A variety of morphologically different α-MoO3 samples were prepared by hydrothermal synthesis and applied in the selective oxidation of propylene. Their catalytic performance was compared to α-MoO3 prepared by flame spray pyrolysis (FSP) and a classical synthesis route. Hydrothermal synthesis from ammonium heptamolybdate (AHM) and nitric acid at pH 1-2 led to ammonium containing molybdenum oxide phases that were completely transformed into α-MoO3 after calcination at 550 °C. A one-step synthesis of α-MoO3 rods was possible starting from MoO3·2H2O with acetic acid or nitric acid and from AHM with nitric acid at 180°C. Particularly, if nitric acid was used during synthesis, the rod-like morphology of the samples could be stabilized during calcination at 550°C and the following catalytic activity tests, which was beneficial for the catalytic performance in propylene oxidation. Characterization studies using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectroscopy showed that those samples, which retained their rod-like morphology during the activity tests, yielded the highest propylene conversion.
- Propylene oxidation
- Molybdenum oxides
- Hydrothermal synthesis
- Structure sensitivity
Schuh, K., Kleist, W., Høj, M., Jensen, A. D., Beato, P., Patzke, G. R., & Grunwaldt, J-D. (2015). Systematic study on the influence of the morphology of α-MoO3 in the selective oxidation of propylene. Journal of Solid State Chemistry, 228, 42-52. https://doi.org/10.1016/j.jssc.2015.04.011