ORNL demonstrates photosynthetic hydrogen production

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.