Adverse effects of potassium on NO_x reduction over Di-Air catalyst (Rh/La-Ce-Zr)

The influence of potassium in Rh on a lanthium promoted zirconia stablised ceria (CZ) catalysts was studied toward NO_xreduction reactivity and selectivity. The results are compared with a Rh/CZ catalyst. The samples were characterised by N₂ adsorption, XRD, SEM, ICP, and H₂-TPR. The study highlighted the...

NO_x reduction in the Di-Air system over noble metal promoted ceria

In this study, the role of the noble metals Pt and Rh (0.5 wt.%) for the selective reduction of NO into N₂ is evaluated by the transient TAP technique and in-situ spectroscopy using a commercial stable ceria support (denoted as CZ) and applying isotopically labelled ¹⁵NO and ¹⁸O₂. The transient...

Fundamental understanding of the Di-Air system (an alternative NO_x abatement technology). I: The difference in reductant pre-treatment of ceria

Toyota's Di-Air DeNO_x system is a promising DeNO_x system to meet NO_x emission requirement during the real driving, yet, a fundamental understanding largely lacks, e.g. the benefit of fast frequency fuel injection. Ceria is the main ingredient in Di-Air catalyst composition. Hence, we investigated the reduction...

The influence of CO₂ on NO reduction into N₂ over reduced ceria-based catalyst

Oxygen defects in reduced ceria are the catalytic sites for the NO reduction into N₂ in the Toyota Di-Air DeNO_x abatement technology. Traces of NO (several hundred ppm) have to compete with the excess amount of other oxidants, e.g., 5% CO₂ and 5% O₂, in an exhaust gas of a lean burn (diesel) engine....

Fundamental Understanding of the Di-Air System: The Role of Ceria in NO_x Abatement

Temporal analysis of product (TAP) is used to investigate the effectiveness of CO, C₃H₆, and C₃H₈ in the reduction of a La–Zr doped ceria catalyst and NO reduction into N₂ over this pre-reduced catalyst. Hydrocarbons are found to be substantially more effective in the reduction of this...