Enhanced activity and stability of Sm-doped HZSM-5 zeolite catalysts for catalytic methyl mercaptan (CH3SH) decomposition

HZSM-5 zeolite catalysts modified with various amounts of Sm were synthesized and evaluated for CH3SH catalytic decomposition tests. The results illustrated that the addition of Sm improved both catalytic activity and stability of the HZSM-5 catalysts. The optimal content of Sm addition was investigated and Sm/HZSM-5 catalyst with 13 wt%-loading demonstrated high stability with no obvious deactivation during the 80 h test, while the pure HZSM-5 catalyst rapidly deactivated after a relatively short time about 15 h on-stream reaction. Based on the characterization results, increased concentration of basic sites were presented on the modified HZSM-5 catalysts. Moreover, the decrease in the amount of strong acid sites over the Sm doped HZSM-5 catalysts significantly suppressed the formation of coke deposit on the catalysts. Acid-base properties of the catalysts were proved to be closely related to the improved catalytic activity and stability. (C) 2017 Elsevier B.V. All rights reserved.