Sulfur-tolerant Pd-Pt/Yb-USY zeolite catalysts used to reformulate diesel oils Original Research Article

Bimetallic Pd-Pt catalysts supported on ytterbium-modified ultrastable Y (USY) zeolite showed excellent hydrodesulfurization (HDS) and hydrodearomatization (HDA) activity as well as high stability when used to reformulate hydrotreated diesel oils; sulfur decreased from 263 to <20 ppm, and aromatics decreased from 26 to <5% after a time on stream of 192 h at a hydrogen pressure of 3.9 MPa at 553 K and WHSV=4 h−1. Modification of USY zeolite with ytterbium by impregnation decreased the number of strong acidic sites, while it increased the dispersion of the Pd-Pt phases, thus, possibly contributing to the increase in the nitrogen- and sulfur-tolerance and stability of Pd-Pt/Yb-USY zeolite catalysts.