AVS 52nd International Symposium
    Nanometer-Scale Science and Technology Thursday Sessions
       Session NS-ThA

Paper NS-ThA7
WCx Nanopartilces as Alternate Catalyst for NOx Reduction

Thursday, November 3, 2005, 4:00 pm, Room 210

Session: Nano Processing
Presenter: A. Rumaiz, University of Delaware
Authors: A. Rumaiz, University of Delaware
S. Shah, University of Delaware
I. Baldytchev, Unversity of Delaware
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WCx nanoparticles were synthesized using Laser Assisted Inert Gas Condensation (LAIGC). In this process either a metal target is be ablated in the presence of a reactive gas or a compound target is used. The evaporated flux obtained by laser ablation is condensed by a circulating He gas to form WC nanoparticles. The structural properties of the samples were investigated using X-ray Diffraction (XRD) and X-ray Photo-Electron Spectroscopy (XPS). The feasibility of using nano WCx as an alternative catalyst for Pt is also addressed. A comparative study on two types of samples of WC (as prepared and carburized W) was done. The samples were used to check for the reduction of NOx in a simple reactor. The carburized W shows activity at temperatures around 400oC, while the as prepared WC shows activity at a slightly higher temperature. The stability of both the samples was studied by exposing them to a NOx environment at a fixed temperature (where the activity is appreciable) for an extended period of time. XPS and XRD confirm the formation of oxide phase after DeNOx. In order to study the nature of oxidation the DeNOx reaction was carried in a CO/O2/Hydrocarbon gas mixture. The results of these will be presented. Valence band measurements were carried out to compare at the Density of States (DOS) for WC and Pt. Theoretical calculations of the DOS were also done using Self Consistent Field approximation using the WIEN2k code.