coke deposition on the reactor wall, which does not meet the requirements of China's energy sustainable development strategy. In addition, the ethylene yield and selectivity achieved by this method are not ideal. In recent years, with the increasingly advanced shale gas extraction technology, the conversion of ethane, the second largest resource in shale gas, into high-value-added chemicals has received increasing attention.

[0003] The oxidative dehydrogenation of ethane to ethylene under the action of CO2 can overcome the above defects and become the most attractive method for producing ethylene. In addition, CO2 has the following advantages when participating in the reaction: 1) CO2, as a mild oxidant, slows down the over-oxidation of ethane and improves the selectivity of ethylene; 2) the process consumes CO2 and reduces greenhouse gas emissions; 3) CO2 can eliminate carbon deposition through the reverse Boudouard reaction. Thermodynamic studies have shown that the C-C bond (377 kJ / mol) of ethane is more easily broken than the C-H bond (423 kJ / mol), and various side reactions such as dry reforming of ethane will occur during the CO2-ODHE reaction process. Therefore, an ideal catalyst for the CO2-ODHE reaction should selectively break the C-H bond of ethane to produce ethylene while inhibiting the breakage of the C-C bond.

[0004] Existing catalysts mainly include noble metal-based catalysts (Pd, Pt, Rh, Ru, and Ir, etc.) and transition metal oxide catalysts (Cr, Ni, Ga, Co, and Zn, etc.). However, the high cost of noble metal-based catalysts limits their wide application, while transition metal oxides have become an ideal choice to replace noble metal catalysts due to their good redox properties, thermal stability, and low cost. Transition metal catalysts represented by Zn-based catalysts have excellent performance in activating the C-H bond of short-chain alkanes and have been widely used in the oxidative dehydrogenation of short-chain alkanes to olefins. However, when such catalysts are used in the CO2-ODHE reaction, they face dilemmas such as low yield, serious deactivation problems, and difficulty in regenerating active centers. Summary of the Invention

[0005] The main object of the present invention is to provide a Zn-doped ZrO2 bifunctional catalyst, its preparation method and application, so as to overcome the deficiencies in the prior art.

[0006] To achieve the foregoing invention object, the technical solutions adopted by the present invention include:

[0007] One aspect of the present invention provides a Zn-doped ZrO2 bifunctional catalyst, which includes: zirconia as a carrier, and zinc oxide uniformly loaded on the zirconia; the zirconia coexists in tetragonal and monoclinic phases, and the zinc oxide is in a hexagonal wurtzite crystal phase.

[0008] Another aspect of the present invention provides a preparation method of the foregoing Zn-doped ZrO2 bifunctional catalyst, which includes: mixing a soluble zinc salt with a Zr(OH)4 precursor, adding an alkaline solution for a first reaction to obtain a precipitate, and then calcining to obtain the Zn-doped ZrO2 bifunctional catalyst.

[0009] Another aspect of the present invention provides the application of the foregoing Zn-doped ZrO2 bifunctional catalyst in the CO2-ODHE reaction.

[0010] Compared with the prior art, the present invention has at least the following advantages:

[0011] The Zn-doped ZrO2 bifunctional catalyst prepared by the present invention, when applied to the CO2-ODHE reaction, synchronously realizes the conversion of ethane and CO2 into high-added-value chemicals, and has an excellent ethylene production rate, exceeding all the catalysts reported in previous literatures, and has a good application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0013] Figure 1 HRTEM image of the ZrO2 material prepared in Comparative Example 1;

[0014] Figure 2 HRTEM image of the Zn-doped ZrO2 bifunctional catalyst (Zn 0.05 ZrO) prepared in Example 2;

[0015] Figure 3 HRTEM image of the Zn-doped ZrO2 bifunctional catalyst (Zn 0.1 ZrO) prepared in Example 3;

[0016] Figure 4 HRTEM image of the Zn-doped ZrO2 bifunctional catalyst (Zn 0.2 ZrO) prepared in Example 4;

