On Thu, 2/27/2025 11:54 AM, Tim Streater wrote:

On 27 Feb 2025 at 16:32:37 GMT, "Tim Streater" <[email protected]> wrote:

On 27 Feb 2025 at 13:59:46 GMT, "Jeff Layman" <[email protected]d> wrote: >>

On 27/02/2025 12:36, Theo wrote:

The Natural Philosopher <[email protected]d> wrote:

On 27/02/2025 11:16, Jethro_uk wrote:

https://eastangliabylines.co.uk/science/sunlight-to-fuel-cambridges-new- >>>>>> breakthrough-in-clean-energy/

Why not use plants instead?

Plants take a lot of effort and inputs (land, fertiliser, water) to grow. >>>> Then you need to process them into something useful.

Being able to skip those steps has a lot of advantages. At the end of the >>>> day it's all about efficiency numbers - remains to be seen how far this >>>> could go in efficiency terms, and whether there are cases where it would >>>> make sense where you don't have those inputs.

The paper is here:
https://www.nature.com/articles/s41560-025-01714-y

I seem to be misunderstanding something in that article. Syngas is a
mixture of carbon monoxide and hydrogen. Where does the hydrogen come
from? Fig.1a shows just air entering the reaction chamber. There is no
mention of hydrogen at all (no green dots).

Fig1.b shows Air/N2 entering the reaction chamber. The "CO2U Unit"
(light red) is shown as containing hydrogen as it has green dots. Where
does that hydrogen come from? In Fig1.a the "CO2U Unit" is not shown as
containing any hydrogen.

Fig.1d has a reaction at the top:
CO2 + 2H+ --> CO + H2 (H2O)
What does the 2H+ signify on the LHS of the equation? What does the H2O
in brackets mean?

Well I dunno for sure. But the reaction seems to be taking place over a
substrate of glycolaldehyde (HOCH2−CHO) and other substances. Perhaps with an
input on sunlght (UV?) it catalyses the breakdown of the glycolaldehyde:

HOCH2−CHO -> 2CO + 2H2

but I'm just guessing. Do we have a real chemical engineer on the strength?

OK - belay that. The actual substrate seems to be mineral only, no organics. The glycolaldehyde and the formate appear to be outputs, not inputs.

I can suggest this much.

It's a Redox reaction.

There are two equations, one is a reduction, one is an oxidation.

The PET and Ethylene Glycol is an attempt to clean up an industrial
pollutant, via using it as part of a half reaction. The "value added chemical" notion, is the outputs are somehow easier to deal with. The glycol aldehyde dimer
is supposed to be a simple sugar.

In normal chemistry notation, one of the reactions
contributes something to the other reaction.

But attempts to get anything to balance, to have a net H2 output
for the Syngas, haven't worked out for me. Normally, you would
need some H2 to make a Syngas, but there is no source of gaseous H2
in the chamber.

The next stage after the making of Syngas, might be
something like this. This could make longer chain hydrocarbons
which are easier to store on site. Perhaps in a liquid form.
The industrial version of this, needs energy input. Looking
for a photochemsitry version, is to harvest the energy from the Sun.

"Photo-driven Fischer–Tropsch"

https://pubs.rsc.org/en/content/articlelanding/2020/ta/d0ta09097b

After reading several papers today, my conclusion is that everyone
is sloppy when writing these papers.

Paul

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On Thu, 2/27/2025 1:30 PM, Jeff Layman wrote:

On 27/02/2025 16:54, Tim Streater wrote:

On 27 Feb 2025 at 16:32:37 GMT, "Tim Streater" <[email protected]> wrote: >>

On 27 Feb 2025 at 13:59:46 GMT, "Jeff Layman" <[email protected]d> wrote: >>>

On 27/02/2025 12:36, Theo wrote:

The Natural Philosopher <[email protected]d> wrote:

On 27/02/2025 11:16, Jethro_uk wrote:

https://eastangliabylines.co.uk/science/sunlight-to-fuel-cambridges-new-
breakthrough-in-clean-energy/

Why not use plants instead?

Plants take a lot of effort and inputs (land, fertiliser, water) to grow. >>>>> Then you need to process them into something useful.

Being able to skip those steps has a lot of advantages. At the end of the >>>>> day it's all about efficiency numbers - remains to be seen how far this >>>>> could go in efficiency terms, and whether there are cases where it would >>>>> make sense where you don't have those inputs.

The paper is here:
https://www.nature.com/articles/s41560-025-01714-y

I seem to be misunderstanding something in that article. Syngas is a
mixture of carbon monoxide and hydrogen. Where does the hydrogen come
from? Fig.1a shows just air entering the reaction chamber. There is no >>>> mention of hydrogen at all (no green dots).

