Observation and Characterization of Vibrationally Active Surface Species Accessed with Nonthermal Nitrogen Plasmas.
Garam LeeChang YanWilliam F SchneiderDavid B GoCasey P O'BrienPublished in: ACS applied materials & interfaces (2024)
Polycrystalline Ni, Pd, Cu, Ag, and Au foils exposed to nonthermal plasma (NTP)-activated N 2 are found to exhibit a vibrational feature near 2200 cm -1 in polarization-modulation infrared reflection-absorption spectroscopy (PM-IRAS) observations that are not present in the same materials exposed to N 2 under nonplasma conditions. The feature is similar to that reported elsewhere and is typically assigned to chemisorbed N 2 . We employ a combination of temperature-dependent experiments, sequential dosing, X-ray photoelectron spectroscopy, isotopic labeling, and density functional theory calculations to characterize the feature. Results are most consistent with a triatomic species, likely NCO, with the C and O likely originating from ppm-level impurities in the ultrahigh-purity (UHP) Ar and/or N 2 gas cylinders. The work highlights the potential for nonthermal plasmas to access adsorbates inaccessible thermally as well as the potential contributions of ppm-level impurities to corrupt the interpretation of plasma catalytic chemistry.
Keyphrases
- density functional theory
- molecular dynamics
- high resolution
- machine learning
- deep learning
- single molecule
- particulate matter
- solid state
- neural network
- quantum dots
- sensitive detection
- mass spectrometry
- room temperature
- molecular dynamics simulations
- magnetic resonance imaging
- genetic diversity
- metal organic framework
- magnetic resonance
- dual energy
- carbon dioxide
- ionic liquid
- reduced graphene oxide
- amino acid