Scientists break staggering platinum melting point record

(ORDO NEWS) — Scientists have figured out how to make platinum more accessible as a catalyst: turn it into a low-temperature liquid.

Noble metals such as platinum, gold, ruthenium, and palladium have been known for centuries to be excellent catalysts for chemical reactions, as they help break chemical bonds between atoms more efficiently than other metals.

But precious metals are rare and expensive, so large industrial manufacturers typically opt for cheaper and less efficient alternatives such as iron. (Iron is used as a catalyst, for example, in the mass production of fertilizers.)

The disadvantage of using lower quality catalysts is that the chemical reactions must be heated to high temperatures, which increases the carbon footprint of many industrial processes.

Researchers at the University of New South Wales in Sydney and RMIT in Australia have achieved the record breaking achievement of dissolving platinum in liquid gallium by splitting the platinum atoms in such a way that less platinum has more catalytic potential.

Platinum typically has a melting point of 1700°C (3092 Fahrenheit), which means that when used as a catalyst, it is usually in the solid state.

By pouring platinum into a matrix of gallium, it assumes the melting point of gallium, a soft, silvery and non-toxic metal that melts mostly at room temperature of 29.8°C.

One of the useful characteristics of liquid gallium is that it dissolves metals (similar to how water dissolves salt and sugar) by separating individual atoms in each molecule.

The invention can reduce energy costs and reduce industrial emissions. production, the researchers say.

“A number of important chemical reactions can be carried out at a relatively low temperature using a more efficient catalyst such as liquid platinum,” lead author and chemical engineer Dr. Arifur Rahim from the University of New South Wales in Sydney told ScienceAlert.

Scientists have been trying to make expensive noble metal catalysts more affordable through a “miniaturization” process since 2011,” Rakhim explains.

When metals are solid, only the atoms on the outside can be used in reactions, so there is a lot of waste. If you break this solid into smaller and smaller clumps (think nanoparticles), you get a more efficient reaction as more metal atoms can enter the muscles – many hands make the job easier.

The most efficient and smallest system will make every single atom available to do the work of the catalyst.

“When you miniaturize a system, you maximize the surface-to-surface ratio. volumetric ratio and atom efficiency so that overall catalyst consumption decreases over time and this can make your product affordable,” Rahim says.

“Theoretically, you get the maximum efficiency of this catalytic metal when it’s at the atomic scale, because you can’t go beyond it.”

In single atom catalysts, the bonds holding the catalyst together are cleaved and each atom is individually anchored in a substance called a matrix.

So, Rahim and his colleagues tested gallium as a matrix. After being dissolved in gallium, they found that every platinum atom separates from every other platinum atom, making it an ideal miniature catalyst.

“When dissolved, platinum atoms are spatially dispersed in the liquid matrix of gallium without clustering of atoms. (i.e., the absence of a platinum-platinum bond) that can trigger various catalytic reactions with appreciable mass activity, ”the researchers write in their article.

Platinum is mobile when in a liquid matrix and is much less prone to coking when solid catalysts are coated with carbon and must be cleaned before reuse.

Gallium is not as cheap as iron. But it can be used over and over for the same reactions. This is because, like platinum, gallium is not deactivated or decomposed during the reaction.

The process of dissolving platinum in gallium requires an increase in temperature to about 400 °C for several hours. But the researchers say it’s a one-time energy investment that prevents further temperature spikes in the chemical production process, the researchers say.

The team hopes their method will lead to cleaner, cheaper products, from fertilizers to organic products. fuel elements.


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