Nitric Oxide (NO) Reduction by Plasma Catalysis at Low Temperature: In-Situ Probing Into Hydrogen Mediated Pathways

Catalytic converters are very effective in the remediation of nitrogen oxides NO_x emissions from combustion processes. However, the catalytic processes require elevated temperatures and for near ambient temperature applications such as during cold start, performance remains suboptimal. Nitric oxide (NO) conversion has been enabled by plasma at ambient temperatures but has mainly been explored in an oxidizing environment. We report hydrogen mediated reaction pathways for NO reduction in plasmas coupled with a nickel catalyst. We specifically investigate reaction timescales and transport leveraging spatially-resolved laser-induced fluorescence (LIF) measurements of NO and H densities in a He-H₂ RF plasma with small admixtures of NO in a capillary tube.