NIST researchers have explored in unprecedented detail a new breed of catalysts that allow some chemical reactions, which normally require high heat, to proceed at room temperature. The energy-saving catalysts use sunlight or another light source to excite localized surface plasmons (LSPs)—oscillations of groups of electrons on the surface of certain metal nanoparticles, such as gold, silver and aluminum. The energy derived from the LSP oscillations drives chemical reactions among molecules that adhere to the nanoparticles.