Preparation method of stable undoped tetragonal zirconium oxide

Abstract

The invention discloses a preparation method of stable undoped tetragonal phase zirconia, and belongs to the field of inorganic nanomaterials, and the preparation method comprises the following steps: respectively weighing ZrOCl2. 8H2O and NH4HCO3 in a beaker, adding deionized water, and fully stirring and dissolving to obtain a zirconium salt solution and an ammonium bicarbonate solution; dropwise adding the ammonium bicarbonate solution into the zirconium salt solution in a stirring state; s2, the solution obtained in the step S2 is aged for 12 h at the room temperature, then centrifugal washing is conducted, an obtained solid product is dried at the temperature of 80 DEG C and then roasted for 0.5-2 h at the temperature of 400 DEG C, and the tetragonal-phase zirconium oxide is obtained. Compared with the prior art, the tetragonal-phase zirconium oxide prepared through the method is pure, relatively stable and free of monoclinic phase components, and the preparation method is simple, free of doping, environmentally friendly and safe.

Description

Technical Field

[0001] The invention relates to a method for preparing stable undoped tetragonal zirconium oxide, and belongs to the field of inorganic nanomaterials. Background Art

[0002] Zirconia is an important nanomaterial with good thermal stability, acid-base properties, surface properties and ion conductivity. It is widely used in catalysis, sensing, solid oxide fuel cells and ceramic products, and therefore has attracted much attention from researchers.

[0003] Zirconia has three crystal structures: monoclinic, tetragonal and cubic. Among them, tetragonal zirconium oxide is widely used in the field of catalysis due to its unique properties, such as catalytic hydrogenation of carbon dioxide to methanol, catalytic synthesis gas to light olefins, etc. However, tetragonal zirconium oxide is a metastable crystal phase, which is easy to transform into a monoclinic phase at low temperatures. In order to obtain high-purity tetragonal zirconium oxide crystal materials, it is generally doped with elements (Y 3+ Mg 2+ , Ca 2+ 、Ce 4+ However, doping will change the nanostructure and surface properties of zirconium oxide, thus affecting the subsequent catalytic reaction performance.

[0004] The Chinese invention patent publication number CN 1935670 A discloses a method for preparing tetragonal zirconium oxide nanopowder by a hydrothermal route, specifically: dissolving a zirconium salt in water, adding a required amount of hydrazine hydrate under stirring to obtain a mixture solution, and then placing the mixture solution in an autoclave, and hydrothermally treating it in a temperature range of 120 to 200 ° C for 10 to 100 hours to obtain a tetragonal zirconium oxide product. The method has relatively simple operation steps and can obtain nano zirconium oxide materials with smaller particle sizes, but the hydrazine hydrate used in the method is highly toxic, and excessive hydrazine hydrate will cause environmental pollution and have long-term adverse effects on aquatic organisms. The synthesis cycle is long and requires high-energy heat treatment and other procedures, which is not conducive to amplification and industrial production. In addition, the product obtained by the method contains a small amount of monoclinic components, not pure tetragonal zirconium oxide. Therefore, it is extremely important to design a method that is simple, undoped, safe, green and stable at room temperature for tetragonal zirconium oxide to meet further application needs in the future. Summary of the invention

[0005] The present invention aims at solving the technical problems existing in the prior art and provides a method for preparing stable undoped tetragonal zirconia.

[0006] The object of the present invention is achieved by the following technical scheme: a method for preparing a stable undoped tetragonal zirconium oxide, the method comprising the following steps:

[0007] Step S1, weigh ZrOCl2·8H2O and NH4HCO3 respectively in a beaker, add deionized water, and stir to dissolve to obtain a zirconium salt solution and an ammonium bicarbonate solution;

[0008] Step S2, adding the ammonium bicarbonate solution dropwise to the zirconium salt solution under stirring;

[0009] Step S3, aging the solution obtained in step S2 at room temperature for 12 hours, then centrifugally washing, drying the obtained solid product at 80° C., and then calcining at 400° C. for 0.5-2 hours to obtain tetragonal zirconium oxide.

[0010] Preferably, in step S1, the molar ratio of ZrOCl2·8H2O to NH4HCO3 is 1:2.

[0011] Preferably, step S2 specifically comprises: under stirring, using a constant flow pump to drop the ammonium bicarbonate solution into the zirconium salt solution at a rate of 2 mL / min.

[0012] Preferably, in step S2, the ammonium bicarbonate solution is added dropwise to the zirconium salt solution, and the pH of the system is controlled at 5.1 to 5.8.

[0013] Preferably, in step S3, the drying temperature is 80°C.