[0017] Figure 5 HRTEM image of the ZnO material prepared in Comparative Example 2;

[0018] Figure 6 XRD patterns of Zn 0.05 ZrO, Zn 0.1 ZrO, Zn 0.2 ZrO, ZrO2, ZnO prepared in Examples 2-4 and Comparative Examples 1-2;

[0019] Figure 7 XRD patterns of Zn 0.05 ZrO, Zn 0.1 ZrO, Zn 0.2 Comparison chart of C2H6 conversion rate performance test for the CO2-ODHE reaction of ZrO, Zn

[0020] Figure 8 Comparison chart of C2H4 yield performance test for the CO2-ODHE reaction of ZrO, Zn 0.05 ZrO, Zn 0.1 ZrO, Zn 0.2 ZrO, ZrO2, ZnO catalysts prepared in Examples 2-4 and Comparative Examples 1-2; Detailed implementation manners

[0021] The present invention will be more fully understood by reading the following detailed implementation manners. However, it should be understood that the specific implementation manners disclosed below are only exemplary of the present invention, and the present invention can be embodied in various forms. Therefore, the specific functional details disclosed herein should not be construed as restrictive, but only as the basis of the claims and as a representative basis for teaching those skilled in the art to adopt the present invention in any appropriate detailed embodiment in fact.

[0022] As an aspect of the technical solution of the present invention, a Zn-doped ZrO2 bifunctional catalyst involved therein includes: zirconia as a carrier, and zinc oxide uniformly loaded on the zirconia; the zirconia coexists in tetragonal and monoclinic phases, and the zinc oxide is in a hexagonal wurtzite crystal phase.

[0023] Furthermore, the zirconia is nanoscale ZrO2, and preferably, the particle size of the zirconia is 10-40 nm.

[0024] Further, the zinc oxide is nano-ZnO. Preferably, the particle size of the zinc oxide > 100 nm.

[0025] Further, the chemical formula of the Zn-doped ZrO2 bifunctional catalyst is Zn x xZrO, where x is 0.01 - 5. Preferably, x is 0.05 - 1.

[0026] Further, the molar ratio of zinc to zirconium in the Zn-doped ZrO2 bifunctional catalyst is 0.01 - 5:1, preferably 0.05 - 1:1.

[0027] As another aspect of the technical solution of the present invention, a preparation method of a Zn-doped ZrO2 bifunctional catalyst includes: mixing a soluble zinc salt with a Zr(OH)4 precursor, adding an alkaline solution for a first reaction to obtain a precipitate, and then calcining to obtain the Zn-doped ZrO2 bifunctional catalyst.

[0028] In some embodiments, the preparation method includes: adjusting the pH value of the soluble zirconium salt aqueous solution to be alkaline with an alkaline solution, then performing a second reaction, followed by aging and drying to obtain the Zr(OH)4 precursor.

[0029] In some embodiments, the preparation method includes: dissolving a soluble zirconium salt in water and stirring to obtain a soluble zirconium salt aqueous solution.

[0030] Further, the soluble zirconium salt includes but is not limited to any one or a combination of two or more of zirconium nitrate, zirconium sulfate, and zirconium chloride. Using soluble zirconium salt and soluble zinc salt as raw materials, the drugs are easy to obtain, the price is low, and the preparation process is simple.

[0031] Further, the concentration of the soluble zirconium salt aqueous solution is 0.01 - 0.50 mol / L, preferably 0.05 - 0.20 mol / L.

[0032] In some preferred embodiments, the preparation method includes: adjusting the pH value of the soluble zirconium salt aqueous solution to be alkaline with an alkaline solution, preferably the pH value is 7 - 10.

[0033] In some embodiments, the temperature of the second reaction is 40 - 80 °C and the time is 1 - 3 h.

