A fundamental breakthrough in chemistry promises to unlock ammonia as a clean fuel, and it could help decarbonize the entire chemical industry in the process. Rice University researchers have created a small, LED-powered device that converts ammonia to hydrogen on the fly. It uses a light-driven catalyst that’s as efficient as expensive thermal catalysts that need thousand-degree temperatures to operate, and it’s made from cheap, abundant copper and iron. And it’s only the beginning of a technology that could radically reduce costs and energy use in industrial chemistry.