Nanopowder Compounds

Nanopowder Compounds List

Nanopowder compounds refer to particles with a size between 1-100 nm, which are located in the transition zone between the cluster of atoms and the macroscopic object. From the usual micro and macro point of view, such a system is neither a typical micro system nor a typical macro system. It is a typical mesoscopic system with surface effects, small size effects and macro quantum tunneling effects. Since its size is close to the coherence length of electrons, its properties have changed greatly due to the self-organization brought about by strong coherence. Moreover, its scale is close to the wavelength of light, and it has the special effect of large surface, so its characteristics, such as melting point, magnetism, optics, heat conduction, electric conductivity and so on, are often different from the properties of the material in the overall state.

Figure 1. Different microscopic morphologies of nanopowder compounds.

Applications:

• Nano-sensor: Nanopowdered zirconia, nickel oxide, titanium dioxide and other ceramics are very sensitive to temperature changes, infrared rays and automobile exhaust. Therefore, they can be used to make temperature sensors, infrared detectors and automobile exhaust gas detectors, and the detection sensitivity is much higher than that of ordinary similar ceramic sensors.
• Nano-semiconductor: Nanopowdered gallium arsenide and other semiconductor materials are made into nanomaterials with many excellent properties. For example, the quantum tunneling effect in nano-semiconductors makes the electron transport of some semiconductor materials abnormal, and the electrical conductivity decreases, and the electrical thermal conductivity also decreases with the decrease of the particle size, and even appears negative. These characteristics play an important role in large-scale integrated circuit devices, optoelectronic devices and other fields. Using semiconductor nanoparticles, a new type of solar cell that has high photoelectric conversion efficiency and can work normally even in rainy days can be prepared. Because the electrons and holes generated by nano semiconductor particles when irradiated by light have strong reducing and oxidizing capabilities, they can oxidize toxic inorganic substances, degrade most organic substances, and eventually generate non-toxic and odorless carbon dioxide, water, etc. So solar energy can be used to catalyze the decomposition of inorganic and organic substances with the help of semiconductor nanoparticles.
• Nano-ceramic materials: In traditional ceramic materials, the crystal grains are not easy to slide, the material is brittle, and the sintering temperature is high. Nano-ceramics prepared by nanopowder compounds have small crystal grain sizes and the crystal grains are easy to move on other crystal grains. Therefore, nano-ceramic materials have extremely high strength, high toughness and good ductility. These characteristics enable nano-ceramic materials to be used in cold working at room temperature or sub-high temperature. If the nano-ceramic particles are processed and shaped at sub-high temperature and then surface annealed, nano-materials can be made into a kind of surface that maintains the hardness and chemical stability of conventional ceramic materials, while the interior still has the ductility of nano-materials.
• Nano-catalyst material: Nanopowder compounds is an excellent catalyst. This is due to the small size of nanoparticles, large surface volume fraction, surface chemical bond state and electronic state different from the inside of the particle, and incomplete coordination of surface atoms. The increase of active sites on the surface provides it with the basic conditions for being a catalyst. Nanoparticles of nickel or copper-zinc compounds are excellent catalysts for the hydrogenation reaction of certain organics, and can replace expensive platinum or palladium catalysts.

References

1. Paramita Das, Ray J. Butcher and Chhanda Mukhopadhyay. Zinc titanate nanopowder: an advanced nanotechnology based recyclable heterogeneous catalyst for the one-pot selective synthesis of self-aggregated low-molecular mass acceptor–donor–acceptor–acceptor systems and acceptor–donor–acceptor triads. Green Chem., 2012, 14, 1376–1387.
2. Tiberio Magno de Lima Alves, Bruno Ferreira Amorim, Marco Antonio Morales Torres, Claudionor Gomes Bezerra, Suzana Nobrega de Medeiros, Pedro Lana Gastelois, Luis Eugenio Fernandez Outoncd and Waldemar Augusto de Almeida Macedo. Wasp-waisted behavior in magnetic hysteresis curves of CoFe₂O₄ nanopowder at a low temperature: experimental evidence and theoretical approach. RSC Adv., 2017, 7, 22187-22196.