"Researchers in Switzerland have demonstrated more-efficient water-splitting solar cells based on a cheap, abundant, and long-lasting material: rust. The advance could lead to a cheap and energy-efficient way to generate hydrogen for fuel-cell vehicles using solar energy."
http://www.technologyreview.com/Energy/17887/
I saw this type of hydrogen separation at a "Home of the Future" show.. the University of California during the competition used Solar to seperate Hydrogen and Oxygen from water. The Oxygen was released into the atmosphere and the hydrogen used to make electricity. The hydrogen mixed with whatever they used in the cells and condensed back in to water and then sent back to the seperation cells again that night. It used distilled water. It was quite impressive.