[0014] The present invention has the following beneficial effects: the present invention provides a method for preparing a stable undoped tetragonal zirconia. The tetragonal zirconia prepared by the method is relatively pure compared with the prior art, does not contain a monoclinic component, and is relatively stable, eliminating the influence of the addition of a second component on the material structure, while simplifying the analysis and characterization of the material, and is more conducive to revealing the mechanism of action of the tetragonal zirconia in the fields of catalysis and sensing, providing a basis for future applications in more fields and designing materials with better performance; at the same time, the preparation method is simple, undoped, green and safe, BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The XRD spectrum of the tetragonal zirconium oxide obtained in Example 1-3;

[0016] Figure 2 This is a comparative XRD spectrum of the zirconium oxide sample obtained in Example 1 after being placed at room temperature for one year;

[0017] Figure 3 The XRD spectra of the zirconium oxide crystals obtained in Example 1 and Comparative Examples 1-3;

[0018] Figure 4 TEM images of the morphology of zirconium oxide particles obtained in Example 1 and Comparative Examples 1-3;

[0019] Figure 5 The XRD spectra of zirconium oxide obtained in Comparative Examples 4-6 are shown in FIG. DETAILED DESCRIPTION

[0020] The following examples also describe certain specific aspects and embodiments, which are provided for illustrative purposes only and should not be construed as limiting the scope of the invention in any way.

[0021] XRD detection conditions: The XRD test in this patent uses the X'Pro diffractometer developed by Philips; specific conditions and parameters (Cu Kα ray ( ); operating current: 40mA; operating voltage: 40kV; temperature: room temperature).

[0022] Example 1

[0023] 1) Weigh 1.288 g ZrOCl2·8H2O and 0.632 g NH4HCO3 into a beaker, add deionized water, and stir to dissolve to obtain a zirconium salt solution and an ammonium bicarbonate solution;

[0024] 2) Under stirring, using a constant flow pump, add the ammonium bicarbonate solution dropwise to the zirconium salt solution at a rate of 2 mL / min, and control the final pH of the system to be between 5.1 and 5.8;

[0025] 3) The obtained solution was aged at room temperature for 12 hours, then centrifuged and washed, the obtained solid product was dried at 80° C., and then calcined at 400° C. for 2 hours to obtain nano zirconium oxide powder.

[0026] Example 2

[0027] 1) Weigh 0.644 g ZrOCl2·8H2O and 0.316 g NH4HCO3 into a beaker, add deionized water, and stir to dissolve to obtain a zirconium salt solution and an ammonium bicarbonate solution;

[0028] 2) Under stirring, using a constant flow pump, add the ammonium bicarbonate solution dropwise to the zirconium salt solution at a rate of 2 mL / min, and control the final pH of the system to be between 5.1 and 5.8;

[0029] 3) The obtained solution was aged at room temperature for 12 hours, then centrifuged and washed, the obtained solid product was dried at 80° C., and then calcined at 400° C. for 1 hour to obtain nano zirconium oxide powder.

[0030] Example 3

[0031] 1) Weigh 1.288 g ZrOCl2·8H2O and 0.632 g NH4HCO3 into a beaker, add deionized water, and stir to dissolve to obtain a zirconium salt solution and an ammonium bicarbonate solution;

[0032] 2) Under stirring, using a constant flow pump, add the ammonium bicarbonate solution dropwise to the zirconium salt solution at a rate of 2 mL / min, and control the final pH of the system to be between 5.1 and 5.8;

[0033] 3) The obtained solution was aged at room temperature for 12 hours, then centrifuged and washed, the obtained solid product was dried at 80° C., and then calcined at 400° C. for 0.5 hours to obtain nano zirconium oxide powder.

[0034] Comparative Example 1

[0035] 1) Weigh 1.288 g ZrOCl2·8H2O and 0.632 g NH4HCO3 into a beaker, add deionized water, and stir to dissolve to obtain a zirconium salt solution and an ammonium bicarbonate solution;

[0036] 2) Under stirring, using a constant flow pump, add the ammonium bicarbonate solution dropwise to the zirconium salt solution at a rate of 2 mL / min, and control the final pH of the system to be between 5.1 and 5.8;

[0037] 3) The obtained solution was aged at room temperature for 12 hours, then centrifuged and washed, the obtained solid product was dried at 80° C., and then calcined at 600° C. for 2 hours to obtain nano zirconium oxide powder.

[0038] Comparative Example 2

[0039] 1) Weigh 1.288 g ZrOCl2·8H2O and 0.632 g NH4HCO3 into a beaker, add deionized water, and stir to dissolve to obtain a zirconium salt solution and an ammonium bicarbonate solution;

[0040] 2) Under stirring, using a constant flow pump, add the ammonium bicarbonate solution dropwise to the zirconium salt solution at a rate of 2 mL / min, and control the final pH of the system to be between 5.1 and 5.8;

[0041] 3) The obtained solution was aged at room temperature for 12 hours, then centrifuged and washed, the obtained solid product was dried at 80° C., and then calcined at 800° C. for 2 hours to obtain nano zirconium oxide powder.

[0042] Comparative Example 3

[0043] 1) Weigh 1.288 g ZrOCl2·8H2O and 0.632 g NH4HCO3 into a beaker, add deionized water, and stir to dissolve to obtain a zirconium salt solution and an ammonium bicarbonate solution;

[0044] 2) Under stirring, using a constant flow pump, add the ammonium bicarbonate solution dropwise to the zirconium salt solution at a rate of 2 mL / min, and control the final pH of the system to be between 5.1 and 5.8;

[0045] 3) The obtained solution was aged at room temperature for 12 hours, then centrifuged and washed, the obtained solid product was dried at 80° C., and then calcined at 1000° C. for 2 hours to obtain nano zirconium oxide powder.

