CN109110794B

CN109110794B - Method for preparing hydrated rare earth carbonate oxide (Re2O (CO3) 2. H2O)

Info

Publication number: CN109110794B
Application number: CN201811190253.4A
Authority: CN
Inventors: 单妍; 郝菲菲; 于薛刚; 陈克正
Original assignee: Qingdao University of Science and Technology
Current assignee: Qingdao University of Science and Technology
Priority date: 2018-10-12
Filing date: 2018-10-12
Publication date: 2021-04-30
Anticipated expiration: 2038-10-12
Also published as: CN109110794A

Abstract

The invention provides Re₂O(CO₃)₂·H₂A hydrothermal preparation method of O (Re ═ Eu, Sm, Gd). Is mainly characterized in that g-C is₃N₄、Re₂O₃The Re can be prepared by taking dilute nitric acid as a raw material and utilizing a hydrothermal process₂O(CO₃)₂·H₂And O. The main principle is as follows: in the hydrothermal process, the surface of carbon nitride is protonated, and the carbon nitride reacts with water to generate NH with the increase of time₄ ⁺、OH^‑、CO₃ ^2‑Ions, rare earth cations in the solution are combined with anions to generate nano hydrated europium oxycarbonate, samarium oxycarbonate and gadolinium oxycarbonate particles, and the product can grow preferentially along with the extension of the reaction time to obtain a rod-shaped product. The method has the advantages of simple operation, high product crystallinity and the like.

Description

Preparation of hydrated rare earth carbonate (Re)2O(CO3)2H2O) process

Technical Field

The invention relates to a preparation method for preparing hydrated rare earth oxycarbonate by a hydrothermal method, belonging to the technical field of material preparation.

Background

Since the 60's of the 20 th century, the laser technology has advanced dramatically, and various laser devices using laser beams as information carriers, such as laser range finders, laser guidance devices, laser radars, etc., are increasingly used in battlefields. The laser has the advantages of large energy, high brightness, good directivity, good monochromaticity, coherence and the like, and when the laser is used as a radar, compared with a common microwave radar, the laser has the advantages of high resolution, strong anti-interference capability, high concealment, small volume, light weight and the like. The throwing precision and the fighting capacity of the laser guided missile or bomb reach the amazing step, so that the laser guided missile or bomb can be found to be hit and destroyed, and therefore, the position of the laser-resistant detection technology (namely, the laser stealth technology) in the modern stealth technology is more and more important, and the laser-resistant detection technology becomes an important aspect of the modern stealth technology. Common laser wavelength is 0.69 μm, 0.93 μm, 1.06 μm, 1.54 μm or 10.6 μm, wherein the laser with the wavelength of 1.06 μm is the most widely and mature laser in military use at present, so that the development of a laser protection material capable of effectively protecting 1.06 μm laser is urgent.

The rare earth elements have special electronic configuration, the 4f layer electron number of each rare earth element is different, the rare earth elements have rich electronic energy levels, and the strong absorption effect on the laser with a certain wavelength can be achieved by utilizing the transition of the 4f electron layer of the rare earth elements in the f-f configuration or the f-d configuration. Research shows that the trivalent rare earth ion Sm³⁺The transition from the f-f, f-d configuration is closest to 1.06 μm. The Zhang Cheng Tu group has prepared SmBO by solid phase method and sol-gel method₃The optical absorption characteristics of the powder were investigated to find Sm³⁺Of ions⁶H_5/2Ground state of the tube⁶F_9/2The transition of the excited state enables the excited state to form a stronger absorption peak in the wave band range of 1.05-1.15 mu m, and the excited state can be used as a laser protection absorbent material aiming at 1.06 mu m laser, but the maximum absorption peak is at 1.075 mu m. As is well known, the difference of the structure and the bonding mode can influence the absorption spectrum of the material, and the Sm is synthesized by a hydrothermal method₂O(CO₃)₂·xH₂O, Sm³⁺The maximum absorption peak of (a) blue-shifts to 1.067 um.

