CN101767997B - A kind of sol-gel preparation method of NiTiO3 nanopowder - Google Patents

Abstract

The invention discloses a method for preparing NiTiO3 nano-powder by sol-gel, which comprises the following steps: adding ethanol into nickel nitrate hexahydrate to obtain solution A; adding tetrabutyl titanate, citric acid, water and acetylacetone into the solution A to obtain a sol B; drying the sol B in a drying oven so as to form a gel, and grinding the dried gel in an agate mortar for later use; calcining the ground dried gel in a muffle furnace, and cooling the dried gel to room temperature to obtain the end product, namely the NiTiO3 nano-powder containing no impurity. The prepared NiTiO3 nano-powder has the advantages of smaller dimension of crystal grains, good dispersion, uniform particle distribution, less agglomeration phenomenon, and no impurity. The method for preparing NiTiO3 nano-powder by the sol-gel has the advantages of short reaction period for preparing the NiTiO3 nano-powder, good repeatability, simple preparation, convenient operation, easily obtained raw materials, and low preparation cost.

Description

A kind of sol-gel preparation method of NiTiO₃ nanopowder

technical field

The invention relates to a preparation method of _NiTiO3 nanometer powder, in particular to a sol-gel preparation method of _NiTiO3 nanometer powder.

Background technique

Titanium-based oxides MTiO ₃ (M=Ni, Pb, Fe, Co, Cu and Zn) containing different metals are widely used in solid oxide fuel cell electrodes (SOFC), metal-air barrier materials, and inorganic functions of gas sensors Material. NiTiO ₃ belongs to the triangular crystal system of ilmenite structure. Because of its semiconductivity and weak magnetism, it is an important chemical material and electrical material, which is used in many industrial fields, such as semiconductor rectifiers, bicarbonate catalysts and surface-coated Dyeing admixture, also used as cladding material to reduce friction and wear under high temperature conditions. NiTiO ₃ has high Q value, low dielectric constant and good acousto-optic and electro-optic properties, and has a wide range of application prospects, which has attracted great attention. Due to its small size and large specific surface area, nano-NiTiO ₃ particles have the characteristics of quantum size effect, surface effect, and macroscopic quantum tunneling effect of nanomaterials, and have more unique properties than traditional materials.

At present, there are not many reports on the preparation of NiTiO ₃ nanopowders, and the preparation of NiTiO ₃ nanopowders is still a relatively new topic in the material field. The traditional methods for preparing NiTiO _nanopowder include solid phase sintering method (F.Tietz, FJDias, B.Dubiel, et al.Materials Science and Engineering.1999, 68:35-41), stearic acid gel method (MS Sadjadi, K.Zare, S.Khanahmadzadeh.Materials Letters, 2008, 62:3679-3681) etc., these methods all can be made crystallization complete NiTiO ₃ powders at relatively low temperature There are few reports on the preparation of NiTiO ₃ powder at high temperature. Peng Zifei, Wang Guozhong, etc. (Peng Zifei, Wang Guozhong, Zhang Lide. Synthetic Chemistry, 1996, (2): 99-101) and Zhou Lan, Liu Xiaojun, etc. (Zhou Lan, Liu Xiaojun, Zhang Shuyi, et al. Journal of Nanjing University, 1997, 33( 1): 32-36) Nano-NiTiO ₃ powders are prepared by chemical precipitation method, but the powders prepared by this method are not high in purity and contain impurities. In addition, KP Lopes et al. (K..L pes a, LS Cavalcante a, AZSimoes, et al. 2009, (468): 327-332) NiTiO ₃ nanopowder prepared by sol-gel method still exists after calcination NiO powder. So far, there has been no report on the preparation of high-purity NiTiO ₃ nanopowder without impurities at a relatively low temperature.

