Exploring Local Spectroscopic Probes of Hot Electron-driven Reactions Produced by a Transient Cold Plasma
Abstract
In situ spectroscopy of key reaction intermediates using surface enhanced Raman scattering (SERS) spectroscopy provides important mechanistic information about the reaction pathways that exist in plasma-driven reactions. In the proposed work, we will generate a hot-electron, low-temperature transient pulsed plasma using high voltage nanosecond pulses in the local vicinity of a surface containing Au nanoparticles. The surface plasmon resonance of these Au nanoparticles increase the Raman scattering cross section by several orders of magnitude through the SERS enhancement phenomenon. We will also characterize these samples using photoluminescence, FTIR, and electroluminescence spectroscopies, as well mass spectrometry and gas chromatography. Several test reaction systems will be explored, including NO and SO2 remediation, in addition to CO2 reduction. While each of these reactions have been demonstrated using plasma-driven processes, the precise chemical pathways not well understood given the complex composition of the plasma, which contains many ionized radicals in various excited (or metastable) states. The proposed measurements will provide key mechanistic insight into the reaction pathways by elucidating key intermediate species in the reaction pathway. With a detailed understanding of these pathways, engineers can later design highly efficient plasma-based chemical processes for driving these reaction systems. The effect of catalytically active surfaces will also be investigated in these plasma-based processes for improving efficiency and selectivity. In addition, local electric fields will be measured the near the electrode surface via the vibrational Stark shift of the molecules.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 06, 2019
- Source ID
- W911NF1910257
Entities
People
- Stephen B Cronin
Organizations
- Army Contracting Command
- United States Army
- University of Southern California