Abstract: The invention provides a process for the production of fumed silica. The process comprises providing a silicon halide feedstock comprising about 80% to 100% methyltrichlorosilane, combining the silicon halide feedstock with hydrogen gas and oxygen gas to form a reactant mixture, discharging the reactant mixture out of a burner, and combusting the hydrogen gas and the oxygen gas of the reactant mixture so as to hydrolyze the silicon halide feedstock to produce fumed silica. Hydrogen (H2) is present in a mole fraction of about 0.11 or less based on the reactant mixture, and/or the velocity of the reactant mixture upon exiting the burner is about 25 m/s or more.

Abstract: A powder batch is described comprising single crystal metal-containing particles having a crystal size of less than 50 nm as measured by X-ray diffraction and having a weight average particle size of from about 10 nanometers to less than 100 nanometers as measured by transmission electron microscopy and including a continuous or non-continuous coating of a ceramic material. The powder batch is preferably produced by flame spraying.

Abstract: Security features, e.g., reflective security features, and processes for forming security features are described. The security features comprise crystalline metal-containing particles having a primary particle size of from about 10 nanometers to less than 500 nanometers and including a continuous or non-continuous coating of a ceramic material. Inks comprising such crystalline metal-containing particles are also described. The crystalline metal-containing particles are preferably produced by flame spraying.

Abstract: Photovoltaic conductive features and processes for forming photovoltaic conductive features are described. The process comprises (a) depositing a composition onto at least a portion of a substrate, wherein the composition comprises metal-containing particles having a primary particle size of from about 10 nanometers to less than 500 nanometers and including a continuous or non-continuous coating of a ceramic material; and (b) heating the composition such that the precursor composition forms at least a portion of a photovoltaic conductive feature. The metal-containing particles are preferably produced by flame spraying.

Abstract: The present invention provides a cerium oxide particulate composition and a process for preparing a cerium oxide particulate composition comprising aggregates of approximately spherical primary particles of cerium oxide. The method involves preparing a solution of a cerium oxide precursor, aerosolizing the cerium oxide precursor solution, and heating the aerosol to provide the cerium oxide particle composition.

Abstract: The present invention provides a catalytic converter for treating internal combustion engine exhaust comprising a substrate, fumed metal oxide aggregates adhered to the substrate, wherein no non-fumed metal oxide is present in the intra-aggregate voids, and at least one catalyst adhered to the fumed metal oxide aggregates. The present invention also provides a method of preparing such a catalytic converter, as well as a method of treating the exhaust of an internal combustion engine comprising contacting the exhaust of an internal combustion engine with a catalytic converter of the present invention.

Abstract: A gas phase process for the production of titanium dioxide powders having well-controlled crystalline and surface area characteristics is disclosed. In this process, which is preferably carried out in a laminar diffusion flame reactor, vapor phase TiCl.sub.4 and oxygen are mixed in a reaction area which is heated externally. The titanium dioxide powder formed is then collected. It is preferred that the heat source used be a hydrocarbon fueled (e.g., methane) flame. Optionally, a vapor phase dopant (such as SiCl.sub.4) may be added to the reaction mixture to desirably affect the physical properties of the titanium dioxide produced. In a particularly preferred embodiment, a corona electric field is positioned across the area where the combustion reaction takes place (i.e., the reaction area). High anatase, high surface area titanium dioxide powders made by this process are excellent photocatalysts. The products of this process and the use of those products as photocatalysts are also disclosed.

Abstract: A gas phase process for the production of titanium dioxide powders having well-controlled crystalline and surface area characteristics is disclosed. In this process, which is preferably carried out in a laminar diffusion flame reactor, vapor phase TiCl.sub.4 and oxygen are mixed in a reaction area which is heated externally. The titanium dioxide powder formed is then collected. It is preferred that the heat source used be a hydrocarbon fueled (e.g., methane) flame. Optionally, a vapor phase dopant (such as SiCl.sub.4) may be added to the reaction mixture to desirably affect the physical properties of the titanium dioxide produced. In a particularly preferred embodiment, a corona electric field is positioned across the area where the combustion reaction takes place (i.e., the reaction area). High anatase, high surface area titanium dioxide powders made by this process are excellent photocatalysts. The products of this process and the use of those products as photocatalysts are also disclosed.