However, these catalysts also oxidise, like the silicon, leaving a limited life as one of the key problems with the artificial leaf, still leaving us puzzling today. When John Turner used his early system, the catalysts used wavelengths of light that plants cannot use and achieved remarkable efficiency. So now we have a Californian Joint Centre for Artificial Photosynthesis with a 122 million grant, larger than any previous investment. Professor John Turner started the whole ball rolling at Golden, Colorado. He still seems near to the elusive energy-efficient goal of energy from light; Credit: Credit: National Renewable Energy Laboratory, US.
Mechanisms to provide this cheapest of fuels vary. Collecting the light so far has been silicon, stacked to increase the poor electron-volt output. Oxygen reacts with it to form insulating "sand terminating the reactions, so antioxidant adds to the initial small cost.