Materials

New five-metal alloy makes for 2D catalyst to convert CO2 into fuels

New five-metal alloy makes for...
Researchers have combined five metals into an alloy, and found that 2D sheets of it perform well as a catalyst
Researchers have combined five metals into an alloy, and found that 2D sheets of it perform well as a catalyst
View 2 Images
Researchers have combined five metals into an alloy, and found that 2D sheets of it perform well as a catalyst
1/2
Researchers have combined five metals into an alloy, and found that 2D sheets of it perform well as a catalyst
An electron microscope image of a flake of the new alloy (top center), and a section showing its atomic structure (lower center) – the elements used to make it up are shown around the edges
2/2
An electron microscope image of a flake of the new alloy (top center), and a section showing its atomic structure (lower center) – the elements used to make it up are shown around the edges

Researchers have created an unusual new alloy made up of not two, but five different metals, and put it to work as a catalyst. The new material is two-dimensional, and was able to convert carbon dioxide into carbon monoxide effectively, potentially helping to turn the greenhouse gas into fuels.

The new alloy belongs to a class of materials called transition metal dichalcogenides (TMDCs), which are, as the name suggests, made up of combinations of transition metals and chalcogens. Extremely thin films of TMDCs have recently shown promise in a range of electronic and optical devices, but researchers on the new study wondered if they could also be used as catalysts for chemical reactions.

The thinking goes that because reactions occur on the surface of a catalyst, materials with high surface areas will be more effective catalysts. And as sheets only a few atoms thick, TMDCs are almost nothing but surface area.

The team created computer models to sort through all the possible combinations of transition metals and chalcogens, and determine which ones would make the most effective catalysts. Eventually, they settled on one that contained an astonishing five transition metals – molybdenum, tungsten, vanadium, niobium and tantalum – along with sulfur as the chalcogen.

“The question was, ‘Could we even synthesize a TMDC alloy that had that many components?’” says John Cavin, an author of the study. “And will they improve the reduction of CO2 into CO?”

An electron microscope image of a flake of the new alloy (top center), and a section showing its atomic structure (lower center) – the elements used to make it up are shown around the edges
An electron microscope image of a flake of the new alloy (top center), and a section showing its atomic structure (lower center) – the elements used to make it up are shown around the edges

After picking the most promising candidate, the team then sent the data off to collaborators at the University of Illinois to synthesize the alloy. Not only was that successful, but in tests the material worked well at converting carbon dioxide into carbon monoxide, with a turnover frequency of 58.3 per second.

That means they could be useful for recycling the greenhouse gas into useable hydrocarbon fuels. The team says that this new alloy, as well as four others that showed some promise as catalysts, could have other uses that haven’t been explored yet.

“These are new materials, they have never before been synthesized,” says Rohan Mishra, lead author of the study. “They may have unanticipated properties.”

The research was published in the journal Advanced Materials.

Source: Washington University in St. Louis

9 comments
9 comments
anthony88
Can you explain how CO is used as a fuel?
Catweazle
By Combustion.
2CO + O2 = 2CO2 + 283 kJ/mol
Simon McCombe
Carbon monoxide is flammable but I’m guessing that it is much more reactive than carbon dioxide and they would use other reactions to build it into more complex hydrocarbons using much less energy than if they were to do it starting from CO2.
Expanded Viewpoint
Well, Carbon is used as a fuel, like in coke in a steel mill, or a less pure form like charcoal in your barbecue, so if you just add in some more Oxygen, you'd get CO2, but then you're right back to your old starting point again!! So I really don't see the big upside here. You're not going to get a perpetual motion chemical reaction system going on, where a waste product is turned back into a feed stock to be immediately turned back into a waste product again ad infinitum.

Randy
Douglas Rogers
What is meant by 58.3/sec. ?
Worzel
As CO2 is the basis for all present life on this planet, I cannot think of anything more stupid, than turning it into fuel!
This is especially so that there is ample other sources of fuel.
Karmudjun
Douglas Rogers, the 58.3 is a quite ambiguous number indicating that CO2 was converted to CO in their sample size of X mm, 58.3 times per second. Other parameters usually quantified are the actual 2D reaction space like 1 mm 2 or 10 mm2 (100 sq mm), and the concentration of CO2 in the starting solution. None of that is listed and I don't have access to the source article at the moment. But a very good question.
Worzel, you may not understand that mammalian life is NOT based on CO2, an extremely toxic poison for all mammals and many reptiles too, but plant life - which produces the amino acids necessary for the development of mammalian life forms does depend on CO2. By driving the toxic CO2 levels down when the Earth was lush and steamy, the plant life provided a significant plant poison (O2) that gave rise to mitochondrial cells which our mammalian cells integrated into the cell lines.
But keep thinking CO2 is great for "All Life".
jerryd
Since other simple catalysts directly make HCs from CO2, water and power now, this is rather lame.
Techrex
Does this TMDC sheet also conduct electricity or electromagnetism? If so, perhaps by tweaking this experiment with those factors, we can increase its CO2 conversion ratio even more!