'Frozen' copper behaves as noble metal in catalysis: study

December 21, 2018, Chinese Academy of Sciences
Unique electron configuration of the 29th element Cu was excited by high energy plasma, resulting in the variation of its chemical property. Credit: SUN Jian and YU Jiafeng

As a non-noble metal, copper oxidizes more easily to a positive valence (Cu+ or Cu2+) than same-family elements Au or Ag. In general, this chemical property is mainly determined by electron structure. Can we change the chemical properties of an element by regulating its electron structure? Can Cu act as a noble metal in catalytic reactions?

A team led by Dr. Sun Jian of the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) gives a positive answer. The team's recently published paper in Science Advances shows that the electron structure of Cu can be changed, assisted by high energy plasma, making Cu exhibit significantly different catalytic behaviors than normal Cu in selective reactions.

The dimethyl oxalate (DMO) hydrogenation , a typical multistep catalytic reaction producing methyl glycolate (MG), or ethanol, was selected as a probe reaction for copper. In this reaction, the common product over supported Cu/SiO2 catalysts is one of the latter two owing to the inevitable co-existence of Cu+ and Cu0 for deep hydrogenation.

The sputtered (SP) Cu, which is bombarded by high energy argon plasma, can be "frozen" at zero valence when exposed to oxidation or reaction atmosphere at a very wide range of temperature, presenting noble-metal-like behaviors.

In DMO hydrogenation, a high selectivity (87%) towards the preliminary hydrogenation product, MG, a high-value chemical, was observed. The molecule level free energy surface in various reaction pathways by DFT calculation also verifies that "frozen" Cu0 is crucial for preliminary hydrogenation.

Freezing Cu as a noble metal like catalyst with oxidization-resistance property facilitates the controlling of selective hydrogenation. This behavior is similar to a warrior with a solid armor resisting the attack on the battlefield. Credit: SUN Jian and YU Jiafeng

Explore further: Chemists turn metal catalysis on its head for a sustainable future

More information: "Freezing copper as a noble metal–like catalyst for preliminary hydrogenation" Science Advances (2018). DOI: 10.1126/sciadv.aau3275 , http://advances.sciencemag.org/content/4/12/eaau3275

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KBK
not rated yet Dec 21, 2018
Interestingly enough, the philosopher's stone, is from gold and is also known as 'the white powder of gold' and is supposedly oxidized nano powder that is superconductive.

There are also 'stones' of a similar nature made with the noble metals.

Oddly enough, copper is in that same group as made by the ancients and is also a 'white powder, oxidized cooper paired superconductive nanopowder.'

The actual method of making them is nothing short of nanopowder manufacturing. But with a very finely tuned cooper paired superconductive state as the final endpoint in the time consuming involved procedures. (over a month to make one batch)

What does modern science say about these 'fantasies'?

Not much it seems, but be it known, every day they get closer to room temperature superconductors is a day where they slowly prove the old works are exactly right and true.

Investigate and you just might find the future in superconductors from the explorers of the ancient past. Good luck...

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