It sounds a bit like spinning straw into gold, but novel metal catalysts may be able to turn greenhouse gases like methane and carbon dioxide into liquid fuels without producing more carbon waste in the process.

If fossil fuels burn completely, the end products are carbon dioxide and water. Today the carbon dioxide is a waste product, one that goes into the air — adding to global warming; or the oceans — acidifying them; or underground — with as yet unknown consequences.

But it’s not impossible, says Liviu M. Mirica, PhD, assistant professor of chemistry at Washington University in St. Louis, to drive things the other way, turning carbon dioxide into fuels such as methanol or hydrocarbons.

Until now reversing combustion has been a loser’s game, because making carbon dioxide into a fuel uses up more energy than combustion releases and produces more carbon dioxide than it reclaims.

But Mirica thinks catalysts might change everything. Catalysts might provide alternative reaction pathways with lower energy barriers. The reactants could then be bumped over those lower barriers with carbonless energy sources such as sunlight.

Instead of being a polluting one-way street, hydrocarbon chemistry could circle back on itself and become a clean carbon-neutral cycle, although one that still consumed energy.