Metal Nano Dispersion

Metal Nano Dispersion List

Metal nanoparticle dispersion refers to the dispersion of one or more metal nanoparticles in another liquid medium. Monodisperse nanoparticle materials are a new generation of nanomaterials developed in the research process of nanomaterials. Their particles are small and uniform, without agglomeration, and can be dispersed in solvents to form nano-dispersions with good transparency or obvious Tyndall effect. Compared with traditional nano-powder materials, nano-powder materials are easier to disperse and apply, thus showing better optical, electrical, magnetic, mechanical, acoustic and catalytic properties, so the research on their preparation and application properties has always been an international cutting-edge research field.

Applications:

• Nano-catalyst: Nano-dispersions can take advantage of their small particles, good dispersion and stability, no internal diffusion and other characteristics to give full play to the quasi-homogeneous nano-catalytic effect. Quasi-homogeneous nano-catalyst means that the nanoparticles are uniformly dispersed in the solvent to form a quasi-homogeneous system, which is used in the catalytic reaction process. It combines the advantages of homogeneous and heterogeneous catalysis, which is similar to the homogeneous system, which is beneficial to the full contact between reactants and catalysts, reduces the problem of mass transfer and diffusion, and improves the catalytic activity. For example, monodisperse nano-palladium (Pd) aqueous dispersion can be used as a quasi-homogeneous nano-catalyst for the reduction of nitrobenzene. The reduction of nitrobenzene is an important catalytic reaction process, and its product aniline is widely used as raw materials or intermediates for the manufacture of fine chemicals. The catalytic activity of the prepared quasi-homogeneous nano-catalyst is more than 30% higher than that of the heterogeneous catalyst reported in the literature, and the reaction time can be shortened by more than half.

Figure 1. Proposed reaction pathway for coupling of nitroaromatic compounds.

• Nanocomposites: Metal nanodispersion can be used to prepare conductive and adsorbing nanocomposites due to its own characteristics. For example, The conductive transparent nanocomposites prepared from nano-Ag particle dispersion and nano-Ag wire dispersion have good light transmittance and electrical conductivity. The sodium tungsten bronze nanosphere dispersion has a high specific surface area and excellent adsorption performance, and can be used in wastewater treatment.

Figure 2. Schematic diagram of the synthesis of a tungsten bronze nanoparticle.

In addition, metal nanodispersions are expected to play a more important role in petrochemical, fine chemical, aerospace, energy environment, flexible wearable devices and other application fields.

Production:

The preparation of metal nanodispersion can be divided into physical dispersion method (such as emulsification-solvent volatilization method, etc.) and chemical reaction method (such as polymerization method). The dispersion principle is mainly divided into the following categories: (1) Enhance the repulsive energy between metal nanoparticles. (2) Strengthen the wettability of the nanoparticle surface to the dispersion medium and change its interface structure. (3) Improve the strength and thickness of the solvated film and enhance the solvent repelling effect. (4) Increase the absolute value of the potential of the electric double layer on the surface of the nanoparticles, and enhance the electrostatic repulsion between the nanoparticles. (5) Adsorbed on the surface of nanoparticles by polymer dispersant to produce and strengthen the three-dimensional protection.

References

1. Sunari Peiris. (2017) "Silver and palladium alloy nanoparticle catalysts: reductive coupling of nitrobenzene through light irradiation." Dalton Trans. 46: 10665-10672.
2. JaehyukChoi. (2015) "Preparation of quaternary tungsten bronze nanoparticles by a thermal decomposition of ammonium metatungstate with oleylamine." Chemical Engineering Journal. 281(1): 236-242.