Presulfidation and activation mechanism of Mo/Al_2O_3 catalyst sulfided by ammonium thiosulfate

摘要

Mo/Al_2O_3 catalyst was presulfided with (NH_4)_2S_2O_3 to elucidate presulfidation and activation mechanism. It is illustrated that the Mo oxide is firstly partially sulfided during presulfidation and then in situ reduced into MoS_(2-x) in activation, and finally sulfided to active state during hydrodesulfurization (HDS). A synergistic effect between the S~(2-) and S~(6+) ions in (NH_4)_2S_2O_3 produces a positive influence on the HDS performance. The S~(2-) ions contribute to the sulfidation of Mo ions, while the S~(6+) species interact with Al_2O_3 support, weakening the interaction of active species with support.