[0034] In some embodiments, the temperature of the aging is 70 - 150 °C, preferably 80 - 120 °C; the aging time is 6 - 18 h, preferably 8 - 14 h.

[0035] In some embodiments, the temperature of the drying is 70 - 110 °C and the time is 2 - 12 h.

[0036] In some embodiments, the preparation method includes: mixing a Zr(OH)4 precursor with an aqueous solution of a soluble zinc salt, adding an alkaline solution for a first reaction until no more precipitate is formed.

[0037] Furthermore, the molar ratio of zinc element in the soluble zinc salt to zirconium element in the Zr(OH)4 precursor is 0.01 - 5:1.

[0038] Furthermore, the preparation method includes: dissolving the soluble zinc salt in water, stirring to obtain an aqueous solution of the soluble zinc salt.

[0039] Even further, the soluble zinc salt includes but is not limited to any one or a combination of two or more of zinc acetate, zinc chloride, and zinc nitrate.

[0040] Furthermore, the concentration of the aqueous solution of the soluble zinc salt is 0.001 - 0.625 mol / L, preferably 0.010 - 0.125 mol / L.

[0041] In some preferred embodiments, the alkaline solution includes but is not limited to any one or a combination of two or more of dilute ammonia water, ammonium carbonate, and sodium hydroxide.

[0042] Furthermore, when preparing the dilute ammonia water, the volume ratio of NH4OH to H2O is 0.1 - 1:1, preferably 0.5 - 1:1.

[0043] In some preferred embodiments, the alkaline solution is added in a dropwise manner.

[0044] In some embodiments, the temperature of the first reaction is 40 - 80 °C.

[0045] In some embodiments, the preparation method includes: drying the precipitate, and then calcining it in an air atmosphere.

[0046] Furthermore, the drying temperature is 70 - 110 °C, and the time is 2 - 12 h.

[0047] Furthermore, the calcination temperature is 400 - 800 °C, preferably 500 - 600 °C; the calcination time is 1 - 6 h, preferably 3 - 5 h.

[0048] In some more specific embodiments, the preparation method of the Zn-doped ZrO2 bifunctional catalyst includes:

[0049] (1) Preparing a Zr(OH)4 precursor:

[0050] A1: Dissolve zirconium nitrate in deionized water, and place it in a water bath at 40 - 80 °C with stirring to obtain a zirconium nitrate solution, where the concentration of the zirconium nitrate solution is 0.01 - 0.50 mol / L;

[0051] A2: Adjust the pH of the zirconium nitrate solution to alkaline with dilute ammonia water, and stir for 1 - 3 h to obtain a reaction solution;

[0052] A3: Age the reaction solution at 70 - 150 °C for 6 - 18 h;

[0053] A4: Filter the precipitate obtained from aging, wash it with deionized water and ethanol, and then dry it in an oven at 70 - 110 °C for 2 - 12 h to obtain a Zr(OH)4 precursor;

[0054] (2) Preparation of Zn-doped ZrO2 bifunctional catalyst:

[0055] B1: Dissolve zinc acetate in deionized water, and place it in a water bath at 40 - 80 °C with stirring to obtain a zinc acetate solution, where the concentration of the zinc acetate solution is 0.001 - 0.625 mol / L;

[0056] B2: Add the Zr(OH)4 precursor to the zinc acetate solution and continue stirring for 10 - 60 min to obtain a mixed solution; the molar ratio of zinc element in zinc acetate to zirconium element in the Zr(OH)4 precursor is 0.01 - 5:1;

[0057] B3: Add dilute ammonia water dropwise to the mixed solution while maintaining the temperature at 40 - 80 °C until no more precipitate is formed;

[0058] B4: Filter the precipitate, dry it in an oven at 70 - 110 °C for 2 - 12 h, and then calcine it at 500 - 600 °C for 1 - 6 h to obtain a Zn-doped ZrO2 bifunctional catalyst.

