A series of bifunctional catalysts with different loadings of NiO supported on a HY ultrastable zeolite, have been characterized by pyridine and NO adsorption. A characteristic i.r. band assigned to pyridine coordinated to Ni+2 ions has been found at 1612 cm−1. This band allows one to distinguish Ni2+ from other cations (Na+,La3+) and metallic nickel, and also to quantify the dispersion of accessible Ni+2, in good agreement with the results from NO adsorption. The use of pyridine makes it possible to characterize, at the same time, the surface acidity of the acid component of the bifunctional catalyst.
Discussion(0)
No comments yet. Be the first to comment.