Direct growth, characterization, and optical properties of silica nanowires on cordierite monolith

We report the direct synthesis of amorphous silica nanowires on cordierite monolith. Our approach is based on a simple catalyst-assisted growth using Sn particles that are formed via the mechanochemical reaction of SnO2 (s) with Al (s, l) or Si (s) during the initial phase of the growth process. The silica nanowires have a diameter of approximately 20 nm and become densely packed upon repeatedly branching and merging with each other. The silica nanowire assemblies grow up to 50 µm in length. The microscopic images reveal that the Sn catalysts govern the growth by controlling the formation of the nuclei on their surface. Remarkably, the Sn catalysts induce the growth of multiple silica nanowire assemblies and the formation of Sn-rich amorphous (Si,Al)Ox nanotube/Al-doped orthorhombic Mg2SiO4 nanofiber as a minor product. The Sn-catalyzed silica nanowires show strong blue emission.