[0059] As another aspect of the technical solution of the present invention, it also relates to the application of the Zn-doped ZrO2 bifunctional catalyst in the CO2-ODHE reaction.

[0060] The present invention will be further illustrated below by way of examples, but the present invention is not limited to the scope of the examples. All reagents and raw materials used in the following examples are commercially available, and the test methods without specific conditions are usually carried out under conventional conditions or according to the conditions recommended by each manufacturer.

[0061] Example 1

[0062] (1) Dissolve zirconium nitrate in deionized water, and place it in a water bath at 65 °C with stirring to obtain a zirconium nitrate solution of 0.16 mol / L; use dilute ammonia water (V 氨水 / V 去离子水= 1) Adjust the pH of the solution to 8 - 9, stir for 1 h; age at 110 °C for 6 h; obtain a precipitate, filter and wash with deionized water and ethanol, then dry in an oven at 110 °C for 12 h to obtain a Zr(OH)4 precursor.

[0063] (2) Dissolve zinc acetate in deionized water and place it in a water bath at 65 °C and stir to obtain a 0.001 mol / L zinc acetate solution; add the Zr(OH)4 precursor obtained in step (1), and the molar ratio of zinc element in zinc acetate to zirconium element in the Zr(OH)4 precursor is 0.01:1, and continue to stir for 10 min, then dropwise add dilute ammonia water (V 氨水 / V 去离子水 = 1) until no more precipitate is produced, filter the obtained precipitate, dry in an oven at 100 °C for 6 h, and then calcine at 600 °C for 3 h to prepare a Zn-doped ZrO2 bifunctional catalyst with the chemical formula Zn 0.01 ZrO.

[0064] Example 2

[0065] Compared with Example 1, the difference is that in step (2), zinc acetate is dissolved in deionized water to obtain a 0.005 mol / L zinc acetate solution, and the molar ratio of zinc element in zinc acetate to zirconium element in the Zr(OH)4 precursor is 0.05:1, and a Zn-doped ZrO2 bifunctional catalyst is prepared with the chemical formula Zn 0.05 ZrO.

[0066] Example 3

[0067] Compared with Example 1, the difference is that in step (2), zinc acetate is dissolved in deionized water to obtain a 0.010 mol / L zinc acetate solution, and the molar ratio of zinc element in zinc acetate to zirconium element in the Zr(OH)4 precursor is 0.1:1, and a Zn-doped ZrO2 bifunctional catalyst is prepared with the chemical formula Zn 0.1 ZrO.

[0068] Example 4

[0069] Compared with Example 1, the difference is that in step (2), zinc acetate is dissolved in deionized water to obtain a 0.020 mol / L zinc acetate solution, and the molar ratio of zinc element in zinc acetate to zirconium element in the Zr(OH)4 precursor is 0.2:1, and a Zn-doped ZrO2 bifunctional catalyst is prepared with the chemical formula Zn 0.2 ZrO.

[0070] Example 5

[0071] Compared with Example 1, the difference lies in that in step (2), zinc acetate is dissolved in deionized water to obtain a zinc acetate solution with a concentration of 0.125 mol / L. The molar ratio of zinc element in zinc acetate to zirconium element in Zr(OH)4 precursor is 1:1, and a Zn-doped ZrO2 bifunctional catalyst with the chemical formula Zn1ZrO is prepared.

[0072] Example 6

[0073] Compared with Example 1, the difference lies in that in step (2), zinc acetate is dissolved in deionized water to obtain a zinc acetate solution with a concentration of 0.600 mol / L. The molar ratio of zinc element in zinc acetate to zirconium element in Zr(OH)4 precursor is 5:1, and a Zn-doped ZrO2 bifunctional catalyst with the chemical formula Zn5ZrO is prepared.