[0046] Comparative Example 4

[0047] 1) Weigh 1.068 g ZrO(NO3)2·2H2O and dissolve it in 80 mL deionized water to obtain a zirconium salt solution;

[0048] 2) Add 2.4 g CO(NH2)2 to the zirconium salt solution while stirring, and continue stirring for 30 min;

[0049] 3) The obtained solution was transferred to a hydrothermal reactor and treated at 140° C. for 12 h, then centrifuged, washed and dried, and calcined at 400° C. for 2 h to obtain nano zirconium oxide powder.

[0050] Comparative Example 5

[0051] 1) Weigh 1.068 g ZrO(NO3)2·2H2O and dissolve it in 80 mL deionized water to obtain a zirconium salt solution;

[0052] 2) Add 2.4 g CO(NH2)2 to the zirconium salt solution while stirring, and continue stirring for 30 min;

[0053] 3) The obtained solution was transferred to a hydrothermal reactor and treated at 140° C. for 12 h, then centrifuged, washed and dried, and calcined at 800° C. for 2 h to obtain nano zirconium oxide powder.

[0054] Comparative Example 6

[0055] 1) Weigh 1.068 g ZrO(NO3)2·2H2O and dissolve it in 80 mL deionized water to obtain a zirconium salt solution;

[0056] 2) Add 2.4 g CO(NH2)2 to the zirconium salt solution while stirring, and continue stirring for 30 min;

[0057] 3) The obtained solution was transferred to a hydrothermal reactor and treated at 140° C. for 12 h, then centrifuged, washed and dried, and calcined at 1000° C. for 2 h to obtain nano zirconium oxide powder.

[0058] Examples 1-3 and Comparative Examples 1-6 were tested and analyzed, and the results are as follows: Figure 1-5 The analysis results are as follows:

[0059] 1. By Figure 1Analysis shows that the crystallinity of the tetragonal zirconia nanocrystals prepared by the method of the present invention gradually increases with the extension of the calcination time, indicating that the preparation method of the present invention can prepare stable tetragonal zirconia nanocrystals, and the optimal calcination time is 2h at 400°C.

[0060] 2. By Figure 2 Analysis shows that the prepared tetragonal zirconia nanocrystals have no change in crystal form after being placed at room temperature for one year, indicating that the tetragonal zirconia nanocrystals prepared by the method of the present invention are stable.

[0061] 3. Pass Figure 3 Analysis shows that when nanocrystals are calcined at a temperature higher than 400°C, the zirconium oxide crystal form gradually changes from tetragonal phase to monoclinic phase as the calcination temperature increases. The sample calcined at 1000°C obtains pure monoclinic zirconium oxide nanocrystals.

[0062] 4. Pass Figure 4 Analysis shows that the tetragonal and monoclinic zirconia samples calcined at different temperatures all show the morphology of nanoparticles. With the change of treatment temperature and crystal form, the size of the particles also changes significantly.

[0063] 5. Pass Figure 5 Analysis shows that the samples prepared by the methods of Comparative Examples 4-6 all correspond to monoclinic zirconia, and the change of treatment temperature does not produce different crystal phases.

[0064] The above description is only a preferred embodiment of the present invention, but is not intended to limit the present invention. Those skilled in the art may make possible changes and modifications to the present invention using the technical contents disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing a stable undoped tetragonal zirconia, characterized in that: The method comprises the following steps: Step S1, weigh ZrOCl2·8H2O and NH4HCO3 respectively in a beaker, add deionized water, and stir to dissolve to obtain a zirconium salt solution and an ammonium bicarbonate solution; Step S2, adding the ammonium bicarbonate solution dropwise to the zirconium salt solution under stirring; Step S3, aging the solution obtained in step S2 at room temperature for 12 hours, then centrifugally washing, drying the obtained solid product at 80° C., and then calcining at 400° C. for 0.5-2 hours to obtain tetragonal zirconium oxide.

2. The method for preparing stable undoped tetragonal zirconia according to claim 1, characterized in that: In step S1, the molar ratio of ZrOCl2·8H2O to NH4HCO3 is 1:

2.

3. The method for preparing stable undoped tetragonal zirconia according to claim 1, characterized in that: Step S2 specifically comprises: using a constant flow pump to drop the ammonium bicarbonate solution into the zirconium salt solution at a rate of 2 mL / min under stirring.

4. The method for preparing stable undoped tetragonal zirconia according to claim 1, characterized in that: In step S2, the ammonium bicarbonate solution is added dropwise to the zirconium salt solution, and the pH of the system is controlled at 5.1 to 5.

8.

5. The method for preparing stable undoped tetragonal zirconia according to claim 1, characterized in that: In step S3, the drying temperature is 80°C.

Images