In his 1874 science fiction tale The Mysterious Island, Jules Verne predicted, “Water will be the coal of the future.” It is a vision of infinite clean energy available for people to use. More than 30 years ago, Japanese scientists took a seminal step in that direction. With a piece of titanium dioxide and some sunlight, they split water into hydrogen and oxygen. Although researchers have tried to refine the process over the years, nobody has come up with a system that is both efficient and inexpensive enough to produce sufficient hydrogen for use as a clean-burning fuel on the roads, in industry, and at home. Recently, however, researchers have picked up the pace of their pursuit of the ultimate water-splitting system.
With rising oil prices and the specter of climate change that’s due to the burning of fossil fuel, the vision of a hydrogen economy looms ever larger in people’s minds. After all, it’s a fuel for which the only by-product is water. And hydrogen packs more energy per unit mass than any fossil fuel does.