[0074] Example 7

[0075] (1) Dissolve zirconium nitrate in deionized water, place it in a water bath at 40 °C and stir to obtain a zirconium nitrate solution with a concentration of 0.16 mol / L; use dilute ammonia water (V 氨水 / V 去离子水 = 0.1) to adjust the pH of the solution to 7, stir for 2 h; age at 70 °C for 18 h; obtain a precipitate, filter and wash it with deionized water and ethanol, and then dry it in an oven at 70 °C for 8 h to obtain a Zr(OH)4 precursor.

[0076] (2) Dissolve zinc acetate in deionized water, place it in a water bath at 40 °C and stir to obtain a zinc acetate solution with a concentration of 0.001 mol / L; add the Zr(OH)4 precursor obtained in step (1). The molar ratio of zinc element in zinc acetate to zirconium element in Zr(OH)4 precursor is 0.01:1, and continue to stir for 10 min; add dropwise dilute ammonia water (V 氨水 / V 去离子水 = 0.1) until no more precipitate is produced. Filter the obtained precipitate, dry it in an oven at 70 °C for 12 h, and then calcine it at 400 °C for 6 h to prepare a Zn-doped ZrO2 bifunctional catalyst with the chemical formula Zn 0.01 ZrO.

[0077] Example 8

[0078] (1) Dissolve zirconium nitrate in deionized water, place it in a water bath at 80 °C and stir to obtain a zirconium nitrate solution with a concentration of 0.16 mol / L; use dilute ammonia water (V 氨水 / V 去离子水 = 0.5) to adjust the pH of the solution to 10, stir for 3 h; age at 150 °C for 10 h; obtain a precipitate, filter and wash it with deionized water and ethanol, and then dry it in an oven at 90 °C for 2 h to obtain a Zr(OH)4 precursor.

[0079] (2) Dissolve zinc acetate in deionized water and place it in a water bath at 80 °C with stirring to obtain a 0.001 mol / L zinc acetate solution; add the Zr(OH)4 precursor obtained in step (1), and the molar ratio of zinc element in zinc acetate to zirconium element in the Zr(OH)4 precursor is 0.01∶1, and continue stirring for 10 min; dropwise add dilute ammonia water (V 氨水 / V 去离子水 = 0.5) until no more precipitation occurs, filter the precipitate, dry it in an oven at 110 °C for 2 h, and then calcine it at 800 °C for 1 h to obtain a Zn-doped ZrO2 bifunctional catalyst with the chemical formula Zn 0.01 ZrO.

[0080] Comparative Example 1

[0081] (1) Dissolve zirconium nitrate in deionized water and place it in a water bath at 65 °C with stirring to obtain a 0.16 mol / L zirconium nitrate solution; use dilute ammonia water (V 氨水 / V 去离子水 = 1) to adjust the pH of the solution to 8 - 9, stir for 1 h; age at 110 °C for 6 h; obtain a precipitate, filter it and wash it with deionized water and ethanol, and then dry it in an oven at 110 °C for 12 h to obtain a Zr(OH)4 precursor.

[0082] (2) Calcinate the Zr(OH)4 precursor obtained in step (1) at 600 °C for 3 h. A ZrO2 material (i.e., ZnO is not doped in ZrO2) is prepared.

[0083] Comparative Example 2

[0084] Dissolve zinc acetate in deionized water and place it in a water bath at 65 °C with stirring to obtain a 0.125 mol / L zinc acetate solution; dropwise add dilute ammonia water (V 氨水 / V 去离子水 = 1) to the solution until no more precipitation occurs, filter the precipitate, dry it in an oven at 100 °C for 6 h, and then calcine it at 600 °C for 3 h to obtain a ZnO material (i.e., only ZnO and no ZrO2).

[0085] Characterize and analyze the particle sizes and material compositions of Zn 0.05 ZrO, Zn 0.1 ZrO, Zn 0.2 ZrO, ZrO2, ZnO prepared in Examples 2 - 4 and Comparative Examples 1 - 2 by HRTEM and XRD, and obtain Figures 1 to 6 .

