At present, precious metal nano materials are used in almost all industries, and these precious metals are usually deeply processed products. The so-called deep processing of precious metals refers to the process of changing the physical or chemical form of precious metals or compounds through a series of processing processes to become more valuable precious metal products. Now through the combination with nanotechnology, the scope of precious metal deep processing has been expanded, and many new precious metal deep processing products have also been introduced.
Nano precious metal materials include several types of noble metal simple substance and compound nanopowder materials, noble metal new macromolecular nanomaterials and noble metal film materials. Among them, the elemental and compound nano powder materials of noble metals can be divided into two types: supported and non-supported, which are the most widely used precious metal nanomaterials in industry.
1. Nanopowder materials of noble metals and compounds
1.1. Non-supported powder
There are two types of nanopowders of noble metals such as silver(Ag), gold(Au), palladium(Pd) and platinum(Pt), and nanoparticles of noble metal compounds such as silver oxide. Due to the strong surface interaction energy of nanoparticles, it is easy to agglomerate between nanoparticles. Usually, a certain protective agent (with dispersing effect) is used to coat the surface of the particles during the preparation process or after the powder product is obtained.
Application:
At present, the unsupported precious metal nanoparticles that have been industrialized and applied in industry mainly include nano silver powder, nano gold powder, nano platinum powder and nano silver oxide. Nano gold particle as a colorant has long been used in Venetian glass and stained glass, and gauze containing nano silver powder can be used for the treatment of burn patients. At present, nano silver powder can replace ultra-fine silver powders in conductive paste, which can reduce the amount of silver and reduce costs; when nano metal particles are used as colorants in paint, the exceptionally bright coating makes it suitable for luxury cars and other high-end decorations. It has huge application potential.
In addition, the slurry made of precious metal colloid has a higher performance-price ratio and stable product quality, and can be used to develop a new generation of high-performance electronic products. At the same time, the precious metal colloid itself can also be directly used in electronic circuit manufacturing and electronic packaging technology, such as precious metal Pd colloids can be made into toner fluids for electronic circuit manufacturing and handicraft gold plating.
1.2. Supported powders
The supported nano materials of noble metals usually refer to the composites obtained by loading the nanoparticles of noble metals and their compounds on a certain porous carrier, and some people also classify them as noble metal composites. It has two major advantages:
① Nano powder materials of very dispersed and uniform noble metal elements and compounds can be obtained, which can effectively prevent the agglomeration of noble metal nanoparticles;
②The production process is simpler than the non-supported type, and the technical indicators are easy to control.
The supported noble metal powders that have been produced and used in industry include Ag, Au, Pt, Pd, Rh and alloy nanoparticles formed between them and some base metals.
Application:
Currently supported noble metal nanomaterials are mainly used as catalysts. Due to the small size and large specific surface area of noble metal nanoparticles, the bonding state and coordination of surface atoms are very different from those in the internal atoms, so that the active sites on the surface of noble metal particles are greatly increased, and they have the basic conditions as catalysts. In addition, the unique chemical stability of precious metals makes them have unique catalytic stability, catalytic activity and regeneration after being made into catalysts.
At present, a variety of high-efficiency nano-scale precious metal catalysts for application in chemical synthesis industry have been developed. For example, colloidal Pt catalyst supported on zeolite-1 is used to convert alkanes into petroleum, colloidal Ru supported on carbon can be used for ammonia synthesis, Pt100 -xAux colloids can be used for n-butane hydrogenolysis and isomerization. Precious metal (especially Pt) nanomaterials as catalysts also play a crucial role in the commercialization of fuel cells: due to the excellent catalytic performance of 1-10 nm Pt particles, nano-scale Pt is used to make fuel cell catalysts, not only catalytic performance. It is improved, and the amount of precious metals can be reduced, so that the preparation cost can be greatly reduced.
In addition, nano-scale precious metals will also play a key role in the development of hydrogen energy. The use of nano-scale noble metal catalysts to split water to produce hydrogen is a direction of the development of noble metal nanomaterials. There are many ways to use noble metal nanomaterials to catalyze hydrogen production. For example, colloidal Ir is an active catalyst for water reduction to hydrogen production.
2. Novel clusters of noble metals
Using the Schiffrin reaction, Au, Ag and their alloys protected with alkyl thiol can be prepared, such as Au/Ag, Au/Cu, Au/Ag/Cu, Au/Pt, Au/Pd and atomic clusters of Au/Ag/Cu/Pd etc. The mass number of the cluster complex is very single and can achieve “molecular” purity. The stable nature allows them to be repeatedly dissolved and precipitated like ordinary molecules without agglomeration, and can also undergo reactions such as exchange, coupling and polymerization, and form crystals with atomic clusters as structural units. Therefore, such atomic clusters are called monolayer protected cluster molecules (MPC).
Application: It has been found that gold nanoparticles with a size of 3-40 nm can be used for internal staining of cells and improve the resolution of internal tissue observation of cells, which is of great significance to the research of cell biology.
3. Precious metal film materials
Precious metals have stable chemical properties and are not easy to react with the surrounding environment, and are often used to make surface coatings and porous films. In addition to the general decorative coating, in recent years, gold-plated glass has appeared as a wall curtain to reflect heat radiation and reduce energy consumption. For example, the Royal Bank of Canada Building in Toronto has installed gold-plated reflective glass, using 77.77 kg of gold.
Hongwu Nano is a professional manufacturer of nano precious metal particles, which can supply elemental nano precious metal particles, precious metal oxide nanoparticles, shell-core nanoparticles containing precious metals and their dispersions in batches. Welcome to contact us for further info!