Infrared hollow waveguide sensors for simultaneous gas phase detection of benzene, toluene, and xylenes in field environments.

Simultaneous and molecularly selective parts-per-billion detection of benzene, toluene, and xylenes (BTX) using a thermal desorption (TD)-FTIR hollow waveguide (HWG) trace gas sensor is demonstrated here for the first time combining laboratory calibration with real-world sample analysis in field. A calibration range of 100-1000 ppb analyte/N(2) was developed and applied for predicting the concentration of blinded environmental air samples within the same concentration range, and demonstrate close agreement with the validation method used here, GC-FID. The analyte concentration prediction capability of the TD-FTIR-HWG trace gas sensor also compares well with the industrial standard and other experimental techniques including GC-PID, ultrafast GC-FID, and GC-DMS, which were simultaneously operated in the field.

Hexagonal nanoporous germanium through surfactant-driven self-assembly of Zintl clusters.

Surfactant templating is a method that has successfully been used to produce nanoporous inorganic structures from a wide range of oxide-based material. Co-assembly of inorganic precursor molecules with amphiphilic organic molecules is followed first by inorganic condensation to produce rigid amorphous frameworks and then, by template removal, to produce mesoporous solids. A range of periodic surfactant/semiconductor and surfactant/metal composites have also been produced by similar methods, but for virtually all the non-oxide semiconducting phases, the surfactant unfortunately cannot be removed to generate porous materials.

Chemical tuning of the electronic properties in a periodic surfactant-templated nanostructured semiconductor.

In this work, we report the synthesis and characterization of a series of hexagonal nanostructured platinum/tin/tellurium inorganic/surfactant composites. The composites are formed through solution-phase self-assembly of SnTe4(4-) Zintl clusters, which are cross-linked with platinum salts in the presence of a cetyltriethylammonium cationic structure directing agent. The cross-linking utilizes various combinations of Pt(II) and Pt(IV) salts.

Probing the effects of interfacial chemistry on the kinetics of phase transitions in amorphous and tetragonal zirconia nanocrystals.

In this work, we examine the phase stability of both uncoated and alumina-coated zirconia nanoparticles using in-situ X-ray diffraction. By tracking structural changes in these particles, we seek to understand how changing interfacial bonding affects the kinetics of amorphous zirconia crystallization and the kinetics of grain growth in both initially amorphous and initially crystalline zirconia nanocrystals. Activation energies associated with crystallization are calculated using nonisothermal kinetic methods.

Synthesis of periodic hexagonal surfactant templated platinum tin tellurides: narrow band gap inorganic/organic composites.

In this work we report the synthesis and characterization of a new nanostructured platinum/tin/telluride inorganic/surfactant composite. The material is synthesized from soluble SnTe(4)(4-) clusters and is shown to have well-defined nanometer scale periodicity along with unique optical properties. Small-angle X-ray scattering indicates that the material forms with a 2D hexagonal honeycomb structure, which is size tunable based on surfactant tail length.