Modulating the Reaction Pathway of Ni 2 P/Al 2 O 3 by Introducing Different Noble Metals for Hydrodesulfurization of Diesel.

Regulating the reaction pathway of a hydrodesulfurization (HDS) catalyst to achieve ultradeep desulfurization of diesel is a low-energy-consumption yet effective strategy but remains a tricky challenge. Herein, we present a Ni 2 P/Al 2 O 3 catalyst with mesoporous properties synthesized by a facile hydrothermal-temperature-programmed reduction and normal impregnation (TPRI) method, and then different precious metals with similar loadings were introduced to prepare M-Ni 2 P/Al 2 O 3 (M = Pt, Pd) catalysts through incipient wetness impregnation. Their structures were analyzed by a series of characterization methods, and their catalytic performances were examined for 4,6-dimethyldibenzothiophene (4,6-DMDBT) HDS. The correlation characterization results revealed that the kind of precious metals significantly affected the surface acidity and then the metal-support interaction (MSI) between Ni 2 P and Al 2 O 3 . Among them, the Pt-Ni 2 P/Al 2 O 3 catalyst exhibits superior HDS activity with 88.5% 4,6-DMDBT conversion to Pd-Ni 2 P/Al 2 O 3 (76.3%) and pristine Ni 2 P/Al 2 O 3 (58.6%) catalysts under reaction conditions of 3.4 MPa, 340 °C, and LHSV = 4.8 h -1 . This should be due to the introduction of Pt, which significantly facilitates the dissociation rate of H 2 and the subsequent generation of more active hydrogen species than Pd, thereby promoting the formation of Brønsted acid sites, remarkably facilitating the isomerization (ISO) pathway, and markedly enhancing the 4,6-DMDBT HDS conversion of Pt-Ni 2 P/Al 2 O 3 . This work provides an efficient protocol to tame the reaction pathway and thereafter the catalytic performance of the HDS catalyst in the future.