Hydrogen is the most abundant element in
the universe. Produced through the splitting of
water molecules, the shift towards renewable
energy has led to a rise in so-called 'green
hydrogen'.
Hydrogen is a clean and useful energy store
and can be used as a fuel, to generate
electricity and can be stored and transported
via the gas networks.
All processes - be they chemical, mechanical
or electrical - are thermodynamically irreversible,
and are less efficient that they otherwise
could be.
This means that in traditional chemical reactors
when hydrogen is produced it needs to be
separated from other products, a process
which is both costly and often energy
intensive.
Describing their new system, the team
demonstrate a chemical reactor capable for
the first time of approaching thermodynamically
reversible operation.
Reacting water and carbon monoxide to
generate hydrogen and carbon dioxide, the
system also prevents carbon being carried
into the hydrogen produce stream as carbon
monoxide or carbon dioxide, thus avoiding
contamination of the product.
'Flipping' the reservoir a bit like a switch,
the team showed it is possible to reach high
conversion in the system so that carbon
dioxide and hydrogen are produced at either
end of the reactor as pure products.
"Whereas conventional hydrogen production
requires two reactors and a separation, our
reactor accomplishes all the steps in one unit,"
adds Professor Metcalfe.
"And while we demonstrate the concept with
hydrogen, the memory reactor concept may
also be applied to other processes."
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