The acidity of bifunctional catalysts
is regarded as one of the
most important factors for FCC gasoline hydrotreatment. To investigate
the effects of acidity on catalytic performance, the CoMo/Al2O3 catalysts modified by MCM-41 and HZSM-5 were prepared
by incipient wetness impregnation. The characterization results showed
that adding molecular sieves changed the distribution of acid sites
of catalysts and had a positive impact on forming longer MoS2 slabs with a slightly higher stacking number related to better hydrodesulfurization
(HDS) performance. The results of catalytic performance indicated
that 1-octene isomerization conversion increased from 4.13 to 33.97%
with the increasing Brønsted acid site/Lewis acid site (BAS/Lewis
acid sites (LAS)) ratio by presenting stronger BAS, resulting in the
increasing selectivity of hydrodesulfurization/olefin hydrogenation
(HDS/HYDO) from 0.89 to 5.41. However, when the BAS/LAS ratio surpassed
0.46 with the presence of weaker and stronger BAS, HDS efficiencies
started decreasing. This understanding sheds light on designing hydrotreating
catalysts to produce high-quality gasoline.