Method for preparing nano-particle self-assembled coralline In2O3 low-heat solid-phase precursor

Abstract

The invention discloses a novel method for preparing a coralline In2O3 nano material by a low-heat solid-phase precursor method. According to the method, indium nitrate hydrate (In (NO3) 3 * xH2O) and sodium hydroxide (NaOH) are used as raw materials, a precursor is generated through a solid-phase chemical reaction, then calcination treatment is carried out under the low-temperature condition of 300 DEG C, and the In2O3 nanosheet material formed by self-assembly of nanoparticles is obtained after washing and vacuum drying. According to the method, a solvent-free solid-phase reaction system is innovatively adopted, the limitation of an organic solvent in a traditional liquid-phase method is broken through, the contact efficiency of a reaction interface is effectively improved, and the reaction energy consumption is reduced. The preparation method has the characteristics of simple operation steps, high safety coefficient, environmental friendliness, easiness in realization of large-scale production and the like, and has certain technical enlightenment for large-scale preparation of high-end nano devices such as photoelectric catalytic materials and gas sensitive sensor elements.

Description

Technical Field

[0001] The invention relates to a low-heat solid-phase precursor method for preparing nanoparticle self-assembled coralline In2O3. Background Art

[0002] Indium oxide (In2O3), a high-quality n-type semiconductor material, belongs to the III-VI group of metal oxides and typically appears as a white or pale yellow solid powder. It exhibits excellent electrical conductivity at room temperature. In2O3 semiconductors exist in two main crystal structures: the hexagonal corundum structure (h-In2O3) and the stable body-centered cubic ferromanganite structure (c-In2O3). In both crystal phases, oxygen atoms are tetracoordinated, while indium atoms are hexacoordinated. The cubic ferromanganite structure of In2O3 is derived from the face-centered cubic fluorite (CaF2) structure and belongs to the fluorite oxygen-deficient structure. This structure is obtained by the orderly removal of one-quarter of anions from a 2×2×2 fluorite superstructure, with a total of 80 atoms per unit cell. In2O3 has been widely used in photocatalysis due to its favorable electrical conductivity, good photoresponse, excellent catalytic activity, environmental friendliness, chemical stability, and thermal stability.

[0003] Currently, the main methods for synthesizing In2O3 nanomaterials include high-temperature solid-phase methods, hydrothermal methods, solvothermal methods, and sol-gel methods. These methods typically require high temperatures and high pressures, long reaction times, and the use of organic solvents. These methods are characterized by harsh reaction conditions, complex synthesis processes, and potential environmental pollution. Therefore, there is an urgent need to develop a method for synthesizing In2O3 nanomaterials that is simple to operate and has mild reaction conditions.

[0004] The low-heat solid-phase precursor method refers to the o C) by chemically reacting solid reactants to prepare a precursor, which is then heat-treated to produce the final product. This method significantly reduces reaction temperatures, is simple to operate, and does not require any solvents, making it an important method for synthesizing nanomaterials.

[0005] The present invention discloses a universal low-heat solid-phase precursor method, which obtains a precursor through a low-heat solid-phase chemical reaction and further calcines it in an air atmosphere to prepare In2O3 nanomaterials. Compared with the traditional high-temperature solid-phase method, the low-heat solid-phase precursor method disclosed in the present invention reduces the synthesis temperature by about 600 o C. The prepared In2O3 nanomaterials have pure phase, small size, uniform morphology and high catalytic activity. Summary of the Invention

[0006] The purpose of the present invention is to provide a universal low-heat solid-phase precursor method for synthesizing In2O3 nanomaterials. This method obtains indium oxide (In2O3) with uniform morphology and pure phase by utilizing simple operating steps and relatively mild reaction conditions.

[0007] The present invention utilizes solid indium nitrate and an appropriate amount of solid sodium hydroxide to undergo solid phase chemical reaction at room temperature to obtain a precursor, and the precursor is heated at 300 o C. Calcination in air atmosphere for 2 hours to obtain coral-like In2O3 nanomaterials self-assembled by nanoparticles.

[0008] Compared with the existing technology, the present invention has the following advantages: it uses cheap and readily available solid raw materials and is based on low-heat solid-phase precursor reaction. First, the precursor is obtained through solid-phase chemical reaction at room temperature, and then o C. The next step is calcination in air atmosphere to obtain In2O3 nanomaterials with a certain morphology.

[0009] Compared with the traditional high-temperature solid-phase preparation method of In2O3, the preparation method of the present invention has a lower synthesis temperature and the product has uniform morphology and smaller size; at the same time, the present invention is practical in the preparation of In2O3 nanomaterials, which makes the present invention have broad application prospects in industrial production.

[0010] In summary, the synthesis scheme proposed in the present invention not only provides substantial technical guidance for the synthesis of In2O3 nanomaterials, but also uses a single synthetic raw material, which makes the present invention more technically enlightening in the design of the synthesis scheme. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 The powder X-ray diffraction pattern of indium oxide (In2O3) prepared in the first embodiment of the present invention;

[0012] Figure 2 This is a field emission scanning electron microscope photograph of indium oxide (In2O3) prepared according to the first embodiment of the present invention; DETAILED DESCRIPTION

[0013] The present invention will be further described below with reference to specific embodiments. These embodiments should be understood as merely illustrating the present invention and not as limiting the scope of protection of the present invention. After reading the contents of the present invention, various changes or modifications made to the present invention based on the principles of the present invention also fall within the scope defined by the claims of the present invention. Example 1:

[0014] A method for synthesizing pure phase indium oxide nanoparticles using a low-heat solid-phase precursor method, characterized by the following steps: accurately weighing 0.006 mol of solid indium nitrate, grinding it into powder, and then rapidly grinding it with 0.006 mol of solid sodium hydroxide to cause a solid-phase reaction. As the reaction proceeds for 5 minutes, the mixture changes from a dry powder to a viscous state. After further grinding for 15 minutes, the mixture changes from a viscous state to a powder to obtain a precursor. Finally, the precursor is heated in a muffle furnace under air atmosphere at 2 o C min -1 The speed increases to 300 o C for 2 hours, then filtered and washed with distilled water, and dried to obtain coral-like indium oxide assembled by nanoparticles.

Claims

1. The present invention discloses a low-heat solid-phase precursor method for synthesizing coral-like indium oxide nanomaterials, characterized in that: Accurately weigh 0.006 mol of solid indium nitrate and grind it to a fine powder. Then, quickly mix it with 0.006 mol of solid sodium hydroxide and grind it in a mortar for 5 minutes. The mixture transforms from a dry powder into a sticky paste. After grinding for another 15 minutes, the sticky mixture transforms into a solid powder, yielding the desired precursor. The synthesized precursor is heated to 300°C in an air atmosphere at a rate of 2°C / min and then held for 2 hours to produce indium oxide nanomaterials.

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