Synthesis of sub-micron silver and silver sulfide particles via solvothermal silver azide decomposition

Many transition-metal azides are thermodynamically unstable with respect to the elements and thus, may serve as energetic precursor sources in nanoscale metal particle synthesis. This report describes the use of silver azide (AgN3) in nonaqueous, solvothermal decomposition reactions to produce crystalline sub-micron silver particles and interconnected structures. The thermal decomposition of AgN3 directly produces silver and N2 and no secondary chemical reducing agent is required. This solvothermal conversion was examined in toluene, tetrahydrofuran (THF), and trioctylamine below 250 °C. The coordinating solvents produced the smallest particles (150–500 nm), while the toluene reaction products were near 1 μm in size. The addition of soluble elemental sulfur to the THF reaction results in the growth of silver sulfide particles near 1 μm in size. The silver and Ag2S products are crystalline by X-ray diffraction and show some faceting by scanning electron microscopy.