Neutron scattering analysis reveals the lamellar
structure of a hydrogen-producing, biohybrid composite material
formed by the self-assembly of naturally occurring, light
harvesting proteins with polymers
One of the biggest problems with the move towards a
hydrogen economy is currently the production of hydrogen
fuel takes a lot of energy, which generally comes from burning
fossil fuels. For hydrogen vehicles to make sense, cleaner more
efficient hydrogen production methods will need to be developed.
One promising approach takes its lead from the natural processes
of photosynthesis in order to
convert sunlight into hydrogen fuel. The latest breakthrough
in this quest comes from Oak Ridge National Laboratory (ORNL)
where scientists have taken an important step towards
understanding the design principles that promote self-assembly
in natural photosynthetic systems.
ORNL researchers have demonstrated a biohybrid
photoconversion system based on the interaction of
photosynthetic plant proteins with synthetic polymers.
Using small-angle neutron scattering analysis, they showed
that light harvesting complex II (LHC-II) proteins can
self-assemble with polymers into a synthetic membrane structure
and produce hydrogen.
It is this ability of LHC-II to maintain the structure of the
photosynthetic membrane that's significant to the development of
biohybrid photoconversion systems. These would consist of high
surface area, light-collecting panes that use the proteins
combined with a catalyst such as platinum to convert the
sunlight into hydrogen, which could be used for fuel.
Although the primary role of the LHC-II protein in plants is
as a solar collector, absorbing sunlight and transferring it to
the photosynthetic reaction centers to maximize their output,
the researchers showed that LHC-II can also carry out electron
transfer reactions.
"Making a, self-repairing synthetic photoconversion system is
a pretty tall order. The ability to control structure and order
in these materials for self-repair is of interest because, as
the system degrades, it loses its effectiveness," ORNL
researcher Hugh O'Neill, of the lab's Center for Structural
Molecular Biology, said.
"This is the first example of a protein altering the phase
behavior of a synthetic polymer that we have found in the
literature. This finding could be exploited for the introduction
of self-repair mechanisms in future solar conversion systems,"
he said.
The
ORNL team’s study is published in the journal
Energy & Environmental Science.
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