Hydrogen From Water And Sun

There are research efforts around the world seeking ways to produce hydrogen starting from water and using clean energy.  Finding an economical and scalable way to do this is a key to the so-called hydrogen economy.



A recent study at Argonne National Laboratory makes use of a chemical
reaction pathway central to plant biology to create a process that converts
water into hydrogen using energy from the sun.




The process combines two membrane-bound protein complexes to perform
the conversion of water molecules into hydrogen and oxygen.




The first protein complex, which the researchers call Photosystem I,
is a membrane protein that uses energy from light to feed electrons to an
inorganic catalyst that makes hydrogen. 
But this represents only half of the overall process.




A second protein complex that they call Photosystem II uses energy
from light to split water and take electrons from it.  The electrons are then fed to Photosystem I.




The two protein complexes are embedded in thylakoid membranes, which
are like those found inside the oxygen-creating chloroplasts in plants.  This membrane is an essential part of pairing
the two photosystems.  It supports both
of the photosystems and provides a pathway for transferring electrons between
the proteins.




The researchers also make use of a synthetic catalyst made from nickel
or cobalt that replaces expensive platinum catalysts used in conventional
water-splitting schemes.  Combining the
light-triggered transport of electrons with the synthetic catalyst results in
what the researchers call the “Z-scheme”, an adaptation of photosynthesis to
produce hydrogen.




The next step is to incorporate the scheme into a living system which the researchers hope will lead to a practical system for hydrogen production.




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Discovery adapts natural membrane to make hydrogen fuel from water




Photo, posted December 25, 2017, courtesy of Flickr.




Earth Wise is a production of WAMC Northeast Public Radio.