CO2-assisted propane-to-propene dehydrogenation over Zn(Cr, Y)SiBEA catalysts: insights of the main process pathway

The effect of the bimetallic Zn( Cr , Y )SiBEA zeolite (Si/Al = 1000) compositions on the preferred pathway of the CO 2 -PDH process, as well as the catalysts' activity and selectivity in direct propane dehydrogenation (PDH) and reverse water-gas shift reaction (RWGS), has been examined. Analysis of the surface functional (redox and acid-base) characteristics reveals that balanced acid-base properties determine the catalysts' activity and selectivity in both the main process and the component reactions—direct propane dehydrogenation and RWGS. High propene selectivity is observed on Zn 2.0 SiBEA (94 %) and Cr 1.0 /Zn 1.0 SiBEA (89.5 %) catalysts, due to alkane activation at acid-base sites and CO 2 activation on base sites. This suggests that the primary pathway of the CO 2 -PDH process on these bifunctional catalysts involves PDH combined with RWGS.