Researchers at the California Institute of Technology have developed an artificial leaf that can produce hydrogen fuel througha process similar to photosynthesis, according to findings published in the journal Energy and Environmental Science. The system is the first complete, efficient, and safe solar-driven device for splitting water to create hydrogen fuels, say the researchers, who have been seeking a cost-effective method for producing energy using only sunlight, water, and carbon dioxide. The new system consists of two electrodes that produce oxygen and hydrogen gases, along with a specialized membrane that keeps the gases separate to prevent the possibility of an explosion. The artificial leaf converts 10 percent of the energy in sunlight into hydrogen fuel and can operate for more than 40 hours continuously, the study says.