solar hydrogen production; this could be big

http://www.sciencedaily.com/releases/2012/05/120509123900.htm

"To make these devices more widely available, Nocera replaced the platinum catalyst that produces hydrogen gas with a less-expensive nickel-molybdenum-zinc compound. On the other side of the leaf, a cobalt film generates oxygen gas. Nocera notes that all of these materials are abundant on Earth, unlike the rare and expensive platinum, noble metal oxides and semiconducting materials others have used."

Hydrogen and oxygen are what propel the space shuttle into orbit.  It's a great clean fuel.  If this really is possible cheaply enough it's a game changer for sure.