Photosynthesis without cells: Turning light into fuel

(Nanowerk News) An entirely human-made architecture that converts light into fuel was built at the Center for Nanoscale Materials. This architecture combines tiny, nano-sized and artificial biological structures. It uses water and sunlight to pump out hydrogen without need of high heat or pressure (ACS Nano, "Cell-free synthetic biology chassis for nanocatalytic photon-to-hydrogen conversion").
his schematic image shows the assembly of synthetic membrane proton pump (ribbon structure) with semiconductor nanoparticles (silver spheres) that produce hydrogen under white light illumination
This schematic image shows the assembly of synthetic membrane proton pump (ribbon structure) with semiconductor nanoparticles (silver spheres) that produce hydrogen (H2) under white light illumination. (Image: Center for Nanoscale Materials)
Plants and other natural systems use energy to move protons across a cell membrane. The motion turns light energy into a cellular “fuel.” The elegance of this process inspires scientists to mimic it for new human-made materials and processes.
A human-made “proton pump” was built. It was then integrated with a tiny embedded titanium and platinum catalyst. The two parts work together to produce hydrogen under illumination. This structure could have practical uses in energy storage, catalysis, and artificial life systems.
At Argonne National Laboratory’s Center for Nanoscale Materials, a U.S. Department of Energy user facility, researchers employed artificial nanodisc membrane technology to develop a structure for converting light into hydrogen. The small nanodisc membranes assist the study of proteins structure.
In this case, the researchers sought to mimic nature’s proton pump machinery. The resulting proton pump was synthetically engineered cell-free, using nanodiscs as a membrane template to facilitate non-biological protein synthesis.
The team then integrated the nanodisc-protein structure with nanoclusters of a titanium oxide semiconductor and tiny dots of platinum co-catalyst (TiO2/Pt). In this form, titanium oxide is a strong conductor for chemical reactions involving light. Once this bioarchitecture was developed, a near constant transformation of light into hydrogen ensued for at least 2 to 3 hours.
This research could have practical applications in energy storage, catalysis, and artificial life systems.
Source: U.S. Department of Energy (DOE), Office of Science
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