SnO2 powder is an important multifunctional material with remarkable gas sensitivity, chemical stability and excellent luminescence properties. As a basic functional material, it has a wide range of applications in gas sensitivity, humidity sensitivity and optical technology. At present, it is one of the most basic raw materials used in gas sensitive components.
Nano stannic oxide has high sensitivity, selectivity and stability to H2, C2H2 and other gases. Due to the quantum size effect and surface effect, the optical properties of nano tin dioxide materials have attracted much attention. The fluorescence emission peaks of SnO2 nanomaterials prepared by different methods are different.
The physical and chemical properties of materials (such as optics, magnetism, electricity, etc.) are closely related to their surface morphology, dimension, particle size and surface defects, etc. The physical and chemical properties of low dimensional nano materials are expected to be improved or show new properties. At present, hydrothermal method, coprecipitation method, sol-gel method and other wet chemical methods have been widely used in the synthesis of various metal oxide nanoparticles, but the nanopowders prepared by most of the methods are agglomerated with uneven distribution.
Macromolecule network gel method, also known as polyacrylamide gel method, is a method that can effectively prevent agglomeration between particles. Its process is simple, easy to operate, good repeatability, easy to produce, and the prepared particles have high purity, uniform particle size, fine particle morphology.
Sn02 nanomaterials were characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, specific surface area method, etc.
The average diameter and particle size distribution of the products could be directly observed by tem.
The morphology and size of the product could be observed by SEM.
X-ray diffraction was used to determine the grain size of the product.
1. Scanning electron microscope (SEM) : Can directly observe the surface structure, morphology, average diameter and particle size distribution of the sample preparation process is simple, don’t slice, the sample can be made in the sample room, translation and rotation of three dimensional and, therefore, can be observed, the samples from various angles to image magnification is wide and has a high resolution, maximum magnified six hundred thousand times, It basically covers the magnification range from magnifying glass, light microscope to transmission electron microscope.
2. Transmission electron microscope (TEM) Observed by transmission electron microscopy (sem) at Sn02 nanomaterials average particle diameter and particle size distribution of electron microscopy (sem) test is to observe absolute method for determination of granularity, thus has reliability and intuitive, high energy electron penetrating to the sample, according to the sample different locations through different intensity or electronic through the crystal samples of diffraction in a different direction, after amplification of electromagnetic lens behind, Display an image on a fluorescent screen.
3, xRD: electron microscope observation method measured is the grain size but not the grain size, X-ray diffraction linewidth method is the best method to determine the grain size. When the particle is single crystal, the method measured is the particle size, when the particle is multi-crystal, the method measured is the average grain size of a single grain composed of a single particle, this measurement method is only applicable to the evaluation of the particle size of crystalline nanoparticles. This method can be used to identify the size and size of the crystalline phase of the material, identify the phase of the sample according to the position of the characteristic peak, detect the purity and structure, and calculate the grain size with Scherer formula.
Pure SnO2 belongs to tetragonal system and rutile structure. The unit cell has six atoms, including two Sn atoms and four O atoms, as shown in the figure below. Each Sn atom is at the center of an approximate octahedron of six O atoms, and each O atom is also at the center of an equilateral triangle of three Sn atoms, forming a 6:3 coordination structure.
Nano SnO2 application
Nano SnO2 is a typical N-type semiconductor with Eg=3.5eV (300K). It has the characteristics of large specific surface, high activity, low melting point, good thermal conductivity and so on. It is widely used in gas sensitive materials, electricity, catalysts, ceramics and cosmetics.
SnO2 powder is a kind of semiconductor gas sensitive material widely used at present. Ordinary SnO2 powder is sintered resistive gas sensitive element made of matrix material. It has high sensitivity to various reducing gases, but the stability and consistency of the device are not satisfactory.
SnO2 nano-powder can be used as glaze and enamel opacification agent in ceramic industry. In the aspect of electricity, antistatic agent shows greater advantages than other antistatic materials, and has great advantages in photoelectric display, transparent electrode, solar cell, liquid crystal display, catalysis and so on.
In addition, nano SnO2 composite is also a hot spot in the current development. In the process of preparing SnO2 material, a small amount of dopant is added to improve its selectivity and reduce the resistivity, or SnO2 is used as the dopant material. Using the infrared reflectance of nano-sno2 powder, combined with the ultraviolet light absorption characteristics of nano-tio2 powder, nano-sno2 powder doped with TiO2 has the characteristics of infrared and ultraviolet resistance, and the cosmetics produced can play a more protective role of skin.