Surfactant-mediated reduction at water microdroplet interfaces enables switchable synthesis of silver nanoparticles and ammonia.

Aqueous microdroplets enable surfactant-mediated macroscopic synthesis of Ag nanoparticles and ammonia under argon and nitrogen, respectively, without external voltage or common reducing agents. Control studies reveal surfactant charge-induced reactivity at aqueous microdroplet interfaces, offering a green route for reduction in confined aqueous environments.