The contribution of anthropogenic emissions, specifically NOx, on Earth’s climate change processes, and the minimization of their effects continues to be of interest in the scientific community. The use of plasma-assisted catalysis is a promising step towards elimination of NOx from exhaust streams. Fundamental knowledge of the chemistry of NO and other NxOy plasma systems, including gas-phase reaction kinetics and energetics, is a key step toward building a potentially commercializable plasma catalysis system. By implementing time-resolved optical emission spectroscopy (TR-OES) and broadband absorption spectroscopy (BAS), the effects of varying precursor gases (including O2, NO, N2O, N2, and N2/O2 mixtures) on species densities (e.g., neutrals, ions, radicals, and excited state species) and the energy partitioning in the system (e.g. vibrational and rotational temperatures, ion energy distributions, electron temperatures) can be explored as a function of applied rf power (50-200 W) and system pressure (50-200 mTorr). Specifically, TR-OES data provide insight into formation and decay rates for various plasma species as a function of plasma parameters. BAS is utilized to further characterize these plasma systems, and allows for direct observation of absorbance of ground state neutral species, leading to the determination of internal energies for NO in a range of systems via spectral simulations. Notably, the vibrational temperature of NO, which is consistently 2-10 times higher than the rotational temperature, is highly correlated with applied rf power, system pressure, precursor gas and the presence of a catalyst. Mechanisms for NO formation and destruction as well as links to surface interactions and energy partitioning in these systems will also be discussed.

Monitoring internal temperatures and kinetics in nitrogen- and oxygen-containing plasma systems

249th National Meeting (2015)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.