Researchers from Tokyo Metropolitan University have revealed how a catalyst in a promising chemical reaction for industry helps make ammonia, a major ingredient in fertilizer. Copper oxide is a key catalyst in the electrochemical nitrate reduction reaction, a greener alternative to the existing Haber-Bosch process. They discovered that copper particles are created mid-reaction, helping convert nitrite ions to ammonia. This insight into the underlying mechanisms promises leaps forward in developing new industrial chemistry.