Sunlight-to-hydrogen system demonstrated

Researchers at the Department of Energy’s Oak Ridge National Laboratory have successfully demonstrated a biohybrid photoconversion system that can convert visible light into hydrogen fuel.

Using small-angle neutron scattering analysis, they’ve confirmed that light-harvesting complex II (LHC-II) proteins can self-assemble with polymers into a synthetic membrane structure and produce hydrogen.

It’s another step towards photoconversion systems that generate hydrogen fuel through a similar process to photosynthesis.

“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,” said ORNL researcher Hugh O’Neill.

“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.

Small angle neutron scattering analysis showed that the LHC-II, when introduced into a liquid environment containing polymers, interacted with them to form lamellar sheets similar to those found in natural photosynthetic membranes.

And this ability to generate an ordered, layered state, instead of an ineffective mush, could lead to biohybrid photoconversion systems. These would consist of high surface area, light-collecting panes rather like solar panels. They would use the proteins combined with a catalyst such as platinum to convert the sunlight into hydrogen fuel.

The protein for the experiment was derived from spinach, processed to separate the LHC-II proteins. Eventually, says the team, the protein could be synthetically produced and optimized to respond to light.