Methods and apparatuses for making nanomaterials are disclosed. The methods involve passing one or more source materials through a high pressure and high temperature chamber with an open throat, and then allowing the reactants to expand into a lower pressure, lower temperature zone. The source material is non-stoichiometric and fuel-rich so that excess un-combusted primary source material can form the nanomaterials. In some cases, the apparatus may be in the form of a modified rocket engine. The methods may be used to make various materials including: carbon nanotubes, boron nitride nanomaterials, titanium dioxide, and any materials that are currently produced by flame synthesis, including but not limited to electrocatalysts. The methods may also be used to make nanomaterials outside the Earth's atmosphere. The methods can include making, coating, or repairing structures in space, such as antennae.

Methods and apparatuses for making nanomaterials are disclosed. The methods involve passing one or more source materials through a high pressure and high temperature chamber with an open throat, and then allowing the reactants to expand into a lower pressure, lower temperature zone. The source material is non-stoichiometric and fuel-rich so that excess un-combusted primary source material can form the nanomaterials. In some cases, the apparatus may be in the form of a modified rocket engine. The methods may be used to make various materials including: carbon nanotubes, boron nitride nanomaterials, titanium dioxide, and any materials that are currently produced by flame synthesis, including but not limited to electrocatalysts. The methods may also be used to make nanomaterials outside the Earth's atmosphere. The methods can include making, coating, or repairing structures in space, such as antennae.

A process for producing a particulate TiO.sub.2 includes supplementing metatitanic acid with an alkali compound in a quantity of 1200 ppm to 2400 ppm of alkali, with a phosphorus compound in a quantity of 0.1 wt.-% to 0.3 wt.-% by weight of P, expressed as phosphorus, and with an aluminum compound in a quantity of 1 ppm to 1000 ppm of Al, expressed as Al, to obtain a mixture. The quantity of the alkali compound, of the phosphorus compound, and of the aluminum compound are with respect to the TiO.sub.2 content. The mixture is calcined at a constant temperature of 940° C. to 1020° C. until a numerical fraction X.sub.50 of TiO.sub.2 has a primary crystallite size of at least 200 nm, to obtain a calcined mixture. The calcined mixture is cooled to obtain a cooled calcined mixture. The cooled calcined mixture is grinded to obtain the particulate TiO.sub.2.

A process for producing a particulate TiO.sub.2 includes supplementing metatitanic acid with an alkali compound in a quantity of 1200 ppm to 2400 ppm of alkali, with a phosphorus compound in a quantity of 0.1 wt.-% to 0.3 wt.-% by weight of P, expressed as phosphorus, and with an aluminum compound in a quantity of 1 ppm to 1000 ppm of Al, expressed as Al, to obtain a mixture. The quantity of the alkali compound, of the phosphorus compound, and of the aluminum compound are with respect to the TiO.sub.2 content. The mixture is calcined at a constant temperature of 940° C. to 1020° C. until a numerical fraction X.sub.50 of TiO.sub.2 has a primary crystallite size of at least 200 nm, to obtain a calcined mixture. The calcined mixture is cooled to obtain a cooled calcined mixture. The cooled calcined mixture is grinded to obtain the particulate TiO.sub.2.

Disclosed herein are embodiments of low temperature co-fireable dielectric materials which can be used in conjunction with high dielectric materials to form composite structures, in particular for isolators and circulators for radiofrequency components. Embodiments of the low temperature co-fireable dielectric materials can be scheelite or garnet structures, for example, bismuth vanadate. Adhesives and/or glue is not necessary for the formation of the isolators and circulators.

Systems and methods are disclosed for a rock-salt structure formed from an electrochemically-driven amorphous-to-crystalline (a-to-c) transformation of nanostructured Nb.sub.2O.sub.5, the rock-salt structure including, upon cycling with lithium ions (Li+), an insertion of lithium ions (Li+) into Nb.sub.2O.sub.5 to form the rock-salt structure (RS—Nb.sub.2O.sub.5).

Porous metal oxide microspheres are prepared via a process comprising forming a liquid solution or dispersion of polydisperse polymer nanoparticles and a metal oxide; forming liquid droplets from the solution or dispersion; drying the liquid droplets to provide polymer template microspheres comprising polymer nanospheres and metal oxide; and removing the polymer nanospheres from the template microspheres to provide the porous metal oxide microspheres. The porous microspheres exhibit saturated colors and are suitable as colorants for a variety of end-uses.

An acidified metal oxide (“AMO”) material, preferably in monodisperse nanoparticulate form 20 nm or less in size, having a pH<7 when suspended in a 5 wt % aqueous solution and a Hammett function H.sub.0>−12, at least on its surface. The AMO material is useful in applications such as a battery electrode, catalyst, or photovoltaic component.

An acidified metal oxide (“AMO”) material, preferably in monodisperse nanoparticulate form 20 nm or less in size, having a pH<7 when suspended in a 5 wt % aqueous solution and a Hammett function H.sub.0>−12, at least on its surface. The AMO material is useful in applications such as a battery electrode, catalyst, or photovoltaic component.

A system for determining pH of a fluid and a method to determine the pH of a fluid contacting a sensor, the method having the steps of: providing the sensor to an environment such that the sensor is in contact with the fluid, wherein the sensor features a fiber extending between a first end and a second end along a longitudinal axis, wherein the fiber further features a medial portion positioned between the first and second ends, wherein the sensor further features a pH sensitive coating on the medial portion of the fiber, and wherein the pH sensitive material features a metal oxide including but not limited to SiO.sub.2, TiO.sub.2, ZrO.sub.2, Ta.sub.2O.sub.5, A.sub.2O.sub.3, and combinations thereof; interrogating the sensor with an optical signal; collecting a modified optical signal after the sensor has been interrogated; and determining the pH of the fluid contacting the pH sensor using the modified optical signal.