Abstract: The present invention generally relates to carbon dioxide (CO2) sensors. In one embodiment, the present invention relates to a carbon dioxide (CO2) sensor that incorporates lithium phosphate (Li3PO4) as an electrolyte and sensing electrode comprising a combination of lithium carbonate (Li2CO3) and barium carbonate (BaCO3). In another embodiment, the present invention relates to a carbon dioxide (CO2) sensor has a reduced sensitivity to humidity due to a sensing electrode with a layered structure of lithium carbonate and barium carbonate. In still another embodiment, the present invention relates to a method of producing carbon dioxide (CO2) sensors having lithium phosphate (Li3PO4) as an electrolyte and sensing electrode comprising a combination of lithium carbonate (Li2CO3) and barium carbonate (BaCO3).

Abstract: A compact oxygen sensor is provided, comprising a mixture of metal and metal oxide an enclosure containing said mixture, said enclosure capable of isolating said mixture from an environment external of said enclosure, and a first wire having a first end residing within the enclosure and having a second end exposed to the environment. Also provided is a method for the fabrication of an oxygen sensor, the method comprising confining a metal-metal oxide solid mixture to a container which consists of a single material permeable to oxygen ions, supplying an electrical conductor having a first end and a second end, whereby the first end resides inside the container as a reference (PO2)ref, and the second end resides outside the container in the atmosphere where oxygen partial pressure (PO2)ext is to be measured, and sealing the container with additional single material such that grain boundary sliding occurs between grains of the single material and grains of the additional single material.

Abstract: Described herein is a composite exhibiting a change in electrical resistance proportional to the concentration of a reducing gas present in a gas mixture, detector and sensor devices comprising the composite, a method for making the composite and for making devices comprising the composite, and a process for detecting and measuring a reducing gas in an atmosphere. In particular, the reducing gas may be carbon monoxide and the composite may comprise rutile-phase TiO2 particles and platinum nanoclusters. The composite, upon exposure to a gas mixture containing CO in concentrations of up to 10,000 ppm, exhibits an electrical resistance proportional to the concentration of the CO present. The composite is useful for making sensitive, low drift, fast recovering detectors and sensors, and for measuring CO concentrations in a gas mixture present at levels from sub-ppm up to 10,000 ppm. The composites, and devices made from the composites, are stable and operable in a temperature range of from about 450° C.

Abstract: The present invention generally relates to carbon dioxide (CO2) sensors. In one embodiment, the present invention relates to a carbon dioxide (CO2) sensor that incorporates lithium phosphate (Li3PO4) as an electrolyte and sensing electrode comprising a combination of lithium carbonate (Li2CO3) and barium carbonate (BaCO3). In another embodiment, the present invention relates to a carbon dioxide (CO2) sensor has a reduced sensitivity to humidity due to a sensing electrode with a layered structure of lithium carbonate and barium carbonate. In still another embodiment, the present invention relates to a method of producing carbon dioxide (CO2) sensors having lithium phosphate (Li3PO4) as an electrolyte and sensing electrode comprising a combination of lithium carbonate (Li2CO3) and barium carbonate (BaCO3).

Abstract: Described herein is a composite exhibiting a change in electrical resistance proportional to the concentration of a reducing gas present in a gas mixture, detector and sensor devices comprising the composite, a method for making the composite and for making devices comprising the composite, and a process for detecting and measuring a reducing gas in an atmosphere. In particular, the reducing gas may be carbon monoxide and the composite may comprise rutile-phase TiO2 particles and platinum nanoclusters. The composite, upon exposure to a gas mixture containing CO in concentrations of up to 10,000 ppm, exhibits an electrical resistance proportional to the concentration of the CO present. The composite is useful for making sensitive, low drift, fast recovering detectors and sensors, and for measuring CO concentrations in a gas mixture present at levels from sub-ppm up to 10,000 ppm. The composites, and devices made from the composites, are stable and operable in a temperature range of from about 450° C.

