Infrared Studies of the Isocyanate Species Formed in the Reaction of NO with CO over Pt and Rh

Abstract
The behavior of isocyanates formed on the surface of Rh and Pt in the reaction of nitrogen oxide with carbon monoxide was studied by means of IR spectroscopy using a flow reactor. The isocyanate species readily reacted with N2O or H2O, however, it did not decompose when dosed with NO or CO. The catalytic activity of Pt–Al2O3 in the reaction of NO+CO declined quickly with an increase in the amount of the surface isocyanate (–NCO). Accordingly, it is concluded that –NCO is not a reaction intermediate but an inhibitor of the reaction.