Abstract
The structure of silica SBA-15-supported molybdenum oxide catalysts is investigated during selective oxidation of propylene at 500 °C using operando Raman spectroscopy. The active catalysts contain mixtures of dispersed molybdenum oxide species exhibiting monooxo and dioxo structure. An increase in molybdenum oxide loading results in a decrease of the ratio of dioxo and monooxo species from 3.8 to 1.9, as determined by quantitative analysis of Raman spectra. Additional in situ Raman studies at 500 °C reveal that the dioxo/monooxo ratio increases in the presence of steam at higher molybdenum oxide loadings. The observed structural changes are assigned to shifts in the equilibrium between dioxo and monooxo species resulting from hydration/dehydration of the catalyst. This study demonstrates that the detailed structure of nanostructured molybdenum oxide catalysts depends on temperature, gas-phase composition, and molybdenum oxide loading.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
