The artificial leaf is an ingeniously developed leaf that does not have the green colour that characterizes almost all plants leaves, and it does not grow. The leaf has a remarkable ability as it is able to turn solar energy into storable chemical fuel for future use. The energy production and storage process is made possible by the specially designed catalysts that are attached on both sides of the leaf (Service, 2011). When the leaf is struck by sunlight, it converts water into oxygen and hydrogen gases, a process that is comparable to the photosynthetic processes occurring in a natural leaf. The hydrogen gas is piped out and stored for future use.
The artificial leaf generally consists of a silicon solar cell with various catalytic materials attached both on the upper and lower sections. These materials include a thin sheet of silicon coated with a cobalt-based catalyst. The former converts solar energy to electric energy while the latter releases oxygen (Zhou, Fan, and Zhang, 2010). On the other side of the leaf, the silicon layer is coated with a thin-layered nickel-molybdenum-zinc compound that releases hydrogen from the split water molecules. The leaf is submerged in a container full of water and placed in an area where it can receive the sun’s rays. When it is receives solar energy, the artificial leaf absorbs the energy and stores it in the bonds of the diatomic Hydrogen molecules liberated when water molecules are split by the silicon cells (Service, 2011). Supposing that the Hydrogen gas produced can be pumped out and stored, the leaf could provide the much-needed cheap and reliable source of alternative energy.
The artificial leaf has provided scientists with insight that could help in the production of clean, cheap hydrogen from sunlight and water in the future. Currently, the efficiency of the leaf is very low (5%) and cannot be used for large-scale hydrogen fuel production (Zhou et al, 2010). Unless the leaf can achieve efficiencies in the teens, it may not be very useful as there are more efficient methods of producing hydrogen.
References
Service, R. F. (2011). Artificial Leaf Turns Sunlight into a Cheap Energy Source. Science, 332(6025), 25.
Zhou, H., Fan, T., and Zhang, D. (2010). An Insight into Artificial Leaves for Sustainable Energy Inspired by Natural Photosynthesis. Catalysis, 3(3), 513-528.