The non loaded 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

At present, precious metal nanomaterials are almost applied in all industries, and the precious metals used are usually products that have undergone deep processing. The deep processing of precious metals refers to the process of transforming the physical or chemical form of precious metal elements or compounds through a series of processing steps, resulting in more valuable precious metal products. Nowadays, by combining with nanotechnology, the scope of deep processing of precious metals has been expanded, and many new products of deep processing of precious metals have emerged as a result.

Family photos of precious metals (gold, silver, platinum, palladium, ruthenium, rhodium, osmium, and iridium) and their relatives (rhenium, copper, mercury)

Precious metal nanomaterialsIt includes several major types, such as noble metal single substance and compound nano powder materials, new noble metal macromolecular nano materials and noble metal membrane materials. Among them, the single substance and compound nano powder materials of precious metals can be divided into two types: loaded and unloaded, which are the most widely used precious metal nano materials in industry.

1、 Precious metal simple substance and compound nanometer powder materials

1. Non loaded powder

There are two types of nanometer powders, including silver, gold, palladium, platinum and other noble metal elements, and silver oxide and other noble metal compounds. Due to the strong surface interaction energy of nanoparticles, they are easily agglomerated. Usually, during the preparation process or after obtaining the powder product, a certain protective agent (with dispersing effect) is used to coat the surface of the particles.

In terms of application:

The non loaded precious metal nanoparticles that have been industrialized and applied in industry mainly includeNano silver powder, nano gold powder, nano platinum powder, and nano silver oxideWait. Nano gold powder has long been used as a coloring agent for Venetian glass and colored glass, and gauze containing nano silver powder can be used for the treatment of burn patients. At present, nano silver powder can replace ultrafine silver powder in conductive slurries, reducing the amount of silver used and lowering costs; When nano metal particles are used as coloring agents in paint, the exceptionally bright coating makes it have great potential for applications in luxury cars and other high-end decorations.

In addition, the slurry made of precious metal colloids has a higher cost performance ratio, stable product quality, and can be used to develop new generation high-performance electronic products. At the same time, precious metal colloids themselves can also be directly used in electronic circuit manufacturing and electronic packaging technology. For example, precious metal Pd colloids can be made into toner fluids for electronic circuit manufacturing and gold plating on handicrafts.

2. Load type powder

Precious metal loaded nanomaterials usually refer to composite materials obtained by loading nanoparticles of precious metals and their compounds onto a certain porous carrier, and some people also classify it as precious metal composite materials. It has two major advantages:

① It can obtain very dispersed and uniform nanometer powder materials of noble metal simple substances and compounds, effectively preventing agglomeration between noble metal nanoparticles;

② The production process is simpler than non load type, and the technical indicators are easy to control.

The supported precious metal powders currently produced and applied in industry include Ag, Au, Pt, Pd, Rh, and alloy nanoparticles formed between them and some base metals.

In terms of application:

At present, loaded precious metal nanomaterials are mainly used as catalysts. Due to the small size and large specific surface area of noble metal nanoparticles, the bond states and coordination of surface atoms differ greatly from those of internal atoms, resulting in a significant increase in the active sites on the surface of noble metal particles and meeting the basic conditions for use as catalysts. In addition, the unique chemical stability of precious metals gives them unique catalytic stability, catalytic activity, and regenerability after being made into catalysts.

At present, various efficient nanoscale precious metal catalysts have been developed for application in the chemical synthesis industry. For example, the colloidal Pt catalyst supported on zeolitic-1 is used to convert alkanes into petroleum, the colloidal Ru supported on carbon can be used for ammonia synthesis, and the Pt100 xAux colloid can be used for n-butane hydrogenation and isomerization. Precious metal (especially Pt) nanomaterials play a crucial role as catalysts in the commercialization of fuel cells: due to the excellent catalytic performance of 1-10nm Pt particles, using nano-sized Pt to make fuel cell catalysts not only improves catalytic performance, but also reduces the amount of precious metals used, resulting in a significant reduction in preparation costs.

In addition, nanoscale precious metals will also play a key role in the development of hydrogen energy. Using nanoscale precious metal catalysts to decompose water for hydrogen productionPrecious metal nanomaterialsOne direction of development is that there are currently multiple ways to catalyze hydrogen production using noble metal nanomaterials, such as colloidal Ir being an active catalyst for water reduction hydrogen production.

2、 New atomic clusters of precious metals

The Schiffrin reaction can be used to prepare atomic clusters of Au, Ag, and their alloys protected with alkyl thiols, such as Au/Ag, Au/Cu, Au/Ag/Cu, Au/Pt, Au/Pd, and Au/Ag/Cu/Pd. The mass number of clusters is very single and can achieve "molecular" purity. The stable properties allow them to dissolve and precipitate repeatedly like ordinary molecules without aggregation, and can also undergo reactions such as exchange, coupling, and polymerization to form crystals with atomic clusters as structural elements. Therefore, this type of atomic cluster is referred to as monolayer protected cluster molecules (MPC).

In terms of application, it has been found that gold nanoparticles with a wavelength of 3-40 nm can be used for staining inside cells, improving the resolution of observing internal tissues, which is of great significance for the study of cell biology.

3、 Precious metal film material

Precious metals have stable chemical properties and are not easily reactive with the surrounding environment. They are often used to make surface coatings and porous membranes. In addition to general decorative coatings, in recent years, gold-plated glass has been used as wall curtains to reflect thermal radiation and reduce energy consumption. The Royal Bank of Canada building in Toronto has installed gold-plated reflective glass, which consumes 77.77 kg of gold.