Post-combustion emission controls

Spatially resolved in situ measurements of transient species breakthrough during cyclic, low-temperature regeneration of a monolithic Pt/K/Al₂O₃ NO_x storage-reduction catalyst

Authors
J-S. Choi, W.P. Partridge, C.S. Daw

Publication
Applied Catalysis A: General 293 (2005) 24–40.

Abstract
We employed a new experimental technique known as Spatially-resolved capillary-inlet Mass Spectrometry (SpaciMS) to observe the evolution of multiple species inside the channels of a monolithic NO_x storage-reduction (NSR) catalyst. The NSR material consisted of a Pt/K/Al₂O₃ washcoat deposited inside cordierite monolith channels. Spatially and temporally resolved measurements were made over the monolith length in a bench flow reactor during fast cycling between synthetic lean and rich environments at 200°C and 300°C. Regeneration was found to be very efficient at 300°C regardless of whether pure H₂, pure CO, or mixtures of H₂ and CO were employed. At 200°C, CO was noticeably less effective than H₂. We conjecture that at 200°C CO may be inhibiting the regeneration process through its strong adsorption on Pt. Generation of H₂ by water-gas-shift was seen at 300°C but not at 200°C.