Hierarchical Self-Assembly of SnO Nanoparticles into Porous Microspheres: Exceptionally Selective Ammonia Sensing at Ambient.

Herein, porous SnO microspheres in a three-dimensional (3D) hierarchical architecture were successfully synthesized via a facile hydrothermal route utilizing d-(+)-glucose and cetyltrimethylammonium bromide (CTAB), which act as reducing and structure-directing agents, respectively. Controlled adjustment of the CTAB to glucose mole ratio, reaction temperature, reaction time, and the calcination parameters all provided important clues toward optimizing the final morphologies of SnO with exceptional structural stability and reasonable monodispersity. Electron microscopy analysis revealed that microspheres formed were hierarchical self-assemblies of numerous primary SnO nanoparticles of ∼3-8 nm that coalesce together to form nearly monodispersed and ordered spherical structures of sizes in the range of 230-250 nm and are appreciably porous.