"In the 1990s a graduate student named Lin Chao at Princeton University decided to bubble carbon dioxide into an electrochemical cell. Using cathodes made from the element palladium and a catalyst known as pyridinium—a garden variety organic chemical that is a by-product of oil refining—he discovered that applying an electric current would assemble methanol from the CO2. He published his findings in 1994—and no one cared.
"But by 2003, Chao's successor in the Princeton lab of chemist Andrew Bocarsly was deeply interested in finding a solution to the growing problem of the CO2 pollution causing global climate change. Graduate student Emily Barton picked up where he left off and, using an electrochemical cell that employs a semiconducting material used in photovoltaic solar cells for one of its electrodes, succeeded in tapping sunlight to transform CO2 into the basic fuel.
I know...more chemistry than physics, but if the process works, I'm not hating!
See: Reverse combustion article, and a start up company trying to turn the technology into GOLD: Liquid Light, Inc.