Synergistic effect of acidity and active phases on DBT HDS performance:
the role of S-edge and Mo-edge sites
Dual-metal modifications on SBA-16 silica were implemented to modulate
the acidities and the distribution and dispersion of active phases for
NiMo catalysts. The results showed that the acidity of S-H groups in
S-edge sites can be promoted by B acid and further facilitate the DDS
selectivity. The NiMo/AT-7.5 catalyst exhibits the highest HDS
efficiency of 97.5% due to its appropriate acidity, highest proportion
of MoS2 phase and concentration of S-edge sites. The kinetic and
thermodynamic analyses were applied to investigate the intrinsic HDS
reactivity for various catalysts. The results confirmed the existence of
synergistic effect in the DBT HDS reaction. The B acid sites can further
increase the desulfurization route (DS) of THDBT to CHB. A higher
dispersion degree of MoS2 could improve DBT HDS efficiency. A high total
concentration of S-edge and Mo-edge will indicate a high HDS efficiency.
The S-edge/Mo-edge ratio and kDDS/kHYD could be correlated.