[0086] It can be seen from Figures 2 to 4 that in the Zn-doped ZrO2 bifunctional catalyst prepared in Examples 2 - 4, the zinc oxide-doped zirconia species are in the form of nanoscale particles, and the particle size of zirconia is 20 - 25 nm; it can be seen from Figure 1and Figure 5 It can be seen that the particle sizes of ZrO2 and ZnO prepared in Comparative Examples 1 and 2 are 10 nm and greater than 100 nm, respectively.

[0087] From Figure 6 it can be seen that in the Zn-doped ZrO2 bifunctional catalysts prepared in Examples 2-4, after the incorporation of ZnO, no corresponding diffraction peak was observed, indicating that ZnO was highly uniformly dispersed in ZrO2. In addition, with the doping of ZnO, the monoclinic phase of ZrO2 disappeared, and only the tetragonal phase of ZrO2 existed in the sample. In the ZrO2 prepared in Comparative Example 1, the coexistence of the monoclinic phase and the tetragonal phase could be clearly observed, and the ZnO prepared in Comparative Example 2 was a hexagonal wurtzite crystal phase.

[0088] Performance test

[0089] The Zn 0.05 ZrO, Zn 0.1 ZrO, Zn 0.2 ZrO bifunctional catalysts prepared in Examples 2-4 and the ZrO2 and ZnO materials prepared in Comparative Examples 1-2 were used for the CO2-ODHE reaction to simultaneously upgrade ethane and CO2 into high-value-added products. The specific steps are as follows:

[0090] (1) Weigh a certain amount of the samples prepared in Examples 2, 3, 4 and Comparative Examples 1, 2 respectively, fill them into a quartz tube, place it in a high-temperature reaction furnace, and introduce N2 protective gas (the N2 space velocity is 6000-12000 mL·g -1 ·h -1 );

[0091] (2) Raise the temperature of the high-temperature reaction furnace to 600-700 °C, introduce the reaction gas C2H6 / CO2 / N2 = 1 / 1 / 2 (the ethane space velocity is 3000-6000 mL·g -1 ·h -1 ) for reaction, and record the concentrations of each product after the reaction by gas chromatography (GC2060). The test results are shown in Figure 7 、 Figure 8 and Table 1.

[0092] From Figure 7 and Figure 8 it can be seen that during the CO2-ODHE reaction, using the ZrO2 and ZnO in Comparative Examples 1 and 2 as a control, the ethane conversion rate and ethylene yield of the Zn x ZrO samples prepared in Examples 2, 3, 4 have been significantly improved. Among them, the ethylene yield (10%) of the Zn 0.2 ZrO sample prepared in Example 4 with the best performance is nearly 4 times higher than the ethylene yield (2.6%) of the pure ZrO2 prepared in Comparative Example 1. Figure 8Among them, although the ethylene yield of ZnO is slightly higher than that of Zn at the beginning of the reaction 0.05 ZrO, its catalysis is not stable and deactivates quickly. After a certain reaction time, its yield is lower than that of Zn 0.05 ZrO.

[0093] Table 1 Catalytic performance data of the Zn 0.2 ZrO sample with the best performance prepared in Example 1

[0094]

[0095] As can be seen from Table 1, the Zn 0.2 ZrO catalyst with the best performance prepared in Example 4, at 700 °C and an ethane space velocity of 3000 mL·g -1 ·h -1 , the formation rate of ethylene is 797.6 μmol·min -1 ·g -1 , exceeding all the catalysts reported in previous literature.

[0096] In addition, the inventors of this case also referred to the foregoing examples and conducted experiments with other raw materials, process operations, and process conditions described in this specification, and all obtained relatively ideal results.

[0097] The above-described embodiments only represent several implementation manners of the present invention. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. A Zn-doped ZrO2 bifunctional catalyst, characterized in that include: Zirconia as a carrier, and zinc oxide uniformly supported on the zirconium oxide; The zirconium oxide coexists in a tetragonal phase and a monoclinic phase, and the zinc oxide is in a hexagonal wurtzite crystal phase.

