Digadolinium tetrahydroxide dihydrate and its preparation and application

The technology of dihydrate tetrahydroxide gadolinium oxide and hydrated tetrahydroxide gadolinium oxide is applied in dihydrate tetrahydroxide digadolinium oxide and the field of preparation and application thereof, can solve the problems of destruction of ozone layer, low efficiency and the like, and achieves simple synthesis device, The effect of good thermal stability and improved mass ratio

Active Publication Date: 2017-01-18
XIAMEN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Traditional gas compression refrigeration technology has been widely used in people's daily life, but with the continuous improvement of people's living standards, the low efficiency of traditional gas compression refrigerators can no longer meet people's requirements
At the same time, the refrigerant Freon used in traditional refrigerators will seriously damage the ozone layer. People began to explore a new type of refrigeration technology, which has the two advantages of high efficiency, energy saving and no environmental pollution.

Method used

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  • Digadolinium tetrahydroxide dihydrate and its preparation and application
  • Digadolinium tetrahydroxide dihydrate and its preparation and application
  • Digadolinium tetrahydroxide dihydrate and its preparation and application

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] The preparation process of the hydroxyl-containing coordination rare earth gadolinium magnetic refrigeration material: 0.25mmol of gadolinium nitrate hexahydrate, 0.33mmol of sodium formate dihydrate and 0.08mmol of glycine were dissolved in 15mL of deionized water. Stir the solution continuously, and adjust the pH to about 6.7 with freshly prepared ammonia water (concentration 1mol / L). The solution was transferred to a 23mL PTFE-lined pressure-resistant stainless steel reactor, heated to 160°C at a rate of 35°C / h and kept at a constant temperature of 4000min, then slowly dropped to room temperature at a rate of 2°C / h, filtered and washed to obtain Colorless needle-like crystals.

Embodiment 2

[0028] Sample characterization:

[0029] 1. Single crystal test:

[0030] The single crystal sample structure of the hydroxyl-coordinated rare earth gadolinium magnetic refrigeration material was collected using an Agilent Super NovaDiffractometer X-ray single crystal diffractometer at 100K. figure 1 with 2 It is the crystal structure diagram of Gadolinium tetrahydroxide dihydrate.

[0031] 2. Rare earth gadolinium magnetic refrigeration material containing hydroxyl coordination: belongs to the orthorhombic system, space group Cmcm, molecular formula is Gd 2 O(OH) 4 (H 2 O) 2 , The unit cell parameters are a=16.5835, b=12.9747, c=7.3106, and V=1573.05. Its structural coordination mode is like figure 2 As shown, each asymmetric unit contains 1 Gd 3+ Ion, 1 / 2 O 2- Ion, 2 OH - Ions and 1 water molecule. There are two crystallographically independent Gd 3+ Ions (Gd1 and Gd2), Gd1 is eight-coordinated with six μ 3 -OH - , A μ 3 -O 2- And an H 2 O is coordinated to form a dodecahedron co...

Embodiment 3

[0035] Magnetic test

[0036] The Quantum Design SQUID MPMS magnetometer was used to test the hydroxyl-containing coordinated rare-earth gadolinium magnetic refrigeration material under the external magnetic field conditions in the temperature range of 2~300K and 1000Oe. Figure 4 It is the temperature-varying magnetic susceptibility diagram of the hydroxyl-containing coordinated rare earth gadolinium magnetic refrigeration material. And in the temperature range of 2 ~ 10K, the magnetic field 0 ~ 7T conditions for testing. Figure 5 It is a graph of the magnetization intensity of a variable temperature and variable field of a hydroxyl-containing coordinated rare earth gadolinium magnetic refrigeration material. Image 6 It is the magnetic entropy change diagram of the hydroxyl-containing coordinated rare earth gadolinium magnetic refrigeration material.

[0037] Figure 4 Show that at room temperature, the hydroxyl-containing coordination rare earth gadolinium magnetic refrigeratio...

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Abstract

The invention discloses tetrahydroxy gadolinium oxide dihydrate and preparation and applications thereof and relates to hydroxyl coordinate rare earth gadolinium materials. The tetrahydroxy gadolinium oxide dihydrate belongs to an orthorhombic system and a space group Cmcm and the molecular formula is Gd2O(OH)4(H2O)2. Cell parameters a is equal to 16.5835, b is equal to 12.9747, c is equal to 7.3106 and V is equal to 1573.05. During preparation, gadolinium nitrate hexahydrate, sodium formate and glycine are dissolved in water, the above is transferred to a reaction still after the pH (Potential Of Hydrogen) is adjusted through ammonium hydroxide, the temperature is risen to 160 degrees and the temperature keeps consistent, then the temperature is reduced to the room temperature, and the tetrahydroxy gadolinium oxide dihydrate which is colorless acicular crystal is obtained after filtering and washing. The tetrahydroxy gadolinium oxide dihydrate can be applied to preparation of magnetic refrigeration materials.

Description

Technical field [0001] The invention relates to a hydroxy-coordinated rare earth gadolinium material, in particular to gadolinium tetrahydroxide dihydrate and its preparation and application. Background technique [0002] Traditional gas compression refrigeration technology has been widely used in people's daily life, but with the continuous improvement of people's living standards, the low efficiency of traditional gas compression refrigerators can no longer meet people's requirements. At the same time, the refrigerant Freon used in traditional refrigerators will also seriously damage the ozone layer. People have begun to explore a new type of refrigeration technology that has the two major advantages of high efficiency and energy saving and no environmental pollution. In 1997, the Ames Laboratory of the U.S. Department of Energy discovered that an alloy composed of Gd, Si, and Ge can exhibit a huge magnetocaloric effect at room temperature. Since then, NASA has begun to develop...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C30B29/54C30B7/14C01F17/00C09K5/14
Inventor 龙腊生杨雁
Owner XIAMEN UNIV
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