Elucidation of sulfidation state and hydrodesulfurization mechanism on Mo/TiO2 catalyst using [formula omitted] radioisotope tracer methods

Abstract

In hydrodesulfurization (HDS) of dibenzothiophene (DBT) the activities on the Mo/TiO2 catalysts with various Mo contents were estimated under the typical HDS reaction conditions. The results show that the activities of the catalysts increased linearly with Mo content up to 6wt.% MoO3, which means that the monolayer dispersion of MoO3 on TiO2 support is maintained up to 6wt.% MoO3. The sulfidation states of MoO3/TiO2 catalysts were investigated using a 35S radioisotope pulse tracer method. The results showed that the sulfidation of TiO2 support would also occur. Moreover, the sulfur mobility on the sulfided 6% MoO3/TiO2 catalyst under the reaction conditions was elucidated by a 35S radioisotope tracer method using 35S-labeled DBT. The results suggested that, compared to Mo/Al2O3 catalyst, Mo/TiO2 catalyst showed a little higher amount of labile sulfur (S0) and about two times higher release rate constant of H2S (kRE), which indicated that higher mobility of sulfur was obtained on sulfided Mo/TiO2 catalyst.