(532bj) Enhancing Reactivity in Olefin Metathesis over Mo-Based Bimetallic Catalyst
AIChE Annual Meeting
2022
2022 Annual Meeting
Catalysis and Reaction Engineering Division
Poster Session: Catalysis and Reaction Engineering (CRE) Division
Wednesday, November 16, 2022 - 3:30pm to 5:00pm
A series of bimetallic (Mox/My-KIT-6) catalysts were successfully synthesized with variable Mo and dopant metal (M=Nb/Zr/Ta/Hf) loadings using a simple wet impregnation technique. The bimetallic Mo2/Nb1.5-KIT-6 and Mo2/Zr1.5-KIT-6 catalysts displayed enhanced propylene yield (45.5 ± 0.5% and 42.0 ± 0.8%) when compared to Mo2/KIT-6 (37.2 ± 0.3%) under identical reaction conditions (Fig 1a). Further, the deconvoluted DR UV-Vis spectra show that compared to Mo2/KIT-6 and Mo2/Zr1.5-KIT-6 catalysts, the Mo2/Nb1.5-KIT-6 catalyst shows a higher ratio of tetrahedral to octahedral MoOx species suggesting an increase in the population of the isolated active site precursors (Fig 1b). These results suggest that the addition of Nb or Zr alters Mo coordination yielding additional active sites (MoNbOx) that are more active than their monometallic counterparts, most likely by varying the O=Mo=O bond angle. The influence of metal loadings along with detailed catalyst characterization results (XRD, EXAFS, In situ Py-IR, Raman, TPD, TPR, XPS, MAS NMR), as well as DFT calculations, will be presented to explain the structure-activity relationships.