Structure and catalytic consequence of Mg-modified VOx/Al2O3 catalysts for propane dehydrogenation.

Supported VO_x catalysts are promising nonoxidative propane dehydrogenation (PDH) materials for their commercially attractive activity and propylene selectivity. However, they frequently suffer from rapid deactivation caused by coke deposition. This article describes the promoting role of magnesium on the stability of VO_x/Al₂O₃ catalysts for PDH. A series of VO_x/Al₂O₃ and Mg-modified VO_x/Al₂O₃ catalysts were synthesized by an incipient wetness impregnation method. The catalysts were carefully characterized by Raman spectra, UV-Vis spectra, STEM, TGA and in situ DRIFTS. We showed that the stability of a 12V/Al₂O₃ catalyst was significantly improved on addition of small amounts of MgO. Experimental evidences indicate that V₂O₅ nanoparticles emerge in the 12V/Al₂O₃ samples, and appropriate Mg addition helps dispersing the V₂O₅ nanoparticles into 2D VO_x species thus decreasing coke formation and improving stability in nonoxidative dehydrogenation of propane. © 2017 American Institute of Chemical Engineers AIChE J, 2017 [ABSTRACT FROM AUTHOR]