Fig1.b shows Air/N2 entering the reaction chamber. The "CO2U Unit"
(light red) is shown as containing hydrogen as it has green dots. Where >>>> does that hydrogen come from? In Fig1.a the "CO2U Unit" is not shown as >>>> containing any hydrogen.

Fig.1d has a reaction at the top:
CO2 + 2H+  -->  CO + H2 (H2O)
What does the 2H+ signify on the LHS of the equation? What does the H2O >>>> in brackets mean?

Well I dunno for sure. But the reaction seems to be taking place over a
substrate of glycolaldehyde (HOCH2−CHO) and other substances. Perhaps with an
input on sunlght (UV?) it catalyses the breakdown of the glycolaldehyde: >>>
   HOCH2−CHO -> 2CO + 2H2

but I'm just guessing. Do we have a real chemical engineer on the strength? >>

OK - belay that. The actual substrate seems to be mineral only, no organics. >> The glycolaldehyde and the formate appear to be outputs, not inputs.

Indeed. Even if the glycolaldehyde was an input, where does it come from? Its synthesis, according to the wiki, is from glycol and H2O2. And that just pushes the "hydrogen" question further down the line! There is the possibility of biosynthesis, and

that's mentioned in the wiki.

Paul's reply downthread has an interesting ref at <https://www.cam.ac.uk/research/news/artificial-leaf-successfully-produces-clean-gas>. That 2019 report mentions the use of sunlight, carbon dioxide and *water* (hooray - a source of hydrogen!) to make

syngas. The original paper (in Nature Materials) which is referenced in that report isn't mentioned in the Nature Energy paper we've been discussing. Shrug...


I can see the "green-ness" of their electron donor half reaction source material (basically it is the recycling of PET plastic). They apparently
used other electron donors of lower complexity as well. Having decided to
make a virtue of that feature of their scheme, they should have written
up the two half reactions in standard form, for the layman to enjoy.

If the H is coming from water, show it.

If the H is coming from the PET, show it.

The important part of this paper, is the cat. Not
the part about grinding up used cola bottles to make
PET for recycling.

The PET + ethylene glycol they use as inputs, these
are also materials found in the reaction vessel of
the plant that made the PET in the first place. These
are materials included as part of a reversible reaction
to "unmake" the PET again. That is why those particular
materials are selected. EG is an input into making PET,
and having some leftovers of it when making PET, would be
part of the output mixture. And then this gadget is
reversing the reaction.

Paul

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On 28 Feb 2025 at 11:02:32 GMT, "Jeff Layman" <[email protected]d> wrote:

According to that section the efficiency is 60%, and the methanol and
THF are recovered by vacuum distillation, as is the ethylene glycol. But that's still a lot of energy required. And I wonder what the efficiency
would be on an industrial scale. It's amazing how things don't scale up
or down the way they do in the lab!

This, of course, is the $64 trillion question.

--
Tim

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Jeff Layman <[email protected]d> wrote:

According to that section the efficiency is 60%, and the methanol and
THF are recovered by vacuum distillation, as is the ethylene glycol. But that's still a lot of energy required. And I wonder what the efficiency
would be on an industrial scale. It's amazing how things don't scale up
or down the way they do in the lab!

Is this the new “cold fusion”, its main function being to separate gullible investors from their money?

Tim


--
Please don't feed the trolls

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On Fri, 2/28/2025 12:25 PM, Tim+ wrote:

Jeff Layman <[email protected]d> wrote:

According to that section the efficiency is 60%, and the methanol and
THF are recovered by vacuum distillation, as is the ethylene glycol. But
that's still a lot of energy required. And I wonder what the efficiency
would be on an industrial scale. It's amazing how things don't scale up
or down the way they do in the lab!

Is this the new “cold fusion”, its main function being to separate gullible
investors from their money?

Tim

Personal opinion, if this was a game of poker, they're overplaying their hand.

I think the paper makes perfect sense, if they had placed a "dummy" counter-reaction
in the picture, and had something innocuous used there. This would not distract from the value of the paper, which is the catalyst design. Other scientists using their materials, or citing them, will be citing them for the catalyst.

They could have put a couple lines in their "for future work" section,
a thing about PET recycling being a possible counter reaction, assuming
ways and means are available to prepare the substance at low cost. Leaving
it as a challenge to other scientists to think up a digestive method.
Playing out their own digestive method, in the middle of a paper with
a limited page count, that's cheeky. I realize you get extra points
for making "an entire black box" as a solution, but that's not how
we beat CO2. CO2 is a collaborative effort. It will require the
best bits and pieces from a number of publications (because of course
there would be resistance to any large scale deployment, and every
amateur scientist alive would have rude things to say about the details).
when it is deployed in multiple countries, some of the starting materials
may not be available, and so substitute donor reactions may be needed.

We've already seen some tiny "test installs" for CO2 handling, and
already there is a lot of laughter. There is much more to this
than just lab work, there is public perception to deal with.

Paul

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