International Collaboration in Chemistry - Modular microtubular architectures for photo-driven water splitting

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The world's present energy requirements are set to double by 2050, and although this increased demand could, in principle, be met by fossil fuels (currently the source of over 70% of our energy), the increased CO2 output would undoubtedly have deleterious consequences.An alternative solution is to harness the abundant energy that comes from the sun: the amount of solar energy that strikes the surface of the earth each hour is more than mankind currently uses each year. Research on all aspects of solar energy capture has increased considerably in recent years because the technical establishments as well as government and business sectors realize both the pressing need and the extraordinary opportunity that exists in the development of green, sustainable sources of energy. Photovoltaic (PV) devices are increasingly competitive based on efficiency, production costs and operating lifetime. Specifically, the best single crystal Si-based PV devices are up to 22% efficient but are currently prohibitively expensive for large-scale use. In contrast, dye-sensitized solar cells (DSSCs) are only about half this efficient but have the potential to be produced in quantity at far lower cost. However, these and other developing PV technology is limited to generation and storage of electrical energy, and while battery technology is improving, the energy density (weight and molar energy density) in our current batteries is far lower than what is available in fuels. This is why much activity at present is aimed at the direct production of fuel using sunlight. There is, of course, one process already known on Earth that achieves production of "solar fuel" - photosynthesis - although even this process, optimized over billions of years, is less then 1% efficient for most terrestrial plants. It is important therefore to consider every possible route towards harnessing solar energy to produce fuels. In this work we will use a novel range of molecular metal oxides, which have already been shown to be promising catalysts for the oxidation and splitting of water in to hydrogen and oxygen and therefore potentially of use for the generation of solar fuels, by the direct combination with dye-units that can transfer the suns energy to molecular oxide. This will exploit the recent discoveries of the US group (very fast water oxidation with a metal oxide catalyst) and the UK group (growth of microscale tubular architectures when the metal oxide is combined with the dye-cation). This means it is possible to 'grow' catalytic heterostructures that could convert sunlight into fuels on surfaces in with high surface area and robustness opening up a whole new area of science and application to 'fossil' free energy solutions.