Contents of the invention

The purpose of the present invention is to overcome the shortcoming of above-mentioned prior art, provide a kind of not only preparation cost is low, and simple to operate, the sol-gel preparation method of _NiTiO3 nanopowder with short reaction cycle, method of the present invention can be relatively The impurity-free NiTiO ₃ nanometer powder was prepared at a lower temperature.

In order to achieve the above object, the technical scheme adopted in the present invention is:

Step 1: Add analytically pure nickel nitrate hexahydrate into absolute ethanol, and keep stirring to prepare a transparent solution with a Ni2 ⁺ concentration of 0.3mol/L to 0.6mol/L, and the obtained solution is denoted as A;

Step 2: Add analytically pure tetrabutyl titanate to solution A so that the molar ratio of Ni ²⁺ to Ti ⁴⁺ is 1:1, and keep stirring, then add citric acid to the solution to make citric acid and Ti 4+ The molar ratio of all cations is 0.7-2:1, and finally add water with a volume ratio of 5:1-10:1 to absolute ethanol and acetylacetone 7:1-15:1, stir well and let stand to form a sol denoted as B;

Step 3: put the above sol B in a drying oven, dry at 80°C-120°C for 8h-12h to form a gel, grind the dried gel finely with an agate mortar and set aside;

Step 4: put the finely ground xerogel into a muffle furnace for calcination, the temperature is controlled at 700°C, the calcination time is 0.5h to 3h, and the furnace is cooled to room temperature to obtain the final product - NiTiO ₃ without any impurities Nano powder.

The _NiTiO3 nanometer powder prepared by the present invention has small grain size, good dispersion, uniform particle distribution, less agglomeration phenomenon, and does not contain any impurities; the preparation of _NiTiO3 nanometer powder has a short reaction period, good repeatability and simple preparation , easy to operate, easy to obtain raw materials, and low preparation cost.

Description of drawings

Fig. ₁ is the NiTiO prepared by the present invention The X-ray diffraction (XRD) collection of nanopowders;

Fig. 2 is a scanning electron microscope (SEM) photo of NiTiO ₃ nanopowder prepared in the present invention.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings.

Embodiment 1: Add analytically pure nickel nitrate hexahydrate in dehydrated alcohol, and constantly stir, be mixed with Ni ^{Concentration} is the transparent solution of 0.3mol/L, and the gained solution is denoted as A; Add analytically pure Tetrabutyl titanate, so that the molar ratio of Ni ²⁺ and Ti ⁴⁺ is 1: 1, and keep stirring, then add citric acid to the solution, so that the molar ratio of citric acid and all cations is 0.7: 1, Finally, add water with a volume ratio of 5:1 to absolute ethanol and acetylacetone of 7:1, stir evenly and leave to form a sol, which is recorded as B; put the above sol B into a drying oven, and dry at 80°C for 12 hours. Make it into a gel, and grind the dried gel with an agate mortar for use; put the finely ground xerogel into a muffle furnace for calcination, the temperature is controlled at 700°C, and the calcination time is 0.5h. The furnace is cooled to room temperature, and the final product-NiTiO ₃ nanopowder without any impurities is obtained.

The resulting NiTiO ₃ nanopowder was analyzed with a Japanese Rigaku D/max2000PC X-ray diffractometer, and it was found that the product was NiTiO ₃ with JCPDS No. 33-0960 (Fig. 1). The sample was observed with a JSM-6390A scanning electron microscope (Fig. 2) produced by Japan JEOL Corporation, and it can be seen from the photo that the prepared NiTiO ₃ nanometer powder is spherical particles.

