New NiMo catalysts supported on ZrO2-modified SBA-15 materials for 4,6-dimethyldibenzothiophene hydrodesulfurization

Zr-SBA-15 supports with different ZrO2 loadings (12.5, 25, 37.5 and 50 wt. %) were prepared by incipient wetness impregnation of pure siliceous SBA-15. ZrO2 species were found to be well-dispersed on SBA-15 surface (DRS, XRD) at low ZrO2 loading (below 25 wt. %). At high ZrO2 loadings the formation of tetragonal and monoclinic crystalline zirconia phases was observed. In the catalysts supported on ZrO2-modified SBA-15 materials, the dispersion of Mo oxide species was found to be much better than on corresponding pure SBA-15 and ZrO2. For Zr-SBA-15-supported NiMo catalysts the formation of crystalline MoO3 was not detected by XRD. Catalytic activity tests in hydrodesulfurization of 4,6-dimethyldibenzothiophene showed that the modification of SBA-15 supports with Zr(IV) species significantly improves the performance of NiMo catalysts in HDS of refractory dibenzothiophenes.