Nanotechnology — or maybe chemistry — to make greenhouse gas into feedstock

It can be hard to tell whether a given piece of research is nanotechnology or “just” chemistry. In this case, I would’ve said the latter, but Nanoforum carried the story (free reg. reg’d), so it’s honorary nanotech at least. In any case, it could be important.

For years we at Foresight have theorized that nanotech would someday be able to pull excess CO2 out of the atmosphere to be used as a feedstock, thereby reducing greenhouses gases and providing a clean source of raw materials to industry. Chemical Technology is reporting that progress is being made toward that goal:

From greenhouse gas to feedstock

Turning carbon dioxide into a useful feedstock chemical could help to reduce levels of this greenhouse gas in the atmosphere, as well as providing a cheap source of carbon.

Now Japanese researchers have isolated the active form of a catalyst that turns CO2 into formic acid using water as a green solvent, a crucial step in developing this technology on an industrial scale.

Seiji Ogo from Kyushu University and co-workers had previously found that water-soluble ruthenium aqua complexes could catalyse the hydrogenation of CO2 without using large amounts of base, which are usually required for the reaction. Base stabilises the formic acid product against decomposition by forming unreactive sodium formate. ‘If CO2 hydrogenation could only be achieved in the presence of bases that would be a dead end,’ explained Ferenc Joo, Chair of the Institute of Physical Chemistry at the University of Debrecen, Hungary.

However, Ogo’s team could not isolate the active form of the ruthenium catalyst, thought to be a hydride complex. Using ruthenium, the slowest step of the reaction involves formation of the hydride complex, which is then rapidly used up to make formic acid.

So they switched to a water-soluble iridium complex, making the reaction of hydride with CO2 the rate-determining step. This means that the active hydride catalyst survives for much longer, allowing them to pin down the active catalyst at the heart of the reaction.

Ogo believes that ‘this work provides a valuable strategy to develop new catalytic systems for the hydrogenation of CO2.’

Whether it’s nanotech or chemistry, this seems to be a step in the right direction. Prof. Seiji Ogo is at the well-named Center for Future Chemistry. Here is his lab tour. Credit: Meridian. —Christine

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