Highly active Mo/Al2O3 hydrodesulfurization catalyst presulfided with ammonium thiosulfate

Ammonium thiosulfate ((NH4)2S2O3) was used as an ex situ sulfiding agent to pretreat Mo/Al2O3 catalyst through impregnation. After H2 activation, Mo/Al2O3 presulfided with (NH4)2S2O3 exhibits much higher catalytic activity in thiophene hydrodesulfurization (HDS) than Mo/Al2O3 in situ sulfided by dimethyl disulfide. Through (NH4)2S2O3 presulfidation, Al2O3 support is modified by sulfate groups, leading to a decrease of interaction between Mo and support; this promotes the formation of multi-layer type II MoS2 that contributes to the high HDS activity of the ex situ presulfided Mo/Al2O3 catalyst.