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.

Hydrogen is a very promising clean fuel that can be burned, or converted directly into electricity through a fuel cell. It's both expensive and difficult to handle, though, since it's a super-lightweight gas that needs to be compressed to 700 atmospheres, or else cryogenically cooled within sight of absolute zero to reach its liquid state.

Ammonia is famously a better hydrogen carrier than hydrogen gas itself; each of its nitrogen atoms binds three hydrogen atoms, and while it's caustic and extremely hazardous in high concentrations, it's a stable liquid at atmospheric temperatures and pressures, and its widespread use in many industries means people have plenty of experience handling it safely under a wide range of conditions.

Ammonia might carry hydrogen exceptionally well, but if you want to use that hydrogen, you need to "crack" it to get the hydrogen out and release the harmless nitrogen back into the atmosphere. This has been difficult for two main reasons: firstly, the reaction is endothermic, so most ammonia cracking is done in large facilities operating at temperatures of at least 650-1,000 °C (1,200-1,800 °F). Secondly, the thermal catalysts required for the cracking operations are typically platinum-group metals like ruthenium – relatively rare and expensive.

With the green hydrogen movement gathering steam as a key pillar of the transition to clean energy, you can see why the Rice University team is excited to have discovered a compact and efficient way to catalyze this cracking reaction at room temperature, using nothing but copper and iron.