Influence of catalyst support geometry and wall thickness on NO x trap desulfation: rich/lean wobbling strategies and hexagonal cell supports for high SO2 selectivity during desulfation

Topics in Catalysis - This Synthetic Gas Bench (SGB) study focuses on the effect of cell geometry and wall thickness on the gasoline NO x trap functionality. The data show that besides a NO x trap...     

Influence of Catalyst Support Geometry and Wall Thickness on NOx Trap Desulfation: Rich/Lean Wobbling Strategies and Hexagonal Cell Supports for High SO2 Selectivity During Desulfation

This Synthetic Gas Bench (SGB) study focuses on the effect of cell geometry and wall thickness on the gasoline NO _x trap functionality. The data show that besides a NO _x trap efficiency improvement, hexagonal cells increase the sulfur resistance of the NO _x trap. This feature is explained by the different wash-coat distributions in the hexagonal channels compared to square ones. The effect of lean/rich fast switching (wobbling) during desulfation was investigated and the SO₂/H₂S selectivity was studied: the combination of hexagonal cells and a wobbling desulfation strategy improves the H₂S/SO₂ selectivity by reducing the amount of H₂S formed.     

EPR Investigation and Reactivity of Diesel Soot Activated (or not) with Cerium Compounds

Parameters influencing the diesel soot reactivity versus the combustion reaction are studied on two diesel soot samples. The presence of cerium additives favours the reactivity of the doped soot and shifts the combustion reaction towards low temperatures. However, these additives do not affect the CO–CO₂ selectivity. Oxygenated and non-oxygenated radicals adsorbed on the carbon particulate are evidenced whatever the composition of the soot sample. After a vacuum treatment, the adsorbed hydrocarbons content drastically decreases and the reactivity of both soot samples is attenuated. However, the cerium-doped sample reveals higher radical contents and also higher reactivity than the non-activated soot. The presence of cerium additives stabilises and strengthens radical–carbon interactions and these hydrocarbon radical species play an important role in the activation of the diesel soot combustion.