Sequential control of catalyst alloying and oxygen-mediated nucleation for continuous synthesis of SnO nanowires floating in the gas phase.

In floating catalyst chemical vapour deposition (FCCVD), nanotubes or nanowires grow suspended in a gas stream using a catalyst aerosol as they travel through a tubular reactor and are collected at the outlet as macroscopic paper-like networks. The method is continuous, removes the need for substrates and reduces the reaction time to seconds. Herein, we demonstrate the fast growth of SnO nanowires with high selectivity through sequential injection of precursors and carrier gases in order to separately control the stages of precursor decomposition, alloying of Au and Sn, and nucleation and growth of SnO as nanowires instead of alloy encapsulation by SnO, all occurring within 10 seconds under continuous flow at atmospheric pressure.

Ordered silicon nanowire bundle networks from aqueous dispersions.

Many applications of nanowires require their processing in large volumes and assembly as ordered arrays with controlled density. Starting from aqueous dispersions of silicon nanowires stabilized through a cationic surfactant, we carry out vacuum filtration to form macroscopic paper-like networks. We controllably induce the assembly of SiNWs as ordered domains within the network, arising from a 2D nematic phase formed due to the relatively high SiNW concentration and long filtration time comparable to their rotational diffusion.

Fractal Scaling in the Gas-Phase Agglomeration of Nanowires.

Assembling 1D nanoparticles (nanowires (NW) or nanotubes) as networks enables bridging multiple scales to form macroscopic materials such as fibers, sheets and electrodes. This can be done directly in the gas phase from 1D nanoparticle aerosols grown by floating catalyst chemical vapor deposition (FCCVD). In FCCVD nanowires/nanotubes grow to high aspect ratios (10-10) floating in a gas stream and can agglomerate to form an aerogel.

Gas-to-nanotextile: high-performance materials from floating 1D nanoparticles.

Suspended in the gas phase, 1D inorganic nanoparticles (nanotubes and nanowires) grow to hundreds of microns in a second and can be thus directly assembled into freestanding network materials. The corresponding process continuously transforms gas precursors into aerosols into aerogels into macroscopic nanotextiles. By enabling the assembly of very high aspect ratio nanoparticles, this processing route has translated into high-performance structural materials, transparent conductors and battery anodes, amongst other embodiments.

Ultrafast synthesis of SiC nanowire webs by floating catalysts rationalised through measurements and thermodynamic calculations.

This work presents the synthesis of SiC nanowires floating in a gas stream through the vapour-liquid-solid (VLS) mechanism using an aerosol of catalyst nanoparticles. These conditions lead to ultrafast growth at 8.5 μm s (maximum of 50 μm s), which is up to 3 orders of magnitude above conventional substrate-based chemical vapour deposition.