What if the carbon dioxide building up in our atmosphere could be put to good use as fuel? For years chemists have chased a catalyst that could aid the reaction converting carbon dioxide to methane, a building block for many fuels - and now Duke University scientists have found just such a catalyst in tiny rhodium nanoparticles. Duke University researchers converted carbon dioxide into methane with the help of rhodium nanoparticles, which harness ultraviolet light's energy to catalyze carbon dioxide's conversion into methane.