Specialeforsvar: "Fe-zeolite catalysts for NH3-SCR of NOx. Durability, active site structure and in-situ spectroscopy"

Taler

Martin Høj

Abstract

Nitrogen oxides (NO_x) are unavoidable byproducts of high temperature fuel combustion in air. NO₂, the most toxic of the two, can cause respiratory symptoms and the recommended limit value for NO₂ is exceeded at several streets in Copenhagen and other places in the world where traffic is heavy. Modern petrol vehicles are fitted with three-way catalysts which removes NO_x, but a large number of diesel vehicles are not fitted with NO_x removal catalysts.

A diesel vehicle catalyst for selective catalytic reduction (SCR) of NO_x which has high conversion of NO_x over a broad temperature interval with high selectivity towards N₂ and H₂O is needed to meet future emissions legislation. Also, the catalyst must be stable towards temperatures of 750° in H₂O and O₂ rich exhaust.

Iron exchanged zeolites are promising candidates to meet these requirements, especially iron-beta zeolite is easy to prepare and shows high activity, stability and selectivity. Different iron-beta zeolites are investigated with several spectroscopic techniques in search for the structure of the active site. Other iron zeolites are investigated for comparison.

Vejleder

Kristine Kilså

Tid og sted

HCØ, auditorium 6, kl. 10:15