A new approach to harnessing solar energy for the production of hydrogen through photosensitized water splitting has been developed by researchers from École Polytechnique Fédérale de Lausanne (EPFL), Switzerland. Materials with high chemical stability and high catalytic efficiencies are featured in the advanced artificial photosynthesis system.

The new process photo-oxidizes water with tetrathiafulvalene (TTF), a self-assembled semi-conductive organic molecule deposited on a solid carbon support. A salt version of TTF self-assembles into microrods that act as antennas to capture visible light and as electron pumps to oxidize water to oxygen. This visible light-driven water oxidation reaction eliminates the need for metallic or organometallic catalysts and sacrificial electron acceptors. TTF is composed of carbon, sulfur and hydrogen atoms, indicating the cost-effective and sustainable nature of a process that does not require the use of platinum or other precious metals.

A study published in the Journal of the American Chemical Society Gold reports high efficiency and stability of the artificial photosynthesis system was demonstrated at neutral pH with no decomposition of TTF during 16 hours of recycling. Constant gas production, constant current and constant increase of the charge were recorded during 100 hours of visible light-induced water oxidation reactions.