Monitoring Reaction Intermediates in Plasma-Driven SO₂, NO, and NO₂ Remediation Chemistry Using In Situ SERS Spectroscopy

In situ surface-enhanced Raman scattering (SERS) spectroscopy is used to identify the key reaction intermediates during plasma-based removal of NO and SO2 under dry wet conditions on Ag nanoparticles. Density functional theory (DFT) calculations are confirm experimental observations by calculating vibrational modes surface-bound intermediate species. Here, we provide spectroscopic evidence that plasma increases NOx through formation highly reactive OH radicals, driving reactions H2SO4 HNO3, respectively. We observed SO3 SO4 species in wet-plasma-driven remediation, while plasma, only identified adsorbed surface. During both NO2 NO3 were surface; however, concentration was enhanced wet-plasma conditions. By closing loop between DFT-calculated spectra, not associated with each peak SERS spectra but also their orientation adsorption site, providing a detailed atomistic picture chemical pathway surface interaction chemistry.