Rare earth carbonates have received much attention because of their excellent luminescence properties. Researches find that the carbon source has very important influence on the type and the shape of the product. In the synthesis of rare earth carbonates, the most commonly used carbon source is urea. Spirigliozzi et al (Advances in Materials Science and Engineering 2016,2016: Article 6096123; Materials 2019,12(13): Article 2062.) prepare 20% Sm doped ceria (Ce) using urea, ammonia, tetramethylammonium hydroxide (TMAH) and ammonium carbonate as co-precipitants_0.8Sm_0.2O_1.9) They found that precipitants affect the morphology of the powder and thus the sintering properties. When ammonium carbonate and urea are used as coprecipitates, the density of the obtained product after sintering is higher. Dell' Agli et al (Ceramics International,2017,43(15): 12799-containing 12808; Ceramics International,2018, 44(15): 17935-containing 17944) prepared cerium oxycarbonate doped with 20% Sm using a coprecipitation/hydrothermal synthesis method, and they found that Ce could be prepared when urea was used as the precipitant₂O(CO₃)₂·H₂The CeCO can be synthesized by using precursor O, but ammonium carbonate as precipitant₃And (5) OH. The graphite phase carbon nitride is a non-metal polymer semiconductor, mainly triazine ring (C)₃N₃) Or a heptazine ring (C)₆N₇) Two kinds of unit structures. The subject group found, g-C₃N₄The decomposition reaction similar to urea can occur under hydrothermal conditions and is very slow, which is beneficial to controlling the size and shape of the product, so the patent application takes g-C₃N₄As carbon source, reacting with rare earth ion under hydrothermal condition to prepare hydrated rare earth carbonate oxide (Re)₂O(CO₃)₂·H₂O)。

Are currently concerned with g-C₃N₄The research on the use of carbon nitride as a raw material is rare, but the application of carbon nitride to the fields of catalysis, sensing, bioprobes, drug delivery and the like is mainly focused on. This patent first converts g-C₃N₄As starting material with RE (NO)₃)₃Sm is synthesized under acidic hydrothermal condition₂O(CO₃)₂·xH₂O、Eu₂O(CO₃)₂·H₂O、 Gd₂O(CO₃)₂·H₂O, and the like.

Disclosure of Invention

The invention aims to provide a simple preparation method of rare earth carbonate oxysalt, which is mainly characterized in that g-C is used₃N₄、 Re₂O₃The Re can be prepared by taking dilute nitric acid as a raw material and utilizing a hydrothermal process₂O(CO₃)₂·H₂O。

The method comprises the following specific steps:

(1)Re(NO₃)₃preparation of (Re ═ Eu, Sm, Gd) solution

Re is treated with a quantity of concentrated nitric acid₂O₃Dissolving, adjusting pH value of the solution to be about 12 with NaOH (10 wt%), generating white precipitate, centrifuging the white precipitate, Re-dispersing in 0.6M dilute nitric acid, and controlling Re₂O₃In different concentrations of Re (NO) can be obtained₃)₃And (3) solution.

Re can also be treated with concentrated nitric acid₂O₃Dissolving, and evaporating under heating to obtain rare earth nitrate crystal. Then dissolving the crystal in water with different volumes to obtain rare earth nitrate Re (NO) with different concentrations₃)₃And (3) solution.

(2)Re₂O(CO₃)₂·H₂Preparation of O

To Re (NO)₃)₃Adding a certain amount of carbon nitride into the solution, performing ultrasonic treatment to uniformly disperse the carbon nitride in the solution, transferring the solution into a reaction kettle, and reacting at 180-220 ℃ for 6-48 h to obtain Re₂O(CO₃)₂·H₂O, different from Re₂O(CO₃)₂·H₂The difference in the shape of the O.

Drawings

FIG. 1 XRD pattern of samarium oxycarbonate prepared in example 1

FIG. 2 SEM spectrum of samarium oxycarbonate prepared in example 1

FIG. 3 UV-VISIBLE ABSORPTION SPECTRUM OF OXYMIUM CARBONATE PREPARED IN EXAMPLE 1

FIG. 4 XRD pattern of europium oxycarbonate prepared in example 2

FIG. 5 XRD pattern of samarium oxycarbonate prepared in example 3

FIG. 6 SEM photograph of samarium oxycarbonate prepared in example 3

FIG. 7 UV-VISIBLE ABSORPTION SPECTRUM OF OXYMIUM CARBONATE PREPARED IN EXAMPLE 3

FIG. 8 XRD pattern of samarium oxycarbonate prepared in example 4

FIG. 9 UV-VISIBLE ABSORPTION SPECTRUM OF OXYMIUM CARBONATE PREPARED IN EXAMPLE 4

Detailed description of the preferred embodiments

The following non-limiting examples further illustrate the embodiments and effects:

