Fernando H Garzon

The Effect of Electrode Ink Processing and Composition on Catalyst Utilization

Platinum surface area was chemically and electrochemically characterized using X-ray diffraction (XRD), H2S adsorption, and electrochemical techniques including half-cells and fuel cells. Electrode ink processing and composition were found to have a strong impact on observed surface area with increased processing leading to a reduction in platinum surface area. Fuel cell electrode measurements show a significant portion of the platinum may not be available. This unutilized Pt may be due to either ionic or electronic connectivity as evidence exists to support both ionic and electronic isolation.

CarbonXS GUI: a graphical front-end for CarbonXS

The crystallographic structure of disordered carbons impacts their performance in components for fuel cells, batteries and catalyst supports. Obtaining parameters such as lattice constants and crystal domain size requires an appropriate model for these carbons, a task accomplished with the Fortran program CarbonXS published in 1993. CarbonXS GUI contains an updated version of CarbonXS and a graphical user interface wrapper. This new version provides a graphical method of configuring and operating CarbonXS, a calculation mode to simulate diffraction patterns, and immediate feedback in the form of fit–source and difference plots. CarbonXS GUI is available for free on Windows, Linux and Mac OSX at http://github.com/lktsui/carbon_xs_gui.

YSZ-Based Electrochemical Gas Sensors for the Detection of Explosives

A zirconia-based mixed potential sensor utilizing dense lanthanum chromite and Pt electrodes and porous YSZ electrolyte was used in an alternating HC mode (unbiased) and total NOx mode (50 nA bias current applied) to detect the HC and NOx deflagration remnants of a nitroglycerin/nitrocellulose propellant (Bullseye{trade mark, serif}), ANFO (ammonium nitrate and fuel oil), blackpowder, and urea (a common, high nitrogen content fertilizer.) Unique HC and NOx sensor responses taken together with sufficient sensitivity to detect microgram quantities of Bullseye{trade mark, serif} - both directly and via capture of trace residue by swiping contaminated surfaces- suggest that detection and discrimination of HE using zirconia-based mixed potentials is possible.