2. The Zn-doped ZrO2 bifunctional catalyst according to claim 1, characterized in that: The zirconium oxide is nano-scale ZrO2, and preferably, the particle size of the zirconium oxide is 10-40nm; And / or, the zinc oxide is nano-sized ZnO, preferably, the particle size of the zinc oxide is >100 nm; And / or, the chemical formula of the Zn-doped ZrO2 bifunctional catalyst is Zn x ZrO, wherein x is 0.01-5, preferably, x is 0.05-1; And / or, the molar ratio of zinc to zirconium in the Zn-doped ZrO2 bifunctional catalyst is 0.01-5:1, preferably 0.05-1:

1.

3. The method for preparing a Zn-doped ZrO2 bifunctional catalyst according to claim 1 or 2, characterized in that: include: A soluble zinc salt is mixed with a Zr(OH)4 precursor, and an alkaline solution is added to carry out a first reaction to obtain a precipitate, which is then calcined to obtain a Zn-doped ZrO2 bifunctional catalyst.

4. The preparation method according to claim 3, characterized in that: include: The pH value of the soluble zirconium salt aqueous solution is adjusted to be alkaline with an alkaline solution, and then a second reaction is carried out, followed by aging and drying to obtain the Zr(OH)4 precursor.

5. The preparation method according to claim 4, characterized in that: include: Dissolving a soluble zirconium salt in water and stirring to obtain a soluble zirconium salt aqueous solution; Preferably, the soluble zirconium salt includes any one or a combination of two or more of zirconium nitrate, zirconium sulfate and zirconium chloride; Preferably, the concentration of the soluble zirconium salt aqueous solution is 0.01-0.50 mol / L, preferably 0.05-0.20 mol / L; And / or, the preparation method comprises: adjusting the pH value of the soluble zirconium salt aqueous solution to 7-10 with an alkaline solution; And / or, the temperature of the second reaction is 40-80°C and the time is 1-3h; And / or, the aging temperature is 70-150°C, preferably 80-120°C; the aging time is 6-18h, preferably 8-14h; And / or, the drying temperature is 70-110° C. and the drying time is 2-12 h.

6. The preparation method according to claim 4, characterized in that: The alkaline solution includes any one or a combination of two or more of dilute ammonia water, ammonium carbonate, and sodium hydroxide; Preferably, the volume ratio of NH4OH to H2O used in the preparation of the dilute ammonia water is 0.1-1:1, preferably 0.5-1:1; And / or, the alkaline solution is added dropwise.

7. The preparation method according to claim 3, characterized in that: include: The Zr(OH)4 precursor is mixed with a soluble zinc salt aqueous solution, and an alkaline solution is added to perform a first reaction to obtain a precipitate; Preferably, the molar ratio of the zinc element in the soluble zinc salt to the zirconium element in the Zr(OH)4 precursor is 0.01-5:1; Preferably, the preparation method comprises: dissolving a soluble zinc salt in water and stirring to obtain a soluble zinc salt aqueous solution; Particularly preferably, the soluble zinc salt includes any one or a combination of two or more of zinc acetate, zinc chloride, and zinc nitrate; Particularly preferably, the concentration of the soluble zinc salt aqueous solution is 0.001-0.625 mol / L, preferably 0.010-0.125 mol / L.

8. The preparation method according to claim 3, characterized in that: The temperature of the first reaction is 40-80°C.

9. The preparation method according to claim 3, characterized in that: include: The precipitate is dried and then calcined in an air atmosphere; Preferably, the drying temperature is 70-110°C and the drying time is 2-12h; Preferably, the calcination temperature is 400-800° C., preferably 500-600° C.; the calcination time is 1-6 h, preferably 3-5 h.

10. Use of the Zn-doped ZrO2 bifunctional catalyst as claimed in claim 1 or 2 in CO2-ODHE reaction.

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