Monolayer MgVOx/Al2O3 catalysts for propane oxidative dehydrogenation: Insights into a role of structural, redox, and acid-base properties in catalytic performance

摘要

Here we report the relationships between the structure of the vanadia species, acid-base, and redox properties of the surface of tailor-made monolayer MgVOx/Al2O3 catalysts and the effects of these features on the performance of such catalysts. Combined Raman and UV-vis DR spectroscopies confirmed the formation of the alumina-supported 2D surface VOx and MgVOx species with different coordination and local environment of the active site. The Mg incorporation into the structure of the surface vanadia species was shown to affect both their redox and acid properties and allows controlling the catalyst activity and selectivity towards propylene. Increasing the binding energy of V-O bonds due to Mg doping was shown to be critical to improve the catalyst performance but is not the only factor determining high selectivity towards propylene that is also affected by the concentration of strong acid sites and surface species structure.