Embodiment 2: Add analytically pure nickel nitrate hexahydrate in dehydrated alcohol, and constantly stir, be mixed with Ni Concentration is the transparent solution of ^0.5mol /L, and the gained solution is denoted as A; Add analytically pure Tetrabutyl titanate, so that the molar ratio of Ni ²⁺ and Ti ⁴⁺ is 1: 1, and keep stirring, then add citric acid to the solution, so that the molar ratio of citric acid and all cations is 1.2: 1, Finally, add water with a volume ratio of 10:1 to absolute ethanol and acetylacetone with a volume ratio of 15:1, stir evenly and leave to form a sol, which is recorded as B; put the above-mentioned sol B in a drying oven, and dry at 100°C for 10 hours. Make it into a gel, and grind the dried gel with an agate mortar for use; put the finely ground dry gel into a muffle furnace for calcination, the temperature is controlled at 700°C, and the calcination time is 1h. After cooling to room temperature, the final product-NiTiO ₃ nanopowder without any impurities is obtained.

Embodiment 3: Add analytically pure nickel nitrate hexahydrate in dehydrated alcohol, and constantly stir, be mixed with Ni ^{Concentration} is the transparent solution of 0.4mol/L, and the gained solution is denoted as A; In A solution, add analytical pure Tetrabutyl titanate, so that the molar ratio of Ni ²⁺ and Ti ⁴⁺ is 1: 1, and keep stirring, then add citric acid to the solution, so that the molar ratio of citric acid and all cations is 1.6: 1, Finally, add water with a volume ratio of 6:1 to absolute ethanol and acetylacetone of 7:1, stir evenly and then stand still to form a sol, which is recorded as B; put the above sol B into a drying oven, and dry at 120°C for 8 hours. Make it into a gel, and grind the dried gel with an agate mortar for use; put the finely ground dry gel into a muffle furnace for calcination, the temperature is controlled at 700 ° C, and the calcination time is 2 hours. After cooling to room temperature, the final product-NiTiO ₃ nanopowder without any impurities is obtained.

Embodiment 4: Add analytically pure nickel nitrate hexahydrate in dehydrated alcohol, and constantly stir, be mixed with Ni ^{Concentration} is the transparent solution of 0.6mol/L, and the gained solution is denoted as A; Add analytically pure Tetrabutyl titanate, so that the molar ratio of Ni ²⁺ and Ti ⁴⁺ is 1: 1, and keep stirring, then add citric acid to the solution, so that the molar ratio of citric acid and all cations is 2: 1, Finally, add water with a volume ratio of 7:1 and acetylacetone with a volume ratio of 10:1 to absolute ethanol, stir evenly and leave to form a sol, which is recorded as B; put the above sol B into a drying oven, and dry at 90°C for 11 hours. Make it into a gel, and grind the dried gel with an agate mortar for use; put the ground dry gel into a muffle furnace for calcination, the temperature is controlled at 700°C, and the calcination time is 3h. After cooling to room temperature, the final product-NiTiO ₃ nanopowder without any impurities is obtained.

Claims (1)

1. NiTiO ₃The process for preparing sol-gel of nano-powder is characterized in that:

Step 1: analytically pure Nickelous nitrate hexahydrate is added in the dehydrated alcohol, and constantly stir, be mixed with Ni ²⁺Concentration is the clear solution of 0.3mol/L～0.6mol/L, and gained solution is designated as A;

Step 2: in A solution, add analytically pure tetrabutyl titanate, make Ni ²⁺With Ti ⁴⁺Mol ratio be 1: 1, and constantly stir, and then in solution, add citric acid, making citric acid and all cationic mol ratios is 0.7～2: 1, adding at last is respectively 5: 1～10: 1 water and 7: 1～15: 1 methyl ethyl diketone with the dehydrated alcohol volume ratio, leaves standstill formation colloidal sol after stirring and is designated as B;

Step 3: above-mentioned sol B is put into loft drier,, make it form gel at 80 ℃～120 ℃ dry 8h～12h, stand-by behind the gel usefulness agate mortar porphyrize that drying is good;

Step 4: the xerogel of porphyrize is put into retort furnace calcine, temperature is controlled at 700 ℃, and calcination time is 0.5h～3h, cools to room temperature with the furnace, promptly obtains final product-NiTiO free from foreign meter ₃Nano-powder.

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