Abstract: A method for manufacturing oriented arrays of ceramic or metal oxide nanostructures, such as titania (TiO2) nanofibers. The nanofibers are formed on the surface of a body that is first sintered at a temperature in the range of about 1,100 to about 1,400 degrees Celsius. Subsequently, the surface is exposed to an H2-bearing gas, such as H2 and N2 in a ratio of about 5:95 at about 700 degrees Celsius for about 8 hours. During heat treatment in the gas phase reaction, sintered titania grains transform into arrays of nanofibers oriented in the same crystallographic direction.

Abstract: A compact oxygen sensor is provided, comprising a mixture of metal and metal oxide an enclosure containing said mixture, said enclosure capable of isolating said mixture from an environment external of said enclosure, and a first wire having a first end residing within the enclosure and having a second end exposed to the environment. Also provided is a method for the fabrication of an oxygen sensor, the method comprising confining a metal-metal oxide solid mixture to a container which consists of a single material permeable to oxygen ions, supplying an electrical conductor having a first end and a second end, whereby the first end resides inside the container as a reference (PO2)ref, and the second end resides outside the container in the atmosphere where oxygen partial pressure (PO2)ext is to be measured, and sealing the container with additional single material such that grain boundary sliding occurs between grains of the single material and grains of the additional single material.

Abstract: A potentiometric sensor for nitrogen oxide (NOX) measurement based on yttria-stabilized zirconia with a zeolite-modified electrode is presented. A potentiometric sensor of the present invention comprises a tube having an interior and an exterior. A cap member comprising yttria-stabilized zirconia closes one end of the tube. The cap member has an interior surface exposed to the interior of the tube where a first electrode is disposed. The first electrode is then covered with a zeolite layer. A second electrode is disposed on the exterior of the cap member.

Abstract: A method for manufacturing oriented arrays of ceramic or metal oxide nanostructures, such as titania (TiO2) nanofibers. The nanofibers are formed on the surface of a body that is first sintered at a temperature in the range of about 1,100 to about 1,400 degrees Celsius. Subsequently, the surface is exposed to an H2-bearing gas, such as H2 and N2 in a ratio of about 5:95 at about 700 degrees Celsius for about 8 hours. During heat treatment in the gas phase reaction, sintered titania grains transform into arrays of nanofibers oriented in the same crystallographic direction.

Abstract: A potentiometric sensor for nitrogen oxide (NOX) measurement based on yttria-stabilized zirconia with a zeolite-modified electrode is presented. A potentiometric sensor of the present invention comprises a tube having an interior and an exterior. A cap member comprising yttria-stabilized zirconia closes one end of the tube. The cap member has an interior surface exposed to the interior of the tube where a first electrode is disposed. The first electrode is then covered with a zeolite layer. A second electrode is disposed on the exterior of the cap member.

Abstract: A method and apparatus for determining the temperature of an environment at an elevated temperature (i.e., one exceeding about 300.degree. C.) wherein oxides that do not melt at such temperatures, do not age significantly at such temperatures and which have a sensitivity for such measurements are employed as thermistor resistors. Such oxides are calcium zirconate, yttria, alumina, dysprosia, magnesia, the oxide combinations alumina-silica, zirconia-silica and titania-silica. Measurements in electric current change is preferably the measurement of alternating current rather than the conventional dc current. A particularly useful instrument for such measurements consists of such a resistor with a laminate of connector metal such as diffusion bonded precious metal sheets or foils on separated surface areas as electrode connectors.

Abstract: Anatase titania is used as the sensitive ceramic for sensing the amount of carbon monoxide and hydrogen in mixed gasses where the changes in electric current characteristics passing through such ceramic when it is exposed to such gases is used to determine the amount of carbon monoxide and hydrogen present. Such sensor is made selective to hydrogen when alumina is included in the ceramic and to carbon monoxide when yttria is included. Additions of a catalytic metal particularly iron or palladium is beneficial to the anatase titania-yttria ceramic in its selective sensing of carbon monoxide.