Solar powered hydrogen fuel production. Illustration showing the production of hydrogen (H2) from splitting water (in drop) using a catalyst of biominerals (left) and nanostructures (hexagonal), and sunlight (yellow). Hydrogen is a clean fuel, releasing only water vapour as a byproduct. However, the production of hydrogen takes huge amounts of energy and traditional methods use environmentally harmful solvents. Using a biomineral catalyst and solar power would overcome these problems.