example 1

Weighing 1.22mmol of Sm₂O₃Adding appropriate amount of concentrated nitric acid into a beaker, ultrasonically dissolving, and magnetically stirring when the solution is yellow and transparentAdjusting the pH value of the solution to 12 by using 10 percent NaOH by mass, continuously stirring for 30min, centrifuging by using a high-speed centrifuge, washing twice by using deionized water, then re-dispersing in a proper amount of dilute nitric acid with the concentration of 0.3M, and ultrasonically dissolving to obtain Sm³⁺The concentration of the solution of (a) is about 0.08M.

10ml of 0.08M Sm (NO) was measured₃)₃Solution, 0.4g of g-C was added₃N₄And 30ml of deionized water, sonicated to g-C₃N₄Uniformly dispersing in the solution, transferring to a reaction kettle, reacting for 8h at 200 ℃, centrifuging the obtained product, washing and drying. The phase, structure and absorption spectrum of the obtained product are shown in figures 1, 2 and 3.

Example 2

10ml of 0.08M Eu (NO) was measured₃)₃Solution, 0.4g of g-C was added₃N₄And 30ml of deionized water, sonicated to g-C₃N₄Uniformly dispersing in the solution, transferring to a reaction kettle, reacting for 8h at 200 ℃, centrifuging the obtained product, washing and drying. Obtained Eu₂O(CO₃)₂·H₂The XRD spectrum of O is shown in figure 4.

Example 3

10ml of 0.08M Sm (NO) was measured₃)₃Solution, 0.4g of g-C was added₃N₄And 30ml of deionized water, sonicated to g-C₃N₄Uniformly dispersing in the solution, transferring to a reaction kettle, reacting for 24h at 200 ℃, centrifuging the obtained product, washing and drying. The obtained product Sm₂O(CO₃)₂·H₂The phase, structure and absorption spectrum of O are shown in figures 5, 6 and 7.

Example 4

5ml of 0.08M Sm (NO) was measured₃)₃Solution, 0.4g of g-C was added₃N₄And 35ml of deionized water, sonicated to g-C₃N₄Uniformly dispersing in the solution, transferring to a reaction kettle, reacting for 8h at 200 ℃, centrifuging the obtained product, washing and drying. The obtained product Sm₂O(CO₃)₂·H₂The phase and absorption spectrum of O are shown in figures 8 and 9.

Claims

1. Monohydrate rare earth carbonate RE₂O(CO₃)₂·H₂A process for the preparation of O, characterized in that it comprises the following steps:

(1) dissolving rare earth oxide with nitric acid to obtain rare earth nitrate solution RE (NO)₃)₃，RE=Eu，Sm，Gd；

(2) Adding a proper amount of carbon nitride and dilute nitric acid into the solution, adding water to a certain volume, and performing ultrasonic treatment to uniformly disperse the carbon nitride in the solution;

(3) transferring the mixed solution into a reaction kettle at 180 DEG^oC~220^oHydrothermal reaction is carried out for 6-48 h at the temperature of C, and the monohydrate rare earth carbonate RE can be prepared₂O(CO₃)₂·H₂O。

2. A monohydrate rare earth oxycarbonate RE according to claim 1₂O(CO₃)₂·H₂Process for the preparation of O, characterized in that RE³⁺The molar ratio of the carbon nitride to the carbon nitride is controlled to be 0.05-2: 1.

3. A monohydrate rare earth oxycarbonate RE according to claim 1₂O(CO₃)₂·H₂Preparation of O, characterized by rare earth RE³⁺Concentration of aqueous solution: 0.01-0.8M.

4. A monohydrate rare earth oxycarbonate RE according to claim 1₂O(CO₃)₂·H₂The preparation method of O is suitable for preparing the monohydrate rare earth carbonate oxysalt of the light rare earth elements.

5. A rare earth samarium carbonate monohydrate prepared by the process of claim 1, wherein: obtained Sm₂O(CO₃)₂·H₂O is nanoparticles of about 100 nm, and has multiple strong absorption peaks at 1000-1400 nm, especially at 1068 nm and 1223 nmThe absorption is strongest; with the prolonging of the reaction time, the product can grow preferentially to obtain a rod-shaped product.