Coupling Photosystem II with Nano-photocatalysts to achieve overall water splitting

The primary processes of photosynthesis in cyanobacteria, algae, and higher plants occur in thylakoid membranes. Light-induced oxidation of water and release of molecular oxygen are catalyzed by the PSII complex (a complex consisting of light-harvesting II (LHCII) and Reaction center II (RCII)), which is an H₂O plastoquinone oxidoreductase. The unique ability of PSII to split water molecules in the oxygen-evolving complex (OEC) evokes great interest for its potential use in the field of clean energy production (Pinhassi et. al 2016). Modern nanotechnology allows the synthesis of different kinds of Nano entities, such as semiconductor nanocrystals, can be engineered to absorb light in a broad optical range from ultraviolet to near-infrared, and plasmonic metal nano-catalysts are creating Localized Surface Plasmon Resonance (LSPR) in which excitation can take place in the visible and near-infrared ranges. As both catalytic and optical properties can be tuned by controlling several physical and chemical parameters at the nanoscale, design-controlled nanomaterials open the door to unlock the full potential of photocatalysis. The lab of Prof. Lilac Amirav has designed a semiconducting nano-rod crystal with the ability of hydrogen evolution at 100% quantum efficiency (Kalisman et al. 2016). Moreover, preliminary results indicate we have been able to conjugate PSII complexes to gold nanoparticles and produce higher photocurrents, compared to the PSII complex alone. We, therefore, hope that combining the PSII complex with the different types of nanomaterials may be the key to novel types of devices for clean, as well as, efficient overall water splitting and energy production.