Search for content and authors

In operando XAS study of porous based catalysts for the selective catalytic reduction of NO with low N2O emissions

Enrique Rodriguez Castellon 1Mona Lisa Oliveira 2Antonio Jimenez-Lopez 1Ramon Moreno-Tost 1Jose Jimenez Jimenez 1Tiago L. Farias 2Carla Silva 2Alfonso Caballero 3Juan P. Holgado 3

1. Universidad de Malaga (UMA), Campus Teatinos, Malaga E29071, Spain
2. Instituto Superior Técnico, Lisboa 1049-001, Portugal
3. Instituto de Ciencia de Materiales de Sevilla (ICMSE), Avda. Americo Vespucio, 49, Sevilla 41092, Spain


One of the main disadvantages of vehicles powered with diesel engines are the emissions of  nitrogen oxides and soot particles. In this context, the urea-selective catalytic reduction  (SCR) process is considered to be the most promising way to decrease  NOx emissions produced by the diesel heavy duty vehicles. When urea is used as reducing agent, it is hydrolised into ammonia and carbon dioxide. The ammonia so produced reacts with NO to form the non contaminating  byproducts water and nitrogen. The commercial catalyst based on vanadium (a toxic element) tends to form N2O, a noxious greenhouse gas, at high reaction tempertaures. We have recently found the natural mordenites based catalysts and porous phosphate heterostructures (PPH), with copper or iron species as active phases, are execllent for the SCR -NO using ammonia or methane as reducing agent, and the very low formation of N2O was observed. In this communciation, this catalytic reaction was study by means of X-ray Absorption Spectroscopy (XAS) using synchrotron radiation, where the chemical environment of Cu and Fe under real operation conditions is checked, since the oxidation state of both elements during the catalytic process is a subject of many controversies. Moreover,  the evolution of the chemical state duting the SCR of NO give us some answers to explain why N2O is not formed with these catalysts, in comparison with some other systems. 


Legal notice
  • Legal notice:

Related papers

Presentation: Oral at E-MRS Fall Meeting 2008, Symposium D, by Enrique Rodriguez Castellon
See On-line Journal of E-MRS Fall Meeting 2008

Submitted: 2008-05-12 13:35
Revised:   2009-06-07 00:48