Abstract
Molybdenum carbide catalysts promoted with K, Na, Co, and Ce have been synthesized by temperature-programmed carburization using a mixture of H 2/C 3H 8 and evaluated for the Fischer–Tropsch synthesis. Both α- and β-Mo carbide catalysts were produced during carburization via the formation of oxycarbide intermediate phase. The two-stage Mo carbide synthesis appeared to be characterized by a compensation effect and isokinetic relationship for both promoted and undoped catalysts suggesting that the solid state transformation mechanism was similar across the promoters. The catalysts possessed relatively high BET area (177–210 m 2 g cat −1) with finely dispersed Mo carbide particles (ca. 10 nm) on the alumina support. The presence of weak and strong acid–base sites was also confirmed by NH 3 and CO 2-TPD runs. CO hydrogenation rate increased with H 2 composition reaching optimal activity at y H 2 between 0.67 and 0.75. FT activity improved with promoter addition in the order; K–MoC 1− x /Al 2O 3 > Na–MoC 1− x /Al 2O 3 > Ce–MoC 1− x /Al 2O 3 > Co–MoC 1− x /Al 2O 3 > MoC 1− x /Al 2O 3 while chain growth probability varied with feed composition and was enhanced by all promoters. The reaction rate data were adequately described by an Eley–Rideal model.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.