Methods for producing nanostructures from copper-based catalysts on porous substrates, particularly silicon nanowires on carbon-based substrates for use as battery active materials, are provided. Related compositions are also described. In addition, novel methods for production of copper-based catalyst particles are provided. Methods for producing nanostructures from catalyst particles that comprise a gold shell and a core that does not include gold are also provided.

Composites of silicon and various porous scaffold materials, such as carbon material comprising micro-, meso- and/or macropores, and methods for manufacturing the same are provided. The compositions find utility in various applications, including electrical energy storage electrodes and devices comprising the same.

Mechanically fluidized systems and processes allow for efficient, cost-effective production of silicon coated particles having very low levels of contaminants such as metals and oxygen. These silicon coated particles are produced, conveyed, and formed into crystals in an environment maintained at a low oxygen level or a very low oxygen level and a low contaminant level or very low contaminant level to minimize the formation of silicon oxides and minimize the deposition of contaminants on the coated particles. Such high purity coated silicon particles may not require classification and may be used in whole or in part in the crystal production method. The crystal production method and the resultant high quality of the silicon boules produced are improved by the reduction or elimination of the silicon oxide layer and contaminants on the coated particles.

Organofunctional silicon particles are covalently functionalized on their surface with at least one organic compound, for example a plurality of —O—(C.sub.1-C.sub.48)-alkyl compounds. The functionalization of the surface of the silicon particles makes it possible to adjust the properties of fluids in terms of their profile of properties by addition of the modified silicon particles. For instance, the alkoxy-functionalized silicon particles may preferably be added to a motor oil as additives for reducing viscosity.

Organofunctional silicon particles are covalently functionalized on their surface with at least one organic compound, for example a plurality of —O—(C.sub.1-C.sub.48)-alkyl compounds. The functionalization of the surface of the silicon particles makes it possible to adjust the properties of fluids in terms of their profile of properties by addition of the modified silicon particles. For instance, the alkoxy-functionalized silicon particles may preferably be added to a motor oil as additives for reducing viscosity.

Hollow bodies having a silicon-comprising shell, are produced by, in a gas comprising at least one silane of the general formula Si.sub.nH.sub.2n+2−mX.sub.m with n=1 to 4, m=0 to 2n+2 and X=halogen, (a) generating a non-thermal plasma by an AC voltage of frequency f, or operating a light arc, or introducing electromagnetic energy in the infrared region into the gas, giving a resulting phase which (b) is dispersed in a wetting agent and distilled, and then (c) the distillate is contacted at least once with a mixture of at least two of the substances hydrofluoric acid, nitric acid, water, giving a solid residue comprising hollow bodies having a silicon-comprising shell after the conversion reaction of the distillate with the mixture has abated or ended.

Hollow bodies having a silicon-comprising shell, are produced by, in a gas comprising at least one silane of the general formula Si.sub.nH.sub.2n+2−mX.sub.m with n=1 to 4, m=0 to 2n+2 and X=halogen, (a) generating a non-thermal plasma by an AC voltage of frequency f, or operating a light arc, or introducing electromagnetic energy in the infrared region into the gas, giving a resulting phase which (b) is dispersed in a wetting agent and distilled, and then (c) the distillate is contacted at least once with a mixture of at least two of the substances hydrofluoric acid, nitric acid, water, giving a solid residue comprising hollow bodies having a silicon-comprising shell after the conversion reaction of the distillate with the mixture has abated or ended.

An apparatus for producing silicon nanoparticles using ICP includes a gas supply part in which first and second pipes for introducing a respective first and second gas into the plasma reactor therethrough are arranged alternately, the first pipes extending from an inlet of the reactor to a plasma initiation region; a plasma reaction part having an ICP coil wound therearound in which the particles are formed as the gases introduced through the respective pipes undergo a plasma reaction; and a collection part for collecting the particles. The apparatus can fully mix the gases introduced through the first gas supply pipes, thus allowing for uniform plasma reaction between the first and second gas, minimizing plasma expansion to increase plasma density within short retention time, easily controlling the size distribution by quenching and capturing nanoparticles, and improving the production yield by preventing the secondary aggregation of particles with cooling gas.

An apparatus for producing silicon nanoparticles using ICP includes a gas supply part in which first and second pipes for introducing a respective first and second gas into the plasma reactor therethrough are arranged alternately, the first pipes extending from an inlet of the reactor to a plasma initiation region; a plasma reaction part having an ICP coil wound therearound in which the particles are formed as the gases introduced through the respective pipes undergo a plasma reaction; and a collection part for collecting the particles. The apparatus can fully mix the gases introduced through the first gas supply pipes, thus allowing for uniform plasma reaction between the first and second gas, minimizing plasma expansion to increase plasma density within short retention time, easily controlling the size distribution by quenching and capturing nanoparticles, and improving the production yield by preventing the secondary aggregation of particles with cooling gas.

By incorporating an additional TCS and/or DCS redistribution reactor in the TCS recycle loop and/or DCS recycle loop, respectively, of a process and system for silane manufacture, efficiencies in the production of silane are realized. Further improvements in efficiencies may be realized by directing a portion of the product from a redistribution reactor into a distillation column, and specifically into the distillation column that formed the feedstock that went into the redistribution reactor.