Rare earth-modified bifunctional Ni/HY catalysts Original Research Article

Rare earth elements (La, Nd, Sm, Gd and Dy) were characterized by NH3-TPD, Py-FTIR and CO-DRIFTS and tested for n-octane hydroconversion. The Bronsted acidity of modified catalysts increased as the rare earth ionic radius became longer. A similar relationship between metallic function and ionic radius was also observed. Among rare earth elements, lanthanum improved the nickel dispersion and then the ratio of metallic to acid functions. This led to the high catalytic activity and isomerization selectivity of Ni/HY catalyst. However, the catalysts modified by the other rare earth elements showed poor catalytic performance due to the reduction of Bronsted acidity and nickel dispersion, especially a lower ratio of metallic to acid functions.