The paper also explains that the pace of chemical reactions typically increases with temperature, and chemical producers have capitalized on this for more than a century by applying heat on an industrial scale.There’s also the possibility of using light-activated (plasmonic) metal nanoparticles to speed up reactions but the best of these are also typically made with precious metals like silver and gold.The researchers, their students and collaborators have worked for years to find non-precious metal alternatives for both the energy-harvesting and reaction-speeding halves of antenna reactors.In it, Halas, Nordlander, Rice alumnus Hossein Robatjazi, Princeton engineer Emily Carter, and others show that antenna-reactor particles made of copper and iron are highly efficient at converting ammonia.“In the absence of light, the copper-iron catalyst exhibited about 300 times lower reactivity than copper-ruthenium catalysts, which is not surprising given that ruthenium is a better thermocatalyst for this reaction,” said Robatjazi, now chief scientist at Houston-based Syzygy Plasmonics."